He states that he can regard the existence of God with at least the same level of certainty as he attributes to the truths of mathematics.
The argument from possibility holds that there must be a Being who is responsible for his creation. If he had created himself, he would have bestowed on himself all the perfection he conceives of as God. More than this, if Descartes had been the cause of his own existence, he would also be the cause of the idea of the perfect, of God, that is in his mind. To accomplish this, he would have to be the perfect being himself. This is the singular argument, but he also argues that there must be a separate Being because if he were himself the being creating this idea, he would have to have the power and action that would be required to produce this idea and create it anew if it did not already exist. If he (Descartes) had this power, he would be conscious of it. Since he is not, there must be a separate Being that cannot be anything less than God, for there must be at least as much reality in the cause as in the effect.
The argument from reality holds that Descartes exists but does not exist necessarily, for only God