The theory of knowledge, epistemology, has had philosophers debating since the ancient Greek era of Socrates. The term epistemology is derived from the two Greek words episteme and logos, translating to knowledge and study of, respectively. In order to define knowledge, this discussion will be based on conceptual analysis, which means to give certain conditions, such that satisfying them will give us knowledge. These conditions branch off into two main categories: necessary and sufficient. The basic formula for necessary conditions is – Q is necessary for P; P cannot hold true without Q. The necessary condition in order for John to be a man, is that he be a mammal; a mandatory requirement. On the other hand, the basic formula for sufficient conditions is – Q is sufficient for P; P to be true is adequate ground for Q to be true. Now applying this condition into the same example, John being a man is sufficient to know that he is a mammal.