On the Twelve Abuses of the World

They deceive, however, because when they announce their own dispositions, something is suddenly ordered from above that disturbs all their plans. Demons are deceived when they predict some things from natural causes, as physicians, sailors, or farmers do, but far more acutely and far more excellently through the cleverer sensation and exercise of the aerial body, because these things are also changed from the unexpected and suddenly by angels who serve the highest God piously, which is unknown to the demons. Demons are also deceived by the desire to deceive and by the envious will by which they rejoice in the error of men. But so that they do not lose the weight of authority among their own followers, they act in such a way that the blame is attributed to their interpreters and to those who conjecture signs, whenever they have been deceived or have lied.