I think this is a case of exactly the problem I diagnosed above.

Compatibilism (and related views) have been mentioned at least since Hume, and have been discussed extensively in modern analytic philosophy. Although it commands a slender majority of philosophers of action, it is not like the entire philosophical community considers compatibilism obviously or decisively the 'right answer' (see here, and here for a long index of reasons/objections etc.). You'd be pretty hard pressed to find a single philosopher of action who considers free will a 'solved problem'.

Yet it seems the less wrong community considers it solved based on a sequence of blog posts which merely explicates compatibilism: I couldn't find any discussion of compatibilism which goes beyond undergrad philosophy level, no discussion of common objections to compatibilism, engagement with any thinkers arguing against, nothing.

The two best explanations I have for this is either compatibilism is just obvious and people of sufficient rationality can be confident that domain experts on free will who don't buy compatibilism are wrong, or that the LW 'solution' is frankly philosophically primitive but LWers are generally too far on the wrong side of the Dunning-Kruger effect to appreciate why it isn't the decisive answer to a 'millenia old philosophical dilemma' they think it is.

Surely the outside view would find the latter account much more plausible?

I don't think there's much value in pretending that issues like God (and the absence thereof) or the compatibility between determinism and (any logically coherent view of) free will haven't been decisively answered.

There are plenty of reasons for putting forward you conclusions as non decisive: (edited)

1. Not sounding as though you are suffering from the Dunning Kruger effect

2. Academic Modesty.

3. You might actually be wrong. No one who calls themselves a rationalist should confuse "Seems true to me" with "is true".

In every discussion I've had since, in any forum, nobody who thinks them to be incompatible can describe even vaguely what "free will" would be supposed to look like if it does not contain determinism inside it.

We haven't met, then. I'm natuarlistic libertarian and therefore an incompatibilist. I may not be right, but so long as I am not completely wrong, EY does not have "the" answer.

Anyway, on to the refutation of "FW requires determinism"..

II.1.i Introduction Compatibilism comes in a stronger form, which does not have a traditional name; We will call it supercompatibilism. According to supercompatibilism, free will is not only capable of existing alongside causal determinism, it cannot exist without determinism.

Here is case that free will requires causal indeterminism.

PRO: "Free will requires the ability to have done otherwise under the very same circumstances, which is only possible in a universe with some degree of indeterminism."

The following argument goes against the usefulness of indeterminism to free will:-

ANTI: "Freedom of a kind worth wanting requires rationality, and rationality mean following rules. Causal Determinism would ensure that the rules are followed. Indeterminism would disrupt the process of rational thought, and result in a capricious, irrational kind of freedom not worth having. An individual cannot call an action his or her own unless they can account rationally account for it, and unless it was caused by their own intentions. Reasons are causes, so to be rational is to be determined.

We will now argue against the ANTI argument, taking it a sentence at a time.

II.1.ii Objection 1: "Freedom of a kind worth wanting requires rationality"

Yes, but it is by no means limited to rationality. free will of a kind worth wanting must facilitate the whole gamut of human behaviour, including creativity, imagination, inventiveness etc.

II.1.iii Objection 2: "Causal Determinism would ensure that the rules are followed."

Casual Determinism only guarantees that everything follows the laws of nature, not that anything follows the laws of thought. If you believe the universe is deterministic, you have to admit that any lapse of rationally is just as determined as everything else. Indeed, we are more likely to look for a deterministic — in the sense of an external cause —explanation for uncharacteristically irrational behaviour than for rational behaviour — so-and-so was drunk, drugged, etc.

II.1.iv Objection 3: "Indeterminism would disrupt the process of rational thought, and result in a capricious, irrational kind of freedom not worth having."

Is that so ? Computer programmes can consult random-number generators where needed, including 'real' ones implemented in hardware. (like this) The rest of their operation is perfectly deterministic. Why should the brain not be able to call on indeterminism as and when required, and exclude it the rest of the time ? And if random numbers are useful for computers, why should indeterministic input be useless for brains ? Is human rationality that much more hidebound than a computer ? Even including such faculties as creativity and imagination ? Pseudo-random numbers (which are really deterministic) may be used in computers, and any indeterminism the brain calls on might be only pseudo-random. But it does not have to be, and if we assume it is not, we can explain realistically why we have the sense of being able to have done otherwise.

And is it so great to be compelled into rule-following rationality ? If you asked some what 5 and 7 make, you would expect the answer 12. But if you asked them the same question ten times in a row, you would expect them to object at some stage, and stop answering, unlike a pocket calculator which will spit out the same answer ad infinitum. Surely the choice of whether or not to follow a set of rules is part of rationality ?

II.1.iv Objection 4: "An individual cannot call an action his or her own unless they can rationally account for it and unless it was caused by their own intentions"

It is true that we would not consider an individual to 'own' a an action or decision if it had nothing to do with his beliefs and aims at the time he made it — that is, if we assume that indeterminism erupts in-between everything that happened to make him the individual he is, and the act itself.

But, we libertarians claim. an act is also not an individual's own if it entirely attributable to causes lying outside him, ultimately traceable to circumstances before he came into existence.

There is no need to be disheartened. If the causal origins of our actions cannot lie before our births or after our decisions have been made, they can still lie, just where they should: during our lifetimes.

Our actions can be determined by our preceding mental state, providing that our mental state is not itself entirely attributable to causes outside of ourselves. This means that, although we can pin actions to immediate purposes, we cannot trace back a chain of purposes-for-purposes ad infinitum.

I do not think that is any loss, since determinism fares no better. All purposes may be causes, but not all causes are purposes. The deterministic causal chain, if traced back, is bound to encounter factors which do not rationally explain, any more than a random occurrence does. Moreover, this process of looking for ultimate rational explanations is unusual to say the least. Our normal attitude is that John and Mary have their reasons, which are very much part of who they are, and that's that. II.1.v Reasons are causes, so to be rational is to be determined. Is it the case that our actions are determined by our reasons, so that indeterminism must entail irrationality?

The reasons we have for actions might be said to cause those actions, but there are a number of differences between reasons and causes, and in any case reasons are not determining causes, as will be argued.

Whereas any event can involve causation, only a small subset of entities in the universe, rational agents, can base their actions on reasons. Causes lie in the past, whereas reasons are generally directed towards some future state of affairs. A causal statement is not a direct substitute for a rational justification. If I kick someone and am asked why I did it, it is no justification — for all that it is true — to say that nerve signals from my brain caused my leg to flex. A Causal chain can continue back to the Big Bang, but a rational explanation for behavour cannot. An individual must explain their behaviour in tersm of their own aims an desires. Once they start claiming they were caused to behave in a certain way, by their environment, genes,etc, they are no longer offering reasoned explanaion. Causal explanation is 'classical' — everything is brought under a uniform, impersonal set of laws. Rational explanation is 'romantic' — people have their own unaccountably individual reasons for doing things. There is no single right answer to "what should I do", as it depends on what you as an individual want to do — nor is there any single right answer to "what should I want".

That reasons are not determining causes is established by the fact that one can have multiple reasons for multiple courses of action. If one accepts the slice of cake, one pleases the hostess; if one rejects it, one sticks to ones diet. If reasons and actions are chosen in pairs there will always be a reason for ones action irrespective of what is actually chosen. This is still true if a choice is made randomly. If one does choose a reason-action pair randomly, it is admittedly true that a reason-for-the reason cannot be given. But it is always the case that chains of reasoning cannot be pursued to infinity; they have to stop somewhere (or be circular). Since real-world reasoning is constrained in this way, limited amounts of indeterminism would not render people any less able to provide chains of reasoning than they are anyway, even though it remains the case that complete indeterminism entails complete irrationality.

If reasons are not determining causes, are they causes at all? It would certainly be a peculiar situation if reasons were causally completely detached from the actions they explain. At least the neural correlates of reasons need to be causes. Reasons themseleves arguably belong to a different language game so that it is a category-error to substitute talk of reasons directly for talk of causes an vicer-versa. This need not imply any ontological dualism, but rather a kind of anomolous monism.

It is sometimes said that we are free to do what we want, but not to choose what we want. The approach sketched so far is pretty much the opposite of this. If we have clear reasons for doing something and are in a rational frame of mind our actions follow almost inevitably. Freedom lies in the fact that our basic aims and goals, our basic nature is not inevitable, We might not have done as we did because we might not have been that kind of person. Freedom is not mere caprice, not does it lie in being the puppet of circumstances, it is self determination, a gradual evolution of selfhood.