Phil 101: Libertarianism

Suppose we abandon Compatibilism and instead become Incompatibilists. What are our options then?

Libertarians, recall, are Incompatibilists who think that we have free will and hence that Determinism is false.

A Challenge for the Libertarian

The simplest kind of Libertarian thinks that our acts and choices are free because they are uncaused. In his book Metaphysics, Richard Taylor calls this view “Simple Indeterminism” (see pp. 47ff. of our reading).

A problem for this kind of Libertarian is the following. (This has aleeady shown up in several of our readings, including Williams pp. 35-6, van Inwagen pp. 192-3, and Kane p. 470 of the earlier reading, and pp. 35-38 of the longer reading.)

To say that our acts and choices are uncaused makes it sound like they are random and arbitrary. But if they are, then how could we be held responsible for them? Suppose Arnold is strapped into a machine which has a 50% chance of making him shoot a gun to the left, and a 50% chance of making him shoot the gun to the right. Surely in this case Arnold is not responsible for which way the gun shoots. He’s at the whim of chance. And why should we be any more responsible if the randomness is located inside our heads, rather than in some machine that we’re strapped into? Suppose there’s an electric pulse travelling through my brain. When it hits a certain nerve, it will either go to the left or to the right. It has a 50% chance of going either way. If it goes to the left I will perform one act, and if it goes to the right I will perform another. I’m no more in control, in this case, than Arnold is. There’s no way for me to influence the pulse, to make it go one way rather than the other. For we said that nothing causes the pulse to go in the way it does. If it goes to the left, that just happens; and if it goes to the right, that just happens, too. I have no choice in the matter. I’m at the whim of chance, just like Arnold is.

Hence, if this kind of Libertarian view is correct, it’s hard to see how I could be any more morally responsible for my actions than I would be if all those actions were causally determined.

(Some philosophers put this argument by saying: Moral responsibility requires that you were in control of what happened, but without the outcome being causally determined, nothing and nobody was in control. So Responsibility and Free Action require Determinism. The Compatibilists will put this by saying “See, they require Determinism, rather than being incompatible with it.” Other philosophers might put it by saying “They require Determinism, and as we argued before, they’re also incompatible with it. That shows how impossible and confused our ideas of Responsibility and Free Action are.”)

How Will Libertarian Respond?

Most Libertarians agree that it’s not enough for them merely to say that our acts and choices are causally undetermined. That by itself doesn’t make something up to us or under our control.

They have to tell some story about how some causally undetermined actions get to be under our control. What is special about them, that distinguishes them from random arbitrary events like we above imagined happening in Arnold’s brain?

Different Libertarians tell different stories about this.

One central story, which we’ll focus on, is called Agent-Causation Theory. This was first proposed by Thomas Reid in the late 1700s, and then developed and defended by Richard Taylor and Roderick Chisholm in the 1960s. Nowadays it has other contemporary advocates.

It’s not the only Libertarian story out there. At the end of our (third, complete) van Inwagen selection, he says that although he wants to be a Libertarian, he finds neither the Simple Indeterminist view described above, nor Agent-Causation Theory, to be satisfying. Kane, who we’ve been reading selections from, has a different kind of account (the details of which we’re not exploring).

But the Agent-Causation Theory was historically important and still plays a central role in the discussion. Other forms of Libertarianism define themself largely by explaining how they’re different from it.

Agent-Causation Theories Explained

As I said, Taylor is an Agent-Causation Theorist, though in our reading he calls this view the “Theory of Agency.” He writes:

In the case of an action that is free, it must not only be such that it is caused by the agent who performs it, but also such that no antecedent conditions were sufficient for his performing just that action. In the case of an action that is both free and rational, it must be such that the agent who performed it did so for some reason, but this reason cannot have been the cause of it… When I believe that I have done something, I do believe that it was I who caused it to be done, I who made something happen, and not merely something within me, such as one of my own subjective states, which is not identical with myself. If I believe that something not identical with myself was the case of my behavior — some event wholly external to myself, for instance, or even one internal to myself, such as a nerve impulse, volition, or whatnot — then I cannot regard that behavior as being an act of mine, unless I further believe that I was the cause of that external or internal event. (p. 51)

In class, we spent some time sketching out a Philosopher’s Map of Reality. One of our take-aways from that exercise was that philosophers primarily think of causation as a relation between events or happenings. One thing’s happening causes other events to happen. The dog’s running into the table caused the bowl to fall off and clatter when it hit the floor. Sometimes we might talk as if things other than events were causes. For example, we might say that the flower bomb made the room smell and look festive. The flower bomb is a thing, not an event. But on reflection, in these cases we should also say it was something’s happening—the flower bomb exploding and throwing its flowers everywhere—that made the room smell and look festive. Fundamentally, causing is a way that some events are related to other events.

As we’ve said a few times in class, and some of our authors also observe, it’s possible to separate the notion of causation from the idea of causal determinism. Arguably it makes sense to talk about causation even in a world where the causes don’t guarantee their outcomes, but merely make them very likely to occur. Whether causation is understood deterministically or not, most philosophers would still think it’s something that fundamentally relates events.

The Agent-Causation Theorists reject this. Sometimes events cause other events. But they think sometimes there is a different kind of causation, too. This is the kind of causing where God created the universe and everything happening within it, just by exercising their will, not because anything happened that caused them to do so. Or the kind of causing where, as I described in class, all the billiard balls are sitting still on the table, and one billiard ball just starts moving itself. It’s not that the ball just randomly starts moving. Rather, the ball makes itself move. In the Agent-Causation Theorist’s picture, every agent making free choices is like God and that billiard ball. The agent themselves cause their acts and choices, without being caused to do so by any earlier events that took place. The agent makes them occur, without any thing/event making them do so.

Evaluating these Theories

Agent-Causation Theories are interesting. They may better capture some of your intuitions about free will than any of the other options we’ve looked at so far. We don’t here have the time or yet have enough sophisticated background to get very deeply into the arguments for and against these theories. I will just briefly sketch a few difficulties they need to address.

  1. The Agent-Causation Theorist says that whenever someone makes a free choice, she starts a new causal chain which was not present in the universe before she made her choice. Hence we can, in principle, test the hypothesis that there is agent-causation. Suppose we lock you in a room, and we have scientists monitor the behavior of all the particles and energy fields in the room, including the neurochemical activity in your brain. At a certain moment, you freely choose to raise your hand. Whoa! That should send the scientists scurrying. Because all of a sudden there are new causal processes going on in the room, which weren’t caused by any event that was going on in the room beforehand. Your arm is going up, it’s moving air molecules, it’s reflecting light in new ways. According to the Agent-Causation Theorist, none of these processes were caused to happen by the events that preceded your choosing to raise your arm.

    Does it really seem plausible that the scientists would notice new causal processes of this sort? If so, we’ll have to scrap science as we currently know it, and start over. Because science as we currently know it tries to explain how the world evolves, by treating the entire world, including our bodies, as a closed system. Scientists don’t think that any “new” causal chains get introduced into the world every time an agent makes a free choice. Hence, from a scientific standpoint, the view that there’s such a thing as agent-causation looks rather dubious.

    As we mentioned in an earlier class, our current best quantum physics does involve probabilities rather than saying “in such-and-such circumstances, so-and-so is guaranteed to happen.” It’s controversial how these probabilities should be understood, but many theorists think they reflect the future not being settled or determined by what came before. Some Agent-Causation Theorists argue that this gives enough room for agent-causings to fit into the scientist’s picture of the world. That idea deserves to be discussed, but it is speculative and involves some hopeful assumptions. As Daniel complains in the Williams dialogue, “Scientists haven’t shown that the uncaused activities of subatomic particles produce our free actions” (pp. 10-11).

    Here is Pereboom (in a passage omitted from our course reading) also complaining that Agent-Causation Theory conflicts with science, whether we understand the world to be Deterministic or not:

    [A]gent-causal libertarians claim that we possess a special causal power—a power for an agent, fundamentally as a substance, to cause a decision without being causally determined to do so. The proposal is that if Anne had this power, by exercising it she would be able to settle which of the two competing decisions occurs—both of which remain as open possibilities given only the causal role of the events. In this way she could be morally responsible for her decision.

    But can agent-causal libertarianism be reconciled with what we would expect given our best physical theories? If the agent-causal position is true, then when an agent makes a free decision, she causes the decision without being causally determined to do so. On the path to action that results from this undetermined decision, changes in the physical world, for example in the agent’s brain or some other part of her body, are produced. But if the physical world were generally governed by deterministic laws, it seems that here we would encounter divergences from these laws. For the changes in the physical world that result from the undetermined decision would themselves not be causally determined, and they would thus not be governed by the deterministic laws. One might object that it is possible that the physical changes that result from every free decision just happen to dovetail with what could in principle be predicted on the basis of the deterministic laws, so nothing actually happens that diverges from these laws… But this proposal would seem to involve coincidences too wild to be believed. For this reason, agent-causal libertarianism is not plausibly reconciled with the physical world’s being governed by deterministic laws.

    On the standard interpretation of quantum mechanics, however, the physical world is not in fact deterministic, but is rather governed by probabilistic statistical laws. Some philosophers have defended the claim that agent-causal libertarianism can be reconciled with physical laws of this sort… However, wild coincidences would also arise on this suggestion. Consider the class of possible actions each of which has a physical component whose antecedent probability of occurring is approximately 0.32. It would not violate the statistical laws in the sense of being logically incompatible with them if, for a large number of instances, the physical components in this class were not actually realized close to 32% of the time. Rather, the force of the statistical law is that for a large number of instances it is correct to expect physical components in this class to be realized close to 32% of the time. Are free choices on the agent-causal libertarian model compatible with what the statistical law leads us to expect about them? If they were, then for a large enough number of instances the possible actions in our class would almost certainly be freely chosen close to 32% of the time. But if the occurrence of these physical components were settled by the choices of agent-causes, then their actually being chosen close to 32% of the time would amount to a wild coincidence. The proposal that agent-caused free choices do not diverge from what the statistical laws predict for the physical components of our actions would run so sharply counter to what we would expect as to make it incredible.

    For more on this issue, here is a selection from Chapter 1 of Kane’s introductory book. Kane himself wants to give a kind of Libertarian story that appeals to quantum indeterminacies. But in this selection he explains the challenges for doing so.

  1. When John raises his hand, science tells us that the hand motion was caused (perhaps deterministically, perhaps not) by events in John’s brain. Maybe the Agent-Causation Theorist should accept this. He just thinks that John himself also did some causing. What is the relation between the brain events and John’s alleged agent-causation? Did they both cause the hand to be raised? Wouldn’t that make the hand-raising be “overcaused” in some sense? (We’ll revisit this idea in a few classes.) Or was it rather that what John agent-caused was his brain events, and not the hand-raising itself? But intuitively, John didn’t do anything to his brain. He needn’t even know that he has a brain. It’s not clear that there’s any satisfying position here for the Agent-Causation Theorist to occupy.

There are also more subtle philosophical difficulties with the Agent-Causation Theory. These make it unclear whether the notion of an agent’s causing something to happen, independently of all earlier events, even makes sense. Some of these difficulties are:

  1. What does an agent’s causing event X consist in? What is the difference between X’s just happening, randomly, and the agent’s causing X to happen? What is it about the agent that makes a difference? The agent’s mere existence usually won’t suffice to bring X about. It seems that no additional event can be what makes the difference either: else X would be caused by that event, rather than by the agent. It looks like the Agent-Causation Theorist has to say that the difference between X’s just happening and the agent’s causing X to happen is primitive, and cannot be further explained. Some philosophers are willing to live with that, but many find it unsatisfying.

  2. Suppose John agent-causes X to happen. Now consider the event J: John’s becoming an agent-cause of X. Is there any such event J? Was J causally determined to happen? If it was, then X would probably end up being determined too, and so John could not have done X freely. So we should assume that J was not causally determined.

    But now consider: did John have any choice about whether J occurred? If not, then it’s hard to see how he had any choice about doing X. So John should have a choice about whether J occurred. Now does that mean that he had to agent-cause J, too? That is, he had to agent-cause his becoming an agent-cause of X? Won’t the problem we’re now considering then just repeat itself, at the next level further back?