Descartes goes about using his method of doubt to cast into doubt our beliefs, which we take for granted as being true, through three arguments. This can be seen as an extended exercise in

Finally, Descartes argues that God might have led him to believe that there is a material world or that two plus two equals four, although he may be wrong each time he calculates the latter equation. Thus, he could be forced by God (being almighty and powerful) to believe something which is in fact false. However, God “being supremely good and the fount of truth”, is not the one that deceives him, it is in fact the existence of a Deceiving Demon/Evil Genius that does.

The Dream argument presupposes that there may not be a material world to begin with and calls into doubt our beliefs based on the existence of that external world. However, this is not enough to make Descartes break his habitual pattern of “slipping back” into his old beliefs. He takes it one step further as to make himself believe that even those things in his dreams are “merely delusions” employed by the Deceiving God to cloud his judgements.

Some topics in this essay:
Firstly Descartes, Mediation” Descartes, Genius Dream, Finally Descartes, Deceiving God, method doubt, material world, external world, , plus equals, beliefs based, cast doubt, doubt beliefs, sensory perceptions, former beliefs, descartes argues,