nges, however it is still called wax because our reason tells us that it is still the same wax. The second type of experience that Descartes considers is imagination. Descartes states that we cannot know whether we are dreaming or not because when we dream we take images as real. Descartes concludes that while doubting, the only thing he cannot doubt is that he is doubting. He realizes that when he is actively thinking, he is aware of himself and he realizes that he exists. Therefore, his essence is a thinking being that exists. At this point, he states his basic foundation: "I am, therefore I exist".
             After finding his own existence as a thinking thing, Descartes starts to question how he realizes that " I think" is certain and he tries to find out things as certain as "I think". He questions what makes this " first principle" certain. Descartes argues that things that are certain appear in his mind clearly and distinctly. This is the reason that the first principle is true according to him. In addition, Descartes states that the same principle is true for mathematical propositions because they are so clear and distinct. Accordingly, he believes that all certain knowledge should be as clear and distinct as mathematical knowledge. This became the fundamental requirement for knowledge that it must be as certain as geometry and algebra. Consequently,
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