 Although its precise form and interpretation have varied, this principle has enjoyed broad support in the history of philosophy. PAP was a standard—even if not universal—presupposition of Greek, medieval, and early modern thought (Irwin 1999: 225; Pasnau 2003: 226; Rowe 1987: 43). And until about fifty years ago, it was usually taken for granted by both sides in debates on whether moral responsibility is compatible with determinism.