 abstract objects |  analytic/synthetic distinction |  Aristotle |  Bolzano, Bernard |  Buridan, John [Jean] |  Descartes, René |  descriptions |  Frege, Gottlob |  Kant, Immanuel |  knowledge: analysis of |  Leibniz, Gottfried Wilhelm |  logical constructions |  logical form |  Moore, George Edward |  necessary and sufficient conditions |  Ockham [Occam], William |  Plato |  Russell, Bertrand |  Wittgenstein, Ludwig 