Three of Descartes’ meditations are discussed. His first meditation is called “Meditation I: Concerning Those Things That Can Be Called into Doubt”. In this meditation, Descartes remembers that he was once deceived by his senses and since that happened before, it can happen again. So he tells himself, if I am being deceived, then my beliefs are treacherous and uncertain. The second meditation called “Meditation II: Concerning the Nature of the Human Mind: That It Is Better Known Than the Body” is an acknowledgment to the first meditation. Descartes believed that since he is a “thinking thing”, then he must exist. Since he is a thing that can deceived and have thoughts and beliefs, he must exist. His third meditation “Meditation III: Concerning God, That He Exists” argues that God is present and he rejects the idea of God being invented. He proposed three types of ideas; Innate, Factitious and Adventitious. The innate ideas are the ones that are and always have been with us, whereas factitious ideas are from our imagination and lastly the adventitious ones come from our experiences from the world. Descartes believed that God is an innate idea and that he is not improvised. That was Descartes’ beliefs when it comes to doubt, as he does not believe that doubt is the key knowledge.Let us discuss the natural sciences at first. Ever since the break of dawn, the human being has been trying to know the truth about his origins and the world around him; have we truly evolved from apes or were we simply created by God? These questions have always been present in the human’s mind and this is the reason behind his doubt concerning this topic. This issue has raised many conflicts among people, but most importantly, created the Darwin theory of evolution. Darwin believed that all living organisms evolved from much simpler single-celled organisms. His doubt in the belief that God created us from nothing made him seek after the answers he wanted to get. He did not believe in what he was told and sought after the truth after questioning this topic, evidently coming up with his widely accepted theory from different people all over the world.