Roscelin of Compiègne (c. 1050 – c. 1121), better known by his Latinized name Roscellinus Compendiensis or Rucelinus, was a French philosopher and theologian, often regarded as the founder of nominalism.
Of his writings there exists only a letter addressed to Abelard on the Trinity, in which Roscellinus "belittles Abélard and makes merry over his castration.
According to Otto of Freisingen, Roscellinus "was the first in our times to institute the theory of words",[4] but the chronicler of the "Historia Francia"[5] mentions before him a "magister Johannes", whose personality is much discussed and who has not yet been definitively identified.
Nominalists held that: In Roscellinus's theory, the universal is merely an emission of sound (flatus vocis), in conformity with Boethius' definition.
[12] Roscellinus was not without his supporters; among them was his contemporary Raimbert of Lille, and what the monk Hériman relates of his doctrine agrees with the statements of the master of Compiègne.
[13] He merely comments on the saying of Anselm characterized by the same jesting tone,[14] and says that to understand the windy loquacity of Raimbert of Lille one has but to breathe into his hand.
This characteristic tritheism, which Anselm and Abelard agreed in refuting even after its author's conversion, seems an indisputable application of Roscelin's anti-Realism.