In some ways it is surprising that the notion of free will has such a hold on us, because it is very easy to dismantle it philosophically and logically. The argument, which is simple enough for a reasonably intelligent child to follow, goes like this:-
Either the universe is wholly deterministic or it is not.
If it is wholly deterministic, then there is no place for free will because all apparent ‘choices’ and ‘decisions’ are entirely determined by prior causes. For humans, these prior causes consist of inherited and cultural factors, or a combination of ‘nature and nurture’.
If the universe is not wholly deterministic, then the only other possibilities are that it is either partly or wholly random. But a ‘choice’ or ‘decision’ made partly or wholly at random does not involve the exercise of free will in any meaningful sense.
So whether the universe is wholly deterministic, wholly random, or some mix of deterministic and random, there is no possibility of free will.
(By the way, no one actually believes that the universe is wholly random. That possibility is only included here to complete the argument. As long as Newton ruled the scientific roost, the smart money was on total determinism. Since quantum physics has entered the fray the possibility of randomness, at least at some level, has been opened up.)
Many philosophers, known as libertarians and compatabilists, cling to the idea of free will and shy away from the implications of acknowledging its absence. In essence, their very complicated arguments usually come down to “I must have free will because I feel as if I do.” Another group of philosophers, known as illusionists, recognise that free will is an impossibility, but advocate that we don’t let the hoi polloi know this in case they get uppity.
Galen Strawson is an interesting philosopher who is more straightforward than many. In a recent radio interview, he acknowledged very honestly that although free will does not exist, it is impossible for him to feel this to be the case in his own everyday life.
Essentially free will is an incoherent idea. No one has ever been able to explain who or what exercises it or in what manner they do so. And once non-duality is directly seen, the philosophical and logical arguments become irrelevant in any case. When the emptiness of the self has been realised, it is simply known that there is no one who could possibly exercise free will. Life is and always has been simply unfolding.
There are some good books about free will. I’d recommend ‘The Free Will Delusion’ by James B Miles. Although it’s maddeningly repetitive and fuelled by a disturbing amount of anger, if you want the arguments spelled out it’s the business.