Lumen Naturale

The lumen naturale — borrowed from the scholastic tradition — is Peirce's name for the human capacity to generate the right hypothesis, or at least a hypothesis close enough to right that subsequent testing can refine it. It is the mystery that abduction logically presupposes but cannot itself explain. Peirce asked: given that the number of possible theories exceeds a trillion, how did humanity ever hit upon the true theories in the tiny number of attempts that characterize actual scientific history? Chance alone cannot explain it. The human mind guesses correctly far more often than random selection would predict, and this guessing capacity is a brute fact about human cognition that logic can describe but cannot fully explain.