The beginning of scholasticism can be identified in the methods used by civil and canon lawyers of the 11th and 12th cent. to reconcile seemingly contradictory statements. St. Anselm in the late 11th cent. took as his life's motto "fides quaerens intelligentiam" [faith seeking understanding], and sought to use reason to illuminate the content of belief. An example of this is his famous ontological proof of the existence of God, based on the assertion that the highest being of which our minds can conceive must exist in reality.
The most important philosophical problem in the 12th cent. was the question of the universal (see realism). Opposing both the extreme nominalism of Roscelin and the realism of William of Champeaux, Peter Abelard taught a moderate doctrine; he recognized the universal as a symbol to which human beings have attached a commonly agreed significance, based on the similarity they perceive in different objects. Abelard's emphasis on the powers of reason, which he exaggerated in his early years, led to his condemnation by Bernard of Clairvaux. John of Salisbury, an English scholar noted for his humanistic studies, was representative of the important work done at the noted school at Chartres.
Hugh of St. Victor, a German scholar and mystic, urged the study of every branch of learning. His treatise On Sacraments was the first summa, an important medieval literary genre. The summae were comprehensive, intricately arranged works on theology and philosophy; they were characterized by their wide scope and vast learning. The Book of Sentences, however, assembled by Peter Lombard in the early 12th cent., was to become the classical source book for medieval thinkers. It was a compilation of sources from the church fathers, especially St. Augustine, and in subsequent years virtually every great medieval thinker wrote a commentary on the Sentences.