Why I Am An Incompatibilist

When I first began studying philosophy seriously, one thing that came as a real surprise was the idea of compatibilism. To me, incompatibilism is intuitive – despite the arguments of Nahmias et al(1). I was, and still am, a “natural incompatibilist”. In an a deterministic universe, we are no different to volcanoes. If Vesuvius was not morally responsible for the deaths in Pompeii, why should humans be considered morally responsible for their actions?

However the compatibilist arguments are undeniably ingenious.

I initially adopted the the Principle of Alternative Possibilities (PAP): a person is morally responsible for an action iff they were able to do otherwise. But this formulation has been attacked by many compatibilists using the conditional analysis: an act is free if the person could have done differently had they chosen to do so. The argument then goes that even in a deterministic universe there are no external constraints preventing us from doing otherwise should we so choose. Without external constraints, the conditional analysis allows for the claim that freedom prevails over determinism and hence for reintroduction of moral responsibility.

That argument caused me to rethink and clarify my position on moral responsibility. I realised that it wasn’t the action that mattered but the choice. I have thus adopted a stronger version of PAP: a person is morally responsible for an action iff they could have chosen to do otherwise. This difference between this position and the conditional analysis of PAP was set out back in 1978 by Chisholm(2):

from our statement (b) above (“If he had chosen to do otherwise, then he would have done otherwise”), we cannot make an inference to (a) above (“He could have done otherwise”) unless we can also assert:
(c) He could have chosen to do otherwise.
And therefore, if we must reject this third statement (c), then, even though we may be justified in asserting (b), we are not justified in asserting (a). If the man could not have chosen to do otherwise, then he would not have done otherwise – even if he was such that, if he had chosen to do otherwise, then he would have done otherwise.

This formulation, where the choice is key to moral responsibility, has significant implications for the Frankfurt cases, which I will discuss at a later time.

So for me, moral responsibility requires the ability to make a choice (note the difference between choice and mere selection). In a deterministic universe, any apparent choice is an illusion as our selection is predetermined. Hence determinism is incompatible with moral responsibility.

It could be argued that the word ‘choice’ is loaded in that the way I use it presupposes some form of agent causation which many philosophers do not believe exists. I agree. But that’s the point: by definition, moral responsibility requires choice which requires agent causation which is incompatible with determinism. It is not necessary to believe that agent causation exists in order to to accept that moral responsibility cannot exist in its absence.

In summary, my position is:

  • There can be no moral responsibility without the ability to choose
  • Determinism removes the ability to choose
  • Hence determinism is incompatible with moral responsibility

I have yet to see an argument that convinces me that either of the premises or the logic of the conclusion is wrong. So, for now, I remain an incompatibilist.


(1) Nahmias, Eddy, Stephen G. Morris, Thomas Nadelhoffer, and Jason Turner. 2006. ‘Is Incompatibilism Intuitive?’ Philosophy and Phenomenological Research 73 (1): 28–53.
(2) Chisholm, Roderick, ‘Human Freedom and the Self’, presented as the Lindley Lecture at the University of Kansas, reprinted in Gary Watson (ed.), Free Will. OUP (1982)

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