Medieval Philosophy

by Peter S. Adamson

many ways: more hair, less interest in philosophy. Or what about a thing and its parts? Is a peanut butter cup the same as its peanut butter center plus its chocolate coating? It may seem so, but consider that if so, anything that loses a part would cease to be the same thing. Do I really make a peanut butter cup no longer the same thing by taking a bite out of it, or make myself no longer the same thing by trimming the little hair I still have? Clearly, then, consideration of the Trinity can lead directly to fundamental issues in metaphysics. The same is true for epistemology. While Christians did invoke passages in the Bible to support the Trinitarian doctrine, they were also tempted to think that human reasoning can establish God’s triune nature without any help from revelation. Anselm already made a case for this in his Monologion. In the twelfth century a number of thinkers went so far as to say that pagan philosophers had reached an understanding of God’s Trinity even before the time of Christ. On the other hand, medieval thinkers frequently hasten to remind us that God lies beyond the grasp of reason. This might seem to apply especially to the mysterious, even paradoxical notion that He is somehow three despite being one, and even simple. The Trinity duly became a kind of litmus test for how far medievals thought that reason can take us in understanding God.