The Gettier Problem and Responses
The Gettier problem is the discovery that a belief can be justified, true, and yet fail to be knowledge because its truth is a matter of luck, and this area surveys the cases that establish the problem and the main strategies for adding the missing condition.
Definition
The Gettier problem is the challenge, raised by counterexamples in which a justified true belief owes its truth to luck rather than to the believer's justification, of specifying a fourth condition that, added to justified true belief, yields an adequate analysis of knowledge.
Scope
This area covers Gettier's original counterexamples and later variants, and the principal families of response: requiring that justification not rest on any falsehood, adding defeasibility conditions, imposing modal conditions of sensitivity or safety, and reformulating the fourth condition in reliabilist or virtue-theoretic terms. It also covers the meta-level worry that Gettier problems may be unavoidable for any fallibilist analysis. The broader structure of justification is treated in a neighbouring area.
Sub-topics
Core questions
- Why do Gettier's cases show that justified true belief is not sufficient for knowledge?
- What extra condition rules out the epistemic luck present in Gettier cases?
- Can any condition be added without generating new counterexamples?
- Is the kind of luck that defeats knowledge best captured causally, modally, or in terms of reliability?
Key theories
- Causal theory of knowing
- Goldman's early response requires that the fact known be appropriately causally connected to the belief, excluding Gettier cases where the belief's truth is causally unrelated to its justification.
- Modal tracking conditions
- Nozick analyses knowledge using sensitivity counterfactuals — roughly, the believer would not hold the belief if it were false and would hold it if it were true — which exclude beliefs that are true only by luck.
- Inescapability of Gettier problems
- Zagzebski argues that as long as justification is fallible and independent of truth, one can always construct cases where a justified false belief becomes true by luck, so Gettier-style counterexamples cannot be fully eliminated.
History
Gettier's three-page 1963 paper overturned the long-standing justified-true-belief analysis with two compact counterexamples, triggering a research program that defined Anglophone epistemology for decades. Responses moved from the no-false-lemmas and causal proposals of the 1960s through Nozick's modal conditions in 1981 to safety-based and virtue-theoretic treatments, even as Zagzebski argued the problem may be in principle inescapable.
Debates
- Whether a successful fourth condition exists
- Optimists pursue refined causal, modal, or reliability conditions that close off Gettier cases, while Zagzebski's argument suggests every fallibilist analysis remains vulnerable, motivating some to abandon the analysis project in favour of knowledge-first or virtue approaches.
Key figures
- Edmund Gettier
- Alvin Goldman
- Robert Nozick
- Linda Zagzebski
Related topics
Seminal works
- gettier1963
- goldman1967
- nozick1981
Frequently asked questions
- What is a Gettier case in a sentence?
- It is a scenario in which someone has a belief that is both justified and true, but whose truth is secured by luck in a way disconnected from the justification, so that we judge the person does not really know.
- Did anyone solve the Gettier problem?
- Many partial solutions exist — no-false-lemmas, defeasibility, sensitivity, safety, and reliabilist conditions — but each faces counterexamples, and there is no consensus solution, with some philosophers arguing the problem is in principle inescapable.