He was born in Italy about 1033, and entered the monastery of Bec in Normandy to study under Stephen Lanfranc, whom he succeeded in office, first as prior of Bec, and later as Archbishop of Canterbury.
In 1087, while still at Bec, he produced his PROSLOGIUM, an outline of his "ontological argument" for the existence of God. Taking as his text the opening of Psalm 14 ("The fool hath said in his heart: There is no God."), Anselm undertakes to show that the fool is contradicting himself -- that the concept of God is unique in that anyone who understands what is meant by the question, "Does God exist?" will see that the answer must be "Yes." The argument has received mixed reviews from the start. Almost at once another theologian, Gaunilon, wrote, "A Reply on Behalf of the Fool." Thomas Aquinas rejected Anselm's argument as inconclusive (and is followed in this by most Roman Catholic writers today). Kant practically made his reputation as a philosopher by explaining in detail what he thought was wrong with Anselm's argument. On the other hand, Leibniz and others have thought it valid. My Plato professor (R E Allen), no friend of Christianity, says of the argument: "It is one of the most exasperating arguments in the history of philosophy. Every time that you think you have finally refuted it, you end up finding something wrong with your refutation." Modern defenders of the argument include Goedel (the writer on mathematical consistency and provability), Hartshorne, and C A Anderson of Minnesota. (Anderson is an atheist. I asked him how he reconciled his atheism with his defense of Anselm, and he said, "I am an atheist on faith. Surely you have met theists who believed in God on faith, despite knowing arguments on the other side that they could not really answer.") For an introduction, see the book GOD AND OTHER MINDS, by Alvin Plantinga.
King William II of England had no fondness for the Church, and at the death of Lanfranc he kept the See of Canterbury vacant until he was gravely ill, whereon he promised to let Anselm be made Archbishop. Anselm was made Archbishop, the King recovered, and the two began to dispute the extent of the King's right to intervene in Church matters. Anselm went into exile in 1097 and remained in Italy for three years until the King died in 1100.
During that time Anselm was instrumental in settling the doubts of the Greek bishops of southern Italy about the doctrine of the Filioque (for details, send the message GET CREED FILIOQUE to LISTSERV@ASUACAD.BITNET or to LISTSERV@ASUVM.INRE.ASU.EDU).
He also devoted the time to writing a book known as CUR DEUS HOMO? (meaning WHY DID GOD BECOME MAN?). In it he puts forward the "satisfaction theory" of the Atonement. Man's offence of rebellion against God is one that demands a payment or satisfaction. Fallen man is incapable of making adequate satisfaction, and so God took human nature upon Him, in order that a perfect man might make perfect satisfaction and so restore the human race. The success of his work may be gauged by the fact that many Christians today not only accept his way of explaining the Atonement, but are simply unaware that there is any other way.
PROSLOGIUM, MONOLOGIUM, GAUNILON'S REPLY, ANSELM ON GAUNILON, and CUR DEUS HOMO are available in a single paperback volume from Open Court Publishers.
From the Preface to the PROSLOGION:
I acknowledge, Lord, and I give thanks that you have created your image in me, so that I may remember you, think of you, love you. But this image is so obliterated and worn away by wickedness, it is so obscured by the smoke of sins, that it cannot do what it was created to do, unless you renew and reform it. I am not attempting, O Lord, to penetrate your loftiness, for I cannot begin to match my understanding with it, but I desire in some measure to understand your truth, which my heart believes and loves. For I do not seek to undertand in order that I may believe, but I believe in order to understand. For this too I believe, that "unless I believe, I shall not understand." (Isa. 7:9)
Jesus, as a mother you gather your people to you: you are gentle with us as a mother with her children; Often you weep over our sins and our pride: tenderly you draw us from hatred and judgement. You comfort us in sorrow and bind up our wounds: in sickness you nurse us, and with pure milk you feed us. Jesus, by your dying we are born to new life: by your anguish and labour we come forth in joy. Despair turns to hope through your sweet goodness: through your gentleness we find comfort in fear. Your warmth gives life to the dead: your touch makes sinners righteous. Lord Jesus, in your mercy heal us: in your love and tenderness remake us. In your compassion bring grace and forgiveness: for the beauty of heaven may your love prepare us.