Abstract

Any argument which attempts to prove God's existence a priori based only on His nature can be termed an "Ontological Argument". Historically, however, the term is inextricably associated with the famous argument presented in Anselm's Proslogion chapter II, and with the later variant advanced by Descartes in his fifth Meditation and subsequently developed by Leibniz. Some have claimed that Anselm's argument was anticipated in the thought either of various classical philosophers (notably Aristotle, Parmenides, Plato, and Zeno of Cition) or of Augustine, but although there are indeed suggestive passages in their writings, Anselm's explicit "proof" of God's existence based on his Nature does appear to be a genuinely original discovery.