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Anselm of Canterbury

Scholastic · Europe · 1033 to 1109

Medieval archbishop who tried to show by reason alone that God must exist. His argument starts from the greatest thing we can think of.

What it is

Anselm of Canterbury (1033 to 1109) was a Benedictine monk and later Archbishop of Canterbury who gave the first form of the ontological argument for the existence of God and described his method as faith seeking understanding. He is the outstanding Christian philosopher and theologian of the eleventh century, and he is still read for his arguments about God, truth and freedom.

He was born in 1033 near Aosta, a border town of the kingdom of Burgundy. He travelled to Normandy and entered the Benedictine abbey at Bec, whose famous school he joined under the teacher Lanfranc. He became abbot of Bec in 1078 and later was enthroned as Archbishop of Canterbury. He died in 1109.

The main ideas

  • Faith seeking understanding. His own phrase for his method, in Latin fides quaerens intellectum, says that belief comes first and that reason's task is to understand what is believed.
  • The ontological argument. In the Proslogion he argued that God is that than which nothing greater can be thought. If such a being existed only in the mind, a greater one that also exists could be thought, so the being must exist in reality as well.
  • An earlier set of arguments. In the Monologion, written in 1077, he gave arguments about God's existence and nature.
  • Why God became human. In Cur Deus Homo he set out a reasoned account of the incarnation and the atonement.
  • Truth and freedom. He wrote treatises on truth, on freedom of choice and on sin, among them On Truth and On Freedom of Choice.

What it looks like in practice

Picture a believer who is asked, 'But can you give a reason?' Anselm would not say that faith needs no reasons, and he would not say that reason must come first. He would say that a person who already believes may use thought to see why the belief makes sense, and that this effort is itself a form of devotion. This is an illustration of his method, not a passage from his books.

Books and moments

  • Monologion (1077) is his first major work.
  • Proslogion contains the ontological argument.
  • Cur Deus Homo is his book on the incarnation.
  • The reply of Gaunilo, a monk who answered on behalf of the fool, and Anselm's response to it.

Questions and criticism

  • Does the ontological argument work? It has been debated ever since. Gaunilo's reply is the earliest criticism, and his question is still asked: can a definition of God make God exist?
  • Where does faith end and reason begin? If belief comes first, it is fair to ask how far the arguments can persuade someone who does not already share it.
  • Is the method too comfortable? Starting from faith can look like arguing for a result already chosen. Defenders reply that the aim was understanding, not proof for outsiders.

Close neighbours

The page on theism describes the family of views he belongs to.

Written by epchē in our own words, and checked against independent sources on 9 October 2026. The sources are listed below.

Philosophies they belong to or are close to

Who they connect to

Influenced

  • John Duns Scotus · Scotus defended and refined Anselm's argument for God.
  • René Descartes · Descartes' argument in the Fifth Meditation revived the reasoning of Anselm's argument from the idea of God.

Influenced by

Reacted against by

  • Immanuel Kant · Kant argued that existence is not a property a thing can have, which undercuts Anselm's argument. (scholars disagree about this link)
  • Thomas Aquinas · Aquinas rejected Anselm's argument that God's existence follows from the idea of God, and preferred proofs that start from the world.

Other Scholastic thinkers

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