In philosophy, can someone explain to me the concept of Descartes 'Cartesian circle'?

[flobadoba_guy]

I know this is related to his attempt at establishing the existence of God but this isn't really making any sense to me

[-.-]

Clear and distinct (C&D) ideas prove God
God proves C&D ideas.

[Joseph]

In a time of upheaval, Rene Descartes (1596-1650) famously sought to ground all knowledge on a foundation he could not doubt: that he was a thinking being. The success of his approach depended crucially on God's benevolence: because we can be sure that the divine being would not mislead us, we can trust that our clear and distinct ideas are true. God's character thus forms the basis for our certainty that there is indeed a reality corresponding to our ideas. God's omnipotence entails the ability to do even what is logically impossible. Descartes also regarded God as not merely uncaused, but somehow the cause of himself.

[brianna fisher]

This paper defends an interpretation of Descartes according to which he sees us as having normative (and not merely psychological) certainty of all clear and distinct ideas during the period in which they are apprehended clearly and distinctly. However, on this view, a retrospective doubt about clear and distinct ideas is possible. This interpretation allows Descartes to avoid the Cartesian Circle in an effective way and also shows that Descartes is surprisingly, in some respects, an epistemological externalist. The paper goes on to defend this interpretation against some powerful philosophical objections by Margaret Wilson and others by showing how Descartes’doctrine of the creation of the eternal truths can be brought in to support his epistemology. This doctrine and other analogous positions in Descartes can also reveal that Descartes, again surprisingly, takes important steps toward doing epistemology without direct appeal to God and God's veracity.