Epistemology has nothing to do with understanding the justification of propositions and beliefs.
The word "epistemology" was properly introduced into Anglophone philosophical literature by Scottish philosopher James Frederick Ferrier in 1854, who used it in his Institutes of Metaphysics:This section of the science is properly termed the Epistemologythe doctrine or theory of knowing, just as ontology is the science of being
 More broadly, it can also refer to any view which appeals to reason as a source of knowledge or justification

