Epistemology is the theory of the nature and grounds of knowledge especially with reference to its limits and validity. This theory has long been highly debated by several influential philosophers over time having started with those thinkers called Pre-Socratics. A few centuries later, Galileo and Descartes raised similar questions which would proceed to revolutionize philosophy and science after vigorous debate throughout the ages. These questions were examined by first exploring what one truly knows. The only thing that one can know is that one exists, however it would be sophomoric to live in complete disbelief of everything that one cannot know. Furthermore, one cannot completely trust one’s senses in providing one with knowledge, and one cannot know that God exists. The necessary condition of the concept of knowledge has a very particular structure. In considering knowledge, one must first acknowledge that one exists, in order to know anything at all. If one cannot be sure that one exists, then one cannot know anything since there is a possibility that this individual may not even exist in the first place. A complete contradiction in the concept of knowledge will give rise if one does not acknowledge one’s own existence. This condition of thinking about knowledge will be explained in more detail throughout the paper. In recognition of this essential condition of the structure of knowledge, one can begin to define knowledge. Something can be considered knowledge if: the individual believes the statement to be true, the statement is in fact true and the statement is thought to be logical or justified in being true. These three conditions must all be met for a statement to be deemed as knowledge. If these standards are not all met, the information at hand can be deceptive and misshape one’s perception of the world. For example, one may believe that the Flyers won the Stanley Cup in 2003. One may whole heartedly believe this, however it is not true. Consequently, this statement is not considered to be knowledge since not all of the basic conditions have been met. A situation was thought of by Descartes which proposes that even in using one’s senses; one cannot know with certainty that the information perceived is true. He summons into consideration the scenario of a dream, in which, he explains that through his senses he perceives and experiences identically to how he does so through them in waking reality. They function so similarly to the extent that one can never be sure if one is dreaming. In other words, this prevents one from knowing that all of one’s perceptions resulting from one’s senses are true. Descartes continues to engender a situation refe