I'm currently reading Derk Pereboom's Living Without Free Will, which defends what Pereboom calls "hard incompatibilism" and then explores its implications.
Hard incompatibilism is similar to hard determinism, but allows for an element of randomness in nature. It consists of two theses: First, all of our actions and choices are either (1) ultimately determined by causal forces that are beyond our control or (2) partially random. Second, this is incompatible with free will. For the second thesis, Pereboom relies upon a Causal History Principle to the effect that we do not have free will if our choices are ultimately determined by certain kinds of events, basically events that are not themselves in our power to control.
I agree with the first thesis, but disagree with the second.
As I understand Pereboom, he thinks that free will of the kind he discusses is a coherent concept, but he also thinks that we don't actually possess it. Though the argument is complex, I'm not convinced: I find it very difficult to believe that the concept is even coherent. When agent causation theorists attempt to state it, they can make it sound as if they are talking about something that makes sense, but in the end this concept of libertarian free will always demands that I actually cause not only my own actions but also the self that caused them ... and whatever events shaped my decisions when I did that. Etcetera. Or else, it requires that my choices be free, yet not flow from, and be attributable, my prior nature. The second these possibilities is surely not consistent with our idea of free will, while the first is clearly not a possibility at all. I conclude that libertarian free will of the kind that agent causation theorists attempt to describe is not even a coherent concept.
That is not to deny that our naive, pre-theoretical idea of free will may resemble the libertarian concept and incline us to adopt it. The naive idea of free will may simply be that choices by a rational agent are ultimate causes, requiring no more explanation. Perhaps we have evolved to have a tendency to think in that way and treat each other accordingly.
However, the slightest intellectual pressure on this idea shows how problematic it is, even without any reliance on scientific accounts of nature. In many circumstances, it may be socially useful to act as if the choices of rational agents are not caused by anything else, not even by the agent's own makeup, but we can also ask whether it's really like that. Once we ask that question, we realise that we must at least say that the agent's choices reflect something about the agent's own makeup, or else we seem to be dealing with agents who act at random, and who cannot be unproblematically criticised for their choices. Moreover, we know that there are, in fact, further causes for how human agents choose and act (brain processes for example, plus the events that, in turn, led to them, such as genetic potentials, environmental influences and so on).
The question is whether it is useful to talk about free will at all (and about moral responsibility, etc.) while rejecting the naive idea and seeing ourselves as part of the causal unfolding of nature.
Nothing said by Pereboom has shaken me from my view that such language is, indeed, still useful. In other words, I remain a compatibilist. It is possible to live with concepts of free will, moral responsibility, etc., that are appropriate to the circumstances of creatures like us, and are distinguishable from the naive view of free will. What we can't find is an ultimate responsibility for our actions sufficiently powerful to break any chain of causation between them and the prior creative acts of an all-powerful diety, thus absolving the deity of any blame for our deeds. The naive idea of free will (or a rationalisation of it) is required for the purpose of theodicy. However, we can get by for ordinary social purposes without the naive idea.
Nonetheless, there may be consequences to abandoning the naive idea of free will, apart from the obvious theological ones, and perhaps that is all Pereboom needs for his book to be useful.
Abandoning the naive idea of free will entails abandoning naive ideas of the related concepts of agency and autonomy, and that does have implications in, for example, debates about designer babies (though that is not the kind of issue that Pereboom is interested in).
We need to think through how to live without the naive idea of free will, but I don't believe that it is a concept that we really need. We should get used to living with a more sophisticated kind of free will that is grounded in educated common sense, which will be a compatibilist version of the idea.