 abstract objects |  Aristotle |  Aristotle, General Topics: metaphysics |  categories |  dualism |  existence |  free will |  incompatibilism: arguments for |  -->logical positivism--> |  material constitution |  mereology |  nominalism: in metaphysics |  ontological commitment |  physicalism |  Platonism: in metaphysics |  properties |  substance |  time 