(philosophy) the doctrine that knowledge is acquired by reason without resort to experience WordNet 3.0 & Open English WordNet

In philosophy, rationalism is the epistemological view that "regards reason as the chief source and test of knowledge" or "any view appealing to reason as a source of knowledge or justification", often in contrast to other possible sources of knowledge such as faith, tradition, or sensory experience. Wikipedia

Philosophical position, theory, or view that reason is the source of knowledge. Wikipedia Disambiguation

Philosophical view that reason should be the chief source of knowledge Wikidata

Elaboration of theories by use of reason alone without appeal to experience, such as in mathematical systems. Wiktionary