Introduction All of the four possible interpretations of the Cartesian circle interpret the fatal flaw in Descartes’ reasoning in Meditations. The “Cartesian Circle explains that according to Descartes, the knowledge of God depends on his clear and distinct understanding. However Descartes seemingly contradicts himself when he argues that God exists and is not a deceiver to in order to guarantee the truth concerning his clear and distinct understandings as explained in the Fourth Set of Objections to Descartes’ Meditations, by Arnauld. In this set of objections, the Psychological interpretation shall be used to try and explain the objection adequately. Discussion The psychological interpretation explains how Descartes goes about explaining his position psychologically. In the beginning, Descartes has the explanation that you cannot doubt an intuition while you are having it. Therefore when one makes obvious God’s existence and authenticity, he/she is able to doubt that a non-deceiving God exists and even if you demonstrate it in any way it still remains clear that you are unable to doubt the conclusion drawn from that demonstration. Later on Descartes explains that it is possible to doubt a fact that you once proved. For example when one no longer attends to the proof of the Pythagorean Theorem, the individual is likely to doubt it even though he had once proved it. However Descartes explains that the question about God’s existence works in a slightly different way; that if you have once proved God’s existence and you posses the memory of the proof of His existence in such a way that you can reproduce it, then you clearly have all the means and ability to put off any doubt that is likely to arise. This is due to the fact that constant recurring of the proof of existence of God builds into a person an incapability to doubt that in intuition that you once possessed is true. Therefore it is possible to fend off all the doubts about all intuitions provided you have the proof of God’s veracity in memory. Through this explanation therefore, Descartes proves that it is possible to reach a state of certainty. If the aim was to reach that certainty in a psychological sense, then there would be no need to remember the proof of God’s existence but rather all that would be needed would be to remember the proof of the Pythagorean Theorem. In case skeptical uncertainties start to come up, you are able to reproduce the evidence and as a result you again become psychologically incapable of doubting that. This is to say that any clear and distinct perception could be definite understanding, even if it was only recalled, even for the case of an atheist – which Descartes clearly denies.(49,101) The psychological interpretation calls for a good understanding of the defeasibility theory since when we look closely at the atheist we realize the importance of the need to understand the latter. An atheist does not believe in God, therefore he must cast doubt on everything that he has specifically and distinctively perceived, as he merely recalls it. In addition, he attends to the affirmation that God surely exist and is not a deceiver. He therefore believes it while attending to the revelation which makes him psychologically compelled to believe in a veracious God. Once he has had the belief, it becomes impossible for the skeptics to raise doubt about the existence of God as clearly and distinctly perceived. So to sta