Rationalism
/ˈræʃ.ən.əˌlɪ.zəm/noun
The belief that reason is the primary source of knowledge or truth.
Did you know?Its core comes from Latin *ratio*, meaning not just “reason” but also “reckoning” and “accounting” — so rational thought was originally tied to calculating and keeping accounts.
Etymological Timeline
Latin
Latin
ratio
“reckoning, calculation, account; later also reason”
Late Latin
Latin
rationalis
“pertaining to reason, calculating, logical”
16th Century
French/English
rational
“based on reason; logical”
17th Century
English
rationalism
“a doctrine emphasizing reason as the chief source of knowledge”
Modern English
English
rationalism
“the philosophical view that reason is the main basis of knowledge or justification”