Why does anyone become a libertarian? Suppose someone becomes an incompatibilist, because she is convinced by the consequence argument (or the direct argument, or the manipulation argument, or the zygote argument, or whatever). Why would she combine her incompatibilism with the belief that free will is actual? In other words, why would anyone ever endorse the following argument?
(1) If we have free will, the universe is (appropriately) indeterministic.
(2) We have free will.
(3) The universe is (appropriately) undeterministic.
Whatever else one might think of this argument, surely – surely – this is a really bad way to do physics. Why would anyone think we can uncover the causal structure of the universe in this kind of way?
But maybe we can. Obviously, the heavy lifting is being done by premise (2) (reject that premise and you’re not a libertarian). We’re supposing that incompatibilism is true, so if premise (2) is also true, the conclusion follows. This would be a prima facie odd result, I think: it would remain odd that we can physics in this kind of way. But the argument seems sound.
Perhaps, though, the oddity of the result counts against the plausibility of (2). In any case, what reason do we have for believing that (2) is true? As I understand things, the main reason that libertarians give for the truth of (2) is experiential. Here are some quotations, lifted from Nahmias, Morris, Nadelhoffer and Turner:
C.A. Campbell writes: ‘Everyone must make the introspective experiment for himself: but I may perhaps venture to report . . .that I cannot help believing that it lies with me here and now, quite absolutely, which of two genuinely open possibilities I adopt’ (1951, p. 463). Keith Lehrer says that such an experience ‘accurately describes what I find by introspecting,and I cannot believe that others do not find the same’ (1960, p. 150). And John Searle asks his readers to ‘reflect very carefully on the character of the experiences you have as you engage in normal, everyday human actions’ and tells them, ‘You will sense the possibility of alternative courses of action built into these experiences . . . that we could be doing something else right here and now, that is, all other conditions remaining the same. This, I submit, is the source of our own unshakable conviction of our own free will’ (1984, p. 95).
In their paper, Nahmias et al. take issue with the libertarian description of the phenomenology of action, and call for a more detailed investigation. I have a different view. I don’t much care what the phenomenology of action is (in this context), because I doubt very much that careful attention to this phenomenology can bear on premise (2). We have no reason to think that the content of our phenomenology can give us evidence about the causal structure of the universe, because we have no reason to think that the phenomenology is veridical.
This view is an induction from the enormous psychological literature on our limited and unreliable access to our mental states generally, bolstered by work (by philosophers like Eric Schwitzgebel) showing that the same sorts of problems seem to beset our access to our own experience. People commonly misreport their own experiences. We don’t even have good insight into how much fun we are having or even whether an experience we are having at a particular moment in time is pleasant or unpleasant. Some examples (among many): being paid a paltry sum to tell another person that the boring and repetitive task in which we have just engaged is fun leads us to think we enjoyed it (Festinger & Carlsmith 1959); observing that we have chosen one item from a range that seems identical leads us to conclude that we have detected differences between them (Nisbett & Wilson 1977). Subjects who experienced arousal caused by an injection of norepinepherine reporting being happy or angry, depending on what cues they’re given (Schachter and Singer 1962), while subjects who exercise prior to encountering an opposite sex confederate of the experimenters rated the confederate more attractive (Allen 1989). We are systematically bad at assessing the causes and the precise character of our experiences. Moreover, there is evidence that our intuitive physics is unreliable. Naïve subjects assume, falsely, that an object that is travelling through a curved tube will continue to follow a curved trajectory when it leaves the tube (McCloskey et al. 1980).
Given the gamut of evidence for the claim that experience is unreliable, and given the oddity of the claim that we can do physics from the armchair, I think libertarianism (supported by this argument, at any rate) is in trouble. Lots of people think that libertarianism is unscientific. What they usually have in mind is that it ignores brain science in favor of wishful thinking. My complaint here is a related one: though libertarians like Robert Kane have done important work showing how (just possibly) libertarian free will could be implemented in the brain, they have not faced up to how their view relies for its plausibility on the implausible assumption that we have good reason to take our experience to be veridical.