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rationalism

RASH-un-ul-iz-um /ˈræʃ.ən.əl.ɪz.əm/

nounC1GRESATUPSC

academicformal

The philosophical belief that reason and deductive intellect, rather than sensory experience, are the primary sources of knowledge.

Implies that foundational truths can be grasped directly by intellectual intuition or logical analysis without needing physical measurement.

The story behind the word. From Latin 'ratio', meaning calculation, account, or reasoning capacity. Seventeenth-century philosophers in continental Europe—notably René Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz—argued that sensory information is inherently deceptive. They built complete systems of metaphysics based on 'a priori' deduction, cementing rationalism as the major rival to British empiricism.

Word relationships

intellectualism: Intellectualism emphasizes the intellect over emotion or exercise of will, whereas rationalism specifically contrasts intellect with sensory observation.

empiricism: Empiricism claims knowledge comes from physical sense perception, whereas rationalism claims it stems from pure reason.

Commonly confused with

rationality: Rationality is the everyday quality of being sensible and logical, whereas rationalism is a specific philosophical doctrine about the origin of knowledge.

Word family

rationalist (noun): An adherent of rationalism.
rational (adjective): Based on or in accordance with reason or logic.
rationalize (verb): To justify an action or belief with plausible reason.

Collocations

philosophical rationalism
pure rationalism
Cartesian rationalism
tenets of rationalism

Example sentences

"Descartes' famous declaration 'I think, therefore I am' stands as a classic pillar of Continental rationalism." Philosophy of mind
"Pure rationalism asserts that essential truths about mathematics and metaphysics can be known prior to any physical test." Epistemological debate

Memory hook

RATIONALISM places total FAITH in your RATIO—the mathematical calculation of pure thought inside your mind. Reason and logic trump sensory perception.

When not to use

Do not use merely to describe acting calmly or sensibly in everyday decision-making.

Fun facts

Descartes attempted to deduce the existence of God and the entire physical universe starting solely from his own self-awareness while sitting beside a warm stove.