Reason or experience
Where does the most reliable knowledge come from, careful thinking or what we see, hear and test? Rationalists give reason a role of its own. Empiricists say all our ideas begin in experience.
What it is
When you know something, how did you come to know it? Some things you learned by looking, listening or trying: the stove is hot, rain makes the road slippery. Other things you seem to know by thinking alone: that two plus two is four, or that a triangle has three sides. The question of reason and experience asks which of the two is the deeper source of knowledge, and whether thinking can give us anything that experience cannot.
It was a central argument in European philosophy in the seventeenth and eighteenth centuries, and the two sides still shape how people think about science, mathematics and morality.
The main views
- Rationalism. Some truths can be known by reason alone, without the senses, and some knowledge or concepts are part of our nature from the start. Descartes, Spinoza and Leibniz are the standard rationalists.
- Empiricism. Experience is the source of our ideas and of our knowledge. The mind begins like a blank slate, and everything in it is traced back to what we have sensed or noticed in ourselves. Locke and Hume are the standard empiricists.
An example
Take the idea of a perfect triangle. You have never seen one: every drawn triangle has wobbly lines. Yet you can reason about a perfect one with complete confidence. A rationalist takes this as a sign that reason supplies something experience cannot. An empiricist replies that the idea is built up from many imperfect triangles you have seen, and that the confidence comes from how we define the shapes.
Why people still disagree
- Each side has hard cases. Rationalists point to mathematics and to concepts that seem to go beyond experience. Empiricists face problems of their own: Hume noticed that we never experience cause and effect itself, only one event following another, and moral ideas and knowledge of God are hard to trace back to the senses.
- The labels are loose. A person can be a rationalist about mathematics and an empiricist about the natural world. The two names also leave out thinkers who fit neither side neatly.
- Most people use both. In daily life we check our reasoning against experience and our experience against reasoning. The disagreement is about which one carries the weight when they conflict.
Written by epchē in our own words, and checked against independent sources on 8 October 2026. The sources are listed below.
Philosophies that answer it
Where each philosophy leans on this question, from the same positions the walk uses.
Reason is the best guide
Experience is the best guide
- Humean empiricism and skepticism
- Epicureanism
- Conservatism
- Atheism and naturalism
- Pragmatism
- Utilitarianism
Sources we used
- Rationalism vs. Empiricism · Stanford Encyclopedia of Philosophy, read on 8 October 2026
- British Empiricism · Internet Encyclopedia of Philosophy, read on 8 October 2026