My intention in this essay is to illustrate that the arguments concerning the existence of God and the fear of deception in Descartes' Meditations on First Philosophy are quite weak and do not justify its conclusions. To support these claims, I will begin by describing two specific meditations and explain the arguments offered. Later, I will critically analyze his arguments, revealing unfair conclusions. Doubts surrounding the text include the suggested characteristics of God, the condition of perfection, and the nature of deception. A conclusion will include a discussion of whether or not Descartes (also called Renatus) succeeded in his project. The bulk of Descartes' arguments regarding the existence of God occur in the third meditation. Having previously stripped himself of all material knowledge, Renatus can only be sure of his own ideas and the fact that he is a “thinking thing” (35). Being a “thinking thing” testifies to its ability to create ideas, and that is really all that proves its existence. Although he emphasizes that the ideas he conceives in his mind cannot be false, he is determined that his application of these ideas in the form of judgments is subject to error (37). Additionally, his ideas are classified as innate, fortuitous and artificial. Innate ideas are instinctive and uninfluenced truths; which contrasts with chance ideas learned through experience. The third thought process involves invented ideas, such as imagination (38). These forms of ideas are necessary to the text because they are essentially the only known things that exist, and to categorize them is to define their origin. The effort is put on understanding objective reality: the application of ideas influences...... middle of paper ......, if it can be a deceiver. For if I do not know it, it seems that I can never be sure of anything else” (36). The arguments he made regarding the existence of a Supreme Being may not have been very powerful, but their implications are essential for Renatus. In defining God, Renatus learned the idea of ​​ultimate good, the conditions of perfection versus imperfection, the emotional "safety net" of religion, a commonality with another being, and had to face corruption associated with evil. Although his project also involved mathematics, geometry, and the senses, their most useful application was in support of his claims about God. In conclusion, although I do not think that Descartes succeeded in his project, he would not have achieved a goal that satisfied him if he had not focused so much on the existence of God and on the question of deception..