Eustratius of Nicaea
Byzantine bishop and commentator on Aristotle, a pupil of John Italos. Against the Latin picture of the Trinity as a line running Father to Son to Spirit, he set an isosceles triangle: the Father at the apex, the Son and the Spirit perfectly level at the two base corners.
Eustratius was a Byzantine bishop and one of the significant Aristotle commentators of his century, a pupil of John Italos. His *Sermon on the Holy Spirit* argues against the Latin addition to the creed using the arithmetic of the Neoplatonists.
His picture is geometrical. The Latin scheme he attacks is a line: Father, then Son, then Spirit. His own is an isosceles triangle, Father at the apex, Son and Spirit at the base corners, exactly level. If you break the symmetry between the two of them, he argues, they stop being a dyad distinct from the Father's monad and the whole structure fails.
Two cautions attach to his name. Much of what is credited to him — in particular the claim that numbers past three add no new principle — is not in his surviving text, which makes a lower-bound claim and no upper-bound claim at all. And his own contemporaries objected: Nicholas Mouzalon and Nicholas of Methone both argued that the numerological approach either generates an unwanted fourth or misdescribes the Trinity from the start.
Where this comes up
Sources
- Eustratius, Sermon on the Holy Spirit, ed. Barmin 2006
- B. Lourié, Scrinium 16 (2020), pp. 344–358