The Enlightenment period was a time when many thinkers began to question everything they are told and everything they believed in. People realized that they have the ability to think for themselves and not just to accept everything they are told. Descartes was one of these philosophers. He suggested the idea of “cogito ergo sum,” which translates to “I think therefore, I am.” This idea reminds all of us that we all exist in this world today because we have the ability to think. His idea stemmed after he realized that we all act on opinions we are uncertain believing in them unquestionably. That is when he decided to doubt everything around him; to treat everything as false. He pretended that all the ideas in his mind so far were all illusions from his dreams. He strongly believes and persuades the reader of the existence of God, who he describes as the most perfect being and that everything in us comes from him. Descartes’ idea of “cogito ergo sum” is important as it is important for all of us to constantly be critically thinking and questioning the things happening around us  because we are able to. Because we think, we exist in this world.