5.5.3 Libertarian Free Will and the Sciences


By the end of this section you will discover:

  • The standard tenets of the Libertarian Free Will position.
  • How the experiments of the neuroscientist Libet seemed to challenge these, but how the philosopher Mele attempted to refute Libet’s conclusions.
  • How the work of sociologist Stanley Milgram seemed to argue against Libertarian Free Will.
  • Arguments suggesting how Libertarian Free Will might be possible, including the arguments from philosopher Roderick Chisholm about event causation and agent causation.
  • Strengths and Weaknesses of the Libertarian Free Will position.

Libertarian free will is a philosophical position on free will that argues that we have genuine free choice in at least some of our decisions and actions. The key tenets of libertarian free will are:

  1. Indeterminism – At the moment of choice, there are multiple possible outcomes that are all consistent with the past and the laws of physics up until that moment. Our choices are not entirely fixed by prior causes.
  2. Agent Causation – When we make a choice from among the possible options available to us, we as conscious agents are able to originate the choice. Our choices are determined by the agent (our self, soul, etc.) rather than just physical causes.
  3. Moral Responsibility – Because we have this power of free choice not predetermined by external causes, we bear ultimate moral responsibility for our choices and actions. We are blameworthy or praiseworthy since we could have chosen otherwise.
  4. Fundamental Mystery – The powers of agent causation and origination of choices remain mysterious and do not necessarily operate according to physical laws governing matter. Conscious choice involves extra causation not described by most modern science.

Thus libertarianism argues for a genuine openness and self-determination to human decision-making – we have free will not just complex reactions to external and internal stimuli fully explained by deterministic chains of physical cause-and-effect. Our uncaused self-caused choices ground moral responsibility.

In what follows, ask:

What challenges to freedom have come from Libet’s experiments in contemporary neuroscience?

The classic studies arguing against Libertarian Free Will  and suggesting that all human action is the inevitable outcome of unconscious brain processes which are doing the bulk of the causal work for action were conducted by Benjamin Libet. Libet’s experiments involved subjects being asked to flex their wrists whenever they felt the urge to do so. Subjects were asked to note the location of a clock hand on a modified clock when they became aware of the urge to act. While doing this, EEG technology scanned their brain activity. What Libet noted is that around 550 milliseconds before a subject acted, a readiness potential (increased brain activity) would be measured by the EEG technology. But subjects were reporting awareness of an urge to flex their wrist around 200 milliseconds before they acted.

This painted a strange picture of human action. If conscious intentions were the cause of our actions, you may expect to see a causal story in which the conscious awareness of an urge to flex your wrist shows up first, then a ramping up of brain activity, and finally an action. But Libet’s studies showed a causal story in which an action starts with unconscious brain activity, the subject later becomes consciously aware that they are about to act, and then the action happens. The conscious awareness of action seemed to be a byproduct of the actual unconscious process that was causing the action. It was not the cause of the action itself. And this result suggests that unconscious brain processes, not conscious ones, are the real causes of our actions. To the extent that free action requires our conscious decisions to be the initiating causes of our actions, it looks like we may never act freely.

What are Mele’s arguments against Libet’s conclusions?

While this research is intriguing, it probably does not establish that we are not free. Alfred Mele is a philosopher who has been heavily critical of these studies. He raises three main objections to the conclusions drawn from these arguments.

First, Mele points out that self-reports are notoriously unreliable (2009, 60-64). Conscious perception takes time, and we are talking about milliseconds. The actual location of the clock hand is probably much closer to 550 milliseconds when the agent “intends” or has the “urge” to act than it is to 200 milliseconds. So, there are some concerns about experimental design here.

Second, an assumption behind these experiments is that what is going on at 550 milliseconds is that a decision is being made to flex the wrist (Mele 2014, 11). We might challenge this assumption. Libet ran some variants of his experiment in which he asked subjects to prepare to flex their wrist but to stop themselves from doing so. So, basically, subjects simply sat there in the chair and did nothing. Libet interpreted the results of these experiments to mean that we might not have a free will, but we certainly have a “free won’t” because we seem capable of consciously vetoing or stopping an action, even if that action might be initiated by unconscious processes (2014, 12-13). Mele points out Finally, Mele notes that while it may be the case that some of our decisions and actions look like the wrist-flicking actions Libet was studying, it is doubtful that all or even most of our decisions are like this (2014, 15). When we think about free will, we rarely think of actions like wrist-flicking. Free actions are typically much more complex and they are often the kind of thing where the decision to do something extends across time. For example, your decision about what to major in at college or even where to study was probably made over a period of months, even years. And that decision probably involved periods of both conscious and unconscious cognition. Why think that a free choice cannot involve some components that are unconscious?

How have experiments in the social sciences, like Milgram’s work on obedience, challenged the notion that we have free will?

A separate line of attack on free will comes from the situationist literature in the social sciences (particularly social psychology). There is a growing body of research suggesting that situational and environmental factors profoundly influence human behavior, perhaps in ways that undermine free will.

Many of the experiments in the situationist literature are among the most vivid and disturbing in all of social psychology. Stanley Milgram, for example, conducted a series of experiments on obedience in which ordinary people were asked to administer potentially lethal voltages of electricity to an innocent subject in order to advance scientific research, and the vast majority of people did so! And in Milgram’s experiments, what affected whether or not subjects were willing to administer the shocks were minor, seemingly insignificant environmental factors such as whether the person running the experiment looked professional or not.

What experiments like Milgram’s obedience experiments might show is that it is our situations and our environments that are the real causes of our actions, not our conscious, reflective choices. And this may pose a threat to free will. Should we take this kind of research as threatening freedom?

How might one object that these experiments are evidence against freedom?

Many philosophers would resist concluding that free will does not exist on the basis of these kinds of experiments. Typically, not everyone who takes part in situationist studies is unable to resist the situational influences they are subject to. And it appears to be the case that when we are aware of situational influences, we are more likely to resist them. Perhaps the right way to think about this research is that there are all sorts of situations that can influence us in ways that we may not consciously endorse, but nonetheless, we are still capable of avoiding these effects when we are actively trying to do so. For example, the brain sciences have made many of us vividly aware of a whole host of cognitive biases and situational influences that humans are typically subject to and yet when we are aware of these influences, we are less susceptible to them. The more modest conclusion to draw here is not that we lack free will, but that exercising control over our actions is much more difficult than many of us believe it to be. We are certainly influenced by the world we are a part of, but to be influenced by the world is different from being determined by it, and this may allow us to, at least sometimes, exercise some control over the actions we perform.

No one knows yet whether or not humans sometimes exercise the control over their actions required for moral responsibility. And so I leave it to you, dear reader: Are you free?   (Daniel Haas, “Freedom of the Will,” Ch. 8 in Salazar, et.al2).

Libertarianism: How Freedom might Work?

As we’ve now seen, the arguments for determinism can be quite powerful.  And despite compatibilist arguments that determinism is compatible with freedom, discomfort often remains.  To many, there still seems to be a way in which we’re free that is incompatible with determinism.  As noted above, those who claim that we are free, and who reject determinism, are called libertarians (not to be confused with the political ideology of the same name).

But how might libertarianism work?  How could we make free choices in this world?  In this final section, we’re going to explore, briefly, one influential set of answers to these questions, the answer proposed by Roderick Chisholm (1916 – 1999).  Here is a very brief summary of Chisholm’s approach presented by contemporary philosophers Fred Feldman & Richard Feldman:

One essential element of Chisholm’s view is the idea that there is a distinction between event causation and agent causation.  In cases exclusively involving event causation, everything that causally contributes to an event is another event.  In cases involving agent causation, among the things that causally contribute to an event is a person.  In virtue of this feature.  Chisholm’s view is generally categorized as a form of libertarianism.  Another essential element of his view is the idea that when a person acts freely, he does something for which there is no event or state or combination of events or states that is a sufficient causal condition for his doing it.  (There is also no event or state that is a sufficient causal condition for his failure to do it, obviously.) In virtue of this feature of his view, it may be seen as incorporating an element of indeterminism. (SEP, “Roderick Chisholm,” Section 6).

In his 1964 Lindley Lecture at the University of Kansas, “Human Freedom and the Self,” Chisholm saw free will as a metaphysical problem. He asserts that a man who performs an act is completely free and uncaused:

The metaphysical problem of human freedom might be summarized in the following way: “Human beings are responsible agents; but this fact appears to conflict with a deterministic view of human action (the view that every event that is involved in an act is caused by some other event); and it also appears to conflict with an indeterministic view of human action (the view that the act, or some event that is essential to the act, is not caused at all).” To solve the problem, I believe, we must make somewhat far-reaching assumptions about the self of the agent — about the man who performs the act.Perhaps it is needless to remark that, in all likelihood, it is impossible to say anything significant about this ancient problem that has not been said before.  (“Human freedom and the self,” The Lindley Lecture, reprinted in Free Will, Gary Watson, ed., 2003; excerpted from: https://www.informationphilosopher.com/solutions/philosophers/chisholm/).

Chisholm says the agent must be able to perform an act and also able not to perform it, he or she could have done otherwise.

Let us consider some deed, or misdeed, that may be attributed to a responsible agent: one man, say, shot another. If the man was responsible for what he did, then, I would urge, what was to happen at the time of the shooting was something that was entirely up to the man himself. There was a moment at which it was true, both that he could have fired the shot and also that he could have refrained from firing it. And if this is so, then, even though he did fire it, he could have done something else instead. (He didn’t find himself firing the shot “against his will,” as we say.) I think we can say, more generally, then, that if a man is responsible for a certain event or a certain state of affairs (in our example, the shooting of another man), then that event or state of affairs was brought about by some act of his, and the act was something that was in his power either to perform or not to perform.  (ibid.)

Roughly, that is, Chisholm argued that there are two kinds of causation at play in the world; event causation and agent causation.

  1. When one billiard ball strikes another billiard ball, for example, the striking causes (event-causation) the second billiard ball to go off in whatever direction, based on the materials out of which the balls are constructed, the direction and momentum of the first billiard ball, the surface on which they lie, etc.. When determinists discuss causation, this is what they have in mind, i.e. event-causation, i.e. when one event (e.g. one billiard ball striking another) causes another event (the struck billiard ball’s motion).  But, according to Chisholm, this is not the only kind of causation that exists.  There is also agent causation, which is when an agent (e.g. a person) causes something to happen.  Event causation always proceeds in accordance with deterministic laws of nature.
  2. Agent causation is different.  Agents (like us) are unique in the world.  At least sometimes, when an agent chooses, they do so freely and are not determined.  Our environment, even our beliefs, and desires can incline us to make certain choices, but ultimately, what we do is (often, at least) up to us, i.e. it is caused by the person themselves and not the forces operating upon them.  Each of us, according to Chisholm, is a source of (potentially miraculous) intervention into the broader, event-causal order.

Chisholm doesn’t attempt to explain how agent causation works, at least not in any detail, but he argues that that is a featureof the way things are.  Agent causation is supposed to be a primitive force in the world, not explicable in other, more fundamental terms. This is another example – like the substance dualism discussed earlier – of metaphysicians attempting to explain what things might have to be like if we want to hold onto the common idea that we are fundamentally unlike rocks and trees and gerbils and everything else in the natural world.  “Something’s gotta give,” in terms of what we can rationally believe about ourselves and our world, and it’s up to future metaphysicians (like you!) to figure out which accounts are most likely to be correct.

Strengths and Weaknesses of the Libertarian Free Will position.

Here are some key strengths and weaknesses of the libertarian freedom position in the free will debate:


  1. Aligns with our subjective feeling of free will and ability to have chosen differently.
  2. Provides strong grounds for moral responsibility if we freely choose actions.
  3. Allows for genuine creativity, dignity, and meaning if choices are not fixed by determinism.
  4. Explains consciousness as a platform for free will requiring indeterminism in the brain.


  1. Conflicts with deterministic physics that some interpret to leave no room for free choice.
  2. Unclear how indeterminism would allow free will rather than just randomness.
  3. Threatens predictability and rationality of behavior if choices are not caused by reasons and character.
  4. Requires a ghost in the machine – extra causation from consciousness outside normal physics.
  5. Still leaves problems of fate, luck, and external limitation on choices.

So in summary, libertarian free will matches many ethical and existential hopes about human freedom and dignity. But has conflict with scientific worldviews seeking physical causes. Difficult philosophical work remains to reconcile human experience of choice with modern science.


Works Cited

Feldman, Richard, and Fred Feldman. “Roderick Chisholm.” Stanford Encyclopedia of Philosophy, Stanford University, 3 July 2019, https://plato.stanford.edu/archives/sum2021/entries/chisholm/#MetIIAgeFreWilPro0.


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PPSC PHI 1011: The Philosopher's Quest by Daniel G. Shaw, Ph.D. is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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