The deus deceptor (French dieu trompeur) "deceptive god" is a concept of Cartesianism. Voetius accused Descartes of blasphemy in 1643. Jacques Triglandius and Jacobus Revius, theologians at Leiden University, made similar accusations in 1647, accusing Descartes of "hold God to be a deceiver", a position that they stated to be "contrary to the glory of God". Descartes was threatened with having his views condemned by a synod, but this was prevented by the intercession of the Prince of Orange (at the request of the French Ambassador Servien). The accusations referenced a passage in the First Meditation where Descartes stated that he supposed not an optimal God but rather an evil demon "summe potens & callidus" ( "most highly powerful and cunning"). The accusers identified Descartes' concept of a deus deceptor with his concept of an evil demon, stating that only an omnipotent God is "summe potens" and that describing the evil demon as such thus demonstrated the identity. Descartes' response to the accusations was that in that passage he had been expressly distinguishing between "the supremely good God, the source of truth, on the one hand, and the malicious demon on the other". He did not directly rebut the charge of implying that the evil demon was omnipotent, but asserted that simply describing something with "some attribute that in reality belongs only to God" does not mean that that something is being held to actually be a supreme God.
The evil demon is omnipotent, Christian doctrine notwithstanding, and is seen as a key requirement for Descartes' argument by Cartesian scholars such as Alguié, Beck, Émile Bréhier, Chevalier, Frankfurt, Étienne Gilson, Anthony Kenny, Laporte, Kemp-Smith, and Wilson. The progression through the First Meditation, leading to the introduction of the concept of the evil genius at the end, is to introduce various categories into the set of dubitables, such as mathematics (i.e. Descartes' addition of 2 and 3 and counting the sides of a square). Although the hypothetical evil genius is never stated to be one and the same as the hypothetical "deus deceptor," (God the deceiver) the inference by the reader that they are is a natural one, and the requirement that the deceiver is capable of introducing deception even into mathematics is seen by commentators as a necessary part of Descartes' argument. Scholars contend that in fact Descartes was not introducing a new hypothetical, merely couching the idea of a deceptive God in terms that would not be offensive.
Paul Erdős, the eccentric and extremely prolific Hungarian-born mathematician, referred to the notion of deus deceptor in a humorous context when he called God "the Supreme Fascist", who deliberately hid things from people, ranging from socks and passports to the most elegant of mathematical proofs. A similar sentiment is expressed by Douglas Adams in The Hitchhikers Guide to the Galaxy in reference to the temptation of Adam and Eve by God:
- puts an apple tree in the middle of and says, do what you like guys, oh, but don't eat the apple. Surprise surprise, they eat it and he leaps out from behind a bush shouting "Gotcha." It wouldn't have made any difference if they hadn't eaten it...Because if you're dealing with somebody who has the sort of mentality which likes leaving hats on the pavement with bricks under them you know perfectly well they won't give up. They'll get you in the end.
Read more about this topic: Misotheism