An action is only free if it was possible to do otherwise. Our thoughts consist of activity in the brain, which is a purely physical phenomenon. Physical activity is either random or deterministic – so our thoughts are either physically inevitable (determined) or controlled by random factors. Neither of these allow for free will.For a start, this isn't very helpful in itself. Like solipsism, it merely proclaims the non-existence of something, not because it's a bad explanation, but just because of an apparent logical difficulty. It denounces a host of experiences as illusory, closing off the possibility of finding better explanations for them. It's not a good approach.
It's also a reductionist argument. It assumes that people's choices must be explained in terms of low-level interactions, as if this form of explanation were more 'fundamental'. Even if we did know all the (inconceivably many) physical events that led to a certain thought, they wouldn't be a good explanation of why the person had that thought. If I think to myself, 'I need to write a blog post', the reason I had that thought could be explained as, 'Because X neurons fired off in Y and Z locations' – but this only tells us what physically prompted my thought. It was already clear that neurons needed to signal in order for me to have had a thought. So it tells us nothing we didn't know already.
Fine, some stuff is emergent. But still, every effect has a cause. Even if my thoughts and actions are caused by emergent ideas and circumstances, according to causality they're still unavoidable. So for every decision I make, I couldn't have done otherwise.People are creative. Ideas change, technology progresses, all the time people form new theories in the light of criticism. It doesn't make sense to talk about creativity in terms of sufficient causes, because if a new idea could be inferred from something that went before, that thing would contain the idea – and so it wouldn't be new at all. The future is unavoidable only on a lower level of explanation with respect to that of knowledge-creators. On the abstract level of creative thought, causal determinism isn't applicable. It is true that there is always a single answer to questions about what *physical* state something will be in in the future. Physically it is determined. But on the emergent level of knowledge creation the future has to be open.
But you don't know what your thoughts are going to be before you think them. And you can't be in control of something if you can't predict what it's going to do, surely. So how can you be in control of your thoughts?Again, if you could predict your own thoughts, those predictions would be the thoughts themselves. There's no real reason to think you can't be in control of a thought as you're having it, though it didn't occur to you to have it beforehand. We pursue certain trains of thought purposefully: we can freely intend to come to a conclusion without knowing in advance what the conclusion will be. This doesn't imply a lack of control; it just implies creativity.
People are free in the sense that they have evitability: They can alter their courses of action according to projected consequences. Even if at the micro-level we are behaving deterministically, we're still free in the sense that matters.This view of free will would mean that a simple computer program could have a little bit of that which makes humans free. It is true that computers can be programmed to follow abstract rules, such that their activities couldn't be explained in purely physical terms. But human freedom is on a higher level of emergence than that, because of creativity. If we were 'free' in the same way as that computer program, just to a higher degree, our actions would be predictable in principle and hence determined. So there's more to it than having purpose and 'evitability'.