Epistemology
theory of knowledge
The study of knowledge — what it is, how we get it, and the limits of what can be known.
In practice
An analyst is confident in a forecast. The epistemological questions are what the confidence rests on, whether that basis would survive being wrong once, and whether the belief being true would be luck or evidence.
The common mistake
Assuming knowledge requires certainty. Most epistemologists treat knowledge as compatible with the possibility of error, and the interesting work is in specifying what a good enough basis looks like.
Epistemology is the study of knowledge: what it is, how it is acquired, and how much of it we are entitled to claim. It sits beside metaphysics and ethics as one of the central divisions of philosophy.
The traditional definition and its collapse
For a long stretch, knowledge was defined as justified true belief. You know something when you believe it, it is true, and you have good reason for believing it. In 1963 Edmund Gettier produced short cases in which all three conditions hold and the person still seems not to know, because the justification and the truth are connected only by luck. The paper set off decades of attempts to add a fourth condition, none of which has become standard.
Where knowledge comes from
Two traditions divide the question of sources.
- Rationalism holds that reason can reach substantive truths about the world on its own. Mathematics is the usual exhibit.
- Empiricism holds that experience is the origin of all contentful knowledge. Locke argued the mind begins as a blank sheet and Hume pushed the view to its skeptical limit with the problem of induction.
Kant proposed a settlement in the Critique of Pure Reason (1781). Experience supplies the content while the mind supplies the structure that makes experience possible at all, which is how he defends synthetic a priori claims.
Doubt as a method
Skepticism is a permanent instrument in the field rather than only a position. Descartes used systematic doubt in the Meditations (1641) to find something that could not be doubted, arriving at the cogito. The modern versions ask what rules out that you are radically deceived, and what your ordinary knowledge claims actually require.
Concept web
Open the full webQuestions
What is epistemology?
Epistemology is the branch of philosophy that studies knowledge — what distinguishes it from mere true belief, where it comes from, and how far claims to know can be justified.
What is the Gettier problem?
A set of cases, published by Edmund Gettier in 1963, in which someone holds a justified true belief but seems not to know, because the belief is true by luck rather than because of the justification.
What is the difference between rationalism and empiricism?
Rationalism holds that reason alone can deliver substantive knowledge of the world. Empiricism holds that all such knowledge originates in sense experience. Kant argued that experience supplies content and the mind supplies structure.