[rash-uh-nl-iz-uh m]


the principle or habit of accepting reason as the supreme authority in matters of opinion, belief, or conduct.
  1. the doctrine that reason alone is a source of knowledge and is independent of experience.
  2. (in the philosophies of Descartes, Spinoza, etc.) the doctrine that all knowledge is expressible in self-evident propositions or their consequences.
Theology. the doctrine that human reason, unaided by divine revelation, is an adequate or the sole guide to all attainable religious truth.
Architecture. (often initial capital letter)
  1. a design movement principally of the mid-19th century that emphasized the development of modern ornament integrated with structure and the decorative use of materials and textures rather than as added adornment.
  2. the doctrines and practices of this movement.Compare functionalism(def 1).

Origin of rationalism

First recorded in 1790–1800; rational + -ism
Related formsra·tion·al·ist, nounra·tion·al·is·tic, ra·tion·al·is·ti·cal, adjectivera·tion·al·is·ti·cal·ly, adverban·ti·ra·tion·al·ism, nounan·ti·ra·tion·al·ist, noun, adjectivean·ti·ra·tion·al·is·tic, adjectivenon·ra·tion·al·ism, nounnon·ra·tion·al·ist, nounnon·ra·tion·al·is·tic, adjectivenon·ra·tion·al·is·ti·cal, adjectivenon·ra·tion·al·is·ti·cal·ly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for rationalist

Contemporary Examples of rationalist

Historical Examples of rationalist

  • Evidently he was less familiar with the opinions of The Rationalist than he had thought.

  • They have all which the rationalist appeals to as his tests of right and wrong.

  • In the early years of his London life, Mill had been only a rationalist.

  • I had left the temple a devotee, and was returned a rationalist.

    The Town

    Leigh Hunt

  • There isn't a rationalist in London that could shake the man's belief.

    A Lost Cause

    Cyril Arthur Edward Ranger Gull

British Dictionary definitions for rationalist



reliance on reason rather than intuition to justify one's beliefs or actions
  1. the doctrine that knowledge about reality can be obtained by reason alone without recourse to experience
  2. the doctrine that human knowledge can all be encompassed within a single, usually deductive, system
  3. the school of philosophy initiated by Descartes which held both the above doctrines
the belief that knowledge and truth are ascertained by rational thought and not by divine or supernatural revelation
Derived Formsrationalist, nounrationalistic, adjectiverationalistically, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for rationalist

"one who follows reason and not authority in thought or speculation," originally especially "physician whose treatment is based on reason," 1620s, from rational + -ist. Applied to a philosophical doctrine 1640s. Related: Rationalism.

Online Etymology Dictionary, © 2010 Douglas Harper