an a priori argument for the existence of God, asserting that as existence is a perfection, and as God is conceived of as the most perfect being, it follows that God must exist; originated by Anselm, later used by Duns Scotus, Descartes, and Leibniz.
Origin of ontological argument
First recorded in 1875–80
Also called ontological proof.
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British Dictionary definitions for ontological argument
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