research paper on free will

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Original research article, free will, determinism, and epiphenomenalism.

• Department of Philosophy, California State University, Los Angeles, CA, United States

This paper articulates a non-epiphenomenal, libertarian kind of free will—a kind of free will that's incompatible with both determinism and epiphenomenalism—and responds to scientific arguments against the existence of this sort of freedom. In other words, the paper argues that we don't have any good empirical scientific reason to believe that human beings don't possess a non-epiphenomenal, libertarian sort of free will.

1. Introduction

There's a very old, very traditional argument against free will that's based on the claim that (D1) our decisions are causally determined (or for-all-practical-purposes causally determined, or some such thing) by prior events, and (D2) this is incompatible with free will. We can think of this as the backward -looking problem of free will because it has to do with the causal antecedents of our decisions. There's a much more recent argument against free will that's forward -looking, or to put the point differently, that arises out of the thought that some sort of epiphenomenalism is true, rather than the thought that some sort of determinism is true. The worry might be put like this: (E1) our decisions aren't the causes of our actions (i.e., our decisions are epiphenomenal ), and (E2) this is incompatible with free will.

You might think that we should respond to the first of these arguments by rejecting (D2). I won't be concerned with such responses here. This isn't because I'm convinced that (D2) is true; it's because I think it doesn't really matter whether it's true. I've argued for this stance elsewhere ( Balaguer, 2010 , 2016 ) and won't rehearse the argument here. Briefly, though, the thought is as follows: (a) we can easily define some kinds of freedom that are compatible with determinism; and (b) we can easily define some kinds of freedom that are incompatible with determinism; and (c) the question of whether free will—i.e., real free will— is compatible with determinism boils down to the question “Which of the various kinds of freedom that we can define is real free will?”; and (d) this latter question is a purely semantic question.

Rather than bogging down in the semantic question of what free will is, I'm going to stipulatively define a variety of freedom that's incompatible with determinism—and also with epiphenomenalism 1 —and I'm going to focus on the question of whether we have that kind of freedom, i.e., the kind that's indeterministic and non-epiphenomenal by definition . Here's an initial, rough characterization of the sort of freedom I've got in mind:

NEL-Freedom (initial, rough definition) : A person is non-epiphenomenal, libertarian free (or for short, NEL-free ) if and only if she makes at least some decisions that are both undetermined (in a libertarian sort of way—more on what this means later) and non-epiphenomenal (i.e., that play an appropriate role in the causation of our actions—again, more on what this means later).

Let NE-libertarianism be the view that human beings are NEL-free. My aim in this paper is to defend this view against recent anti-free-will arguments that proceed by trying to motivate claims like (D1) and (E1). The arguments I'll be responding to are based on empirical scientific findings. Thus, in essence, what I'm going to be arguing is that the scientific arguments that have arisen in recent years against the existence of free will—the arguments that proceed by trying to (empirically) motivate the claim that our decisions are epiphenomenal and/or causally determined (or for-all-practical-purposes determined)—are not good arguments.

I should say here that I'll be assuming that mind-brain materialism is true; in particular, I'll assume that our decisions are physical events, presumably neural events. It follows pretty quickly from this that the relevant kinds of determinism and epiphenomenalism—i.e., (D1) and (E1)—are empirical claims. But if this is right, and if I'm right that we don't have any good empirical-scientific reason to endorse (D1) or (E1), then I think it can be argued pretty quickly that we don't have any good reason to believe (D1) or (E1)—i.e., that we don't have any good reason to think that our decisions are causally determined or epiphenomenal in ways that would be incompatible with the sort of freedom that I'll be defining in this paper.

I, of course, can't respond here to every empirical-science-based argument for (D1) and (E1). I'll focus on arguments based on results from psychology and neuroscience. In connection with (E1), these are pretty obviously the most important arguments, but in connection with (D1), you might doubt that the most important results come from psychology and neuroscience; for you might think we have good reason to endorse some deterministic interpretation of quantum mechanics—and, hence, good reason to endorse universal determinism. I argued in Balaguer (2010) that we in fact don't have good reason to endorse any specific interpretation of quantum mechanics—deterministic or indeterministic—and that, because of this, we don't have any good reason to endorse universal determinism. I also argued there that we don't have any reason to believe that all neural events are determined. I can't rehearse the arguments for these claims here, but if they're right, then the question we should be focused on, vis-à-vis (D1), is the very specific question of whether our decisions are determined in some freedom-undermining way. And the places to look for evidence for the claim that our decisions are determined in some such way are presumably psychology and neuroscience.

In section 2, I'll list some reasons (based on findings from psychology and neuroscience) for thinking that (D1) and (E1) are true—and, hence, for doubting that we have free will (or, at any rate, NEL-freedom). In section 3, I'll provide a much more careful characterization of NEL-freedom—i.e., the kind of freedom that I'll be defending against the anti-free-will considerations of section 2. And in section 4, I'll respond to those anti-free-will considerations—i.e., I'll argue that they don't give us any good reason to doubt that human beings are NEL-free.

2. Worries About Free Will

A lot of studies have been done by psychologists and neuroscientists that raise doubts—both backward-looking determinism-based doubts and forward-looking epiphenomenalism-based doubts—about the hypothesis that human beings have free will. Some of the prominent forward-looking considerations are as follows:

F1. Consciousness is sluggish. In particular, conscious awareness of certain kinds of actions and processes comes after the occurrences of the actions and processes themselves (see e.g., Velmans, 1991 ; Wegner, 2002 ). Consider, e.g., the processing of incoming speech and quick reactions in emergency situations (e.g., when a driver yanks her steering wheel to the side to avoid hitting someone who has stepped in front of her car). There's reason to think that we only become aware of preforming these actions after we perform them; and this suggests that they're not under our conscious control.

F2. People often don't know why they perform certain actions, and they confabulate reasons for their actions—i.e., they construct false theories of why they perform certain actions, seemingly without knowing that the theories are false. There is a lot of evidence for this; see e.g., Festinger (1957) , and for interesting split-brain studies related to this, see Gazzaniga (1983) .

F3. We're often completely unaware of why we perform certain actions, and we have to infer what our reasons were from our behavior—in the same way that we infer what other people's reasons are from their behavior (see e.g., Nisbett and Wilson, 1977 ).

F4. While it's true that we experience our decisions, we don't experience our decisions causing our actions. We have to infer that our decisions cause our actions from the fact that they precede our actions.

F5. We can be duped into thinking that we willed certain kinds of actions (or caused certain kinds of bodily movements, e.g., hand movements) that were in fact performed by someone else (see e.g., Nielson, 1963 ; Wegner and Wheatley, 1999 ). Moreover, we can be duped into thinking that we didn't perform certain kinds of actions that we in fact did perform—consider, e.g., the experiences that some people have with Ouija boards.

These results seem to fit very poorly with the hypothesis that human beings have conscious control over their actions. And, more generally, they fit poorly with the view that we intuitively have of ourselves as being something approaching ideal agents—i.e., agents who (a) have reasons for actions, and (b) weigh those reasons against one another in deliberation, and (c) consciously decide what to do, based on our deliberations, in ways that guide our behavior.

Some of the prominent backward-looking (i.e., determinism-based) anti-free-will considerations are as follows:

B1. Our decisions and actions are often causally influenced by unconscious mental states (or, more precisely, events involving us having unconscious mental states) and brain processes that we're not aware of. (This is virtually undeniable; if we've learned anything in empirical psychology over the last hundred years or so, it's that this is true; and this, of course, raises worries about whether our actions are under our conscious control.)

B2. Our decisions and actions are often influenced by situational factors like mood that, intuitively, seem unimportant (see e.g., Milgram, 1969 , and for a discussion, see Nelkin, 2005 ).

B3. Conscious choices can be causally influenced by magnetic stimulation to the brain. In a study done by Brasil-Neto (1992) , subjects had to choose between raising their left fingers and raising their right fingers, and their choices were correlated with whether their brains were magnetically stimulated on the left side or the right side.

B4. Conscious decisions are preceded in the brain by non-conscious neural processes that seem (or at any rate, have seemed to some) to be part of the mechanism that actually causes our actions (see e.g., Libet et al., 1983 ).

B5. There are neural processes that precede our conscious decisions by as much as 7–10 s that can be used to predict which options we'll choose in certain kinds of decisions. To say a bit more, in recent studies performed by Haynes (2011) , subjects were given two buttons, one for their left hand and one for their right, and they were told to make a decision at some point as to whether to press the left button or the right button and to then go ahead and push the given button. Using fMRI, Haynes found unconscious brain activity that predicted whether subjects would press the left button or the right; moreover, he found that this activity arose 7–10 s before the person made the conscious decision to push the given button.

These results are compatible with the non-epiphenomenal hypothesis that our decisions cause our actions; but they seem to imply that our decisions are caused by prior events in ways that are incompatible with the hypothesis that human beings have a traditional, libertarian sort of free will.

(You might think that B4 and B5 are backward-looking and forward-looking—i.e., that they motivate some sort of epiphenomenalism as well as some sort of determinism. I don't think this is true; for it could be that (a) the mechanisms that cause our actions start running before we consciously decide to perform those actions, and (b) these mechanism go through our conscious decisions. But it doesn't matter whether I'm right about this; for if the responses that I'll give in section 4 to B4-B5-style worries about determinism are right, then they'll bring with them responses to B4-B5-style worries about epiphenomenalism as well).

3. Ne-Libertarianism

Taken together, considerations F1-F5 and B1-B5 might seem to provide powerful evidence for the claim that human beings don't have free will and, in particular, that they don't have libertarian freedom. But I think these appearances are deceiving. In this section, I'll characterize a kind of non-epiphenomenal libertarian freedom—namely, NEL-freedom —and in section 4, I'll argue that the considerations that I just listed in section 2 don't give us any good reason to doubt that human beings are NEL-free. I'll proceed somewhat slowly in this section, getting into the details of the NE-libertarian view—i.e., the view that humans beings are NEL-free. This is because we'll need to have these details in place in order to see why considerations F1-F5 and B1-B5 don't in fact undermine NE-libertarianism.

I'll start by defining libertarian-freedom (or L-freedom); then I'll define libertarianism in terms of L-freedom; then I'll articulate a specific version of libertarianism that I'll call “thin libertarianism”; then at the end, I'll define NEL-freedom and NE-libertarianism.

3.1. L-Freedom

To say that a person is L-free is, for starters, to say that some of her decisions are undetermined—i.e., not causally determined by prior events. But indeterminacy by itself is not enough for L-freedom; for undetermined events can be random in ways that are incompatible with the sort of freedom that libertarians have in mind. Thus, we can define L-freedom like this:

A person is libertarian-free —or for short, L-free —if and only if she makes at least some decisions such that (a) they are undetermined and appropriately non-random, and (b) the indeterminacy is relevant to the appropriate non-randomness in the sense that it procures the non-randomness, or increases it, or enhances it, or some such thing.

More needs to be said about what appropriate non-randomness is. There are various views you might endorse here, but however the details go, we should all agree that the relevant sort of non-randomness consists in a kind of agent-involvedness . For example, one might say that it consists in the agent controlling which option is chosen, or authoring the choice, or being the source of the choice, or making a rational choice, or some combination of these things. Also, many libertarians would follow Kane (1996) in requiring plural control (or authorship or whatever)—i.e., in requiring it to be the case that even if the agent had chosen differently, she still would have controlled it (or authored it, or whatever).

Also, more needs to be said about clause (b) of the above definition. To see why this clause is needed, consider the following view:

Humeanism with a smidge of irrelevant indeterminism : Our decisions are caused by our reasons, and so they count as ours (i.e., appropriately non-random, under our control, and so on). But our decisions aren't deterministically caused by our reasons; there are unimportant quantum indeterminacies buried in our decision-making processes; in particular, the prior-to-choice probabilities of our decisions going the way that they in fact go is always extremely high (0.999999, or whatever) but not 1.

This isn't a libertarian view because the indeterminacy is irrelevant to the freedom of our choices. Libertarians think that indeterminacy is needed for freedom—and that's why I've included clause (b) in the definition of L-freedom.

3.2. Libertarianism

I'll use the term ‘libertarianism' to denote the view that human beings are L-free. This is a bit non-standard. A more standard definition would take libertarianism to be the view that (i) humans are L-free, and (ii) L-freedom is free will. On this way of proceeding, we could say that thesis (i) is the metaphysical half of libertarianism and thesis (ii) is the semantic (or conceptual ) half. But thesis (ii) won't be relevant at all to the arguments of this paper, and so to keep things simple, I'm going to use ‘libertarianism' to denote thesis (i).

(On this usage, libertarianism doesn't entail that free will (as opposed to L-freedom) is incompatibilism with determinism, and it doesn't entail that human beings have free will; indeed, it doesn't entail anything about free will. So this is definitely non-standard usage. But no harm will come of this) 2 .

3.3. Thin Libertarianism

Thin libertarianism is a specific version of the sort of libertarianism that I just defined. There are five main features of thin libertarianism.

First, thin libertarianism involves a commitment to mind-brain materialism . In particular, on this view, conscious decisions are physical events, presumably neural events.

Second, thin libertarianism is an event-causal view; in other words, on this view, L-free decisions are non-deterministically caused (or probabilistically caused) by prior events, presumably agent-involving events, e.g., events having to do with the agent's reasons. So, importantly, thin libertarianism doesn't involve any sort of irreducible agent causation.

Third, thin libertarianism does not involve the claim that all of our actions are L-free, or even undetermined. We perform a lot of actions. Just in the course of a single minute, you might perform twenty actions. Think, for instance, of what you do when you drive somewhere. You get in the car; you put your seatbelt on; you put your key in the ignition; you turn the key; you push your foot down on the gas; you put the car in gear, you look in the mirror; and so on. We're almost constantly doing things. We barely even notice them. And we certainly don't consciously decide to do all of these things. Life would be an unbearable nightmare if we had to consciously decide to do everything we do; we'd have to constantly think thoughts like this: “Move your left foot forward; now your right; left again; right; etc., etc., etc.” We don't want to have to decide to do all of the things we do; we want to be free to think about other things while we're strolling through parks.

The upshot of this, it seems to me, is that the question of free will isn't about the gigantic set of actions we perform; it's about our conscious choices , or decisions . At any rate, this is what thin libertarianism is about. Indeed, it's really about a certain subset of our conscious decisions, namely, what I've elsewhere (2010) called “ torn decisions.” We can define torn decisions as follows:

A torn decision is a decision in which the person in question has reasons for multiple options, feels torn as to which option is best (and has no conscious belief as to which option is best), and decides without resolving the conflict, i.e., decides while feeling torn.

We seem to make decisions like this many times a day about things like whether to have cereal or yogurt for breakfast, or whether to walk to work or drive, or whatever. But we can also make torn decisions in potentially life-changing situations; e.g., you might have a good job offer in a city you don't like, and you might have a deadline that forces you to decide while feeling utterly torn.

Torn decisions should be distinguished from three other kinds of decisions. First, they should be distinguished from leaning decisions ; these are decisions in which the agent chooses while leaning toward one of her live options, whereas in a torn decision, the agent feels completely torn. Second, torn decisions should be distinguished from Buridan's-ass decisions ; these are similar to torn decisions except that the various tied-for-best options are more or less indistinguishable, and because of this, the agent doesn't feel torn . (For example, if you want a can of tomato soup, and there are ten cans of the same kind on the shelf, you won't feel torn—you'll just grab one and be on your way 3 ). Third, torn decisions should be distinguished from what Kane (1996) calls self-forming actions , or SFAs. The most important difference here is that whereas SFAs are defined as being undetermined, torn decisions are not. Torn decisions are defined in terms of their phenomenology. So we know from experience that we make some torn decisions—in fact, we make a lot of them—and it's an open empirical question whether some of these decisions are undetermined.

To see why thin libertarianism is about torn decisions, rather than other kinds of decisions, consider the following two decisions:

Non-Torn Decision (or for short, NTD ): You live in a city you hate because you have a job there and can't find another job. You also hate the job in many ways but you keep it because you can't find anything better. You dream of living in City C and having a job at Institution I. Then you're offered a job at institution I, in City C, with a starting salary three times greater than what you presently make. You have to decide whether to accept the offer. All of your reasons favor accepting it, and none of them favor turning it down. Torn decision (or for short, TD) : You live in your favorite city; you have a job that's OK, but you're not wild about it. You dream of working for Institution I. Then you're offered a job at Institution I, but it's in City C, and you hate City C. You deliberate for a week about whether to take the job, but you still feel completely torn about whether to take the offer, and the deadline is right now, and you have to decide while feeling torn.

It's easy to understand why people would want their torn decisions—decisions like TD—to be undetermined. For one might think that (a) if decisions like TD are determined, then they're determined by things outside of our conscious reasons and thought, and (b) if this is true, then we don't really author and control these decisions, and hence, they aren't fully free. In contrast with this, it's hard to see why anyone would want decisions like NTD to be undetermined. Indeed, it seems to me that we should want decisions like this to be determined by our reasons for action (or, more precisely, by events involving us having the reasons that we have).

In any event, the kind of libertarianism that I'm currently describing—i.e., thin libertarianism—is a thesis about torn decisions. Roughly (I'll make this more precise below), it's the thesis that at least some of our torn decisions are L-free (i.e., undetermined, appropriately non-random, and so on).

Simplifying a bit, we can think of a thin-libertarian agent as someone who (a) mostly plods through life in a roughly Humean way—doing things without making conscious decisions, being driven (mostly unconsciously) by reasons for action, not exercising anything like L-freedom—but who (b) comes to a fork in the road every once in a while (sometimes once an hour, sometimes less, sometimes more) and has to make a torn decision about which way to go.

This picture is simplified—e.g., because it ignores leaning decisions—but it gives us a rough idea of what I have in mind. To be clear, though, I do not think that torn decisions are the only kinds of decisions that can be L-free, or that one might reasonably want to be L-free. For example, one might wonder whether our leaning decisions are L-free. But for a variety of reasons, I think that torn decisions are the most important decisions to focus on; indeed, I've argued elsewhere (2010) that human beings are L-free if and only if some their torn decisions are L-free, so that the question of whether we're L-free comes down to the question of whether some of our torn decisions are L-free. But I won't try to argue for this here; I'm just going to focus on torn decisions; and I'm going to take thin libertarianism to say that some of our torn decisions are L-free and to not say anything about any non-torn decisions.

Fourth, note that the claim here is that some of our torn decisions are L-free. Libertarianism is perfectly compatible with the claim that some of our torn decisions are causally determined by prior events; e.g., it's compatible with the claim that some of these decisions are determined by subconscious reasons that we're not aware of 4 All libertarianism says is that some of our decisions are undetermined and L-free.

Fifth and finally, it's important to get clear on the kind of indeterminacy that's required for torn decisions to be L-free. This sort of indeterminacy can be defined as follows:

A torn decision is wholly undetermined at the moment of choice—or, for short, TDW-undetermined —if and only if the actual objective moment-of-choice probabilities of the various reasons-based tied-for-best options being chosen match the phenomenological probabilities—or what the probabilities seem to us to be—so that these moment-of-choice probabilities are all more or less even, given the complete state of the universe and all of the laws of nature, and the choice occurs without any other significant causal inputs, i.e., without anything else being causally relevant in a significant way to which option is chosen.

It's important to note that this sort of indeterminacy is compatible with various features of the decision being fully determined. Suppose, e.g., that I'm about to make a torn decision between options A and B. It could be determined that (i) I'm going to make a torn decision (i.e., I'm not going to refrain from choosing), and (ii) I'm going to choose between A and B (i.e., I'm not going to choose some third option that I don't like as much), and (iii) the objective moment-of-choice probabilities of A and B being chosen are both 0.5. All of this is perfectly consistent with the decision being TDW-undetermined. All that needs to be undetermined, in order for the choice to be TDW-undetermined, is which tied-for-best option is chosen .

It's also important to note that TDW-indeterminacy lies at one end of a spectrum of possible cases and that there are degrees of the kind of indeterminacy I'm talking about here. To see what I've got in mind by this, suppose that Ralph makes a torn decision to order chocolate pie instead of apple pie. Since this is a torn decision, we know that given all of Ralph's conscious reasons and thought, he feels completely neutral between his two tied-for-best options. But it might be that, unbeknownst to Ralph, there are external factors—things that are external to Ralph's conscious reasons and thought (e.g., unconscious mental states, or non-mental brain events that precede the decision)—that causally influence the choice and wholly or partially determine which option is chosen. Indeed, there's a spectrum of possibilities here. At one end of the spectrum, which option is chosen is TDW-undetermined, so that the objective moment-of-choice probabilities of the two tied-for-best options being chosen are 0.5 and 0.5, and nothing else significantly causally influences which option is chosen. At the other end of the spectrum, the choice is fully determined—i.e., factors external to Ralph's conscious reason and thought come in and, unbeknownst to Ralph, cause him to choose chocolate. And in between, there are possible cases where the objective moment-of-choice probabilities are neither 0.5 and 0.5 nor 1 and 0—i.e., where they're 0.8 and 0.2, or 0.7 and 0.3, or whatever; in these cases, external factors causally influence the choice without fully determining it, so that which option is chosen is partially determined and partially undetermined 5

3.4. The Central Libertarian Thesis

In order to fully define thin libertarianism, I need to say a few words about a well-known philosophical argument against libertarianism. The argument I have in mind can be put like this:

The randomness argument : Even if our decisions are undetermined in the way that's needed for L-freedom, it doesn't matter because undetermined events are just random events. In other words, they occur by chance —i.e., they just happen . Thus, if we introduce an undetermined event into a decision-making process, that would seem to either (a) increase the level of randomness in that process or (b) leave the level of randomness alone (if the indeterminacy ends up not mattering). So it's hard to see how the introduction of an undetermined event into a decision-making process could increase non -randomness. Thus, since this is precisely what's needed for L-freedom, it seems that we don't have L-freedom; indeed, it seems that L-freedom is impossible 6

I think that libertarians can respond to this argument by arguing for the following thesis:

Central Libertarian Thesis (CLT) : If our torn decisions are undetermined in the right way—i.e., if they're TDW-undetermined—then they're appropriately non-random and L-free.

If we take TDW-indeterminism to be the view that some of our torn are TDW-undetermined, and if we assume (as I am here—see above) that libertarianism is true if and only if some of our torn decisions are L-free, then CLT can be put more succinctly as follows:

CLT (alternate formulation): If TDW-indeterminism is true, then libertarianism is true.

If CLT is true, then it turns the randomness argument completely on its head. The randomness argument says that indeterminacy implies randomness. CLT, on the other hand, says that the right kind of indeterminacy implies non -randomness. If this is right (and if I'm right that libertarianism is true if and only if our torn decisions are L-free), then the question of whether libertarianism is true reduces to the purely empirical question of whether TDW-indeterminism is true.

I argued for CLT at length in Balaguer (2010) . I can't rehearse all of my arguments here, but I'd like to say a few words about one of them. If indeterminism is true, then there are at least some physical events that are undetermined. These undetermined events are events that determine how the universe will evolve. So, for example, suppose that I'm going to be in an ice cream parlor tonight and that at some specific time—say, 8:00 p.m.—I'm going to make a torn decision about whether to order chocolate or vanilla ice cream. If indeterminism is true—and, in particular, if it's not yet determined whether I'm going to order chocolate or vanilla ice cream—then there's some undetermined event E (or some collection of undetermined events, but let's simplify and suppose that it's a single event) that will occur between now and 8:00pm tonight that will determine whether the universe evolves in an I-get-chocolate-ice-cream way or an I-get-vanilla-ice-cream way. Now notice the following crucial point: if TDW-indeterminism is true, then E is my torn decision . In other words, the undetermined physical event that, so to speak, spins the universe off in an I-get-chocolate-ice-cream direction, instead of an I-get-vanilla-ice-cream direction, just is my conscious decision—i.e., it's the mental event with a me-choosing-now phenomenology.

This follows straightforwardly from TDW-indeterminism (together with the mind-brain materialist assumption that decisions are physical events) 7 So if TDW-indeterminism is true, then we get the result that my conscious decision is the undetermined physical event that settles whether the universe evolves in an I-get-chocolate-ice-cream way or an I-get-vanilla-ice-cream way. I argued in Balaguer (2010) and Balaguer (in progress) that if this is true—if our torn decisions are the undetermined events that settle which of our tied-for-best options get chosen—then (i) our torn decisions are appropriately non-random (e.g., we author and control these decisions in important ways); and (ii) the indeterminacy procures the appropriate non-randomness, so that our torn decisions are also L-free; and (iii) this gives us everything we want, or should want, out of libertarianism. But I can't argue for all of these points here.

3.5. Thin Libertarianism Defined

Given everything I've said, we can define thin libertarianism as the view that TDW-indeterminism is true—i.e., that at least some of our torn decisions are TDW-undetermined—and, hence, that at least some of these decisions are appropriately non-random and L-free.

3.6. NEL-Freedom

I think that thin libertarianism captures the backward -looking claim that libertarians should endorse. But it doesn't make any forward -looking claims; in particular, it's compatible with the epiphenomenalist thesis that our torn decisions don't play any role in causing our actions. If libertarians want to avoid this result, then they need to define a kind of libertarian freedom that requires non-epiphenomenalism. We can do this as follows:

A person P is NEL-free (short for non-epiphenomenal libertarian free ) if and only if at least some of P's torn decisions are such that (a) they're TDW-undetermined (and hence also appropriately non-random and L-free), and (b) they're not inappropriately epiphenomenal—i.e., they play an appropriate role in the causation of P's actions.

More needs to be said about what it would mean for our torn decisions to be “inappropriately epiphenomenal.” The most obvious worry you might have about our torn decisions being epiphenomenal is based on the thought that (a) physical events always have physical causes, and so (b) our torn decisions can't cause any physical events (including bodily movements), because (c) torn decisions are mental events, not physical events. But I'm assuming mind-brain materialism here, and so while it's true that torn decisions are mental events, on the view I'm articulating, they're also physical events, presumably neural events. So this first worry doesn't even get off the ground.

But there's another worry you might have about our torn decisions being epiphenomenal. You might worry that (a) there are wholly non-conscious neural events that occur before our torn decisions that are common causes of our torn decisions and the corresponding actions, and (b) our torn decisions aren't causally upstream from our actions in the right way. In other words, you might worry that the causal map looks like this:

If this is how things work in our brains, then it would seem to be freedom-undermining in an obvious sort of way. Thus, I'll assume that this is the relevant worry about our torn decisions being epiphenomenal. And so I'll take clause (b) of the definition of NEL-freedom to say that the torn decisions in question are not epiphenomenal in this way.

3.7. NE-Libertarianism

Given all this, we can say that NE-libertarianism is the view that human beings are NEL-free. In other words, it's the view that at least some of our torn decisions are (a) TDW-undetermined (and, hence, L-free) and (b) not epiphenomenal in the above way.

4. Responses to the Worries About Free Will

NE-libertarianism has a backward looking claim (namely, TDW-indeterminism) and a forward-looking claim (non-epiphenomenalism). These are both empirical claims, and so NE-libertarianism could be undermined by empirical findings that suggested that one or both of its empirical claims aren't true. The question I now want to ask is whether the empirical considerations discussed in section 2—i.e., F1-F5 and B1-B5—give us reason to think that NE-libertarianism isn't true.

I want to argue that the answer to this question is “No.” Indeed, now that we've got a clear picture of the sort of indeterministic, non-epiphenomenal freedom that we should be focused on—namely, NEL-freedom—I think it's easy to see that most of the supposedly anti-free-will considerations that I listed in section 2 are in fact entirely irrelevant to the question of whether human beings are NEL-free. In particular, it seems to me that all five of the forward-looking (epiphenomenalism-based) worries about free will from section 2 (i.e., F1-F5), and the first three of the backward-looking (determinism-based) worries (i.e., B1-B3), are transparently irrelevant to the question of whether we're NEL-free. In other words, the only anti-free-will considerations that I discussed in section 2 that aren't transparently irrelevant to the question of whether we're NEL-free are B4 and B5—i.e., the considerations based on the Libet studies and the Haynes studies. I'll discuss those studies in sections 4.2 and 4.3. For now, I just want to discuss F1-F5 and B1-B3.

4.1. F1-F5 and B1-B3

To illustrate the fact that considerations F1-F5 and B1-B3 are irrelevant to NE-libertarianism—i.e., to the thesis that we're NEL-free—I simply want to point out that NE-libertarianism is perfectly compatible with all of the following claims (NE-libertarianism doesn't entail any of these claims, but it's perfectly consistent with them):

1. The vast majority of our actions are not caused by—or, indeed, even preceded by—conscious choices. For example, when I take the 43rd step on my stroll through the park, I do not decide to do that in any interesting sense of the term; and the same thing is true of the vast majority of my actions.

2. We often have no idea why we do what we do.

3. We often have to infer what our reasons were for some of the actions we perform.

4. We often confabulate reasons for our actions, after the fact.

5. Many of our actions aren't caused by reasons at all—we just do them.

6. Conscious awareness of action often lags behind action—e.g., in speech processing and emergency situations.

7. We can sometimes be duped into thinking that we performed actions that we didn't perform; and we can sometimes be duped into thinking that we didn't perform actions that we did perform.

8. We are not directly aware of the causal link between our decisions and our actions; the claim that there's a causal link here is an empirical claim that requires evidence.

9. We do not have any good non-empirical reason to believe that our torn decisions are TDW-undetermined; indeed, for all we know, it could be that all of our torn decisions are fully determined by events that took place before we were born; the claim that TDW-indeterminism is true—i.e., that some of our torn decisions are TDW-undetermined—is an extremely controversial empirical hypothesis that requires evidence.

10. Many of our actions (and, indeed, many of our torn decisions) are causally influenced by subconscious mental states (and non-mental neural events) that we're not aware of at all.

11. Many of our actions (and, indeed, many of our torn decisions) are causally influenced by situational factors like mood.

12. Our torn decisions can be manipulated by external stimuli, e.g., magnetic stimulation to the brain. (Even if we assume that torn decisions can be causally influenced by magnetic stimulation to the brain, it doesn't follow that ordinary torn decisions— without magnetic stimulation—aren't TDW-undetermined. Here's an analogy: even if we can weight a coin to make it extremely likely that it will come up heads when we toss it, it doesn't follow that the outcomes of fair coin tosses are determined by prior events; it could be that the objective probability of getting heads on a fair coin toss is usually about 0.5. Or again: even if our torn decisions can be influenced by alien manipulation, it doesn't follow that when aliens aren't present, our torn decisions aren't TDW-undetermined and L-free).

All of these claims are perfectly compatible All of these claims are perfectlywith NE-libertarianism. This is entirely obvious—there's simply nothing in NE-libertarianism that says anything that's even remotely incompatible with any of the above claims. But the whole point of F1-F5 and B1-B3—i.e., the five forward-looking anti-free-will considerations and the first three backward-looking anti-free-will considerations—was that claims like the above (i.e., claims 1-12) are true. Thus, considerations F1-F5 and B1-B3 are all entirely irrelevant to the question of whether NE-libertarianism is true—i.e., whether we humans are NEL-free.

In a nutshell, the reason that F1-F5 and B1-B3 don't do anything to undermine NE-libertarianism—i.e., the reason that claims 1-12 are compatible with NE-libertarianism—is that (a) NE-libertarianism is a claim about torn decisions only , and (b) NE-libertarianism only says that some of our torn decisions are TDW-undetermined and non-epiphenomenal. If we keep these two points in mind when we read through claims 1-12, it becomes very clear that there's nothing in any of these claims that's incompatible with NE-libertarianism. Moreover, it also becomes clear that the anti-free-will argument here—the one based on claims like 1-12, or considerations like F1-F5 and B1-B3—is a straw-man argument. It's directed against a bizarre view of human beings that no one could take seriously. The NE-libertarian that I have in mind wants to respond to this argument by saying something like the following:

We're not idiots. We don't think that human beings are ideal (or event close to ideal) agents. We, of course, think that human beings are sometimes causally influenced by subconscious mental states and non-conscious brain processes that they're not aware of; and we, of course, think that human beings are often completely in the dark about why they do lots of what they do; and likewise for all of the claims that you're making here about human beings—we don't need to deny any of these claims. All we're saying—all that needs to be true in order for human beings to be NEL-free—is that at least some or our torn decisions are TDW-undetermined and non-epiphenomenal . And this is perfectly compatible with claims 1-12 and considerations F1-F5 and B1-B3.

It's important to note here that NE-libertarians can admit that some of our torn decisions are causally determined by factors that we're completely unaware of. Indeed, it seems to me that we have strong empirical reasons to believe that many of our torn decisions are causally influenced by factors that we're not aware of. But as far as I can see, we don't have any good reason to think that all of our torn decisions are causally influenced by such factors. To bring this out, consider an ordinary case in which an ordinary person—say, Ralph—makes a torn decision to order chocolate ice cream instead of vanilla. Do considerations like F1-F5 and B1-B3 give us good reason to think that this decision—made very calmly and consciously—wasn't TDW-undetermined and non-epiphenomenal? It seems to me that the answer to this question is obviously “No.” And it seems even more obvious that these considerations don't give us any good reason to think that none of our torn decisions is TDW-undetermined and non-epiphenomenal. The evidence we have just doesn't support this claim. Think of a typical day; you might make torn decisions about whether to have fruit or toast for breakfast, whether to take a walk before going to work, whether to work through lunch or go out to a restaurant, whether to work late or go to a concert, and so on. Does the existing evidence (in particular, the evidence concerning considerations like F1-F5 and B1-B3) really support the claim that none of these decisions is TDW-undetermined and non-epiphenomenal? The answer, I think, is that it does nothing of the sort. It supports the claim that we're often influenced by subconscious factors; but it just doesn't support the claim that none of our torn decisions is TDW-undetermined and non-epiphenomenal. Indeed, the existing evidence seems perfectly consistent with the thesis that a significant percentage of our torn decisions are TDW-undetermined and non-epiphenomenal. And that's all that NE-libertarians need 8

At this point, you might object as follows:

You're not appreciating the fact that when we discover something about the way the mind-brain works in specific cases, we can infer that it works that way in all cases. So, for example, if consciousness is sluggish in some cases, then it's presumably sluggish in all cases. After all, it's not as if the neural processes involved in our conscious thinking can suddenly speed up .

I want to say two things in response to this objection, one related to the fact that (a) NE-libertarians think that we need to focus on torn decisions in particular , and one related to the fact that (b) NE-libertarians claim only that some of our torn decisions are TDW-undetermined and L-free. Point (a) is enough to give us a response to the worry about the sluggishness of consciousness. NE-libertarians obviously don't think that the neural processes involved in our conscious thinking sometimes speed up; rather, their position is that these processes don't need to speed up in order to be causally relevant to our torn decisions in the manner required for the truth of NE-libertarianism. Why? Because torn decisions are very different from, e.g., the processing of incoming speech and the jerking of steering wheels in emergency situations. Consciousness can't keep up with things like speech processing and emergency steering maneuvers; but there's no reason to think that it can't keep up with torn decisions. And this isn't because consciousness can “go faster” in connection with torn decisions; it's because there's no reason to think that torn decisions (about things like whether to order chocolate or vanilla ice cream) occur as quickly as speech processing and emergency steering maneuvers do. So we can't infer from the fact that consciousness is too sluggish to play a causal role in speech processing and emergency steering maneuvers to the conclusion that consciousness is too sluggish to play a causal role in torn decisions. So it's not that NE-libertarians are failing to take note of the fact that results obtained about specific cases generalize to other cases; it's rather that NE-libertarians are pointing out that the generalizing inference doesn't go through in the specific case at issue here because there are relevant disanalogies between torn decisions and, e.g., speech processing and emergency steering maneuvers.

Analogous points can be made about many of the other empirical results at issue in connection with considerations F1-F5 and B1-B3. But there's a second point that NE-libertarians need to make in order to provide a full response to the above objection. The second point concerns the psychology of our torn decisions rather than the neural processes involved in those decisions. The point is this: (a) there's no good reason to think that if some of our torn decisions are causally influenced by subconscious mental states or events (in ways that are incompatible with TDW-indeterminism), then all of them are; and (b) the sum total of the evidence that we presently have does not justify an inference to a claim of universality here. Now, I am not claiming that we could never be in position to infer from individual cases to a universal claim here. If we had the ability to locate torn decisions in our brains and to observe the causal antecedents of those decisions—and these are obviously things that we can't do right now—then if we observed a random (and reasonably large) sample of ordinary torn decisions and found that in all observed cases, our torn decisions were causally influenced by subconscious mental states or events (in ways that were incompatible with TDW-indeterminism), then it would be very rational for us to conclude that this was true in general. And so it would be rational for us to conclude in this scenario that NE-libertarianism was false. But we're just not in this situation right now. We don't have the ability to look at a random sample of ordinary torn decisions and determine whether they're causally influenced by subconscious mental states or events (in ways that are incompatible with TDW-indeterminism). And so while we've got good reason to think that some of our torn decisions are causally influenced by subconscious mental states or events, we're just not in a position to rationally infer that all of them are.

4.2. B4—The Libet Studies

Perhaps the most famous arguments against free will that have been generated by work in psychology and neuroscience are based on the work of Benjamin Libet. In this subsection, I'll explain why Libet's results don't give us any good reason to doubt NE-libertarianism—i.e., why they don't give us good reason to doubt that we're NEL-free.

Libet's studies were a follow-up to a neuroscientific discovery from the 1960s, in particular, the discovery that voluntary decisions are associated with a certain kind of brain activity known as the readiness potential (see e.g., Kornhuber and Deecke, 1965 ). Libet's studies were designed to determine a timeline for the readiness potential, the conscious intention to act, and the act itself (see e.g., Libet et al., 1983 ). In the main experiment, subjects sat facing a large clock that could measure time in ms, and they were told to flick their wrists whenever they felt an urge to do so and to note the exact time that they felt the conscious urge to move. What Libet found was that the readiness potential—the physical brain activity associated with our decisions—arose about 350–400 ms before the conscious intention to act and about 550 ms before the act itself. These results were immediately seen as raising a problem for free will. The argument against free will proceeds differently depending on the kind of free will that we have in mind. In our case, we can see Libet's results as raising a problem for TDW-indeterminism. In particular, the idea here is that (a) TDW-indeterminism requires indeterminacy at the moment of conscious choice, but (b) the fact that our conscious decisions are preceded by nonconscious brain processes (namely, the readiness potential) seems to suggest that the neural mechanisms responsible for our decisions are already up and running before our conscious thinking enters the picture.

The problem with this reasoning is that it's not clear what the function of the readiness potential is. In particular, there is no evidence for the claim that, in torn decisions, the readiness potential is causally relevant to which option is chosen 9 There are many other things that the readiness potential could be doing. One way to see that this is true is to recall from section 3 that NE-libertarianism is perfectly consistent with the idea that various aspects of our torn decisions are causally determined. In particular, as we saw above, a torn decision could be TDW-undetermined and NEL-free even if it was determined in advance that (i) the torn decision in question was going to occur, and (ii) the choice was going to come from among the agent's tied-for-best options, and (iii) the objective moment-of-choice probabilities of these options being chosen were all more or less even. The only thing that needs to be undetermined, in order for a torn decision to be TDW-undetermined and NEL-free, is which tied-for-best option is chosen . Given this, it should be obvious how NE-libertarians can respond to the Libet studies. They can say that for all we know, it could be that the readiness potential is part of a process that's causally relevant to our torn decisions but doesn't causally influence which tied-for-best option is chosen. For instance, it could be part of a causal process that leads to the occurrence of a torn decision without influencing which tied-for-best option is chosen 10 Or it could be that the readiness potential is part of the process whereby our reasons cause our decisions; and it could be that while in connection with certain kinds of non-torn decisions this process determines which option is chosen, in connection with torn decisions, it merely causes the choice to come from the agent's tied-for-best options (and perhaps also causes the objective moment-of-choice probabilities of these options being chosen to be more or less even).

So the point here is that we don't presently have good reason to think that, in torn decisions, the readiness potential is causally relevant to which tied-for-best option is chosen. There just isn't any evidence for this, and so the existence of the readiness potential gives us no reason to think that, in torn decisions, which tied-for-best option is chosen is causally affected by prior-to-choice nonconscious brain processes. So it doesn't give us any good reason to doubt TDW-indeterminism. In other words, the existence of the readiness potential is perfectly compatible with the NE-libertarian claim that some of our torn decisions are TDW-undetermined 11

4.3. B5—The Haynes Studies

I now want to consider the objection to NE-libertarianism that's based on Haynes's studies. Prima facie , these studies seem to give rise to a devastating objection to TDW-indeterminism, but I'm going to argue that this appearance is deceiving and that, in fact, Haynes's studies don't give us any good reason to doubt TDW-indeterminism.

Haynes's studies seem tailor-made to provide anti-libertarians with a way of responding to what I just said in section 4.2 about the argument based on Libet's studies. My central objection to that argument was that it fails to distinguish between the occurrence of a torn decision and the issue of which tied-for-best option is chosen . More specifically, my objection was that for all we know right now, the readiness potential could be part of what causes our torn decisions to occur without doing anything to cause a specific tied-for-best option to be chosen. But Haynes's studies seem to be explicitly constructed to block this sort of response. To bring this out, let's recall how the main Haynes study went. Haynes gave his subjects two buttons, one for the left hand and one for the right, and he told them to make a decision at some point as to which button to push, and he used a very simple method to estimate the time at which the conscious decision occurred (in particular, subjects were presented with a randomized stream of letters, and they had to report which letters they were looking at when they made their conscious decisions). What Haynes found was that there was unconscious neural activity in two different regions of the brain that predicted whether subjects were going to press the left button or the right button. Moreover, he found that this activity arose as long as 7–10 s before the person's conscious decision to push the given button.

These results seem to generate a serious objection to TDW-indeterminism and NE-libertarianism. For (a) the results seem to suggest that our decisions are already determined before we make them, and (b) TDW-indeterminacy (and NEL-freedom) require indeterminacy at the moment of conscious choice. Prima facie , this line of thought seems extremely powerful, but I want to argue that when we look at the details of Haynes's study, the argument against TDW-indeterminism completely falls apart.

There are two details of the study that I want to discuss. The first has to do with the specific regions of the brain where the pre-conscious-choice neural activity was found; in particular, it was found in the parietal cortex (or for short, PC) and in what's known as Brodmann area 10 (or for short, BA10). Why this is important will become clear below. The second important detail is this: the pre-choice brain activity that Haynes found (in PC and BA10 regions) was actually not a very reliable guide to predicting the outcomes of his subjects' choices. Indeed, it was only 10% more reliable than blind guessing. If we just guess which button subjects are going to push, we'll be right about 50% of the time, whereas if we use information about the activity in PC and BA10 regions of subjects' brains, we'll be right at best 60% of the time. This is definitely statistically significant, so it's showing something . But it's not immediately obvious what it's showing, and as I will explain in what follows, it doesn't show (or, indeed, give us any good reason to believe) that TDW-indeterminism and NE-libertarianism are false.

But let me slow down and explain the significance of the fact that the pre-choice brain activity was found in PC and BA10 regions of the brain. The strange thing about this is that these regions are not associated with free conscious decisions. However, they are associated with plans , or intentions . In particular, they're associated with the generation and storage of plans 12 , 13 This is extremely important. In fact, when we combine this with the fact that the neural activity in PC and BA10 regions is only 10% more predictive than blind guessing, the argument against TDW-indeterminism comes unraveled. The reason is that when we put these two facts together, they suggest an alternative explanation of Haynes's results that's perfectly consistent with TDW-indeterminism and NE-libertarianism. I will say in a moment what this alternative explanation is, but before I do, I need to make a background point.

When someone asks you not to think about something, it suddenly becomes very difficult to obey them. For instance, if I don't want you to think about Abraham Lincoln right now, one of the worst things I could do is tell you not to think about him. If I just say nothing, then the odds that you would think of Lincoln in the next few minutes are vanishingly small. But as soon as I say, “Don't think about Abe Lincoln,” it becomes very hard for you to avoid thinking about him, even if you sincerely want to obey me. The problem is that the temptation to think about what you're not supposed to think about can be almost overwhelming.

The same goes for little decisions , like picking a number between 1 and 10. Suppose I say this to you: “In a minute, I'm going to ask you to pick a number between 1 and 10, but don't do it yet.” It's actually rather difficult to refrain from thinking of a number in situations like this. Indeed, it's fairly likely that before I can even spit out the second half of my sentence, you will already have thought of a number between 1 and 10. As soon as I tell you that you're going to be asked to pick a number between 1 and 10, you might pick the number 7 before you even hear me say that you shouldn't choose yet.

Now, once you hear me tell you that you're not supposed to pick yet, you might try to undo what you already did—i.e., you might try to unpick the number 7. But the result of this will probably not be that 7 gets, so to speak, “put back into the hopper.” Instead, it will be that 7 is eliminated from consideration all together. This is because we can't turn ourselves into random number generators. The problem is that you won't be able to forget that you already thought of the number 7. So after a minute passes and I tell you to pick a number, it's unlikely that you'll pick 7 again. If you did, you wouldn't think you were being truly random and that it was just a coincidence that you picked 7 twice in a row; you'd probably think you were cheating —that you were flagrantly disobeying the command not to choose in advance. So even if you didn't realize this, I think the real result of undoing your choice would very likely be that 7 is simply eliminated from consideration.

But now suppose that instead of telling you that you're going to have to pick a number between 1 and 10, I tell you that you're going to have to pick either the number 1 or the number 2 . And suppose that you instantly think of the number 2. Now, what's going to happen when I tell you that I don't want you to choose yet, that I want you to wait 60s and then pick a number? You might try to unpick the number 2, but if the result of this is that 2 is eliminated from consideration, then the only option left is 1. So unless you really manage to completely forget about the fact that you chose the number 2 before, the choice you end up making is not going to be truly random. It's going to be weirdly influenced by your attempt to follow the instructions despite the fact that you started off by picking the number 2.

So that's one point. Here's another point: even if you don't start out by thinking of one of the two numbers, it's actually somewhat difficult to keep yourself from thinking of one of them. Try it right now. Flip an hourglass over and tell yourself that you're not going to think of 1 or 2 until all the sand runs out and that, when the sand does run out, you're going to choose one of the two numbers. This isn't that easy. I'm not saying you can't succeed in doing it. Of course you can. You might be able to distract yourself and think about something else entirely. But you might not succeed. In short, the point here is that sometimes , when we're asked not to think about something, we fail.

Now, here's the really important point for us. You might fail in this task even if you don't realize it . You might subconsciously think of the number 1, and you might subconsciously store the plan to pick that number when the time comes. This shouldn't be controversial at all. For here are two things that we know to be true about humans: first, it's somewhat difficult for us to avoid thinking about something when someone tells us not to think about it; and second, we do all sorts of things unconsciously. We might not do everything unconsciously, but it's clear that we do a lot of things unconsciously. When we put these two points together, we get the following (highly probable) hypothesis:

If you tell a group of human subjects that in 60s they're going to be asked to pick the number 1 or the number 2, and if you tell them not to pick yet—in other words, if you tell them to wait until the 60s are up before they choose—at least some of these subjects will (without realizing it) subconsciously think of one of the two numbers before the 60s have elapsed, and they will subconsciously store the plan to pick that number when the time comes.

Again, given what we know about ourselves, this seems extremely plausible. Indeed, it seems to me that it would be surprising if it wasn't true. (By the way, I'm not claiming here that any time someone subconsciously thinks of a given option, she commits to it. That's obviously not true. But all that's needed here—and this will come out more clearly below—is that in cases like the ones we're considering here, there can be subconscious mental activity that causally influences how the decisions go. And, again, this doesn't seem very controversial.)

In any event, this is all just background. But it's highly relevant to the Haynes studies because it suggests an explanation of Haynes's results that's perfectly consistent with TDW-indeterminism and NE-libertarianism. The explanation that I have in mind—and we'll see later that this isn't the only explanation of Haynes's results that's compatible with TDW-indeterminism and NE-libertarianism—can be put in the following way:

An explanation of Haynes's results that's perfectly consistent with TDW-indeterminism and NE-libertarianism: A significant percentage of the subjects in Haynes's study (say, 20% of them) unconsciously failed to make truly spontaneous decisions about whether to press the right button or the left button. They genuinely wanted to follow Haynes's instructions, but for whatever reason, and without realizing it, they unconsciously formed prior-to-choice plans to push one of the two buttons. They unconsciously stored this information in their brains, and then when the time came, these plans were activated. In other words, the regions of the brain where these plans were stored were activated. And this brain activity caused the subjects to choose in the ways in which they had unconsciously planned on choosing. This explains why (in some subjects) there was prior-to-choice brain activity in PC and BA10 regions of the brain (and, remember, while these regions are associated with the formation and storage of plans , they're not associated with free conscious decisions). It also explains why this brain activity predicts whether subjects will push the left button or the right button. And finally, it also explains why using this brain activity to predict how subjects will choose is only 10% more reliable than blind guessing—the reason is that not all subjects unconsciously formed plans about what they were going to do. Only some of them did. Most of the subjects managed to avoid doing this, and so most of them succeeded in making truly spontaneous decisions. (Of course, the claim here isn't that most of us are NEL-free, but some of us aren't. The claim is that all of us sometimes fail to be NEL-free; we're all sometimes driven by things like unconscious plans; but we aren't always driven by such things.)

The first point to note about this explanation is that if it's right, then there's no problem here for TDW-indeterminism or NEL-freedom. All Haynes's results show is that sometimes our decisions are influenced by unconscious factors. But we already knew this. NE-libertarians don't think (or at any rate, they shouldn't think) that all of our torn decisions are NEL-free. As we've already seen, they should admit that our torn decisions are often causally influenced by unconscious factors in ways that make it the case that they're not TDW-undetermined. What NE-libertarians claim is that this isn't always the case—i.e., that some of our torn decisions are TDW-undetermined. But given this, if my explanation of Haynes's findings is correct, then those findings don't give us any good reason to doubt the NE-libertarian view because they don't give us any good reason to think that our torn decisions are never TDW-undetermined. All they show is that our torn decisions aren't always TDW-undetermined. And so these findings are perfectly consistent with the NE-libertarian view that some of our torn decisions are TDW-undetermined and NEL-free.

One might object to my argument here in something like the following way:

Whenever someone uses scientific data to argue for a hypothesis H, we can always respond to the argument by presenting an alternative explanation of the data that doesn't involve the claim that H is true. But in order to have a good response to the argument for H, the alternative explanation can't be a cockamamie story. It has to be just as plausible (or just as likely to be true) as the original explanation—i.e., the explanation that leads to the conclusion that H is true. But in our case, it's not clear that your alternative explanation of Haynes's findings is as plausible as explanations that are hostile to TDW-indeterminism and NE-libertarianism.

I want to respond to this objection by arguing that my explanation is actually more plausible—or more likely to be true—than any explanation that's hostile to TDW-indeterminism and NE-libertarianism. In order to argue for this, I first need to clarify what these other explanations (that are hostile to TDW-indeterminism and NE-libertarianism) say . There are two different views that enemies of TDW-indeterminism might endorse here, namely, the following:

The early-signature-of-the-decision view : The brain events that Haynes found (in PC and BA10 regions of the brain) were early neural signatures of the conscious decisions themselves—i.e., the decisions that the subjects experienced 7–10 s later. The prior-cause view : The brain events that Haynes found occurred prior to the subjects' conscious decisions, and they caused those decisions to go in the ways that they went.

But there are problems with both of these views—or at any rate, with opponents of TDW-indeterminism endorsing these views. Let me start with the prior-cause view. The first point I want to note about this view is that, as it's stated here, it's compatible with TDW-indeterminism. Indeed, the interpretation of Haynes's results that I'm proposing in this paper more or less entails the prior-cause view—for according to that interpretation, the outcomes of Haynes's subjects' conscious decisions were caused by events in which the subjects subconsciously formed prior-to-conscious-choice plans to choose in certain ways. But it's crucial to this interpretation that this is true of only some of Haynes's subjects; in other words, according to the interpretation I'm proposing, Haynes's results don't give us good reason to think that this generalizes to all subjects.

It's worth pausing to emphasize the sort of TDW-indeterminist/NE-libertarian view we're talking about here. Before we even encountered Haynes's studies, we already acknowledged that TDW-indeterminists (and NE-libertarians) would be wise to admit that some of our torn decisions are causally determined by subconscious mental states or events. And these theorists were already committed to claiming that as of right now, we don't have any reason to think that this is universally true. We can think of the interpretation of Haynes's results that I'm proposing here along these lines. What I'm suggesting is that TDW-indeterminists can say this:

Look, we already admitted that some of our torn decisions are causally influenced by prior events (and, hence, that some of these decisions are not TDW-undetermined). Haynes's results just confirm this point.

So if you want to claim that Haynes's results undermine TDW-indeterminism, and if you want to endorse the prior-cause view, then you need to endorse the following:

Allism : Haynes's results suggest that the outcomes of all human torn decisions are caused by prior-to-conscious-choice brain events.

But it's hard to see how we have any reason to believe this. If what I argued in previous sections of this paper is right, then before Haynes performed his studies, there was a plausible view on the table according to which some but not all of our torn decisions are causally determined by prior events. (This view is obviously controversial; my claim is just that, prior to Haynes's study, it was compatible with our evidence.) But given this, it seems that in order for us to have good reason to believe allism—i.e., in order for us to plausibly claim that Haynes's results show that all of our torn decisions are causally determined by prior events—we would need evidence for the claim that causal factors of the kind that Haynes found occur in all cases. But we just don't have evidence for this. For all we know, it could be that causal factors of the kind that Haynes found are present in some cases not but not all. For example, it could be that the causal factors that Haynes found have to do with the causation of torn decisions by subconscious mental states or events, and it could be that while this kind of causation is present in some cases, it's not present in all cases. More generally, the claim that I'm making here is that (i) we don't have any good reason to think that all torn decisions are caused by events of the same kind, and (ii) Haynes's results don't do anything to change this situation.

These remarks bring out an important point. There's nothing special about the interpretation of Haynes's results that I'm suggesting here—i.e., the interpretation that has to do with the formation of subconscious plans. This is just one interpretation among many that TDW-indeterminists could endorse. All that TDW-indeterminists need to say here, in order to maintain that Haynes's results don't undermine their view, is this: while Haynes's results do seem to suggest that our torn decisions are sometimes caused by prior events, there's no evidence for the claim that the causal factors that Haynes has found are present in all cases. My story about subconscious plans is one story of the some-but-not-all kind that TDW-indeterminists can tell here; but it's not the only one.

So I don't think the prior-cause view gives us a plausible way of attacking TDW-indeterminism. What about the early-signature-of-the-decision view? Well, one thing this view has going for it is that it avoids the problem I just raised for the prior-cause view. For while we don't have any good reason to think that all of our torn decisions are caused by events of the same kind, I think that we do have good reason (at least until we're proven wrong) to suppose that torn decisions are neural events of a fairly unified kind. So if observation revealed that some torn decisions were neural events of some kind K, that would give us prima facie reason to think that other torn decisions were of that kind.

But I don't think the early-signature-of-the-decision view is very plausible. There are at least three different arguments for thinking that my explanation of Haynes's data is more plausible than the early-signature-of-the-decision view. Here are the three arguments:

1. We have strong independent evidence for the hypothesis that PC and BA10 regions of the brain are relevant to the formation and storage of plans and intentions, and we have no reason to think that these regions are relevant to conscious decisions. Therefore, since my explanation takes the brain activity that Haynes found in those regions to be related to the formation and storage of long-term plans, it fits with what we already know about those regions, and so it's more plausible than the early-signature-of-the-decision explanation, which takes this activity to be an early neural signature of the conscious decision itself.

2. The fact that there's a 7–10 s time gap between the brain activity in PC and BA10 regions and the conscious decision counts as strong evidence that that brain activity is not part of the decision. This is a bit ironic because, intuitively, the 7–10 s gap is the thing that makes Haynes's results so striking. When you first hear about these studies, you're likely to think that if neuroscientists can predict how you'll choose 7–10 s before you make a conscious decision, then you couldn't possibly be NEL-free. But upon further reflection, the 7–10 s time gap turns out to be part of what undoes the Haynes argument. This is because we have extremely strong reasons to think that human beings are way faster than this when it comes to making decisions. There is experimental evidence (see e.g., Trevena and Miller, 2010 ) that suggests that we can make decisions in less than half a second . Moreover, we all know that this is true. We have all had lots of experience making snap decisions in way less than 7 s. Therefore, since we know that decisions take less than 7 s, it's not plausible that the brain activity that Haynes observed—a full 7-10 s before the conscious choice—was an early neural signature of the conscious decision itself. It's much more plausible to suppose that this brain activity was doing something else. And my explanation provides a compelling story about what it was doing—it was related to the storage of a long-term plan that was made unconsciously and unwittingly by the subject.

3. My interpretation of the data explains why using the brain activity in PC and BA10 regions is only 10% more reliable than blind guessing. It's because only some of the subjects unwittingly formed unconscious plans about what they were going to do. Some of them didn't do this. Some of them managed to refrain from doing this so that their conscious decisions were genuinely spontaneous last-second choices. On the other hand, the early-signature-of-the-decision explanation of Haynes's results doesn't explain why using the brain activity in PC and BA10 regions is only 10% more reliable than blind guessing. People who favor the early-signature-of-the-decision explanation have no option but to say that the reason there's only a 10% increase in reliability here is that we're just not good enough yet at gathering data from people's brains. This seems much less plausible to me.

So, again, it seems to me that my explanation of the data is better than the early-signature-of-the-decision explanation. Now, I don't want to claim that I've proven that the latter explanation is definitely wrong. It is, of course, possible that the brain activity in PC and BA10 regions is an early neural signature of the conscious decision itself. But there's no evidence for this. Thus, it seems to me fair to conclude that Haynes's results don't give us any good reason to doubt the NE-libertarian hypothesis that some of our torn decisions are TDW-undetermined and NEL-free 14 , 15

In closing, I should say that I do not take myself to have provided a positive argument for NE-libertarianism, and in fact, I don't think we have any very good reason to believe it. But I also think that we don't have any good reason to dis believe it.

Author Contributions

The author confirms being the sole contributor of this work and has approved it for publication.

Conflict of Interest Statement

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

1. ^ I suppose you might think that just as compatibilists reject (D2), so too we should reject (E2). Now, my own view is that the idea that (E2) is false (i.e., that free will is compatible with epiphenomenalism) is considerably less plausible than the idea that (D2) is false (i.e., that free will is compatible with determinism). But it doesn't matter; for I would deal with the suggestion that (E2) might be false in the same way that I'm dealing here with the suggestion that (D2) might be false, namely, by just stipulating that I'm talking about a non-epiphenomenal kind of freedom—i.e., a kind of freedom that just is incompatible with epiphenomenalism.

2. ^ Many people have defended libertarian views. Recent examples include van Inwagen ( 1983 ), Ginet (1990) , Clarke (1993) , Kane (1996) , Ekstrom (2000) , O'Connor (2000) , Griffith (2007) , Balaguer (2010) , Franklin (2011) , Mawson (2011) , Steward (2012) , and Todd (2016) .

3. ^ I should say that it's possible to make a torn decision while in a Buridan's-ass situation—because you could be weird enough to care which can of Campbell's tomato soup you get, and so you could feel genuinely torn about it. But most of us don't make torn decisions in Buridan situations. For example, in the above situation, most of us would just grab a can of soup without thinking about it.

4. ^ Again, to be more precise, I should say that libertarianism is compatible with the claim that some of our torn decisions are determined by events involving us having subconscious reasons that we're not aware of. I won't keep making this clarification.

5. ^ I guess there's a usage of the term “determined” on which expressions like ‘partially determined' don't make sense. But I'm not using the term in that way.

6. ^ Arguments of this general kind have been put forward many times by numerous philosophers. See, e.g., Hobbes (1651) , Hume (1748) , Hobart (1934) , Fischer (1999) , Haji (1999) , Mele (1999) , and Levy (2011) .

7. ^ TDW-indeterminism implies that nothing causally influences the decision at the moment of choice; so it guarantees that the decision is itself an undetermined event—indeed, the undetermined event that determines whether I get chocolate or vanilla ice cream. It might seem that the indeterminacy could be resolved by an event that occurs before the decision; but the assumption of TDW-indeterminism rules out this possibility because it requires indeterminacy at the moment of choice .

8. ^ Strictly speaking, all NE-libertarianism says is that some of our torn decisions are NEL-free. But it's plausible to suppose that there's a good deal of regularity here, so that if any of our torn decisions are NEL-free, then a significant percentage of them are—or some such thing.

9. ^ Indeed, we have good reason to think that the readiness potential is not part of a causal process that's relevant to which option is chosen. The lateralized readiness potential (LRP) is a more plausible candidate for being relevant here; for more on this, see Haggard and Eimer (1999) and Haggard's contribution to Haggard and Libet (2001) ; and for an argument that even the LRP isn't part of a causal process that's relevant to which option is chosen, see Schlegel et al. (2013) .

10. ^ A similar point, though a bit different, has been made by Haggard and Eimer (1999) ; and, again, see also Haggard and Libet (2001) .

11. ^ Responses to Libet-style worries about free will have been given by many people. See e.g., Mele (2009) , Balaguer (2010) , Bayne (2011) , Roskies (2011) , Schurger et al. (2012) , Levy (2014) , Nahmias (2015) .

12. ^ For evidence that the BA10 region is associated with the storage of plans and intentions, see, e.g., Burgess et al. (2001) , Haynes et al. (2007) . And for evidence that the PC region is associated with the generation of plans, see e.g., Desmurget and Sirigu (2009) .

13. ^ You might think that to make a decision just is to generate a plan [see e.g., Mele (2009) for a view along these lines]. I think there are problems with this definition, but it doesn't matter here. For instead of speaking of decisions , we can speak of conscious decisions. It may be that if I subconsciously generate a plan to do something then I've made a “decision” in some (I think pretty odd) sense of the term; but I certainly haven't made a conscious decision.

14. ^ There's another point worth making here that's pretty ironic. The early-signature-of-the-decision view doesn't actually undermine TDW-indeterminism. For if it were really true that the brain events that Haynes found were early neural signatures of the decision itself, then the proper conclusion to draw would be that the relevant brain events were parts of the conscious decision, not prior to it. But if they're parts of the decision, then there's no problem here for TDW-indeterminism. (I don't actually believe that these events are parts of the decision; but that's only because I don't believe that decisions take 10 s to occur; I'm simply pointing out what you should say if you do believe that decisions take 10 s to occur.)

15. ^ Other responses to Haynes-style worries about free will can be found in Balaguer (2014) , Levy (2014) .

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Keywords: free will, determinism, epiphenomenalism, Libertarianism, torn decisions, non-randomness

Citation: Balaguer M (2019) Free Will, Determinism, and Epiphenomenalism. Front. Psychol . 9:2623. doi: 10.3389/fpsyg.2018.02623

Received: 14 August 2018; Accepted: 05 December 2018; Published: 09 January 2019.

Reviewed by:

Copyright © 2019 Balaguer. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Mark Balaguer, [email protected]

This article is part of the Research Topic

The New Science of Free Will: The Ephiphenomenalist Challenge to Freedom

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Free Will and Neuroscience: From Explaining Freedom Away to New Ways of Operationalizing and Measuring It

Andrea lavazza.

Neuroethics, Centro Universitario Internazionale, Arezzo, Italy

The concept of free will is hard to define, but crucial to both individual and social life. For centuries people have wondered how freedom is possible in a world ruled by physical determinism; however, reflections on free will have been confined to philosophy until half a century ago, when the topic was also addressed by neuroscience. The first relevant, and now well-known, strand of research on the brain correlates of free will was that pioneered by Libet et al. ( 1983 ), which focused on the allegedly unconscious intentions taking place in decisions regarded as free and voluntary. Libet’s interpretation of the so-called readiness potential (RP) seems to favor a sort of deflation of freedom (Soon et al., 2008 ). However, recent studies seem to point to a different interpretation of the RP, namely that the apparent build-up of the brain activity preceding subjectively spontaneous voluntary movements (SVM) may reflect the ebb and flow of the background neuronal noise, which is triggered by many factors (Schurger et al., 2016 ). This interpretation seems to bridge the gap between the neuroscientific perspective on free will and the intuitive, commonsensical view of it (Roskies, 2010b ), but many problems remain to be solved and other theoretical paths can be hypothesized. The article therefore, proposes to start from an operationalizable concept of free will (Lavazza and Inglese, 2015 ) to find a connection between higher order descriptions (useful for practical life) and neural bases. This new way to conceptualize free will should be linked to the idea of “capacity”: that is, the availability of a repertoire of general skills that can be manifested and used without moment by moment conscious control. The capacity index, which is also able to take into account the differences of time scales in decisions, includes reasons-responsiveness and is related to internal control, understood as the agent’s ownership of the mechanisms that trigger the relevant behavior. Cognitive abilities, needed for one to have capacity, might be firstly operationalized as a set of neuropsychological tests, which can be used to operationalize and measure specific executive functions, as they are strongly linked to the concept of control. Subsequently, a free will index would allow for the search of the underlying neural correlates of the capacity exhibited by people and the limits in capacity exhibited by each individual.

Introduction—Free Will as a Problem (Not Only) for Science

The concept of free will is hard to define, but crucial to both individual and social life (Kane, 2005 ). Free will can be the reason why someone is not sent to jail during a trial upon appealing to insanity: the subject was not “free” when they committed the crime, not because someone was pointing a gun to their head, but because a psychiatric illness prevented them from controlling their actions. According to a long-standing philosophical tradition, if someone was not “free” when they did something, they cannot be held responsible for their deed (Glannon, 2015 ). And the freedom in question is both “social” freedom (linked to constraints imposed by our peers or by external factors), and the one indicated by the term free will .

Free will can be defined by three conditions (Walter, 2001 ). The first one is the “ability to do otherwise.” This is an intuitive concept: to be free, one has to have at least two alternatives or courses of action between which to choose. If one has an involuntary spasm of the mouth, for example, one is not in the position to choose whether to twist one’s mouth or not. The second condition is the “control over one’s choices.” The person who acts must be the same who decides what to do. To be granted free will, one must be the author of one’s choices, without the interference of people and of mechanisms outside of one’s reach. This is what we call agency, that is, being and feeling like the “owner” of one’s decisions and actions. The third condition is the “responsiveness to reasons”: a decision can’t be free if it is the effect of a random choice, but it must be rationally motivated. If I roll a dice to decide whom to marry, my choice cannot be said to be free, even though I will freely choose to say “I do”. On the contrary, if I choose to marry a specific person for their ideas and my deep love for them, then my decision will be free.

Thus defined, free will is a kind of freedom that we are willing to attribute to all human beings as a default condition. Of course there are exceptions: people suffering from mental illness and people under psychotropic substances (Levy, 2013 ). Nevertheless, the attribution of free will as a general trend does not imply that all decisions are always taken in full freedom, as outlined by the three conditions illustrated above: “We often act on impulse, against our interests, without being fully aware of what we are doing. But this does not imply that we are not potentially able to act freely. Ethics and law have incorporated these notions, adopting the belief that usually people are free to act or not to act in a certain way and that, as a result, they are responsible for what they do, with the exceptions mentioned above” (Lavazza and Inglese, 2015 ).

It is commonly experienced that the conditions of “ability to do otherwise”, “control” and “responsiveness to reasons” are very rarely at work all at once. Moreover, they would require further discussion, because there is wide disagreement on those conditions as regards their definition and scope (Kane, 2016 ). But for the purposes of this article, this introductory treatment should suffice. In fact, the description of free will that I have sketched here is the one that dominated the theoretical discourse on, and practical applications of, the evaluation of human actions. From a philosophical point of view, however, starting with Plato, the main problem has been that of the actual existence of freedom, beyond the appearances and the insights that guide our daily life. The main challenge to free will has been determinism: the view that everything that happens (human decisions and actions included) is the consequence of sufficient conditions for its occurrence (Berofsky, 2011 ). More specifically, “It is the argument that all mental phenomena and actions are also, directly or indirectly, causally produced—according to the laws of nature (such as those of physics and neurobiology)—by previous events that lie beyond the control of the agents” (Lavazza and Inglese, 2015 ). Determinism was first a philosophical position; then, the birth of Galilean science—founded on the existence of immutable laws that are empirically verifiable—has increased its strength, giving rise to the concept of incompatibilism, namely the idea that free will and natural determinism cannot coexist. Only one of them can be true.

Throughout the centuries, despite its conceptual progress, philosophy hasn’t been able to solve this dilemma. As a result, today there are different irreconcilable positions about human free will: determinism is not absolute and free will exists; free will does not exist for a number of reasons, first of all (but not only) determinism; free will can exist even if determinism is true (Kane, 2011 ). A little more than 30 years ago, neuroscience and empirical psychology came into play. Although biological processes cannot be considered strictly deterministic on the observable level of brain functioning (nerve signal transmission), new methods of investigation of the brain, more and more precise, have established that the cerebral base is a necessary condition of behavior and even of mental phenomena. On the basis of these acquisitions, neuroscience has begun to provide experimental contributions to the debate on free will.

In order to better understand the neural bases of free will, provided that there are any, in this article I’ll review and integrate findings from studies in different fields (philosophy, cognitive neuroscience, experimental and clinical psychology, neuropsychology). Unlike previous reviews on free will and neuroscience (Haggard, 2008 , 2009 ; Passingham et al., 2010 ; Roskies, 2010a ; Brass et al., 2013 ), I have no claim of being exhaustive. My goal is to highlight a paradigm shift in the analysis and interpretation of the brain determinants preceding and/or causing free or voluntary action (Haggard, 2008 takes voluntary decision to be non-stimulus driven, as much as possible). Firstly, following Libet’s experiments, a widespread interpretation of the so-called readiness potential (RP) went in the direction of a deflation of freedom (Crick, 1994 ; Greene and Cohen, 2004 ; Cashmore, 2010 ; Harris, 2012 ). Indeed, the discovery of the role of the RP has been taken as evidence of the fact that free will is an illusion, since it seems that specific brain areas activate before we are aware of the onset of the movement. However, recent studies seem to point to a different interpretation of the RP, namely that the apparent build-up of the brain activity preceding subjectively spontaneous voluntary movements (SVM) may reflect the ebb and flow of the background neuronal noise, which is triggered by many factors (Schurger et al., 2016 ). This interpretation seems to bridge, at least partially, the gap between the neuroscientific perspective on free will and the intuitive, commonsensical view of it (Roskies, 2010b ), but many problems remain to be solved and other theoretical paths can be hypothesized. After analyzing the change of paradigm of these perspectives, I’ll propose to start from an operationalizable concept of free will (Lavazza and Inglese, 2015 ) to find a connection between higher order descriptions (useful for practical life) and neural bases.

Neuroscience: Purporting to Explain Free Will

The discovery of the readiness potential.

As a preliminary consideration, it is important to underline that the idea of using an experiment (or a series of experiments) to establish whether the human being can be said to have free will implies accepting a direct link between a measurement of brain functioning and a pre-existing theoretical construct. This direct connection, as it is known, presents several problems and as we shall see, needs conceptual refinement to avoid simplifications and unfounded claims. What one can see and measure in brain activity may in fact only grasp a part of the idea of free will that we would like to test. This was one of the main criticisms to the experiments conducted so far (Mele, 2009 ; Nachev and Hacker, 2014 ). What is measured at the level of brain functioning in the laboratory does not match the concept of free will we refer to, for example, to determine whether someone who engaged in violent behavior could have done otherwise in that specific circumstance.

The first relevant, and now well-known, strand of research on the brain correlates of free will was that pioneered by Libet et al. ( 1983 ), which focused on the allegedly unconscious intentions affecting decisions regarded as free and voluntary. It should be noted that the concepts involved—“conscious intentions”, “voluntary decisions”, “free decisions”—have no clear and shared definition (Nachev and Hacker, 2014 ), and the experiments themselves have been differently interpreted and often criticized (Lavazza and De Caro, 2010 ). In any case, Libet’s experiments and their variants have been repeated several times until very recently, confirming their findings with a sufficient degree of reliability.

Libet based his work on Kornhuber and Deecke’s ( 1965 ) discovery of the bereitschaftpotential : the RP, a slow build-up of a scalp electrical potential (of a few microvolts), mainly measured through electroencephalography (EEG), that precedes the onset of subjectively SVM (Kornhuber and Deecke, 1965 ). According to its discoverers, the RP is “the electro-physiological sign of planning, preparation, and initiation of volitional acts” (Kornhuber and Deecke, 1990 ). “The neurobiologist John Eccles speculated that the subject must become conscious of the intention to act before the onset of this RP. Libet had the idea that he should test Eccles’s prediction” (Doyle, 2011 ).

In his experiments, Libet invited the participants to move their right wrist and to report the precise moment when they had the impression that they decided to do so, thanks to a big clock they had in front of them (Libet et al., 1983 ). In this way, it was possible to estimate the time of awareness with respect to the beginning of the movement, measured using an electromyogram (which records the muscle contraction). During the execution of the task, brain electrical activity was recorded through electrodes placed on the participants’ scalps. The attention was focused on a specific negative brain potential, namely the RP, originated from the supplementary motor area (SMA): a brain area involved in motor preparation, which is visible in the EEG signal as a wave that starts before any voluntary movement, while being absent or reduced before involuntary and automatic movements.

When one compares the subjective “time” of decision and what appeared at a cerebral level, the result appears as a striking blow to the traditional view of free will (Libet, 1985 , 2004 ). In the experiment, the RP culminating in the execution of the movement starts in the prefrontal motor areas long before the time when the subject seems to have made the decision: participants became aware of their intention to take action about 350 ms after the onset of such potential. The volitional process is detected to start unconsciously 550 ms before the action is made in the case of non-preplanned acts and 1000 ms before in the case of preplanned acts. Thus these findings seem to show that our simple actions (and therefore, potentially, also more complex ones) are triggered by unconscious neural activity and that the awareness of those actions only occurs at a later time, when we think we are willing to act.

In the first phase of its intervention in the debate on free will, therefore, neuroscience seemed to argue for a deflation of freedom. Neuroscientists identified a specific aspect of the notion of freedom (the conscious control of the start of the action) and researched it: the experimental results seemed to indicate that there is no such conscious control, hence the conclusion that free will does not exist. However, it is important to highlight that this interpretation strongly depends on the idea that free choices or actions are fully internally generated, in the sense that they are not externally determined—where “external” means outside the subject’s conscience and the subject is something akin to the self. As we shall see, though, this distinction seems to be neither relevant nor truly informative when considering if and how choices are free.

In fact, Libet left the subject some time to veto: about 150 ms. This is the time needed for the muscles to flex in response to the command of the primary motor cortex (M2) through the spinal motor nerve cells. In the last 50 ms the action is realized with its external manifestations (bending the wrist) without any more possible intervention by the prefrontal brain areas (see “The Veto Power” Section). Libet thought there was a role for conscious will precisely in this situation: conscious will can let the action go to completion or it can block it with the explicit veto of the movement implemented by the prefrontal areas (Doyle, 2011 ). But the intentional inhibition of an action (a decision itself) is preceded by neural activity as well (Filevich et al., 2012 , 2013 ). So it cannot be a completely different decision from that to take a positive decision to act.

In their experiments, Haggard and Eimer ( 1999 ) used Libet’s method, but asked the participants to perform a different task. They had to move at will either the right index finger or the left in a series of repeated trials. The authors have compared the RP and the lateralized readiness potential (LRP) in trials in which awareness appeared in shorter or longer time, that is, considering the latency of awareness compared to the RP. In their words, “the RP tended to occur later on trials with early awareness of movement initiation than on trials with late awareness, ruling out the RP as a cause of our awareness of movement initiation. However, the LRP occurred significantly earlier on trials with early awareness than on trials with late awareness, suggesting that the processes underlying the LRP may cause our awareness of movement initiation” (Haggard and Eimer, 1999 ). From this, one can deduce that the awareness of the intention to move one finger or the other comes after the decision was “taken by the brain”, as reflected in the LRP.

Sirigu et al. ( 2004 ) and Desmurget et al. ( 2009 ) have shown that, repeating Libet’s experiments on patients with parietal lesions, it appears that they become aware of their decision to take action only when the action itself is being carried out. In these subjects the awareness of the decision does not even come before the beginning of the movement, as it tends to coincide with the motor action. It seems that in such cases the brain alteration has reduced, if not cancelled altogether, the interval of consciousness preceding the actual implementation of the action. The authors proposed that when a movement is planned, activity in the parietal cortex, as part of a cortical sensorimotor processing loop, generates a predictive internal model of the upcoming movement. And this model might form the neural correlate of motor awareness.

Fried et al. ( 2011 ) recorded the activity of 1019 neurons as 12 subjects performed self-initiated finger movements. They found progressive neuronal recruitment, particularly in the SMA, over 1500 ms before subjects reported making the decision to move. A population of 256 SMA neurons was sufficient to predict in single trials the impending decision to move: 700 ms before the participants became aware of the decision, the accuracy of the prevision was higher than 80%. Fried et al. ( 2011 ) were also able to predict, “with a precision of a few 100 ms, the time point of that voluntary decision to move”, and they implemented a computational model thanks to which “volition emerged when a change in the internally generated firing rate of neuronal assemblies crossed a certain threshold”.

Unreliability of the Conscious Intention

A slightly different trend of research compared to Libet’s comprises studies suggesting that the conscious intention of an action is strongly influenced by events that occur after the action itself was performed. In this sense, intentions are therefore partially reconstructed according to a process of inference, based on elements that come after the action. For instance, a study by Lau et al. ( 2006 ) has produced results that empirically support this hypothesis. The authors have used transcranic magnetic stimulation (TMS) on the pre-supplementary motor (pre-SM) area, while the subjects were performing Libet’s task. The stimulation of the pre-SM through TMS happened at different time intervals, in relation to a simple voluntary movement. When the stimulation was applied 200 ms after the movement, the judgment W was moved back in time, indicating that the perception of the intention was influenced by the neural activity of the pre-SM after the motor action was made (cf. also Lau et al., 2004 ; Lau and Passingham, 2007 ).

In another experiment, Banks and Isham ( 2009 ) have set a slightly different version of Libet’s task: participants were asked to push a button whenever they wanted, and later they had to indicate the precise moment when they had the intention to do so. When they pushed the button, subject received an auditory feedback with a delay from 5 to 60 ms, so as to give them the impression that the response happened after they pushed the button. Even though the subjects weren’t aware of the delay between the action and the auditory feedback, the intention to press the button was reported as happening later in time, according to a linear function with the delay of the auditory signal feedback. The identification of the moment in which the subject had intended to press the button—measured by judgment W—was therefore largely determined by the apparent time of the subject’s response, and not the actual answer. This result indicates that the people evaluate the time when they have had the intention to take an action based on the consequences of their action and not just on the motor action itself.

Kühn and Brass ( 2009 ) conducted an experiment combining the paradigm of the stop signal (Logan et al., 1984 ) with an intentional action paradigm. The subjects had to react in the quickest possible way by pushing a button as soon as a stimulus (e. g., a letter) was displayed at the center of a computer screen. Sometimes, just after the presentation of the stimulus, either a stop signal or a decision signal was shown: in the first case, the subjects had to try to stop responding; in the second case they could decide whether to press the button or stop responding. In the decision trials in which subjects had provided an answer, the subjects were asked if it had actually been the result of a decision, or if it had been inhibited—that is, if they had not been able to stop before the decision signal was presented.

The results have shown that in some instances, the subjects judged as intentional responses—i.e., as the result of a decision—those answers that in reality, on the basis of reaction times, were failed inhibitions. In other words, sometimes the subjects had a subjective experience of having intentionally decided to perform an action that they had actually not decided to take. These studies have empirically supported the hypothesis that the intentions to take voluntary actions are strongly influenced by events occurring after the execution of the action. In addition, they seem to confirm that the brain motor system produces a movement as the final result of its inputs and outputs; consciousness would be “informed” of the fact that a movement is going to occur and this would produce the subjective perception that the movement was decided voluntarily (Hallett, 2007 ).

Predicting Choices

More recently, studying the activity of the frontal and parietal cortex, other neuroscientists of the group coordinated by Soon et al. ( 2008 , 2013 ) have managed to detect the “rise” of a behavioral or abstract choice/decision (to move either the right finger or the left one; to perform a mathematical operation or another with two numbers) a few seconds before the subject becomes aware of it. An unconscious brain process has already “decided” what to do when the subject still does not know what she would choose and thinks she still has the power to decide. More precisely, Soon et al. ( 2008 ) studied “free decisions” between many behavioral options using the multivariate pattern classification analysis (MVPA) which, combined with fMRI, allows one to identify specific contents of cognitive processes. “A pattern classifier, usually adopted from machine learning, can be trained on exemplars of neural patterns acquired when participants make different decisions and can learn to distinguish between these. If the activation patterns contain information about the decisions, the trained classifier can then successfully predict decision outcomes from independent data” (Bode et al., 2014 ).

In Soon et al.’s ( 2008 ) experiment, subjects carried out a freely paced motor-decision task (choosing to press a button with either the left or the right index finger) while their brain activity was being measured using fMRI. The subjects then had to report the moment of the decision, not by using a clock as in Libet’s experiment, but by selecting a letter in a stream that was being presented during the task. Soon et al. ( 2008 ) used fMRI signals to find local neural patterns and draw from such patterns all possible information decoded second by second thanks to the statistical techniques of pattern recognition. The brain areas that were mostly involved in the performance of the actions are the primary M2 and the SMA, while two other brain regions encoded the subject’s motor decision ahead of time and with high accuracy. Indeed, the frontopolar cortex (BA10) and a portion of the cingulate cortex can be monitored to understand what kind of choice will be made by the person before they are conscious of having taken a specific decision in the task they were given. The prediction can be made, with a relevant approximation (60% mean accuracy), up to 7 s before the conscious choice is experienced by the subject, thanks to the fMRI signals detected in the BA10 (one should take into account that the subjects are asked to think hard about the choice before making it, whereas usually simple choices do not require long subjective reflection). “The temporal ordering of information suggests a tentative causal model of information flow, where the earliest unconscious precursors of the motor decision originated in frontopolar cortex, from where they influenced the buildup of decision-related information in the precuneus and later in SMA, where it remained unconscious for up to 10 s” (Soon et al., 2008 ).

This seems to revive the old issue of God’s foreknowledge that forced theologians to wonder if man can be considered free, if someone already knows his future choices. Indeed, the authors speak of “free” decisions determined by brain activity ahead of time by placing “free” between inverted commas, as freedom is taken to be a commonsensical hypothesis. In this regard, the authors claim: “we found that the outcome of a decision can be encoded in brain activity of prefrontal and parietal cortex up to 10 s before it enters awareness. This delay presumably reflects the operation of a network of high-level control areas that begin to prepare an upcoming decision long before it enters awareness” (Soon et al., 2008 ).

Another interesting study is that conducted by Alexander et al. ( 2016 ): using a new experimental design, it found that the RP also occurs in the absence of movement. It suggests that “the RP measured here is unlikely to reflect preconscious motor planning or preparation of an ensuing movement, and instead may reflect decision-related or anticipatory processes that are non-motoric in nature” (Alexander et al., 2016 ). The experimental design used a modified version of Libet’s task. Subjects had to choose between four letters whenever they wanted, by taking note of the exact moment of their choice. Later, in half the trials, the subjects had to push a button as soon as they made the decision, whereas in the other half subjects had to do nothing to mark their choice. At the end of the task, all subjects had to report when they had made their decision. In this way, by EEG, electrooculography (EOG) and electromyography (EMG), it was possible to see the RP of the decision-making both in motor and non-motor contexts.

The authors did not find any strong differences between the two RPs, thereby affirming that there is a pure cognitive contribution to RP that does not reflect processes related to movement. They thus suggest that cognitive RP might reflect action preparation, general anticipation and spontaneous neural fluctuations. Interestingly, they exclude that the RP reflects action preparation since it is a non-motor processing. And as to anticipation they cannot exclude that RP may be specifically associated with free choice. So the RP could merely reflect the average of spontaneous fluctuations (see “Other Neuroscientific Hypotheses on Free Will” Section).

Free Will as an Illusion

All these experiments seem to indicate that free will is an illusion. Yet, these relevant experiments can be interpreted in many ways. A possible view is that, in some way, determinism can be observed directly within ourselves. This interpretation might lead to the conclusion that free will is just an illusion. In fact, if one considers as a condition of free will the fact that it should be causa sui (i.e., it should be able to consciously start new causal chains), such a condition is incompatible with determinism as it is usually defined. For it, in fact, all events are linked by casual relations in the form of natural laws, which started long before we were born and which we cannot escape.

However, determinism has generally been regarded as a metaphysical claim, not refutable by empirical findings. One could properly talk of automatism in the brain, not of determinism, based on the evidence available. (In any case, endorsing indeterminism might lead to consider our behavior as the causal product of choices that every time produce different results, as if we rolled a dice. This doesn’t seem to make us any freer than if determinism were overturned; cf. Levy, 2011 ). Most importantly, another feature of freedom seems to be a pure illusion, namely the role of consciousness. The experiments considered thus far heavily question the claim that consciousness actually causes voluntary behavior. Neural activation starts the decisional process culminating in the movement, while consciousness “comes after”, when “things are done”. Therefore, consciousness cannot trigger our voluntary decisions. But the role of consciousness in voluntary choices is part of the definition of free will (but the very definition of consciousness is a matter of debate, cf. Chalmers, 1996 ).

Empirical research in psychology also shows that our mind works and makes choices without our conscious control. As proposed by psychologist Wegner ( 2002 , 2003 , 2004 ) and Aarts et al. ( 2004 ), we are “built” to have the impression to consciously control our actions or to have the power to freely choose, even though all that is only a cognitive illusion. Many priming experiments show that people act “mechanically” (even when their behavior might appear suited to the environment and even refined). Automatic cognitive processes, of which we aren’t always aware, originate our decisions, and they were only discovered thanks to the most advanced scientific research. Ultimately, consciousness, which should exercise control and assess the reasons for a choice, is thus allegedly causally ineffective: a mere epiphenomenon, to use the terminology of the philosophy of mind. This is what has been called Zombie Challenge , “based on an amazing wealth of findings in recent cognitive science that demonstrate the surprising ways in which our everyday behavior is controlled by automatic processes that unfold in the complete absence of consciousness” (Vierkant et al., 2013 ).

These experiments have triggered a huge debate and led scientists, philosophers and intellectuals to claim (or insist even more, if they already denied free will) that free will doesn’t exist (Greene and Cohen, 2004 ; Cashmore, 2010 ; Harris, 2012 ). It seemed as though neuroscience had produced empirical evidence against free will, so that the century-long debate on it could be considered solved. However, Libet’s experiments have been also criticized. Much criticism was directed to the philosophical interpretation of these studies (Mele, 2014 ) or to their theoretical assumptions (Nachev and Hacker, 2014 ), which are important but not relevant here. Among the forms of criticism, one has to mention the theories of action that separate the deciding from the initiating (Gollwitzer, 1999 ; Gollwitzer and Sheeran, 2006 ). In that case, free and conscious deliberating could still have a relevant casual role, long before the actual performance of the action.

Other objections, more markedly neuroscientific, were made for instance by Trevena and Miller ( 2010 ). They argued that the RP is not an intention to move, but only indicates that an attentional process is in place in the brain, since when subjects “attended to their intention rather than their movement, there was an enhancement of activity in the pre-SMA” (Lau et al., 2004 ). In any case, “there was no evidence of stronger electrophysiological signs before a decision to move than before a decision not to move, so these signs clearly are not specific to movement preparation”, (Trevena and Miller, 2010 ). Others have noted that the introspective estimates of event timing are disputable or inaccurate, and measures in general are not sufficiently exact (Dennett, 1984a , b , 2003 ).

More than Explaining Away

Other studies using multivariate pattern analysis with EEG confirmed that the subjectively free decisions might be made in the brain in the same way as evidence-based perceptual decisions (Bode et al., 2012a , b , 2013 ). Indeed, Bode et al. ( 2012b ) wrote,

we directly decoded choice-predictive information from neural activity before stimulus presentation on pure noise trials on which no discriminative information was present. Choice behavior on these trials was shown to be primed by the recent choice history. Modelling of sequential effects in RT and accuracy confirmed that such choice priming biased the starting point of a diffusion process toward a decision boundary, as conceptualized in evidence accumulation models of perceptual decision making (Bode et al., 2012b ).

In other words, the authors found that internally (and maybe stochastically) generated neural activity can bias decisions that are expected to be stimulus-responsive or (possibly) reason-responsive. In this case, as in others that I will consider below, the understanding that we begin to have of the neuronal processes in play shows us that there is a complexity of factors at work. Some of these factors seem to be genuinely random, due to the pure noise produced by the default brain activity, while other factors can be traced back to the previous history of decisions taken in similar situations or related to the present one. Therefore, there is no “mysterious” start of the action as a linear process that, from the initial command, is then executed, as in Libet’s simplified model. Rather, this outcome is the result of a multiplicity of causal elements, which are homogeneous from the viewpoint of proximal mechanisms but of different relevance from the viewpoint of interpretation in terms of intentional psychology.

Another study has shown that attempts to account for (make sense of) insufficient perceptive clues use the same neural networks as those involved in “free” decision-making (Bode et al., 2013 ). An fMRI-based pattern classifier can be trained to differentiate between different perceptual guesses and try to predict the outcome of non-perceptual decisions, like those made by the participants in the experiments considered so far. Specific activation patterns detected in the medial posterior parietal cortex have allowed the authors to make correct predictions on the participants’ free choices based on the previously decoded perceptual guesses decoded, and the other way round.

The task was the following: the participants were given a masked stimulus and had to say what category the stimulus belonged to. They had to freely choose among many categories. Thanks to the multivariate pattern analysis it was possible to identify the model of “free decisions” to make correct predictions in the context of perceptual judgments and identify the model of the “guess decisions”, to make correct predictions in the context of “free decisions”. It thus seems that a similar neural code for both types of decision is present. In those cases one could say that guessing is similar to making a free decision, since the brain, in the absence of sufficient external cues, has to decide internally. So perceptual decisions can be predicted from specific preceding neural activity when the brain doesn’t have enough internal elements to reach the threshold of perceptive decision.

Studies and commentaries have nevertheless drawn attention to possible confounds and bias in those experiments, namely they might be affected by previous choices with a form of auto-correlation in spontaneous decisions. In particular, Lages and Jaworska ( 2012 ) “trained a linear classifier to predict “spontaneous decisions” and “hidden intentions” from responses in preceding trials and achieved comparable prediction accuracies as reported for multivariate pattern classification based on voxel activities in frontopolar cortex”. Lages et al. ( 2013 ) have stressed a possible sequential information processing between trials that can introduce a confound, and recommended that “rather postulating a 50% chance level, prediction should be tested with a permutation test and/or separate multivariate classification analyses conditional on the previous response”.

The prediction of perceptual decisions from specific preceding neural activity is linked to what is defined “evidence accumulator model for free choice” (Bode et al., 2014 ). The explanation starts with the fact that predictive activation patterns preceding decisions become increasingly similar to the patterns detected when the decision is consciously experienced by the subject. This could mean that a slow build-up of decision-related activity occurs, as it happens in accumulation of decision-related evidence to a decision threshold (Ratcliff, 1978 ; Ratcliff and McKoon, 2008 ). Also, as already noted, when no external feedback is available, the previous choice is used as external feedback (Akaishi et al., 2014 ). The history of previous decisions has a systematic effect on subsequent choices, related to the activity in medial posterior parietal cortex/posterior and posterior cingulate cortex (Bode et al., 2011 , 2013 ). And the systematic effect can go in the direction of repetition or of avoidance of repetition depending on the task (Mochizuki and Funahashi, 2014 ).

Here is an important point that deserves study from the neuroscientific point of view but also from that of a philosophical interpretation of free will. It consists in the fact that the internally generated brain activity has to do both with the stochastic noise and with the history of the subject’s choices. On the one hand, the stochastic noise comes both from the configuration that the brain has on average as a result of evolution (adaptive significance) and from individual development, resulting from random processes and environmental influences. On the other hand, the history of the choices is derived from the same process (in part stochastic) that I have just described.

In any case, if (at least some) very short-term decisions have a genesis similar to that described here, these decisions contribute to shaping the brain activity, and then, presumably, also to influencing decisions on a longer time scale that it is not yet possible to investigate experimentally. Ultimately, this could mean that there is a confluence of causal factors at the level of microdecisions. These factors add up in a way that it is hardly possible to tackle for current science. Then also the reasons motivating an action, typical of free actions, such as “I punched the stalker because it is right to punish those who behave in this way and because I wanted to set an example for all”, encoded in neural activity, can be part of the sum of neural causes.

In fact, experimental psychology has been trying to take into account long-term influences. In the so-called marshmallow experiment, researchers focused on delayed gratification (Mischel et al., 1972 , 1989 ). A child was given a choice between one small, immediate reward and two small rewards (i. e. a larger reward) if they were able to wait some minutes while the psychologist left the room and then came back. Children who waited longer for the their rewards tended to have better life outcomes and accomplishments. Such experiments are relevant in terms of explanations and predictions, but it seems hard to trace behavioral profiles back to specific profiles of cerebral activation, once we are aware of the complexity of causal chains in the evidence accumulation model.

As Bode et al. ( 2014 ) write, in the hypothesis of an evidence accumulator that collects sensory evidence until a decision threshold is reached,

task instructions, participants’ internal motivation, and previous choices all have a strong influence on how decision tasks are performed when external information is either unavailable (as in free decisions), or unhelpful (as in perceptual guessing). In the case of free decision tasks, fluctuating intention for one or the other option may result from active competition between neural representations of both options in decision networks (or rather although not consciously monitored by the participants, the previous choice history, embodied in dynamic states of decision networks, can become the primary determinant of behavior, simply because nothing else is available (Bode et al., 2014 ).

However, in this way things get more complicated and at a macroscopic level of behavioral observation, this blurs but doesn’t do away with the idea of free behaviors and behaviors that could be taken as unconscious decisions, of which we become aware only when the action has been performed. What remains to be solved is the problem of the distinction between external stimuli that trigger a stimulus-response circuit, and internal self-paced intentions and decisions that trigger voluntary circuit (Haggard, 2008 ).

Other Neuroscientific Hypotheses on Free Will

Beyond determinism and consciousness.

The concept of free will relevant to our moral and legal, personal and social practices is much more complex than that captured by the experiments considered up to now. But here what matters are not so much theoretical considerations or those derived from experimental psychology (such as the role played in decisions by implementation intentions, which then re-evaluate the active role of consciousness; Gollwitzer, 1999 ), but those that originate from the neuroscientific research itself. In what might be called a new phase of empirical investigation on free will, the problem of determinism and the role of consciousness is left in the background, and the focus goes to other factors that enter the brain mechanisms of decision-making, without asking first if those processes (necessarily the most simple, at least for now) are deterministic or stochastic. On the other side, neuroscientists are trying to confine the concept of free will to operationalizable situations, so as to measure it and be able to identify, at least as a goal, its neural correlates.

There is a line of research on non-human primates, but more recently also on humans, which studies fine decision-making at the neuronal level, bringing it back to a mechanistic process that might be the neuronal interface of our common sense descriptions. This trend has been well described by Roskies ( 2010a , b , 2013 ), who is one of the major supporters of this approach. For example, in Shadlen and Newsome’s ( 2001 ) experiments, monkeys are trained to look at stimuli consisting of points that move randomly to the right and to the left and to “indicate” the overall direction of the points. The monkeys give this indication moving their eyes (with a saccade) to the right or to the left. What emerges is that the activity of the neurons of the lateral interparietal (LIP) area increases with the information in the sensory cells of the middle temporal (MT) area and upper middle temporal (MST) area. The discharge rates rise up to reaching a given level, at which the monkey performs the saccade and the neurons stop discharging. This is the threshold for a decision to take place. The time taken to reach the threshold level depends on the perceptual characteristics of the stimulus (the strength of the movement over time) and the discharges stop after the answer was given.

The discharges also depend on whether the monkey is asked to answer when he wishes, or rather to hold back the response until the signal is given for the saccade. If the monkey is asked to wait until the signal is given to respond, LIP neurons continue to discharge even in the absence of the visual stimulus (Gold and Shadlen, 2007 ). According to Roskies ( 2010b ), this is the discharge scheme of a neuron involved in the decision-making process; the levels of discharge can be maintained in the absence of the stimulus, signifying the independence of the decision from the inputs on which it operates, and the activity continues until it reaches the critical level at which the response is generated, or until the neurons that represent the elements accumulated in favor of a different choice lead to eye movement. In addition, electrical stimulation of LIP neurons can influence the monkey’s decision, indicating that LIP cells causally contribute to the process that triggers decision and action (Hanks et al., 2006 ). It remains, however, to be established whether this role is that of deliberation that leads to a decision or that of the decision itself.

The reaction times and the accuracy in the evaluation are very similar between monkeys and humans, with the probability of choice and the response time connected in a similar way to the difficulty of discriminating the stimulus, so that it can be assumed that also in humans these neural processes are similar. A mathematical description of the dynamics of this system allows one to talk about the race towards the critical threshold (Gold and Shadlen, 2007 ; Wong et al., 2007 ). According to this model, the neuronal populations with specific response properties represent different “hypotheses”. The discharge rates represent the strength of the evidence in favor of those hypotheses based on evidence gathered from the environment. When the evidence for and against each hypothesis is integrated, the discharge rates reach or move away from the critical level, which represents the decision point. This is the point at which the animal “made a choice” about the overall direction of movement. The first group that reaches this threshold “wins”, leading the motor response.

Schurger et al. ( 2012 ) proposed a different interpretation of the premovement buildup of neuronal activity preceding voluntary self-initiated movements in humans as well. They used “a leaky stochastic accumulator to model the neural decision of “when” to move in a task where there is no specific temporal cue, but only a general imperative to produce a movement after an unspecified delay on the order of several seconds”. According to their model, “when the imperative to produce a movement is weak, the precise moment at which the decision threshold is crossed leading to movement is largely determined by spontaneous subthreshold fluctuations in neuronal activity. Time locking to movement onset ensures that these fluctuations appear in the average as a gradual exponential-looking increase in neuronal activity” (Schurger et al., 2012 ).

The model proposed by Schurger et al. ( 2012 ) accounts for the behavioral and EEG data recorded from human subjects performing the task and also makes a specific prediction that was confirmed in a second electroencephalography experiment: fast responses to temporally unpredictable interruptions should be preceded by a slow negative-going voltage deflection beginning well before the interruption itself, even when the subject was not preparing to move at that particular moment. The task was to repeatedly push a button, sometimes at will, sometimes in response to a sound produced by the experimenters according to a causal sequence. The speed of response (pressing the button) when the sound is produced is related to the proximity to the peak of the background brain activity, which appears to be random, an ebb and flow that has its highest point in the threshold at which it produces the decision to push the button.

According to this explanation, “the RP does not reflect processing within a specific action domain. Our finding that movement does not significantly modulate RP amplitude supports this aspect of their claim by extending the RP to the domain of covert decisions” (Alexander et al., 2016 ). Another consequence is the fact that the neural decision to move at a specific time happens much later compared to Libet’s hypothesis, and the RP is only a by-product of a drift diffusion process. But the RP would still be predictive in that it precedes action and conscious awareness of both motor and cognitive action. However, the RP is predictive with regards the whether and the when, if a known task is performed, but not with regards to the what of the action (Brass and Haggard, 2008 ).

Jo et al. ( 2013 ) seems to go in the same direction with their work: they considered both the positive and the negative potential shifts in a “self-initiated movement condition” as well as in a no-movement condition. The comparison of the potential shifts in different conditions showed that the onset of the RP appeared to be unchanged. “This reveals that the apparently negative RP emerges through an unequal ratio of negative and positive potential shifts. These results suggest that ongoing negative shifts of the SCPs facilitate self-initiated movement but are not related to processes underlying preparation or decision to act” (Jo et al., 2013 ).

Murakami et al. ( 2014 ) confirmed those findings. They used rats, who had to perform a specific task: wait for a tone (which was purposely delayed) and decide when to stop waiting for it. The rats’ neuronal activity of the secondary M2 was recorded and resulted consistent with the model of integration-to-bound decision. “A first population of M2 neurons ramped to a constant threshold at rates proportional to waiting time, strongly resembling integrator output. A second population, which they propose provide input to the integrator, fired in sequences and showed trial-to-trial rate fluctuations correlated with waiting times” (Murakami et al., 2014 ). Also, an integration model based on the recorded neuronal activity in the considered brain areas has allowed the researchers to quantitatively foresee the inter-neuronal correlations manifested during the task performance. “Together, these results reinforce the generality of the integration-to-bound model of decision-making. These models identify the initial intention to act as the moment of threshold crossing while explaining how antecedent subthreshold neural activity can influence an action without implying a decision” (Murakami et al., 2014 ).

Schurger et al. ( 2016 ) stress that the main new finding about the brain activity preceding SVM “is that the apparent build-up of this activity, up until about 200 ms pre-movement, may reflect the ebb and flow of background neuronal noise, rather than the outcome of a specific neural event corresponding to a “decision” to initiate movement”. The model used is the bounded-integration process, “a computational model of decision making wherein sensory evidence and internal noise (both in the form of neural activity) are integrated over time by one or more decision neurons until a fixed threshold-level firing rate us reached, at which the animal issues a motor response. In the case of spontaneous self-initiated movement there is no sensory evidence, so the process is dominated by internal noise” (Schurger et al., 2016 ). The stochastic decision model (SDM) used by Schurger et al. ( 2012 ) allowed them to claim that bounded integration seems to explain stimulus-response decision as relying on the same neural decision mechanism used for perceptual decisions and internal self-paced intention and decision as “dominated by ongoing stochastic fluctuations in neural activity that influence the precise moment at which the decision threshold is reached” (Schurger et al., 2016 ). And this mechanism seems to be shared with all animals including crayfish (Kagaya and Takahata, 2010 ).

The philosophical implications could be that “when one forms an intention to act, one is significantly disposed to act but not yet fully committed. The commitment comes when one finally decides to act. The SDM reveals a remarkably similar picture on the neuronal level, with the decision to act being a threshold crossing neural event that is preceded by a neural tendency toward this event” (Schurger et al., 2016 ).

The Veto Power

Another recent study has brought back to the center of neuroscientific research the space of autonomy that the subject seems to have compared to the idea of free will as an illusion supported by the experiments based on the alleged unconscious onset of the action. Schultze-Kraft et al. ( 2016 ) showed that people are able to cancel movements after elicitation of RP if stop signals occur earlier than 200 ms before movement onset. In the real-time experiment, “subjects played a game where they tried to press a button to earn points in a challenge with a brain–computer interface (BCI) that had been trained to detect their RPs in real time and to emit stop signals” (Schultze-Kraft et al., 2016 ).

The subjects had to press with their foot a button on the floor after a green light flashed: they could so whenever they wanted after about 2 s. Participants earned points if they pressed the button before the red light to come back (the stop signal). The experiment was composed of three phases. In the first phase, the stop signals were lit at random and the movements of the subjects were not predicted. In the second phase, the authors used data taken from the EEG on the participants in the first phase. In this way a classifier was trained to predict (with imperfect accuracy) the movements (the When and the Whether, not the What). In this phase, the BCI could foresee the fact that the subject would press the button thanks to the detection of the RP and therefore turned on the red light to earn points against the subject if it could not stop the movement. In the third phase, the subjects were informed that the BCI could “see their preparation of the movement” and they had to try to beat the computer by moving in an unforeseeable way.

In all phases of the experiment, there was no difference between RPs. While in the first phase, in 66.5% of the cases, subjects were winning by pressing the button with the green light on, in stages two and three trials in which subjects were able to beat the computer, by not pushing the button with the red light on, decreased to 31%, and warning participants of the prediction of the BCI would not help them do any better. The authors could thus claim that “despite the stereotypical shape of the RP and its early onset at around 1000 ms before EMG activity, several aspects of our data suggest that subjects were able to cancel an upcoming movement until a point of no return was reached around 200 ms before movement onset. If the stop signal occurs later than 200 ms before EMG onset, the subject cannot avoid moving” (Schultze-Kraft et al., 2016 ). The explanation of the minimum threshold of 200 ms could reflect the time necessary for the stop signal to light up, the subject to perceive it and cancel the movement that was already being prepared.

As to which cortical areas are involved in vetoing an already initiated movement, some studies have tried to identify them. Brass and Haggard ( 2007 ) examined the voluntary inhibition using an experimental paradigm that was based on the Libet task. The subjects were asked to press a button while watching a cursor moving along the face of a clock. Every time, after pressing the button, the subjects had to signal the precise moment when they thought they decided to press the button. In addition, the instructions specified that the participants had to inhibit the execution of the response in some tests of their choice. Comparing this voluntary inhibition condition with the condition in which the action had not been inhibited, the authors observed an activation of the dorsal fronto-medial cortex (DFM). This area is different from the brain regions involved in the stop signal tasks, in which the inhibition is controlled by external signals. Furthermore, the DFM cortex is also distinct from the brain regions controlling the activity linked to the when and what components of voluntary action. Brass and Haggard ( 2007 ) have interpreted this finding as evidence that there is a mechanism of voluntary inhibition that can be dissociated, in neuroanatomo-functional terms, from an “environmental” inhibiting mechanism, which involves the lateral prefrontal cortex.

This finding was replicated in a subsequent study of Kühn et al. ( 2009 ), in which the subjects had to avoid dropping a ball sliding down a ramp, by pressing a button before the ball came down and broke. In some tests of their choice, they could choose to voluntarily inhibit the response. The comparison of the condition of voluntary inhibition with the condition of voluntary action still showed activation of the DFM cortex, supporting the idea that this area is involved in the inhibition of voluntary action (Schel et al., 2014 ).

Finally, Schultze-Kraft et al. ( 2016 ) declared to be agnostic about the interpretation of their data in regards of RP. As the RP is predictive of the subsequent movement, it could be read as “the leaky integration of spontaneous fluctuations in autocorrelated neural signals”. Theoretically, the question remains about the departure of the intention to block the action while the movement is being prepared, along with the possible coexistence of two intentions suggested by the commands of the experimenters. The participants in the experiment, in fact, want to win against the computer, therefore they want to push the button, and also have the intention, partly contrasting, not to push the button when the computer turns the red light on.

A More Realistic Model

This novel perspective offered by the line of research by Schurger et al. ( 2012 ) here described works on very simple decision-making processes and could be exposed to the same criticism in this regard have been made to Libet’s research line. But Roskies ( 2010b ) has suggested some tracks along which to develop research on more complex decision-making processes, close to those relevant to social life. First, one must introduce the value of the decision, seen as a subjective or moral feature that drives action. By manipulating the expected rewards for correct action or for a particular type of decisions, or by manipulating the probabilities of the outcomes, both the decision and the activity levels of LIP neurons are altered (Platt and Glimcher, 1999 ; Glimcher, 2002 ; Dorris and Glimcher, 2004 ; Sugrue et al., 2004 ). In this way it is possible to change the monkey’s choice about the objective of the saccade by offering her favorite reward. Although it is not known how the figures are represented, it seems that the Lip neurons can integrate the information on the value or on the reward in the decision-making process, and that information has a causal role.

As for the reasons, and the responsiveness to them, Roskies ( 2010b ) suggests that also the reasons, albeit discursive and propositional, may be encoded as information at the neuronal level. Simplifying, in her view one might think that in a situation where, say, there is little food and many people, different populations of neurons represent the content “I am hungry”, while others represent “others need this more than I do”, others “the weak come first” and so forth, weighing reasons in terms of activation and modulation of the response of the populations of neurons delegated to the choice and the final decision. However, such a model (Dorris and Glimcher, 2004 ) should be considered as purely hypothetical because first we do not know what are the specific populations of neurons, we don’t yet have the instruments to identify them, and we do not know their interactions (also considering the recent failures of naturalized semantics).

Secondly—and perhaps most importantly—it is unclear how what we externally call “reasons” could be activated and weighed by the decision-maker understood as a unitary subject or self, according to the description for which we truly act based on reasons. In this case, I believe one cannot seek a simple neural interface for commonsensical concepts and notions. In fact, the idea of a deep and unitary self—the idea of a conscious subject controlling her behavior instant by instant—has been strongly challenged by evidence coming from empirical psychology and cognitive neuroscience (Dennett, 1991 ; Metzinger, 2004 , 2009 ). Therefore, one should avoid the temptation to reproduce such a description in neural levels. But if we trace back the reasons to populations of neurons in a mechanistic model—if we trace them back to thresholds—it is not easy to figure out who makes the decisions and why. If it is true that some people seem to be more sensitive to specific reasons, other than those to which other people are sensitive, and if people can change over time the reasons by which they are usually motivated, and in certain situations the same people may not to respond to the reasons to which they are usually sensitive, one has to wonder if what prevails are processes that we would call random or that, in any case, are beyond our control.

Here the role of consciousness seems again to be relevant. If experiments à la Libet seemed to have ruled it out from a causal standpoint, the experiment by Schultze-Kraft et al. ( 2016 ) on movement vetoing seems to reassess its role in blocking the preparation process triggered in the brain. In this sense, this seems to be a more realistic line of neuroscientific investigation on free will, one that contemplates, even in broad terms, stochastic brain processes, for the most part triggered by environmental stimuli, which often are not aware of (the same as our train of thoughts arising spontaneously without us being able to orientate it from the beginning), but also by spontaneous activity of the brain (Changeux, 2004 ; Brembs, 2011 ) that creates models of reality. “Learning mechanisms evolved to permit flexible behavior as a modification of reflexive behavioral strategies. In order to do so, not one, but multiple representations and action patterns should be generated by the brain” (De Ridder et al., 2013 ). And this repertoire is not infinite. Indeed, “our evolutionary-evolved brain potential to generate multiple action plans is constrained by what is stored in memory and by what is present in the environment” (De Ridder et al., 2013 ). Schurger and Uithol ( 2015 ) also argue that the “actions emerge from a causal web in the brain” and that the “proprioceptive feedback might play a counterintuitive role in the decision process”. They, thus recommend the use of dynamical systems approach for the study of the origins of voluntary action.

On these spontaneous processes we can exercise control, which can be considered automatic and unconscious when evaluated with the classical theoretical criteria of conscious control. First, there is an innate behavioral repertoire of provisions linked to survival in the environments within which we evolved. Secondly, there is a repertoire of behavioral provisions that is stratified in terms of conscious repetitions due to environmental stimuli or to internal choices (with all the limitations that this expression has in reference to the brain mechanisms analyzed so far) and then becomes automatic. The control can, however, also be explicit, with obvious limitations and cases of complete control failure. Based on this complex self-construction (which has a neural correlates), we are creatures with a higher or lower degree of free will. This free will may then be better understood and circumscribed, so as to be more objectively operationalized and also measured.

Operazionalizing, Measuring and Verifying: From the Action to the Brain

My view is that a richer conceptualization of free will—one that is able to overcome the stall of the metaphysical debate as well as the current difficulties of neuroscience (Nachev and Hacker, 2014 ) and empirical psychology (Nahmias, 2014 )–has to be linked to the idea of “capacity”. In fact, as claimed by Mecacci and Haselager ( 2015 ), the kind of free will investigated by neuroscientific experiments, which is self-generated and defined according to the absence of cues, “does little justice to the common sense practice of holding people responsible for their freely willed actions that consists in asking explanations and justifications from the actor” (Mecacci and Haselager, 2015 ).

Another important point is that there are differences in time scales between laboratory tasks (the milliseconds to seconds time range) and real life or, better, life as we measure it temporally (seconds, minutes, hours, weeks, years) regarding decisions that really concern us. Even if the underlying mechanism might be the same, the experiments described so far cannot investigate whether decisions with a longer maturation process are free and to what extent they are such. It might be possible to distinguish between proximal and distal mechanisms, but this doesn’t seem feasible lacking the tools to address decisions involving longer time scales. For this reason it might be useful to introduce other and different ways to conceptualize and operationalize (supposedly) free actions.

“By capacity, in the context of free will, we mean the availability of a repertoire of general skills that can be manifested and used without the moment by moment conscious control that is required by the second condition of free will we have previously seen” (Lavazza and Inglese, 2015 ). The concept of capacity is related to that of internal control, understood as the agent’s “ownership” of the mechanism that triggers the relevant behavior and the reasons-responsiveness of that mechanism (Fischer and Ravizza, 2000 ). And reasons-responsiveness must involve a coherent pattern of reasons-recognition. “More specifically, it must involve a pattern of actual and hypothetical recognition of reasons that is understandable by some appropriate external observer. And the pattern must be at least minimally grounded in reality” (Lavazza and Inglese, 2015 ). The concept of capacity used in this sense, and combined with the idea of reasons-responsiveness, also avoids the objection of determinism that has always weighed on the debate on free will. From a philosophical point of view, the approach related to capacity may fall indeed in the strand of so-called compatibilism, which defends the fact that human freedom can exist even if determinism is true of the physical world.

Cognitive abilities might be firstly operationalized as a set of neuropsychological tests, which can be used to operationalize and measure specific executive functions, as they are strongly linked to the concept of control. Executive functions, also known as control functions, are essential to organize and plan everyday behavior—which is not the instant behavior found in Libet’s experiments. Those skills are necessary to perform the greater part of our goal-oriented actions. They allow us to modulate our behavior, control its development and change it according to the environmental stimuli (the environment being both physical and social). Also, executive functions allow us to change our behavior based on it effects, with a sophisticated feedback mechanism; finally, they are also necessary for tasks of abstraction, inventiveness and judgment. Those who, for whatever reason, have a deficit in their executive functions cannot respond to their social environment appropriately, and struggle to plan their behavior or to choose between alternatives based on their judgment or interest. Sufferers of these deficits in executive functions often fail to control their instinctive responses and to modify their regular courses of action, or are unable to concentrate or persist in the pursuit of a goal (Barkley, 2012 ; Goldstein and Naglieri, 2014 ).

In general terms, the executive functions refer to the set of mental processes necessary for the development of cognitive-behavioral patterns adaptive in response to new and demanding environmental conditions. The domain of executive functions includes (Lavazza and Inglese, 2015 ):

• the ability of planning and evaluation of effective strategies in relation to a specific purpose related to the skills of problem-solving and cognitive flexibility.
• inhibitory control and decision-making processes that support the selection of functional response and the modification of the response (behavior) in relation to changing environmental contingencies.
• attentional control referred to the ability to inhibit interfering stimuli and to activate the relevant information.
• working memory referring to the cognitive mechanisms that can maintain online and manipulate information necessary to perform complex cognitive tasks.
• (and it can be added with regards to free will) creativity and the ability to cope with environmental changes through novel solutions.

Those of empirical psychology are higher order concepts, which act as a bridge between free will, which is something that is not in the brain but can be observed in behavior (along with its causes), and the underlying brain processes. It has been convincingly suggested that in the construction of a hierarchy of mechanisms and explanations (Craver, 2007 ), also to guide the exploration, one must go from inside to outside and from outside to inside. One goes from measurable skills to their brain basis, and from the tentative index of free will to the underlying (real) mechanisms.

Based on the evidence presented, I believe that a viable proposal is to construct an index related to compatible tests whose relevance can be uniformly ascertained. It would be a kind of IQ-like profile that would allow for the operationalization and quantification of a person’s cognitive skills. All the tests used (for example, Stroop Test, Wisconsin Card Sorting Test, Weigl’s Color-Form Sorting Test, Go-No Go Test) should be related to the subject’s age and education and then transformed in new standardized scores (Equivalent Scores, ES) on an ordinal scale, e. g. ranging from 0 to 4, with 0 representing scores below cut-off point and 4 representing scores equal to or better than average. Specific standardized scores exist in many countries or linguistic areas. The subjects would get for each test a raw score (or RS), given by the sum of the scores obtained in each item that makes up the test, which would then be standardized.

A synthetic index such as the one here proposed measures a certain range of cognitive and behavioral control skills that configure a certain kind of free will at the psychological-functional level. These are potential capacities measured with standardized instruments in laboratory situations, which do not consider any other factors that may restrict the freedom of a subject in specific situations, such as those that are relevant in moral scenarios and legal contexts. The same goes for moral judgment. However, an index such as the one I’m proposing here could be the first step, albeit certainly imperfect, towards more objective measures to discriminate between people who have more or less “free will” or, in other words, are more or less capable of self-control and rational choice (i.e., a reasons-responsive choice).

This hypothesis would be in line with the proposals of operationalizing free will advanced so far. According to Vohs ( 2010 ), freedom might be conceived of as the sum of executive functions and goal-directed, future-oriented behaviors, which include rational choice, planning, intelligent thought, and self-control. Free will can be then constituted by a limited stock of energy, devoted to guiding executive functioning processes. The free will index I am proposing is also consistent with Baumeister’s contribution:

Psychologists should focus on what we do best: collecting evidence about measurable variance in behaviors and inner processes and identifying consistent patterns in them. With free will, it seems most productive for psychologists to start with the well-documented observation that some acts are freer than others. As already noted, dissonance, reactance, coping with stress, and other behaviors have been shown in the laboratory to depend on variations in freedom and choice. Hence, it is only necessary to assume that there are genuine phenomena behind those subjective and objective differences in freedom. In a nutshell, we should explain what happens differently between free and unfree actions (Baumeister, 2008 ).

Empirical research on how human beings work has recently focused on self-control as a feature of free will. Self-control can be defined as the exertion of willpower on behavior. Self-control is thus generally regarded as the capacity to override inappropriate impulses and automatic or habitual responses and to suppress or delay immediate gratification so as to reach a long-term goal (Gailliot and Baumeister, 2007 ). “Being in control” includes the capacity to maintain goals, to balance long- and short-term values, to consider and evaluate the consequences of a planned action, and to resist being “carried away by emotion” (Churchland, 2006 ). Self-control can also be regarded as the ability of higher-order functions to modulate the activity of lower-level functions, where higher-order functions manifest themselves externally in complex behavior, adjusted according to the environmental needs, while lower-level functions are manifested in simple and stereotyped behaviors, not adjusted according to the demands of the environment (Roskies, 2010a ). Everyone exhibits a different degree of self-control compared to other individuals, and for each person the degree of self-control varies over time (Baumeister et al., 2006 ; Casey et al., 2011 ; Dang et al., 2015 ). The variability of self-control that is manifested in behavior and can be measured with the test has its base in neuronal functioning, which in turn depends on education and habits, external circumstances and the internal neuronal noise.

However, two executive functions turn out to be central:

(i) the ability to predict the future outcomes of a given action; and (ii) the ability to suppress inappropriate, i.e., not sufficiently valuable, actions. Importantly, these two executive functions operate not only during the genesis of an action, but also during the planning of an already selected action. In fact, during the temporal gap between the time when an action has been chosen and the moment when the motor output is going to be generated, the context might have changed, altering the computed value of the action and thus requiring a radical change of the planned motor strategy (Mirabella, 2014 ).

It seems that the peculiarity of our freedom at the cognitive level is the ability to modulate or block courses of action that environmental stimuli automatically or unconsciously arouse in us—a reproposal in different form of Libet’s free won’t and Schultze-Kraft’s vetoing . These psychological-functional indicators must then lead to their cerebral bases. For instance, one can consider a situation in which one’s needs are satisfied (or not) and the consequent motivation to act based on the evaluation process of the need satisfaction.

This is an essential process and one that is continuously performed by our motor system. In fact, in most places where we live, if not all, we are surrounded by tools whose sight automatically activates motor schemas that would normally be employed to interact with those objects. These actions are prompted by the features of the objects, the so-called affordances (Gibson, 1979 ). It has been shown that even the simple observation of pictures depicting affordable objects (such as graspable objects) activates a sub-region of the medial frontal cortex, the SMA, even when there is no requirement to actually act on those stimuli (Grèzes and Decety, 2002 ). These stimulus-driven activations are rapid, involuntary, and unconscious (Mirabella, 2014 ).

Environmental stimuli, in this case, can induce a subject to make specific choices through a priming process that exploits our action tendencies. Typically, individuals are able to control their behavior, but in some cases they fail to do so; for example if suffering from microlesions of the SMA, people have a tendency to invariably implement a certain type of action, even if the environment, both physical and social, does not require it (Sumner et al., 2007 ). In fact, “the suppression of a triggered action might be seen not as an active process, but rather as an automatic consequence of the evaluative procedure” (Mirabella, 2014 ). One could then say that those who have the ability to better monitor, control and direct their own behavior are “freerer” than those who do not have this capability. Individuals affected by disorders of the executive functions are not able to grasp and process environmental stimuli to direct their behavior. For example, these people may not be able to stop the utilization behavior, an automatic mechanism that tends to make us interact with all the objects that are in our perceptual sphere.

Churchland ( 2006 ) and Suhler and Churchland ( 2009 ) proposed a hypothesis concerning the neural basis for control, which can bridge the gap between higher-order concepts and brain mechanisms. As she wrote,

Perhaps we can identify various parameters of the normal profile of being in control, which would include specific connectivity patterns between amygdala, orbitofrontal cortex, and insula, between anterior cingulate gyrus and prefrontal cortex, and so forth. Other parameters would identify, for each of the six non specific systems [identified via the neurotransmitter secreted at the axon terminals: serotonin, dopamine, norepinephrine, epinephrine, histamine and acetylcholine], the normal distribution of axon terminals and the normal patterns of neurotransmitter release, uptake, and co-localization with other neurotransmitters such as glutamate. Levels of various hormones would specify another set of parameters. Yet other parameters contrast the immature with adult pattern of synaptic density and axon myelinization. At the current stage of neuroscience, we can identify the normal range for these parameters only roughly, not precisely (Churchland, 2006 ).

This hypothesis would allow for specific brain correlates of a free will index based on the executive functions-guided self-control and even, hypothetically, a direct brain measure of being in control For example, a recent study (Bartelle et al., 2016 ) highlights the possibility of having MRI imaging of dopamine release thanks to a engineered protein that binds to the neurotransmitter and works as a MRI-visible probe. As the authors put it, “one could imagine a future in which molecular fMRI is used to determine brain-wide neurochemicals maps corresponding to a universe of stimuli and behavioral programs”. Even though one should always consider that there isn’t perfect correspondence between higher-order concepts and putative neural correlates.

In particular, one must consider that what matters in interpersonal relations and in law, to give two examples of practical relevance of free will, is freedom as actually performed: that is, freedom as it can be observed and with some approximation, also measured through a series of psychological tests. This does not mean that the same level of freedom manifested in behavior matches the same level of activation of the related brain areas. However, one can investigate the brain causes of “freedom deficit” compared with the average shown by relevant samples of the population, and so come to a progressive refinement of the research on the neural bases of free will.

Another example is given by the investigation of the role of the cholinergic interneurons in behavioral flexibility (Aoki et al., 2015 ). This class of neurons seem to be connected to survive in an ever-changing world, which requires behaving flexibly. Flexibility can be assessed (and measured) at a behavioral level, but cerebral mechanisms remain largely unknown. Using conventional tests on behavioral flexibility, which require animals to shift their attention from one stimulus property (e.g., color) to another (e.g., shape), researchers probed the effects of an immunotoxin-induced lesion of cholinergic interneurons in the striatum.

A selective cholinergic ablation was made by means of injections of immunotoxin, which targeted neurons containing choline acetyltransferase in the dorsomedial or ventral striatum. A control group was instead injected with saline. “When encountering a change of behavioral rules after the set-shift, either lesion made animals stick to a previously correct but now invalid response strategy. They also showed less exploratory behavior toward finding a new rule. Most interestingly, ablation of cholinergic neurons in the dorsomedial striatum impaired a shift of set when it required attention to a previously irrelevant cue. On the other hand, ventral cholinergic lesions had an effect on a shift in which a novel stimulus was introduced as a new directional cue” (Aoki et al., 2015 ). Animals thus can be taken to be “less free” when striatal cholinergic interneurons don’t work properly.

This last example serves to indicate how to bridge the gap between overt behaviors (to which we tend to attribute the property of freedom) with neuronal mechanisms that are clearly identifiable and even manipulable. In fact, it is not so important to look at the conscious aspect of a single proximal mechanism, but rather to consider the manifest behavioral effect that the considered mechanism helps to produce. This way there would be a paradigm shift with respect to the neuroscience research on free will, which seems to have long been too closely linked to the falsification of the theoretical assumption that an action is free only if it has a beginning that is fully controlled by a conscious process. The proposal, I am making here has only the ambition to be a potentially helpful contribution to theoretical debate and empirical research, although its limits are very clear. First, it focuses on a specific part of what is intuitively called “free will”, relating it to the idea of “capacity”. Second, it proposes to measure free will at a psychological level by means of a unitary index that inevitably misses many nuances of the notion and the relative capacity. Furthermore, the search for the neural correlated of such capacities implies not only the identification of causal mechanisms, but also the consideration of many cerebral areas. All of this makes things harder compared to approaches à la Libet. Nevertheless, there is manifest advantage: there is a greater degree of realism and adherence to the actual behavioral manifestation of what we call “free will”.

Free will is an elusive but crucial concept. For many years we have known that the functioning of our brain has to do not only with the belief that we have free will but also with the existence of free will itself. Evidence of the unconscious start of movement, highlighted by the RP signal, has led to believe that we had reached an experimental proof of the non-existence of free will—which many already claimed at a theoretical level based on the argument of the incompatibility between determinism and freedom. Along with other evidence provided by experimental psychology, the branch of studies inaugurated by Libet has contributed to seeing free will as an illusion: this view seemed to be reliably supported by science, and in particular by neuroscience. Recent studies, however, seem to question this paradigm, which sees the initiation and conscious control of the action as the first requirement of free will, allegedly proving that there are no such things.

The stochastic models and the models of evidence accumulation consider decision as the crossing of a threshold of activity in specific brain regions. They do not restore the idea of conscious control but turn away from the previous paradigm. These studies cannot yet fully explain how the intention to perform an action arises in the brain, but they better account for the complexity of the process. In particular, they recognize the role of the spontaneous activity of the brain, of external cues and other factors—including those that might be called “will” and “reasons” (which, however, do not currently have precisely identified neural correlates)—in reaching the critical threshold. Studies that show how we can consciously block movements whose preparation has already begun unconsciously, then, indicate how the subject is able to exercise a form of control, whose genesis however is still unclear.

One could state that free “decision-making draws upon a rich history of accumulated information, manifested in preferences, attitudes and motivations, and is related to the current internal and external environment in which we act. Complete absence of context is impossible” (Bode et al., 2014 ). In this framework, I have here proposed to integrate neuroscientific research on free will by connecting higher-level concepts with their neural correlates through a psychological operationalization in terms of skills and cognitive functions that do not necessarily imply a continuous conscious control over the decision-making and action process. This may also allow one to create a quantitative index, albeit still quite rudimentary, of the degree of freedom of each subject. This freedom would be specifically defined and therefore may not perfectly coincide with the intuitive concept of free will. Starting from these functional indicators, which psychology has well clarified, one could then move on to investigate the precise neural correlates for a different and (possibly) more fundamental level of explanation in terms of brain processes that enable the executive functions.

According to Craver ( 2007 ), a mechanistic explanation is able to lead to an inter-field integration. There are two relevant aspects to this approach. The functional knowledge that can be drawn from psychological research is a tool to identify neural mechanisms; the knowledge of the brain structure can guide the construction of far more sophisticated psychological models (Bechtel and Mundale, 1999 ). The index of free will that I am proposing (Lavazza and Inglese, 2015 )—despite surely needing further refinement—might be useful to explore the brain mechanisms that underlie what appears in behavior as “free will”, which no longer seems to be an illusion, not even for neuroscientific research.

Author Contributions

AL confirms being the sole contributor of this work and approved it for publication.

Conflict of Interest Statement

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Choice matters: New insights into the philosophy, psychology, theology, and neuroscience of free will

INTRODUCTION

Our lives might be well-described as a rich and endless chain of decisions and consequences: just about everything we do, say, or even think can be described as some form of selection between options (say this or that, stand or don’t stand, pick out this item at the market). But are all those choices really ours — given the exact starting conditions, was everything that happens simply bound to happen? And if so, is choice (and the responsibility for our choices) simply an illusion? Matters of choice, responsibility, and free will have entranced and entangled philosophers, theologians, and scientists for millennia. Questions of free will cut to the heart of what it means to be human, and at times to the very nature of reality itself.

Recent work across many disciplines outlined in this 67-page white paper commissioned by the John Templeton Foundation is offering a few answers — and teasing out new questions as to what free will looks like, both in theory and in practice.

THE METAPHYSICS AND PHILOSOPHY OF FREE WILL

To understand the debates about free will you need to start by defining some key terms.

From a metaphysical perspective, free will is a logic puzzle that hinges on precisely defined terms and well-explored counterfactuals. Philosophers of various bents have explored which understandings of free will are compatible with which understandings of the universe. For some, free will remains a logical impossibility; for others, such freedom exists in forms more rare or attenuated than, say, a libertarian economist or a hard-charging district attorney might want to believe. How much conscious control does someone need to have exercised free will? Is our ability to behave as free agents best thought of not as an on-off switch but as a continuum, where circumstances and other “nudges” may push us towards actions without fully dictating our choices? For free will to be free does it have to appear random from the outside? From a free will perspective, is declining to act another form of action? 

THE NEUROSCIENCE OF FREE WILL (AND FREE WON’T)

In 1983 Benjamin Libet, a professor at the University of California, San Francisco, began publishing a series of pioneering neuroscientific studies testing the claim that conscious internal decisions are the true causes of actions. Using EEGs, Libet’s team watched participants’ brains as they made and acted on simple decisions about when to flex their wrists. Intriguingly, Libet’s tests showed that the participants initiated the process of action about a third of a second before they said that they were  consciously aware of having made the decision to move. This posed a problem for free will: if we start to act before we have decided to do so, how can we say that our actions are the result of our decisions? Libet himself suggested that they weren’t — but that people might still exert a form of control he termed “free won’t” — the ability to consciously override actions that had already been initiated. For decades, Libet’s paradigm has informed other tests of the decision-making process as neuroscientists work to tease out reliable biomarkers for what happens when we make decisions and act on them. Although such results have provided fodder for determinist criticisms of the idea of free will, some critics respond that the Libet paradigm extrapolates too much (“Humans don’t have free will”) from too little (the decision to move one’s wrist), while promoting exacting requirements of free will that have little to do with the ways that everyday people conceive of it. (For instance, the paradigm assumes that conscious awareness of a decision needs to be the first event in the chain of neurological actions in the decision-action process to be relevant.)

THE PSYCHOLOGY OF FREE WILL

How is free will compatible with various concepts of God?

Both the neuroscientific and the philosophical approaches to evaluating free will operate according to exacting terms that would seem to exclude most if not all decisions that a person might make during the course of his life. (How many choices have we made that were unaffected by outside circumstance and influence, or by how we were feeling at the time?). Psychology, for its part, has tended to examine free will at the street level, exploring how we make our choices in the course of life and what circumstances might make them more or less free. 

A large body of psychological studies has examined whether the character trait of self-control might be a proxy for free will. Research shows that our capacity for self-control is not unlimited — if we exercise a lot of self-control completing one task, we will have a harder time immediately tackling another one that also requires self-control. Studies have shown intriguing links between self-control levels and physiological markers including resting heart rate and blood glucose and cortisol levels. Developmental psychology suggests that self-control and responsibility for our actions mature as we develop (which is why we generally assume young children aren’t fully in control of their behavior). All of this raises questions about whether free will — regarded in this context as a spectrum of levels of freedom for conscious deliberation over our choices —  can be strengthened as well as weakened. University of Calgary neuroethicist Walter Glannon has done interesting work on how advances in neuroscience ranging from psychopharmacology to brain-computer interfaces might make individual acts of free will (and corresponding responsibility for those actions) more or less possible .

One of the most significant drivers of free will may be whether a person thinks free will really exists. Research shows that people’s beliefs about free will have been shown to significantly affect their behavior. In one study, participants induced to disbelieve in free will tended to be more likely to conform with others’ actions and judgments. A strong belief in free will has been associated with positive outcomes including life satisfaction, tendencies towards gratitude and forgiveness, and higher reported commitment to relationships. Interestingly, one way to increase people’s belief in free will is to expose them to immoral behavior — this result bears out both in carefully controlled lab settings and in country-level data that shows that countries with higher crime rates report stronger general belief in free will. 

Some psychologists have argued that, despite the exacting work of philosophers and neuroscientists, free will represents a genuine psychological reality, not mere window-dressing for the inevitable actions of physical systems and neurons. Our everyday conscious processes are the result of high levels of integrated self-organization that can be seen as constituting a system of free will atop deterministic elements. Even the challenge of the Libet paradigm, suggesting that conscious intentions don’t initiate our actions, need not cancel the notion of free will. According to that view, the conscious mind isn’t so much competing with unconscious processes as complementing them, in the way that a skilled jazz improviser mixes instinct and honed conscious practice when playing a solo.

STILL CURIOUS?

Read the full white paper, Recent Work on Agency, Freedom, and Responsibility: A Review .

Discover our other research papers on discoveries. Explore topics such as:

• intellectual humility
• positive neuroscience
• benefits of forgiveness
• science of free will
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The Neuroscience of Free Will

Can science set us free, new $5.34 million grant to examine the neuroscience of free will.

Think about a decision you’ve made — a big one like where to go to college, or a tiny one like whether to pick up your phone. People take for […]

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