Gilbert of Poitiers (Gilbertus Porretanus)

Gilbert of Poitiers (Gilbertus Porretanus, c. 1085–1154) was Bishop of Poitiers and one of the most subtle and controversial metaphysicians of the 12th century. He studied and taught at the Cathedral School of Chartres and at Paris.

Metaphysics of Participation

Gilbert's primary philosophical achievement was his Commentary on Boethius's De Trinitate, in which he pushed Boethian participation metaphysics to its logical limits, distinguishing sharply between God's subsistent being (quo est) and the form of being that creatures participate in (quod est). This distinction was condemned at the Council of Reims (1148) as dangerously close to dualism — a sign of the radical nature of his thinking. His probable authorship of De sex rerum principiis is established by Mark Damien Delp through close stylistic and doctrinal comparison with the Boethius commentary. The six principles of the treatise are the direct application of Gilbert's participation metaphysics to cosmology.