The dilemma explored in Plato’s dialogue Euthyphro. Are pious things pious because the gods love them, or do the gods love them because they are pious? The dilemma poses the question of whether value can be conceived as the upshot of the choice of any mind, even a divine one. On the first option the choice of the gods creates goodness and value. Even if this is intelligible it seems to make it impossible to praise the gods, for it is then vacuously true that they choose the good. On the second option we have to understand a source of value lying behind or beyond the will even of the gods, and by which they can be evaluated. The elegant solution of Aquinas is that the standard is formed by God’s nature, and is therefore distinct from his will, but not distinct from him.

The dilemma arises whatever the source of authority is supposed to be. Do we care about the good because it is good, or do we just call good those things that we care about? It also generalizes to affect our understanding of the authority of other things: mathematics, or necessary truth, for example. Are truths necessary because we deem them to be so, or do we deem them to be so because they are necessary?