Early modern Europe · 1637 – mid-18th c.
Rationalism
Reason alone, reasoning from clear and certain first principles as geometry does, can reveal the basic structure of reality.
Can reason alone give us certain knowledge of the world?
The new science of Galileo and Kepler was undermining Aristotle’s physics, and the revival of ancient skepticism made many doubt that anything could be known for sure. Descartes set out to rebuild knowledge on a foundation that no doubt could shake, taking mathematics as the model of certainty.
The senses sometimes deceive us, so knowledge built on them alone cannot be certain. Yet some truths — that I think, that I exist, the axioms of mathematics — are grasped by reason with a clarity that resists all doubt. From such innate or self-evident principles, careful deduction can reach truths about mind, God and nature.
- Some ideas are innate, not learned from experience.
- Clear and distinct reasoning, modelled on geometry, yields certainty.
- Reality is rationally ordered: nothing happens without a reason.
Rationalism set the agenda of modern philosophy — the mind–body problem, the foundations of knowledge — and its clash with empiricism is what Kant tried to resolve.
Thinkers
1596–1650René DescartesFrench mathematician who rebuilt philosophy on the certainty of thought1632–1677Baruch SpinozaDutch lens-grinder, expelled by his synagogue, who equated God with Nature1646–1716Gottfried Wilhelm LeibnizGerman polymath, co-inventor of calculus, theorist of monadsKey texts
Where it came from
Reacted againstScholasticismDescartes, schooled by Jesuits at La Flèche, replaced scholastic forms and qualities with a mechanical nature described by mathematics, while recasting scholastic proofs of God.Reacted against
Pyrrhonism & Academic skepticismDescartes radicalised the skeptics’ doubt so that, by defeating the strongest possible doubt, he could give knowledge an unshakable foundation.Grew out of
PlatonismLike Plato’s doctrine of recollection, the rationalists held that the mind has innate ideas that the senses only prompt, never supply.
What it led to
Opposed byBritish empiricismBook I of Locke’s Essay attacks the doctrine of innate ideas, arguing that everything in the mind can be traced to experience.Carried on by
The EnlightenmentDescartes’ method of doubt and Spinoza’s critical reading of the Bible taught that tradition and scripture must answer to reason.Carried on by
Kant’s critical philosophyKant was trained in the Leibniz–Wolff school and kept its conviction that some knowledge is a priori, while denying that pure reason can reach beyond experience.Carried on by
German IdealismThe 1785 “pantheism controversy” over Spinoza made his one-substance monism a model for the idealists’ absolute.Carried on by
PhenomenologyHusserl recast Descartes’s search for certainty in the thinking subject as a science of consciousness.Carried on by
Early analytic philosophyFrege presented his Begriffsschrift as a step toward Leibniz’s dream of a universal logical language.Opposed by
Analytic philosophy of mindThe field defined itself largely against Descartes’s dualism of an immaterial mind and a mechanical body.
Its answers to the big questions
MetaphysicsWhat is ultimately real?One infinite substance, God or Nature; minds and bodies are its modes.KnowledgeHow can we know anything?Doubt everything; what survives (“I think, therefore I am”) is the foundation.Mind & selfWhat is the self?A thinking thing, wholly distinct from the extended body.On the record
The school links to the Wikipedia article “Rationalism”.
English Wikipedia has no separate article on Continental rationalism: the title “Continental rationalism” redirects to “Rationalism”, which covers Descartes, Spinoza and Leibniz along with rationalism in general. The link stands.
Sources: Wikipedia, “Continental rationalism” (redirect to “Rationalism”)