In this thesis I scavenge the history of philosophy for answers to the question ‘How are claims to knowledge justified?’. I argue that Plato’s psychological doctrine of knowledge marks the starting point of a philosophical inquiry motivated by the possibility to discover foundations of knowledge through investigating the nature of mind. At the core of this inquiry lies the hypothesis that if the psychological mechanisms that govern the capacity for knowledge acquisition is fully understood, then answers will follow about why judgements are true or false. The prospective result of the inquiry is a theory of universal epistemic justification which demarcates epistemically warranted beliefs from unwarranted beliefs. I suggest that there is a historically persistent case of cognitive dissonance within the epistemological enterprise — a tension between two of its central theses — which is caused by the persistence of the of the hitherto unsuccessful but ongoing quest for universal epistemic justification, and its inciting promises. The contradicting theses are those of certain justification (that one is justified in believing that p only if p is entailed by evidence) and proportional justification (that one is proportionally justified in believing that p to the extent that evidence makes p credible). I discuss the consequences of giving up one of the respective theses. I conclude that the thesis of certain justification cannot be given up unless an adequate theory of proportional justification is proposed, and that the legacy of searching for universal epistemic justification will continue unless epistemologists are able to construct one.