The Zygote Argument is invalid: Now what?

Abstract

Alfred Mele’s original Zygote Argument is invalid. At most, its premises entail the negative thesis that free action is incompossible with deterministic laws, but its conclusion asserts the positive thesis that deterministic laws preclude (make impossible, undermine) free action. The original, explanatory conclusion of the Zygote Argument can be defended only by supplementing it with a best-explanation argument that identifies deterministic laws as menacing. (By the same reasoning, it follows that every manipulation argument pinpointing a specific threat to free will requires a best-explanation argument). Arguably, though, the best explanation for the manipulation victim’s lack of freedom and responsibility is his constitutive luck, which is a problem irrespective of the natural laws that obtain. This proposed explanation leads to a new “diagnostic” version of the Zygote Argument which concludes that free action is impossible even though deterministic laws pose no threat whatsoever to free will.