It is taken to be self-evident that freedom requires being able to do otherwise, by most incompatibilists, and some compatibilists; however, there are more than one way to interpret the meaning of “being able to do otherwise.” In this paper, two different versions of principle of alternative possibilities (PAP) are discussed: One of these PAPs is related to determinacy, and the other is related to supervenience. I defend that PAP which is about determinacy and, which is widely being used by incompatibilist has nothing to do with freedom, and the other PAP cannot be satisfied in a physicalistic world.
