« Cogito ergo sum - I think therefore I am. » The mathematician, scientific thinker and metaphysician René Descartes used this term in his “Meditation on First Philosophy”. This term has become famous particularly in Western philosophy. However, this term is not the only legacy of Descartes. His legacy includes the development of Cartesian coordinates, philosophical books and theories. Although the distinction between mind and body dates back to the Greeks, Descartes' account of the relationship between mind and body has been considered the first and most influential. Descartes was born in 1596 in France, from 1628 to 1649 Descartes remained in Holland, during this period he composed several works which prepared the ground for all subsequent philosophical studies of the mind and body. (René Descartes and the legacy of mind/body dualism) “Meditation on First Philosophy” is one of Descartes’ famous treatises. First published in the 17th century, it consists of six meditations. In the first meditation, Descartes eliminates all belief in things that are not certain, basically he takes everything off the table. Then, one by one, he examines each belief and determines whether any of them can be known with certainty. Meditations three and five focus on the existence of God. This ontological argument is both fascinating and poorly understood in the philosophical community. Descartes attempts to prove the existence of God using simple but influential foundations. (Nolan). The innate proof of Descartes' ideas and the ontological proof of the existence of God will be evaluated through the summary of Meditation You and Meditation Five, while his work will also be compared to Anselm's ontological argument on the existence of God. The first and second meditate...... middle of paper...... is not only an idea but also a real thing. Thus, the proof of the innate idea leads to the proof of the ontological argument which completes Descartes' analysis of the existence of God. Even though Descartes is one of the most important works cited1. “RENÉ DESCARTES AND THE LEGACY OF MIND/BODY DUALISM.” René Descartes and the legacy of mind/body dualism. Internet. . .2. Nolan, Laurent. “Descartes’ Ontological Argument.” Stanford University. Stanford University, June 18, 2001. Web. . .3. “Some key arguments from meditation III-V.” New York University. New York University, Web..4. Descartes, René and Roger Ariew. Meditations, objections and responses. Indianapolis, IN: Hackett Pub., 2006. Print.