Chisholm v. Classical Compatibilism: Part III

Sadly, the classical compatibilist derivation of PAPC from PAP will not apply in any straightforward way to the claim that you couldn't have decided to do anything other than what you did decide to do.

Here's a straightforward derivation:

You have the ability to decide otherwise.

Therefore, had you decided to decide otherwise you would have decided otherwise.

The problem is that it is not at all clear that the classical compatibilist's counterfactual analysis of ability (and hence practical modality) makes much sense here. If having the ability to decide otherwise requires that (in nearby metaphysically possible worlds) I decide to decide otherwise and so decide otherwise, I am doubtful I have this ability.