(My) self-referential reason to believe in free will

I was recently talking with someone about the problem of free will, and I realised that for many years now I have always had the same response, without really ever soliciting broader critical feedback. The notion of free will here refers to a naive, libertarian, non-strictly-defined approach of “when I feel I make choices, I really had a choice”, and all of the associated implied moral philosophy (laziness is a thing, I can be blamed for my choices etc.)

The starting assumption is that I want to believe in true things (I leave open the question of whether this epistemic duty is itself justified or not). I propose a trilemma, where exactly one of the following propositions holds:

  1. Either the notion of ‘free will’ is meaningless, or

  2. It is meaningful, and I do have in fact have free will, or

  3. It is meaningful, but I happen to not have it

If (1) is true, then the whole discussion is moot: nothing can be true or false, and whatever I believe is equally justified. If (2) is true, then I want to believe in having free will (since it is true that I have it). If (3) is true, then “should” is a meaningless concept—there is no way I would be able to change my view one way or the other.

So, the only possible world where I get to make this choice is a world in which free will is true, so I should believe in it—and mostly ignore the debate about compatibilism, the nature of physics, dualism etc. Which is what I do.

One potential issue is that (1) can be true or false depending on the precise definition (but then what even is a precise definition?). Still, I suspect that no matter which one I instantiate it with, as long as it is sensible, the general (self-referential) structure of the argument will stay the same.

Thanks to Jakub S. for the feedback on this post and his suggestion to formalise this argument as the epistemic duty of maximising the probability of holding correct beliefs.