 Aquinas, Thomas |  Aristotle |  behaviorism |  consciousness |  Descartes, René |  epiphenomenalism |  functionalism |  haecceity: medieval theories of |  Hume, David |  James, William |  materialism: eliminative |  mental causation |  mind/brain identity theory |  neutral monism |  personal identity |  physicalism |  Plato |  qualia |  qualia: knowledge argument |  vagueness 