Proofs For God’s Proofs For God’s ExistenceExistence

(or are they really proofs?)(or are they really proofs?)

St. Anselm of Canterbury St. Anselm of Canterbury (1033/34-1109)(1033/34-1109)

Born Aosta, Italy (then Born Aosta, Italy (then Piedmont)Piedmont)

fleeing his family, fleeing his family, traveled to Normandy, traveled to Normandy, where he became a where he became a Benedictine (1060), then Benedictine (1060), then later to Englandlater to England

Became Archbishop of Became Archbishop of Canterbury 1093 (against Canterbury 1093 (against his will)his will)

Proslogion composed Proslogion composed 10781078

Anselm’s argumentAnselm’s argument

God =df. “something greater than which cannot God =df. “something greater than which cannot be thought” (in other translations: “that than be thought” (in other translations: “that than which no greater can be thought”)which no greater can be thought”)

Such a thing can be thought of (what is meant Such a thing can be thought of (what is meant by the expression can be understood) without by the expression can be understood) without any commitments to its existenceany commitments to its existence

Q: what is strange/unique about Anselm’s Q: what is strange/unique about Anselm’s formulation?formulation?

Anselm’s argument (cont’d.)Anselm’s argument (cont’d.)

Such a thing cannot consistently be thought of Such a thing cannot consistently be thought of as not existing. Why not?as not existing. Why not?

To think of “something greater than which To think of “something greater than which cannot be thought” as not existing would involve cannot be thought” as not existing would involve thinking a contradiction (which is impossible); thinking a contradiction (which is impossible); therefore that thing cannot be thought of as not therefore that thing cannot be thought of as not existing. Therefore, that thing exists.existing. Therefore, that thing exists.

Therefore, God existsTherefore, God exists (elegant little proof, isn’t it?)(elegant little proof, isn’t it?)

Problems with Anselm’s Problems with Anselm’s argument?argument?

Does the expression of the concept Does the expression of the concept involve some kind of verbal trickery? (for involve some kind of verbal trickery? (for e.g. must “the most perfect dog” exist?)e.g. must “the most perfect dog” exist?)

Is this really a proof? (for e.g. what would Is this really a proof? (for e.g. what would a proof for the claim “a bachelor is an a proof for the claim “a bachelor is an unmarried male person” look like?)unmarried male person” look like?)

Is there really a contradiction here?Is there really a contradiction here?

Thomas Aquinas (1225-1274) Thomas Aquinas (1225-1274)

Joined Dominican order Joined Dominican order against the wishes of his against the wishes of his family; led peripatetic family; led peripatetic existence thereafter.existence thereafter.

Considered the most Considered the most learned man of his day; learned man of his day; much in demand as much in demand as teacher and lecturer.teacher and lecturer.

Summa TheologicaSumma Theologica never never finished, following finished, following ‘ecstasy’ in Dec. 1273‘ecstasy’ in Dec. 1273

Aquinas on God’s existenceAquinas on God’s existence

Believed, as against several interesting Believed, as against several interesting objections, that God’s existence can (and needs objections, that God’s existence can (and needs to be) ‘demonstrated’ (‘proved’, in the modern to be) ‘demonstrated’ (‘proved’, in the modern sense).sense).

By this he meant 2 things:By this he meant 2 things:1. That God exists is not ‘self-evident’ or 1. That God exists is not ‘self-evident’ or

axiomatic or a matter of definitionaxiomatic or a matter of definition2. That God exists is something which we 2. That God exists is something which we

can be completely sure of, as a matter of reason can be completely sure of, as a matter of reason (and not simply of faith)(and not simply of faith)