In medieval Christian tradition, the Devil is a mimic, an actor, a performance artist, imitating the wonders of nature and the divine work of creation. His medium is illusion. Unlike God, the Church Fathers argued, his antagonist cannot perform miracles or truly alter phenomena. He is merely God’s impostor, the master of lies, imitation, simulation, and pretense — yet powerless when it comes to the ability to transform substance and matter.

He can only conjure visions as illusions, as he does when, in the figure of Mephistopheles, he summons the Seven Deadly Sins for Doctor Faustus and later seduces him with the beguiling appearance of the spirit of Helen of Troy. In this way, he conjures images in the mind’s eye, playing on the desires and weaknesses of his victims. He toys with us, above all, by creating spectacles that are not truly there, for the very word illusion comes from ludere, “to play” in Latin.