In its modern sense, Rationalism is "any view appealing to reason as a source of knowledge or justification”. In more technical terms it is a method or a theory "in which the criterion of the truth is not sensory but intellectual and deductive.” Different degrees of emphasis on this method or theory lead to a range of rationalist standpoints, from the moderate position "that reason has precedence over other ways of acquiring knowledge" to the more extreme position that reason is "the unique path to knowledge.” Given a pre-modern understanding of reason, "rationalism" is identical to philosophy, the Socratic life of inquiry, or the zetetic interpretation of authority (open to the underlying or essential cause of things as they appear to our sense of certainty).

-Wikipedia