Libertarian freedom is supposedly distinguished from compatibilism because it holds we have “the ability to do otherwise.” I am not necessarily endorsing compatibilism here, but I see a potential absurdity – or at least difficulty – in this claim, which is this. Just WHERE is the ability to do otherwise located, or WHEN is it actualized?
Pick any moment in time. At that moment, the person’s will is DOING something. Therefore they cannot AT THAT MOMENT be free to do otherwise. Therefore they must be free in the NEXT moment. But if that’s the case, how is that different from compatibilism, which could also hold that the will is, from one moment to the next, free to do what it does (i.e. that it can be different from one moment to the next)? Further, just what is it that gives rise to the particular act that could have been different, and could THAT thing, at THAT moment, be different? If it is what it is it cannot be different (for then it would be something else) – and in which case, how could what it gives rise to be different? If all things are equal the effect will be equal, unless the principle of sufficient reason is false. So there seems to be an infinite regress here, insofar as you must eventually posit something that just IS what it IS at a particular moment, which means that it cannot AT THAT MOMENT be otherwise.
Hugh McCann has an interesting take on freedom which has to do with de re modality. He thinks that the terms “necessary” and “contingent” apply on to the conceptual realm – i.e. they essentially equate to what we cannot imagine and what we can imagine. But they don’t impose some sort of tight metaphysical structure onto reality itself whereby things fall into the category of “has to be this” and “may be that.” That is just how our finite, ignorant minds work. We, being less than all knowing, imagine various things, and this ability makes us think things MAY or MAY NOT be other than they are. But in reality, McCann holds, things just ARE the way they are. It’s not that they are necessary or that they are contingent – they just ARE. Thus, it is not the case that humans HAVE to have the power of seeing, nor that we could not exist without it. It is just that as a matter of fact we DO have this ability. And there’s the end of the matter.
Perhaps we should think of the will like this, not as having to do what it does (i.e. determined by some metaphysically antecedent mode of being called “necessity”), nor that it just contingently is what it is, but it could have been different. Rather, perhaps we should think of it as simply doing what it does and being what it is: i.e. the “definition” of free will is just what in fact occurs and is willed by us.