If the human soul is made for good, then how do we choose evil? On the other hand, perhaps the human soul is not made for good. Perhaps the magnitude of human depravity reveals that the human soul may directly choose evil. Notably, Thomas Aquinas rejects this explanation for the prevalence of human sin. He insists that in all our desires we seek what is good. How, then, do we choose evil? Only by mistaking evil for good. This solution to the difficulty, however, leads Aquinas into another conundrum. How can we be held responsible for sins committed under a misunderstanding of the good? The sinner, it seems, has simply made an intellectual blunder.