Unfortuneately the ‘incompatibilst’ term there is not the same use of the term on the JC post comments.
And so welcome to the wonderful mixed up world of philosophy.
I’ll make some general points but also try to focus on this issue of incompatibilism. It’s worth asking ‘incompatible with what?’ and then note the following points.
1) The incompatibilists (I’ll get to incompatibilist later) commenting on the JC post are determinists who claim that free-will is incompatible with determinism, and that we live in a deterministic universe, and so there is no free-will. But this particular free-will that is rejected is that of dualism – the notion of the mind being something separate from the body, that for religious believers has some existence of its own that might live on after death of the body, such as the soul. We incompatibilists determinists think there’s no evidence for such a mind, and that everything is physical, and so the brain is a physical system and that free-will is merely the human feeling that we do have such a mind. This is why we think free-will is an illusion – that is the dualist free-will is an illusion.
2) Compatibilists also think everything is physical. They don’t think there is a separate mind, or a soul. They are not dualists in this respect. But, they think that what happens in a human brain is so complex and so self-contained that it does make sense to think of it as free-will.
One part of the dispute is about whether, for low level philosophical and scientific purposes, we should abandon the use of the term ‘free-will’ to describe what both compatibilists and incompatibilists agree on. There are other issues, such as that about the attribution of responsibility, that seem to cloud the dibate, but the core issue is whether we should use the term free-will for what both sides really do agree on, that is what is happening in a brain, particular when some behaviours are framed as (a) ‘it makes decisions’ (compatibilist) or (b) ‘is caused to produce an outcome that we commonly call a decision’ (incompatibilist)
3) The term ‘determinist’ sometimes causes confusion because we all accept that quantum physics introduces indeterminism into our understanding of the universe. There are several sub-issues here. Even a fully deterministic universe would still be indeterminate to humans because it is too complex to determine all the detailed outcomes. And quantum events, once they occur, have deterministic effects. And quantum effects are not sufficient to give back the dualist the free-will they are looking for. All this has to be accounted for when interpreting how incompatibilists determinists use the term determinism. Many, possibly most, compatibilists will also agree with these points, so determinism isn’t specifically a problem of contention. Except that a few compatibilists do wonder if quantum effects play a part in what they perceive to be free-will. Having said that, non-compatibilists would probably agree that quantum effects can have a moment-by-moment effect that makes the universe and any brain process (e.g. a decision) indeterminate, but would still not call this free-will. So, even give or take some variation in the strictness of the use of the term ‘determinism’ many compatibilists and incompatibilists still agree on the physical basis of brain function and still dispute the use of the term ‘free-will’.
4) Now for the Stanford ‘Incompatibilism’. The title and the introduction to that article use the term to describe what is essentially a dualist free-will account. It is portraying incompatibilists as those people who think that there is a free-will that is incompatible with determinism. Meanwhile in our discussion here some of us have picked up on the use of ‘incompatibilists’ as being the determinists that think free-will is incompatible with determinism.
From the Stanford article: “According to McCann (1998: 163-64), when one makes a decision, intrinsic to the decision is one’s intending to make that very decision.”
When compatibilists make such statements the determinists see this as a dualist statement – but in this instance it is a dualist statement. The qestion is, what caused the ‘intending’? Answer: physical activity in the brain. What caused ‘that’ physical activity? Answer: more physical activity. The problem for determinists is that when compatibilists make such statements we know they don’t really mean dualist free-will decision, but the compatibilists object when we say this is not free-will because it is still a determined outcome.
More from Stanford: “Kane holds that a free decision or other free action is one for which the agent is “ultimately responsible” (1996b: 35). Ultimate responsibility for an action requires either that the action not be causally determined or, if the action is causally determined, that any determining cause of it either be or result (at least in part) from some action by that agent that was not causally determined (and for which the agent was ultimately responsible).” [my emphasis]
This is pure dualism. This is not the determinism that we incompatibilists or determinists here are suggesting is the case. This is not the free-will of compatibilists.
There is a distinction that isn’t made clear. Determinist incompatibilists are those (including me) that infer from all available evidence that the universe is deterministic (broadly) and that non-material minds do not exist, and therefore free-will is an illusion. Dualist incompatibilists are those dualists (proponents of a non-material mind, or a soul) that infer from their conviction to dualism that determinism cannot be a full description of the universe. Quite often we find philosophers not being clear on this distinction, declaring incompatibilism an unsustainable position because they are only thinking about the dualist incompatibilists. Dan Dennett seems muddle on this point – at least as he writes in his derision of incompatibilism.
5) What’s been happening in the particular JC post is that we’ve adapted the language to use the terms compatibilist and incompatibilists (using the latter as opposed to determinist).
Now it may well be that we non-professional-philosophers do misuse philosophical terms sometimes, but we’re in good (bad) company, since many professional philosphers seem to change the meaning of words at the behest of their own free-will (ahem, which they don’t have, of course).
This is also why this ground is covered so often in so many ways, why points are made and re-made in different terms. It’s all part of the process of trying to understand what the hell is going on in the context of incomplete science, and a mad history of philosophy that’s all over the place.
Some people deride this process (Oh no! Jerry Coyne is banging on about free-will again! Enough already!). Well, maybe they can only take so much. But for the rest of us these are interesting points, with interesting outcomes (how we view responsibility) that depend on how we view human behaviour, and even how we frame it (free-will as an illusion or a reality).
So, I’m afraid you’ll have to wade through a lot of crap from all sides. At least you can narrow it down to what is basically a love-fest threesome: dualist (actual separate free-will), compatibilist (an emergent free-will worth having), incompatibilists (free-will is an illusion). They are the three main categories, with lots of overlap.