 Aristotle, General Topics: logic |  Bosanquet, Bernard |  categories: medieval theories of |  causation: counterfactual theories of |  ethics: virtue |  facts |  Green, Thomas Hill |  Heraclitus |  logic: classical |  logic: informal |  logic and ontology |  metaphysics |  Parmenides |  realism: challenges to metaphysical |  Reid, Thomas |  Russell, Bertrand |  Ryle, Gilbert |  Scottish Philosophy: in the 19th century |  square of opposition |  states of affairs 