This paper has two parts. In the first part, I concede an error in an argument I have given for the incompatibility of free will and determinism. I go on to show how to modify my argument so as to avoid this error, and conclude that the thesis that free will and determinism are compatible continues to be—to say the least—implausible. But if free will is incompatible with determinism, we are faced with a mystery, for free will undeniably exists, and (...) it also seems to be incompatible with indeterminism. In the second part of this paper, I will defend the conclusion that the concept of agent causation is of no use to the philosopher who wants to maintain that free will and indeterminism are compatible. I conclude that free will remains a mystery---that is, that free will undeniably exists and that there is a strong and unanswered prima facie case for its impossibility. (shrink)

‘Molinism’, in contemporary usage, is the name for a theory about the workings of divine providence. Its defenders include some of the most prominent contemporary Protestant and Catholic philosophical theologians.¹ Molinism is often said to be the only way to steer a middle..