Notre Dame, born 1942

Peter van Inwagen

If determinism is true, everything you do is a consequence of the laws of nature and events in the remote past. But what went on before you were born is not up to you, and neither are the laws of nature. So the consequences, including your acts, are not up to you either.

The view

Van Inwagen, long at the University of Notre Dame, is one of the most important metaphysicians of his generation. In An Essay on Free Will (1983) he gave incompatibilism its most rigorous modern statement. Versions of the argument go back centuries, but his careful formulation, which he called the consequence argument, has been the centre of the debate ever since.

Van Inwagen is also a libertarian: he believes we have free will, and therefore that determinism is false. But he is unusually candid about the cost. Indeterminism seems to make free will a matter of luck, he admits, and he does not know how free will can exist. He believes that it does, he says, because the alternative, that no one is ever morally responsible for anything, is unbelievable. Free will is, in his word, a mystery.

The argument

If determinism is true, then our acts are the consequences of the laws of nature and events in the remote past. But it is not up to us what went on before we were born, and neither is it up to us what the laws of nature are. Therefore the consequences of these things, including our present acts, are not up to us. After van Inwagen, An Essay on Free Will (1983)

The argument relies on a principle about "no choice": if you have no choice about something, and no choice about the fact that it leads to something else, then you have no choice about the second thing either. Walk the chain below.

Van Inwagen also gave the standard statement of the opposite worry, sometimes called the Mind argument after the journal where versions of it appeared. If an act is undetermined, then, given everything up to the moment of choice, it might or might not happen; so whether it happens seems to be a matter of chance, which is not up to us either. Free will seems to be incompatible with determinism and with indeterminism alike. That is why he calls it a mystery.

Where he meets Dennett

Both prized clarity and argument over rhetoric, and both took the other side's best case seriously. Van Inwagen agrees with Dennett that indeterminism does not obviously help, the point of the Mind argument; Dennett would have welcomed the admission. And both agree that if we must give up either determinism or moral responsibility, it is responsibility we should keep.

Where they part

At the first premise, really the meaning of "up to us". Dennett denied that "not up to us" carries over from the past to the present in the way the argument needs. Whether my act is up to me depends on whether it flows from my deliberation, responds to reasons and could have gone differently in nearby situations. All of that can be true even if the act, like everything else, follows from the past and the laws. The consequence argument, he thought, quietly assumes that to be in control I must control the whole causal history of my act, which nobody could. That is the bogeyman of making yourself small, in logical dress.

See every view compared →

Further reading

• Peter van Inwagen, An Essay on Free Will (Oxford, 1983).
• Peter van Inwagen, "Free Will Remains a Mystery", Philosophical Perspectives 14 (2000).
• Arguments for incompatibilism, Stanford Encyclopedia of Philosophy.