 There is variation in the interpretation of the doubt, even concerning the number of deceivers Descartes means to be citing. I suggest that a natural reading of the First Meditation passages provides for a unified account of a deceiver hypothesis. The passage represents the meditator as having long believed in a creator who’s both all-powerful and all-good. Here’s the thinking that seems to follow from such belief. A creator with these attributes would not allow its creatures to be deceived about the existence of the external world, nor about such transparent truths as that 2+3=5. But likewise, neither should a creator with these attributes allow its creatures ever to be deceived. Yet they are. Since even occasional deception seems to pose a reductio on the very existence of an all-powerful, all-good creator, the implication is that the creator (if there be one) must be lacking in either power or goodness. Suppose the creator is all-powerful but not all-good – i.e., an “evil genius” of sorts. In that case, it seems we might be deceived about even the most evident of matters.