The 'Great Debates in Philosophy' series of books aims to introduce advanced students to a particular topic by presenting philosophy as it is actually done, by professionals debating one another. The authors are selected from among the most prominent writing on a particular topic, and the results are usually of interest to other professionals as well as their students. This latest offering in the series is exemplary. It brings together four of the most interesting thinkers writing on the topic of free will; the result is a fruitful and fascinating exchange.

Robert Kane begins by presenting his event-causal libertarianism, deservedly the most influential such theory in existence today. On Kane's view, agents act with direct freedom when they find themselves in situations in which they experience a significant degree of conflict, which causes quantum level indeterminacies in their brains to be magnified. In such circumstances, they have genuine alternative possibilities — the laws of nature allow for more than one continuation of their history. Kane argues that possessing such possibilities is necessary for agents to be free. He also argues that there is a sourcehood condition on free will: agents are free only if they are partially responsible for the characters they have. His indeterministic theory seems to satisfy both these conditions. However, it seems vulnerable to an important objection. On the event-causal view, the agent apparently does not control which undetermined action, out of those which her character makes available to her, she actually selects. It seems to be merely a matter of chance or luck how things actually turn out.  Kane recognizes that the objection is forceful, and devotes much of his exposition to attempting to head it off.

Compatibilism — the view that free will is compatible with causal determinism — is represented by John Martin Fischer. In one way, this is a strange choice, since Fischer is neither a compatibilist, nor is the work for which he is best-known a view about free will. Yet such is his prominence in the free will literature, he could hardly have been left out. Fischer calls his view semicompatibilism: he is a compatibilist about moral responsibility but agnostic about free will, insofar as free will is understood as requiring alternative possibilities. Fischer presents a traditional compatibilist view sympathetically, but argues that his semicompatibilism is more plausible because it does not conflict with the intuitiveness of the intuition that free will requires genuine alternatives. Frankfurt-style cases — cases in which an agent lacks alternative possibilities, but is not aware that this is the case, and in which the lack of alternative possibilities plays no role in explaining why they act as they do — seem to establish that moral responsibility does not require alternatives. Instead, it requires only reasons responsiveness: the ability to grasp reasons, and at least sometimes to adjust behavior in their light. An agent whose choices are the product a reasons-responsive mechanism exercises what Fischer calls guidance control over their behavior, and guidance control suffices for moral responsibility.

Next, Derk Pereboom presents his well-known hard incompatibilist view. Incompatibilism is the view (which Pereboom shares with Kane) that free will is incompatible with causal determinism. Hard determinists combine incompatibilism with the view that determinism is true. Sensibly, Pereboom is agnostic on causal determinism; however he holds that free will is incompatible both with causal determinism and with any kind of indeterminism likely to be true. Hence hard incompatibilism. Pereboom is a source, rather than a leeway, incompatibilist: he does not think that free will requires access to genuine alternative possibilities — he shares with Fischer the view that Frankfurt-style cases show that such alternatives are not necessary for responsibility (unlike Fischer, Pereboom takes moral responsibility to be a good guide to free will) — but it does require that we are the source of our actions. Pereboom believes that causal determinism rules out sourcehood of the required type.

Pereboom develops the case for the incompatibility of causal determinism and sourcehood via his well-known four case argument. He presents us with a case in which an agent who satisfies prominent compatibilist conditions on freedom (including Fischer's conditions) is manipulated into performing a morally significant action, and is intuitively not responsible for the action. He then presents three further cases, each of which differs from the original case by a greater margin, and the last of which is just a standard case of causal determination. He then challenges the compatibilist to identify the difference between the fourth case and one or more of the earlier cases, such that agents are responsible in the fourth but not in earlier cases. Pereboom holds that the best explanation of why the agents lack responsibility in all the scenarios is causal determinism.

Hard incompatibilism might be a despairing doctrine, inasmuch as not just moral responsibility, but also meaningfulness and even love have sometimes been held to require free will. Pereboom is optimistic that we can live without free will. He argues that morality does not require moral responsibility, and that most valuable aspects of our lives either do not require free will or, if they do, can be sustained by substituting other emotions for the reactive attitudes which depend upon free will.

The final view is the newest, Manuel Vargas's revisionism. Vargas holds that the everyday notion of free will is incompatibilist (he shares with Kane a skepticism about Frankfurt-style cases), but believes that the kind of indeterminism required by incompatibilist notions is extremely unlikely to be true. He therefore counsels that we substitute a compatibilist-friendly kind of freedom for the everyday notion. Vargas defends his revisionist account by reference to the alleged function of responsibility ascriptions. He advances a broadly consequentialist account of this function: what he styles the responsibility system has the aim of making agents attend to moral reasons and governing their conduct in the light of these reasons. Vargas's is a two level account: whereas responsibility is justified on consequentialist grounds, consequentialism is relevant only at the justificatory level and does not enter into the content of the responsibility norms themselves.

One of the best things about this book is that after each author has presented their preferred account of free will or moral responsibility, they are then given the opportunity to reply to the others. The free will world is a relatively small one, and each of these theorists is well-known to the others; hence there are no real surprises in the replies. Nevertheless, they may help move the debate forward. Kane presents a plausible case for the importance of alternative possibilities for ultimate responsibility: only if agents are responsible for their wills, he argues, can they be ultimately responsible for their actions, and responsibility for our wills requires that we sometimes possess alternative possibilities. Pereboom highlights an important problem that besets the debate: the possibility that different theorists work with different accounts of moral responsibility. Fischer had responded to his four-case argument by claiming that the agents it features are responsible but not blameworthy. Pereboom concedes that there might be a sense of responsibility in which this is so, but he claims that it is not the sense at issue in the debate. Much greater clarity about the sense of moral responsibility at issue in each context, as well as about the entailments and presuppositions of each sense, is clearly needed to advance the debate further. Vargas, too, addresses this issue, though he phrases the discussion in terms of desert. In effect he rejects Pereboom's claim that the sense of moral responsibility at issue in the debate is the basic deservingness sense that Pereboom identifies. It seems to me that he is wrong about this; clearly, however, all sides need to do more work to defend their claims.

Each of these theorists has made an important contribution to one of the oldest and thorniest problems in philosophy. Remarkably, each of them writes clearly and plainly enough to convey the gist of the debate, and of their unique contribution to it, to those who lack a background in these issues. There is no better introduction to the debate available. This is a book that will be read with profit by anyone who opens it, specialist or newcomer.

© 2007 Neil Levy

Neil Levy, Ph.D., Senior Research Fellow Program Manager, Ethical Issues in Biotechnology, Centre for Applied Philosophy and Public Ethics, University of Melbourne

Categories: Philosophical