Abstract: According to Descartes, the standard of truth lies in that kind of perception which has the characteristic of clearness and distinctness. However, there is a limit to what a subject can consciously fathom at any given moment, which renders that any complex mathematical reasoning cannot be dealt with in only one Cogito. This fact demands that the recollection of the middle conclusion must be true, which is confirmed by God's benevolence in Descartes'opinion. Accordingly, Descartes concludes that mathematics and belief in God must go hand in hand. However, the paper argue that, while theism adds a layer of psychological reassurance, the mind-independent reality of God would ensure the preservation of past demonstrations for atheists as well.