Avicenna divides “actual” beings, as opposed to impossible things, into necessary in itself and possible in itself but necessary through another (Davidson 1987: 292–3; McGinnis 2010: 159–164). The necessary in itself is that which has existence in its essence and an impossibility arises whenever it is assumed not to exist. By contrast, the possible in itself but necessary through another is that which “has no existence in essence” and “no impossibility” arises whether it is assumed to exist or n