The existence of God is a very controversial philosophical argument that has mystified philosophers since the time of the “Enlightenment”. However, many of the various arguments put forward and analyzed have not adequately proven the existence of God. However, to move forward, failed arguments must be studied to ensure that errors are not repeated. One of these arguments is the ontological argument. This argument was first recorded by Saint Anslem (1033-1109). Descartes adapts this argument in the fifth meditation of “Meditations on First Philosophy”. He first establishes that whenever he thinks of a triangle, certain properties must be present for the shape to be a triangle. Furthermore, "although perhaps no such figure exists, or has ever existed, outside of my thinking" (Cottingham, 1996), recognized properties, such as "its three angles are equal to two right angles” (Cottingham, 1996) remain. this reasoning to the existence of God. Descartes thinks of “a supremely perfect being” (Cottingham, 1996) just as he thinks of the triangle. This being is God and has all the properties associated with God that make him perfect in every way. He concedes that “essence” is distinct from “existence,” since knowing the properties of something does not mean that it exists. Nevertheless, he maintains that God is different and relates his existence to the number of sides of a triangle. Therefore, Descartes reasons if God did not exist, then he would not be as perfect as a God who does exist, which contradicts the first hypothesis. Thus, “God exists”. (Cottingham, 1996) This argument seems justifiable, but the feeling that something has gone wrong persists. This is the view of Gaunilo, who was the first to launch his object...... middle of paper ...... us, if God existed, then according to Descartes' reasoning, he would be perfect, but if it did not exist, that does not detract from its perfection. (Hospers, 1997) Thus, based on the noted objections, the ontological argument appears flawed. Works cited Cardinal, D. et al. (2010) Philosophy of Religion London: Hodder Murray. Cottingham, J. (1996) Descartes' meditations on early philosophy: with selected objections and replies Cambridge: Cambridge University Press. Grim, P. (1982) “In the Name of the Fool.” International Journal of Philosophy of Religion. Flight. 13, number 1, n° 0020-704, March 1, 1982, p. 34.Hospers, J. (1997) An introduction to philosophical analysis. 4th edition. London: Routledge Ltd. Scruton, R. (1995) A Brief History or Modern Philosophy: From Descartes to Wittgenstein. 2nd edition. London: Routledge.