Proofs For God’s Existence (or are they really proofs?)

St. Anselm of Canterbury (1033/ ) Born Aosta, Italy (then Piedmont) fleeing his family, traveled to Normandy, where he became a Benedictine (1060), then later to England Became Archbishop of Canterbury 1093 (against his will) Proslogion composed 1078

Anselm’s argument God =df. “something greater than which cannot be thought” (in other translations: “that than which no greater can be thought”) God =df. “something greater than which cannot be thought” (in other translations: “that than which no greater can be thought”) Such a thing can be thought of (what is meant by the expression can be understood) without any commitments to its existence Such a thing can be thought of (what is meant by the expression can be understood) without any commitments to its existence Q: what is strange/unique about Anselm’s formulation? Q: what is strange/unique about Anselm’s formulation?

Anselm’s argument (cont’d.) Such a thing cannot consistently be thought of as not existing. Why not? Such a thing cannot consistently be thought of as not existing. Why not? To think of “something greater than which cannot be thought” as not existing would involve thinking a contradiction (which is impossible); therefore that thing cannot be thought of as not existing. Therefore, that thing exists. To think of “something greater than which cannot be thought” as not existing would involve thinking a contradiction (which is impossible); therefore that thing cannot be thought of as not existing. Therefore, that thing exists. Therefore, God exists Therefore, God exists (elegant little proof, isn’t it?) (elegant little proof, isn’t it?)

Problems with Anselm’s argument? Does the expression of the concept involve some kind of verbal trickery? (for e.g. must “the most perfect dog” exist?) Does the expression of the concept involve some kind of verbal trickery? (for e.g. must “the most perfect dog” exist?) Is this really a proof? (for e.g. what would a proof for the claim “a bachelor is an unmarried male person” look like?) Is this really a proof? (for e.g. what would a proof for the claim “a bachelor is an unmarried male person” look like?) Is there really a contradiction here? Is there really a contradiction here?

Thomas Aquinas ( ) Joined Dominican order against the wishes of his family; led peripatetic existence thereafter. Considered the most learned man of his day; much in demand as teacher and lecturer. Summa Theologica never finished, following ‘ecstasy’ in Dec. 1273

Aquinas on God’s existence Believed, as against several interesting objections, that God’s existence can (and needs to be) ‘demonstrated’ (‘proved’, in the modern sense). Believed, as against several interesting objections, that God’s existence can (and needs to be) ‘demonstrated’ (‘proved’, in the modern sense). By this he meant 2 things: By this he meant 2 things: 1. That God exists is not ‘self-evident’ or axiomatic or a matter of definition 2. That God exists is something which we can be completely sure of, as a matter of reason (and not simply of faith)