I have said that the two deepest strands in this debate are the logical and the personally evaluative. The first was raised finally at the end of Chapter XII, and the second has emerged throughout Chapter XIII. I now take up the question raised at the end of Chapter XII, namely the determinist’s claim that the libertarian was still rejecting the Principle of Sufficient Reason. Is it true that the libertarian must just grant his opponent possession of this citadel, and retreat to his own strongpoint of the experience of choice? Many libertarians may seem to have thought so. I think that this concedes too much to the determinist, but my argument on the point will require a fairly lengthy digression.