A few people have responded to my 2007 PPR paper, “Is Incompatibilism Intuitive?” co-authored with Stephen Morris, Thomas Nadelhoffer, and Jason Turner. But most of the responses have focused on the experimental results that suggested incompatibilism is not as intuitive to non-philosophers as incompatibilists have claimed. While I (unsurprisingly) think these results are illuminating, I also think that the more interesting parts of that paper came before and after the discussion of the experiments themselves. And I don’t think anyone has responded to the arguments we offer in those parts--perhaps illustrating that I’m wrong about those arguments being interesting, but I’ll be charitable and hope that it’s because those arguments were drowned by the flood of excitement about the experiments. ;-}
In any case, Shaun Nichols asked me recently if anyone had a response to our (interrelated) arguments that the burden of proof should be on incompatibilists (rather than compatiblists) and that there is little reason to accept libertarians’ more demanding conditions for free will unless they are motivated by widespread intuitions supporting them. I am hoping some of you might offer food for thought about these arguments. Below I have cut from pp. 30-33 of the article to summarize some of these arguments. I would love to hear where people think we went wrong (or right).
[After showing that incompatibilists have tended to claim their view is commonsensical and compatibilism is counterintuitive and then explaining why we think ordinary intuitions matter to the free will debate, we say…]
It is especially important for incompatibilists that their view is supported by ordinary intuitions for the following three reasons. First, incompatibilism about any two concepts is not the default view. As William Lycan explains, “A theorist who maintains of something that is not obviously impossible that nonetheless that thing is impossible owes us an argument” (2003: 109). Either determinism obviously precludes free will or those who maintain that it does should offer an explanation as to why it does. The philosophical conception of determinism—i.e., that the laws of nature and state of the universe at one time entail the state of the universe at later times—has no obvious conceptual or logical bearing on human freedom and responsibility. So, by claiming that determinism necessarily precludes the existence of free will, incompatibilists thereby assume the argumentative burden.[note 1]
Second, the arguments that incompatibilists accordingly provide to explain why determinism necessarily precludes free will require conceptions of free will that are more metaphysically demanding than compatibilist alternatives. These libertarian conceptions demand more of the world in order for free will to exist: at a minimum, indeterministic event-causal processes at the right place in the human agent, and often, additionally, agent causation. To point out that incompatibilist theories are metaphysically demanding is not to suggest that they are thereby less likely to be true. Rather, it is simply to say that these theories require more motivation than less metaphysically demanding ones.
Consider an example. Suppose two philosophers—Hal and Dave—are debating what it takes for something to be an action. Hal claims that actions are events caused (in the right sort of way) by beliefs and desires. Dave agrees, but adds the further condition that the token beliefs and desires that cause an action cannot be identical to anything physical. Now Dave, by adding this condition, does not thereby commit himself to the claim that token beliefs and desires are not physical. But he does commit himself to the conditional claim that token beliefs and desires are not physical if there are any actions. On our view, if T1 and T2 are both theories of x, then to say that T1 is more metaphysically demanding than T2 is to say that T1 requires more metaphysical theses to be true than T2 does in order for there to be any x’s. So, Dave’s theory is more metaphysically demanding than Hal’s because it requires more metaphysical theses to be true in order for there to be any actions. Likewise, incompatibilists—whether libertarians or skeptics—have more metaphysically demanding theories than compatibilists since they say that special kinds of causation (indeterministic or agent-causation) must obtain if there are any free actions.[note 2]
Since incompatibilist theories of free will say the existence of free will is incompatible with determinism, these theories, other things being equal, will be harder to motivate than compatibilist theories, which do not require the existence of extra metaphysical processes, such as indeterminism or agent causation, in order for free actions to be possible. As we’ve seen, many incompatibilists have attempted to motivate their metaphysically demanding theories, at least in part, by suggesting that other things are not equal, because our ordinary intuitions support incompatibilist views. This is not to say that incompatibilists must appeal to such intuitions in order to motivate their demanding theories (see §§4.2-4.3 below). Nonetheless, it is certainly unclear why, without wide-scale intuitive support for incompatibilism, the argumentative burden would be on compatibilists, as suggested by Ekstrom when she claims that the compatibilist “needs a positive argument in favor of the compatibility thesis” (2000: 57) and by Kane above [“Ordinary persons have to be talked out of this natural incompatibilism by the clever arguments of philosophers” (1999: 217).]
Finally, if it were shown that people have intuitions that in fact support incompatibilism, it would still be open to foes of incompatibilism to argue that, relative to ordinary conceptions of freedom and responsibility, their view is a benign revision towards a more metaphysically tenable theory.[note 3] Incompatibilists, on the other hand, do not seem to have this move available to them in the event that their view is inconsistent with pre-philosophical intuitions. After all, it is difficult to see why philosophers should revise the concept of free will to make it more metaphysically demanding than required by ordinary intuitions (see §4.3).[note 4] So, if incompatibilism is not the intuitive view, or if no premises that support incompatibilist conclusions are particularly intuitive, then there seems to be little motivation for advancing an incompatibilist theory of free will.
 See Warfield (2000) for an explanation of why the proper incompatibilist view is not the contingent claim, “If determinism is true then there is no freedom,” but the stronger claim, “Necessarily, if determinism is true then there is no freedom” (169). See also Chalmers (1996) who writes, “In general, a certain burden of proof lies on those who claim that a certain description is logically impossible…. If no reasonable analysis of the terms in question points towards a contradiction, or even makes the existence of a contradiction plausible, then there is a natural assumption in favor of logical possibility” (96).
 Even though hard determinists or skeptics about free will are not committed to the existence of libertarian free will, they are committed to the libertarian conception of free will since their arguments require this conception to reach the conclusion that free will does not (or could not) exist. Hence, skeptics, like libertarians, require motivation for the accuracy of this conception, and they often do so by suggesting that incompatibilism is the commonsensical or intuitive view (see, for instance, Strawson 1986 and Smilansky 2003).
 See Vargas (forthcoming). Compatibilists may also be better situated to offer error theories to explain why people sometimes express incompatibilist intuitions even though this need not commit them to incompatibilist theories. See, for instance, Velleman (2000) and Graham and Horgan (1998).
 There is a fourth reason that some incompatibilists should want their view to be intuitive to ordinary people. Peter Strawson (1962) offered a compatibilist argument to the effect that we cannot and should not attempt to provide metaphysical justifications for our practices of moral responsibility (e.g., praise and blame), which are grounded in reactive attitudes such as indignation and gratitude. He suggested such practices are subject to justifications and revisions based only on considerations internal to the relevant practices and attitudes, but not on considerations external to the practice, including, in his view, determinism. But incompatibilists, notably Galen Strawson, have responded to this argument by suggesting that the question of determinism is not external to our considerations of moral responsibility (see also Pereboom 2001). That is, they claim that our reactive attitudes themselves are sensitive to whether human actions are deterministically caused. As Galen Strawson puts it, the fact that “the basic incompatibilist intuition that determinism is incompatible with freedom … has such power for us is as much a natural fact about cogitative beings like ourselves as is the fact of our quite unreflective commitment to the reactive attitudes. What is more, the roots of the incompatibilist intuition lie deep in the very reactive attitudes that are invoked in order to undercut it. The reactive attitudes enshrine the incompatibilist intuition” (1986: 88). If it turned out that this claim is false—that most people’s reactive attitudes are not in fact sensitive to considerations of determinism—then this particular incompatibilist response to the elder Strawson’s argument would fail. While there are other responses to Peter Strawson’s views, we interpret some of the claims that incompatibilism is intuitive as attempts to shore up this response that our ordinary reactive attitudes and attributions of moral responsibility are sensitive to determinism. And we accordingly view any evidence to the contrary as strengthening Peter Strawson’s suggestion that determinism is irrelevant to debates about freedom and responsibility and, accordingly, as weakening incompatibilism.