Is the burden of proof on incompatibilists?

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.

FOOTNOTES

[1] 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).

[2] 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).

[3] 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).

[4] 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.

Comments

[Kevin Timpe]

Eddy,

For what it's worth, I agree with you on the burden of proof issue here. I deal with this issue a bit at the end of the first chapter of my book. In particular, I agree with first reason that you give (or adopt from Lycan). I'd also agree with you on the second point that more metaphysically demanding theories require more motivation than less demanding ones (though I think that there are good arguments that provide that motivation, just as I think there are good arguments for incompatibilism. I doubt that you feel the same way about them, but that is another issue).

I'm not as persuaded by the third reason you give, however, as I don't see why there cannot be philosophical concepts that are justifiably more demanding than required by ordinary intuitions. Here I am thinking of cases where an ordinary intuition might be 'close enough to true' to work in many facets of life, but that argument or counterexample show to not be demanding enough to carry the philosophical load they are expected to carry.

[Justin Coates]

Hi Eddy,

I think I'm in agreement with Kevin about the third reason your offer. After all, if it turned out that the folk conception of knowledge wasn't factive, we might still prefer a more demanding concept--in this case, an account of knowledge that's factive. If our aim in conceptual analysis isn't merely to systematize common sense intuitions but also, to explicate technical concepts that can do some theoretical heavy lifting, then we might favor more metaphysically demanding concepts in our theories of knowledge or even free will. Luckily for us, in the latter case, the less metaphysically demanding theory will do the job.

[Mike from MI]

Whether there is a burden of proof at all depends on whether the question is theoretical or practical. Practical questions have a burden of proof; theoretical questions do not. This is a because a question of right action (such as whether release a defendant) admits of only two possibilities (set him free or not), but a question of truth (did the defendant commit the crime) admits of three possible answers (yes, no, or we don't know). This mismatch between questions of what we can reasonably assert to be true and questions of how we should act is why contestatory legal proceedings require one side to assume the burden of proof. But the use of the notion of burden of proof by philosophers in purely metaphysical debates is fallacious. Like careless appeals to intuition, it is just one of those bad practices that have crept into the institutional culture of "professional" philosophers. If the question is simply whether some thesis is true or false, there is NO burden of proof -- if the evidence is inconclusive, then we simply don't know the answer. But is the free will question a purely theoretical question? Arguably not. But to the extent that it is practical, it is also practical considerations that will determine who bears the burden of proof here.

[Eddy Nahmias]

Mike, that's an interesting point. I can't decide if I agree yet, but I see where you're going with it. Is this an accepted view (or out there in the literature)? It certainly seems that, in the free will debate, people try to shift the burden of proof quite often, and not just because they see it as a practical question. In fact, that was my main motivation for doing the experimental philosophy on free will--I was tired of incompatibilists claiming the burden was on compatibilists based on the unsubstantiated claim that compatibilism is counter-intuitive.

In any case, I'm inclined to view the free will problem as partially theoretical (or metaphysical) and partially practical--the correct view depends in part on our practices and beliefs concerning moral responsibility and attribution of praise, blame, etc. (That discussion happens in the paper just before the excerpt posted here.)

Kevin and Justin, I see that one may have reasons to develop a libertarian conception of free will even if ordinary intuitions (and practices) do not explicitly demand such a conception (and the metaphysical baggage it carries). But I can't see what those reasons would be exactly (except perhaps implicit commitments from ordinary intuitions and practices). I'd like to hear more about what y'all and others think about this.

Our point in the passage was simply that, if people have conflicting intuitions or conceptions of free will, it seems easier and perhaps more practical to revise them in a way that strips off the incompatibilist elements. It certainly seems we would not want to strip off the compatibilist elements since libertarian views typically require them too. (See Vargas.)

As we say in the footnote, it also seems one could give an error theory for why people think incompatibilist elements are required when they are not (e.g., my theory that those elements derive from the mistaken view that determinism entails mechanism and/or epiphenomenalism). But what would an incompatibilist revisionist or error theory move look like?

[Justin Capes]

Eddy,

It's been a while since I've read the paper, so forgive me if you addressed these worries there.

Though I'm inclined to be suspicious of the experimental results, suppose they're basically right. I'd be interested to here more about why this result would be significant (I'm not saying it's insignificant). Incompatibilists have indeed made "burden of proof" assertions, but no recent incompatibilist that I've read ( though I haven't read everyone) places much, if any, argumentative weight on such assertions. I think, for example, of both van Inwagen's "Essay on Free Will" and Tim O'Connor's "Persons and Causes". I recall both authors making somewhat disparaging remarks about the prima facie plausibility of compatibilism, but neither author places any weight on these rhetorical flourishes. Indeed, I can think of no recent sophisticated defense of incompatibilism that does. Rather incompatibilists have appealed to their arguments, which sound or not, have proved quite powerful. And while these arguments are not the sort of thing that non-philosophers could be expected to "just see", they do employ very attractive premises that many of the folk would likely find plausible (e.g. no power over the past or laws, etc.). So even if incompatibilism is not the default position, if the arguments for it are persuasive, would argumentative burden really be much of a burden in your eyes?

[Kip Werking]

Before I go into critical points, I want to say that I remain deeply impressed with Eddy's work in obtaining empirical data about how people actually use the terms we argue about here at the Garden (I think this is a necessary step to achieving progress in the debate), and also with Vargas' work in critiquing both compatibilist and libertarian views (even if I remain unconvinced about his revisionist project, as explained below).

Some points:

1. I tentatively agree with the spirit of Mike's comment. On that note, I think one can address Eddy's arguments indirectly, via example:

Is SWAMBATLE compatible with determinism?

[Note that SWAMBATLE is just an arbitrary word I made up (if it actually means something, to someone, already, please substitute the made-up word of your choice).]

It seems to me that it is neither the s-compatibilist's nor s-incompatibilist's burden to prove that SWAMBATLE is compatible with determinism (s-compatibilism: SWAMBATLE is compatible with determinism). First, you have to determine what SWAMBATLE even is, and then both parties can decide whether it is compatible with determinism.

If your reaction to the SWAMBAT example, like mine, is that there is no default position regarding compatibilism, then we should agree that the same applies to free will and related terms (because semantic ambiguity seems to be causing the difficulty in both cases).

2. Similarly, I agree that libertarian conceptions (or impossibilist conceptions) of free will are more demanding that compatibilist ones. I won't challenge the compatibilist on that point.

But, contrary to the impression I get from Eddy's argument, I don't see this fact as counting against libertarian or impossibilist conceptions *in the slightest*! Consider, again, SWAMBATLE: suppose there are two competing ideas of what SWAMBATLEs are, one of them (A) less demanding and existent, the other (B) more demanding and non-existent. Does the fact that B is more demanding and non-existent mean that we favor A over B? Only if we have a preference (prejudice?) in favor of defining/revising concepts so that they refer to existent things! But that completely begs the question against the person who asserts that such things don't exist.

Just consider the consequences of such a preference: we should start revising our concepts for leprechauns, unicorns, Big Foot, the teapot on the other side of the moon, and arguably souls, God, and objective morality, all to make "them" safer for the world (I say "them" because the revisionist hasn't made the original things any safer for the world, that's impossible; the revisionist has just relabeled things in what strikes me as a misguided act of equivocation).

It is only with this unjustified preference that compatibilists can suggest that the availability of this move to the compatibilist, but not the incompatibilist, is a feather in the compatibilist's cap. (Even if revisionism does favor compatibilism, I am not sure this would be a feather in its cap, because I'm not sure what's so great about a term's being revisable; but, as I explain below, I don't think the idea of revisionism favors compatibilism).

If the preference is unjustified, as I argue, then one can see that the opposite presumption: that we should revise things to make them non-existent, is equally (un)justified. That is, the choice between revising one way or the other is arbitrary, and only seems to reflect the personal motivations of the reviser. If one is going to revise free will be compatibilist, one could just as well revise it to be incompatibilist, and I have yet to be persuaded that we should go either way (perhaps through no fault but my own).

[Eddy Nahmias]

Justin, briefly (since we do address some of your concerns in the final section), I think you are underestimating the frequency with which incompatibilists (and compatibilists) appeal to intuitions (though not always *folk* intuitions). As you suggest, they offer arguments, but these arguments then bottom out (unsurprisingly) in an appeal to the intuitiveness of the premises. Consider van Inwagen's defense of principle Beta (or Frankfurt cases). And the problem is that philosophers on the other side often do not find these premises (or principles) intuitive, resulting in a "dialectical stalemate). As we say, it may not help (or work) to consult the folk in these more complex cases.

In any case, it seems clear (to me) that the disparaging remarks incompatibilists make about the plausibility of compatibilism are not meant to be mere rhetorical flourishes. And, one of the points of the arguments I present in this post is to suggest that, IF intuitions (folk and philosophical) and arguments that rely on them leave us deadlocked, then it seems that compatibilism should be the default position.

[Kevin Timpe]

Eddy,

I think it is important to keep the following two issues about intuitions separate here: (1) the use and content of folk intuitions and (2) the use and content of what you call philosophical intuitions.

Regarding (1), I think that a number of incompatibilists have made claims about the strength and content of folk intuitions that you (and others) have now called into question. But, like Justin (I think), I see these (perhaps false and unjustified) claims are not meant to do the lion's share of the work these philosophers are trying to do. Perhaps they are more than just rhetorical flourishing, more along the lines of a kind of motivation for their view. But then come the arguments.

Regarding (2), let me make two points. First, as I think you are willing to agree, these intutions are substantially different than folk intuitions and thus have a different role to play. My intuitions about, say, Beta'' are very different than the sorts of general intuitions about incompatibilism that Kane and Ekstrom mention. Second, it's not just incompatibilists who offer and make use of these kinds of intuitions. Compatibilists do too (e.g., Fischer, Frankfurt), as you note; and I think one finds such intuitions in the vast majority of areas in philosophy, not just the free will literature. Of course, this does nothing to adjudicate the debates over the import of these intuitions. Here, as well as on the larger issue of this post, it seems to me that you and I agree.

[Clayton Littlejohn]

Eddy,

This struck me as a pretty weak rationale:
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).

Surely we don't think that if two concepts are not obviously incompatible we do not default, as it were, to the view that they are compatible. Don't we simply remain agnostic?

I find the second rationale somewhat confusing. I just don't see that there's much to the claim that if analysis A1 requires more of an x to be an F than A2 requires, ceteris paribus, A1 offers a preferable analysis than A2. I cannot imagine how we'd possibly assess the merits of A1 and A2 without taking into account the ability of A1 and A2 to accommodate the relevant intuitions and accommodate the platitudes about what it is to be an F and once _that_ is in place, I cannot see that the fact that A1 is less demanding than A2 counts in favor at all. Would we even use 'less demandingness' as a tie breaker for selecting between analyses?

[Saul Smilansky]

Eddy,

But why is the burden of proof issue only between incompatibilists and compatibilists? This reminds me of Pascal's wager, which sounds pretty convincing until one sees that God might prefer very different religions from one's own, and betting on the wrong one might be fatal too. As you know, I think that we need to be in some sense dualists on the compatibility question, and accept both compatibilism and hard determinism. Or, in other words, both monisms are partly false (the assumption that we must be either compatibilists or incompatibilists I thus call the Assumption of Monism). There are good reasons to think that compatibilist forms of control are important, but likewise the absence of libertarian free will is a moral tragedy. And it seems to me that some of the experimental data actually supports the more complex view. I don't think burden of proof moves will get us far in any case. But if I play this game, why is not the burden of proof on anyone who opts for monism?

[Mike from MI]

Re. literature on burden of proof: I'm sure I've read complaints about BOP arguments somewhere but I can't remember where. I vaguely recall reading these complaints and realizing that I hadn't given the matter much thought until then. I don't think there is an "accepted view" so much as an institutionalized (mal)practice. The appeal to theory vs. practice to distinguish legitimate vs. illegitimate uses of BOP is my own view.

Like many libertarians, I regard compatibilism as equivocation or doublethink, or at best an attempt to square the circle, and not a genuinely distinct option. Hard determinism and libertarianism are the real options, and the issue between them has not been and probably cannot be decided on purely theoretical grounds. On practical grounds, I place the BOP on the determinist: I find it easier to live with the puzzles raised by libertarianism than live without the moral discourse that determinism would render false or meaningless. But others may have different priorities, and for them the default choice may be different.

[jon kvanvig]

Mike, I know others have complained about BOP arguments, as have I, but I don't recall who. My complaint has been that the notion of a BOP has a natural home in the legal sphere, where some positions get, as a matter of law, a presumption in their favor. I don't know why any position in philosophy should get such a presumption.

This is a different claim, of course, than that a position that has some evidence for it, or some plausibility considerations in its favor, can then claim that the BOP is on opponents. Such an appeal to the notion of a BOP doesn't identify some position as privileged in virtue of the nature of the claim in question or the nature of the attitude recommended. Thus, e.g., agnosticism about a view deserves no presumption in its favor, nor does belief or disbelief. You need a good argument for whichever attitude or proposition you recommend. In the absence of any information about which attitude is best, no attitude has a presumption in its favor.

I do recall a piece by Plantinga criticizing various Scriven-like attempts to defend a presumption in favor of negative claims over positive ones. Typical fun Plantinga stuff, but I don't have the reference off the top of my head.

[Tomkow]

People don't seem to be getting Lycan's point.

To show that p and q are consistent one must describe a possible world where p and q. That is the only kind of proof of metaphysical consistency there is.

So here we go.

T) There is at least one possible world in which people have free will and are responsible even though everything that happens in that world is causally determined.

So if the burden of proof were ever on the compatibilist I have just removed it by offering a proof of the consistency of free will and determinism. Again, this is the only kind of proof there could be.

Now if you have incompatibilist intuitions you will hope to show that T is false. To do that you will have to produce an argument that there is some sort of contradiction hidden in T's description of a determined world with free agents. The burden of proof is now on you.

But note that the fact that you (or any one else) has this intuition is not itself an argument for anything. Philosophically speaking, intuitions are here, as always, beside the point.

[Dan Speak]

Hey Eddy et al,

Nice post. And nice paper, too.

I have a question about the idea that incompatibilism is more demanding metaphysically. This seems right if what we mean is that the incompatibilist demands more of the world in order for free will to obtain. It is metaphysically demanding with respect to the way the world needs to be to permit free will. But the contemporary compatibilist is (typically) not a soft determinist. Most of the new fangled compatibilists want to claim that determinism is simply irrelevant to freedom. We can have it whether determinism is true or not, they say. But this means that the compatibilist has to be committed to offering good answers to skeptical challenges that are based on the assumption of determinism AND on the assumption of indeterminism. These compatibilists have to respond both to the consequence argument AND the luck argument, for example. The incompatibilist (more specifically, the libertarian) only faces the challenges from indeterminism. I’m tempted to put the point this way. Yes, the incompatibilist demands more from the world than does the compatibilist. But the compatibilist demands more from agency than does the incompatibilist. Probably a little loose, but you get the idea.

Maybe some of the commenters are right that burden-of-proof concerns are inappropriate or untoward in this context. But if there is something to them, then shouldn’t considerations about how much a view is required to show be relevant to the burden?

[Brian Parks]

Eddy,

It's a creative argument, but I disagree.

“Free will” is a term. If you are willing to define the term precisely, then there should be no problem assessing its compatibility with causal determinism.

Many compatibilists define “free will” as a condition where an organism’s behavior follows causally from its phenomenological states: its thoughts, feelings, desires and so on. Such a conception of “free will” is clearly compatible with causal determinism.

But the compatibility of that kind of "free will" is not what is at issue here.

What is at issue is the compatibility of moral responsibility and causal determinism. More specifically, if causal determinism is true, can it be morally justified to exact retribution—suffering imposed for the sake of suffering—against individuals who engage in destructive behaviors?

Most of us would accept the idea that it is worse to punish an individual who does not deserve punishment than it is to not punish an individual who does deserve punishment. This idea is enshrined in the justice system of most western countries: the burden of proof is always set on the side of the prosecuting party.

If the burden of proof is anywhere, then, it is on your side. If you want to imprison individuals in environments intentionally designed to increase their suffering above the level that is necessary for their rehabilitation, and if you are willing to accept the thesis that their behaviors were causally determined to occur long before anyone human being ever existed, then by western principles it is your job to show that these two moves are compatible with each other, given the reasonable allegation that they are not.

Am I missing something here?

[Megan Williams]

Could those who allege the relevance of causal determinism to this debate please refer me to a coherent discussion of what this phrase means in current philosophical discussion, and how it relates to issues of mind, brain, action, etc.?

(No, this is not a joke. I looked on the Stanford Encyclopedia of Philosophy under "causal determinism," and found that there was nothing remotely like a coherent, agreed-upon definition there. So, I am hoping that one of you will direct me to a reference, online or in print, that can help me out--a good philosophy textbook would be great.)

If you don't know what "causal determinism" actually means or what work that concept might be relied upon to do, that would of course be interesting, too.

[Kip Werking]

Brian:

You ask: "Am I missing something here?"

I am *very* sympathetic to the ideas in your post. I absolutely agree that, if the question is between compatibilism and anti-realism (about free will), and this choice determines whether we live in a world with retributivist punishment greater than that in a "medicalized" or rehabilitation-focused world, then the burden should be on the party arguing for more human suffering.

But I think the debate here is just the question of compatibilism---between compatibilism and incompatibilism, not between compatibilism and anti-realism. It's natural to think that libertarians might punish people even more than compatibilists, and so I don't think it's quite fair to ignore libertarians in this particular debate.

[Kip Werking]

Megan,

I don't have a textbook definition handy, but I regard determinism and causal determinism to be relevantly similar for the purposes of the discussions at the Garden (I don't think any Gardener hinges their view on determinism being causal). And I regard determinism as just the view that the state of the world at X determines a single, unique future of the world. That is, I don't regard determinism as necessarily being bi-directional, although I know others do. But, again, I don't think anyone hinges their view on the bidirectionality of determinism.

It's an interesting question: what does causal determinism mean? It might mean, for example, that each state of the world not only determines a single, unique future, but also that each state causes the next. I think that captures the gist of what people mean, when they use that term. But I may be wrong about all of this.

[Brian Parks]

Megan,

In the paper, Eddy et. al. use the following definition of determinism: that the laws of nature and state of the universe at one time entail the state of the universe at later times.

Eddy's et. al. definition will probably work for the purposes of this debate.

If you are looking for something more philosophically precise, John Earman gives a definition in terms of possible worlds on p. 13, Chapter 2.6 of “A Primer on Determinism”,

“Letting W stand for the collection of all physically possible worlds, that is, possible worlds which satisfy the natural laws obtaining in the actual world, we can define the Laplacian variety of determinism as follows. The world w in W is Laplacian deterministic just in case for any w’ in W, if w and w’ agree at any time, then they agree for all times.”

The term ‘causal’ does not add anything to this definition, other than to suggest that some unspecified type of causation holds in w.

The claim that a person has ‘free will’ implies a privileged mereology of the universe on which there is a distinctly existing ‘self’ with the capacity to ‘cause’ behaviors.

The addition of the term ‘causal’ to the term ‘determinism’, then, should not raise any issues for those who argue in favor of the existence of ‘free will’, because they will eventually have to embrace a specific conception of causation anyway.

We can define the more limited (and more relevant) thesis of neurobiological determinism as follows: for any phenomenological behavior (thinking, feeling, choosing) of a human organism at time t, the behavior is uniquely specified or set by the physical state of the universe (specifically, the physical state of the organism’s brain) at some time t – dt, let dt be any number greater than 0.

[Juliette]

I am certainly unqualified to comment - let this be a disclaimer.

However, upon reading this paper I subjected my younger sister (utterly unexposed to philosophy, age 14) to example 1, which involves a supercomputer using the state of the universe and the laws of nature to determine the future with 100% accuracy.
Her response was paradoxical and, too some extent, incoherent:
Given that it is possible to determine the future, Jeremy had no free will, because free will is impossible.
On the other hand, Jeremy, who did not know of the computer's prediction, had free will, or at least as much as anyone ever had. I assume that she means here that he acted under internal and not external factors, and was proceeding under a different definition of freedom here.

To remedy this, I would suggest rerunning the experiment, but prefacing it by asking all participants to offer their definition of free will, which might clarify their thinking (and explain the intuition that one could have no free will but be morally responsible, shared by many participants).

[Eddy Nahmias]

Thanks everyone for the interesting discussion. I can't respond to everyone's points in depth (I hope others will chime in), but here are five relatively quick points, three in this post discussing points made by Megan, Kip, Clayton, Tomcow, and Kevin, and two in the next post discussing points made by Saul (and Juliette) and Brian (and Kip).

1. Megan, the definitions of determinism Brian offers are what most in the debate use. Or they follow van Inwagen in defining deterministic universes as ones in which:
Necessarily[(Past & Laws) --> Future] or perhaps replace "Future" with "State of universe at any other time." Note that van Inwagen (1983) explicitly rejects tying notions of causation to notions of determinism.

But my view is that, in the debate as it stands, at least as much depends on one's conception of free will (and moral responsibility) as on one's conception of determinism. For instance: does one take determinism to involve certain types of causation (what type?)? Are the laws Humean or necessitarian? Can the laws include psychological laws (for some reason, van Inwagen says ‘no’)? Does determinism preclude agent causation? Does determinism entail predictability (in principle, in practice?)? And so on. I think that many incompatibilist intuitions are pumped by presenting determinism to entail or at least suggest things that it probably shouldn't, such as mechanistic reductionism, predictability of human behavior, the causal inefficacy of conscious mental states, a scientific worldview, etc. Sorting out exactly what determinism is and what exactly it properly entails is an important project to better understand exactly what is supposed to be incompatible with free will and responsibility.

2. Regarding Kip and Clayton's suggestions about burden of proof, I think (along with Lycan, Chalmers, and Tomcow's nice comment above) that compatibilism about two concepts or (propositions describing a universe) should be the default position, barring an explanation of why they are incompatible. After all, quantifying over possible worlds, compatibility is an existential claim, while incompatibility is a universal claim. We need a reason to think that there isn’t just one possible world where the two proposed propositions cannot be true together. Even with SWAMBATLE, I think you *begin* your investigation assuming it’s compatible with any other possible proposition, including determinism. You need to learn something important by investigation and argument to discover it’s incompatible with any other proposition (or concept or whatever). Maybe this is just my intuition!

3. Speaking of which, Kevin, you are right that much depends on what sort of intuitions we are talking about. But I’m worried about philosophical intuitions in these debates, since they tend to diverge according to different philosophers’ theories. But rather than go on, I’d rather try to lure some Gardeners over to my post at the Experimental Philosophy blog on the nature of intuitions, since people in the free will debate seem to mention intuitions (folk and philosophical) a lot: http://experimentalphilosophy.typepad.com/experimental_philosophy/2008/07/what-are-intuit.html

[Eddy Nahmias]

4. Saul, perhaps we (Westerners?) have more than one concept of free will (perhaps that is what Juliette’s sister and some of our students and my subjects suggest in their responses). In that case, perhaps there is a burden on anyone who suggests there is one concept. I guess I’m inclined to think there is a libertarian-like concept out there but I don’t think that it’s the one that is properly tied up to questions of moral responsibility (e.g., I disagree strongly with your claim that “the absence of libertarian free will is a moral tragedy” though I agree that the absence of free will, properly construed, might be a moral tragedy). And so the arguments in my post might be understood as suggesting that the burden should be on those philosophers who suggest that determinism precludes that we have the sort of freedom involved in our concepts and practices of moral responsibility. (I think I've butchered you view a bit since you think even *that* concept of freedom is both compatibilist and libertarian, if I remember correctly.)

5. In response to Brian, let me elaborate on Kip's point, that it is likely the libertarian who has the burden of proof if we are considering retributivist practices. Here's an argument (that I've adopted from Randy Clarke, if I remember correctly):
1) Moral responsibility requires free will. [assumption of most in the debate]
2) Free will requires indeterminism (of the right sort). [libertarian assumption]
3) So, we are not morally responsible if indeterminism (of just the right sort) does not occur in us. [from 1,2]
4) We do *not* have good evidence that such indeterminism occurs in us. [contentious claim on basis of current knowledge and perhaps possible knowledge we could obtain]
5) So, we do not have good evidence that we actually are morally responsible. [from 3,4]
6) To treat someone as morally responsible (in a retributivist sense) without good evidence that they are morally responsible is unjust. [plausible stipulation about burden of proof in such matters]
7) So, in order to avoid being unjust, we should not treat people as morally responsible (in a retributivist sense).

The skeptic about free will should like this argument and might also wield something like it against the compatibilist by replacing 4 with something like “we do not have good evidence that compatibilism is true” and moving from there.

But the compatibilist, it seems, can use this argument to suggest that the libertarian conception of free will (the one required for both libertarians’ and skeptics’ arguments to go through) has metaphysical commitments that go beyond the compatibilists’, and, without good reason for accepting such a conception, it sets the bar for just retributive practices beyond what we could plausibly gain evidence to get over. I mean, how exactly are we supposed to discover that agent causation or indeterminism in the right places in the brain occurs in us anyway? (Stipulating that it must since we know we are morally responsible seems problematic, to say the least.)

Now, Dan may think the compatibilist has a higher bar to overcome, but I don't think that's right. But these posts have gone on too long...

[Paul Torek]

Eddy,

Rather than burden of proof, I prefer to consider prior probabilities, in accordance with Bayes's Theorem. If the prior probability of a proposition is low - because it belongs to a class with relatively few truths and more falsehoods - then we require fairly strong specific evidence in its favor before we view it as probable. Controverted claims of inconsistency are a class of propositions with relatively few truths and many falsehoods. That is, if you come across a controversy about whether a certain set of propositions is inconsistent, your money should (initially) be on the result that it will turn out to be consistent.

We can see this from examining the cautionary tales in logic texts, regarding the closely related concept of a valid argument. There is a long list of common mistakes whereby invalid arguments are taken for valid ones: they are called fallacies. There is by contrast a very short list of valid argument forms frequently mistaken for invalid. That kind of mistake is rare enough that we don't even have a collective name for them (I call them "trulacies").

Since an argument is valid iff the conjunction of its premises plus the denial of its conclusion is inconsistent, every controversy over whether an argument is valid is at the same time a controversy over the consistency or inconsistency of a set of statements.

On this ground, to a newbie who has yet to examine the arguments, compatibilism would seem far more probable than incompatibilism. But then, compatibilism also belongs to another, cross-cutting category: the category of comfortable reassuring depictions of ourselves. (Or so our resident skeptics may argue - others may not find it reassuring to be morally responsible, thus "on the hook" for one's actions.) And when there's a controversy over a comfortable reassuring self-depiction, that self-depiction usually turns out to be false. How do these two opposing probabilistic considerations weigh up? Figuring the net probability may be harder than just addressing the arguments.

[Kip Werking]

Eddy,

I'm glad someone took the time to address my crazy remarks about SWAMBATLE.

However, I remain unconvinced, and I have a simple argument for my point. You say:

"Even with SWAMBATLE, I think you *begin* your investigation assuming it’s compatible with any other possible proposition, including determinism."

But surely "any arbitrary proposition" may be ~P as well as P. ~P is just as much a proposition as P, and a preference for one over the other seems unjustified if---as you say---any proposition will do.

[Brian Parks]

Eddy,

After reading Kip’s and your response, I’m not entirely sure whether the argument in your original paper was directed specifically against libertarians or against all incompatibilists. If it was directed specifically against libertarians, intended as a kind of in-house appeal that urges them to take the path of least resistance and to refrain from unnecessarily placing themselves inside specific metaphysical boxes, then I think it makes sense. From my readings on this forum, there seem to be a number of prominent libertarians—for example, Alfred Mele and David Hodgson—who agree with the argument and who embrace compatibilism as the backup plan.

But if the argument was directed against skeptics and hard-incompatibilists, then it falls on deaf ears. We do not share your goal of developing and defending a robust theory of free will, and so the argument that we should minimize our metaphysical demands misses the point—our demands are informed by what we think would be required of such a theory for it to serve as a basis for moral responsibility (and retributive punishment), not by what would make the theory easiest to establish or defend.

You say: “But the compatibilist, it seems, can use this argument to suggest that the libertarian conception of free will (the one required for both libertarians’ and skeptics’ arguments to go through) has metaphysical commitments that go beyond the compatibilists’, and, without good reason for accepting such a conception, it sets the bar for just retributive practices beyond what we could plausibly gain evidence to get over.”

And?

If this were a scholastic debate, and the goal were to set the burdens of the affirmative and negative sides so that each participant enjoys an equal chance of winning, then you would have a point. But that is not what this is.

When it comes to retribution, the burden to refute reasonable objections always rests on the prosecuting party. This holds true regardless of whether the prosecuting party can provide sufficient evidence to ‘get over’ the burden.

The claim that a person can be morally responsible for behaviors that were deterministically entailed by the physical conditions of the universe 14 billion years ago is an extremely peculiar claim. It requires significant argumentative justification, especially if it is going to be used as a basis for killing someone, or for permanently confining someone in a locale intentionally designed to cause substantial amounts of suffering.

If you are unable to demonstrate the compatibility of moral responsibility and determinism, then the solution is simple: establish the existence of the appropriate kind of indeterminism, or stop endorsing retributive punishment. If you cannot establish the latter, then the solution is even more simple: stop endorsing retributive punishment.