Theory of justification is an element of epistemology that attempts to be aware of the justification involving propositions and beliefs. Epistemologists are related to various epistemic options that come with belief, which add the ideas of justification, warrant, rationality, and also probability. Of these types of four terms, the term that was most widely applied and discussed through the early 21st centuries is “warrant”. Often speaking, justification is the reason that someone retains a belief.