Peter Abelard

French philosopher and theologian — who created conceptualism (the middle way between realism and nominalism) — whose affair with Héloïse and subsequent castration is the most famous personal catastrophe in medieval intellectual history — whose Sic et Non established the scholastic method.

Creates the scholastic method — Abelard's Sic et Non (Yes and No) collected contradictory opinions from Church Fathers on 158 theological questions without resolving them, teaching students to use logic to reconcile apparent contradictions; this method defined medieval university philosophy (scholasticism) for 300 years.