attributes which faith ascribes to Him. Anselm says the same in the Preface to the Proslogion:
"Considering that the prior work was woven out of a concatenation of many arguments, I set to seek within myself (mecum) whether I might not discover one argument which needed nothing else than itself alone for its proof; and which by itself might suffice to show that God truly exists, and that He is the summum bonum needing nothing else, but needed by all things in order that they may exist and have well-being (ut sint et bene sint); and whatever we believe concerning the divine substance."
The famous proof which at length flashed upon him is substantially this: By very definition the word God means the greatest conceivable being. This conception exists even in the atheist's mind, for he knows what is meant by the words, the absolutely greatest. But the greatest cannot be in the intellect alone, for then conceivably there would be a greater which would exist in reality as well. And since, by definition, God is the absolutely greatest, He must exist in reality as well as in the mind.[1] Carrying out the scholia to this argument, Anselm then proves that God possesses the various attributes ascribed to Him by the Christian Faith.
That from a definition one may not infer the existence of the thing defined, was pointed out by a certain monk Gaunilo almost as soon as the Proslogion appeared. Anselm answered him that the argument applied only to the greatest conceivable being. Since that time Anselm's proof has been upheld and disproved many times. It was at all events a great dialectic leap; but likely one may not with such a bound cross the chasm from definition to existence—at least one will be less bold to try when he realizes that this chasm is there. Temperamentally, at least, this proof was the summit of Anselm's idealism: he could not but conceive things to exist in correspondence to the demands of his conceptions. He never made another so palpable leap from conception to conviction as in this proof of God's existence; yet his theology proceeded through like processes of thought. For example, he is sure of God's omnipotence, and also sure that God can do nothing which would detract from the perfection of His nature: God cannot lie: "For it
- ↑ The locus classicus is Proslogion, cap. 2.
