Epistemology

Overview

Epistemology is the branch of philosophy concerned with the theory of knowledge. It asks fundamental questions: What is knowledge? How is it acquired? Can we ever be certain of anything? For GCSE Philosophy, examiners expect you to master the definitions of different types of knowledge and critically evaluate the traditional definition of propositional knowledge as 'Justified True Belief' (JTB).

Historically, the JTB account dates back to Plato and stood largely unchallenged for over two millennia. However, in 1963, Edmund Gettier published a brief paper that completely upended this consensus by demonstrating that JTB is not sufficient for knowledge. Understanding this debate — the definition, the conditions, and the counter-examples — is critical for success in this topic.

Key Concepts & Developments

The Three Types of Knowledge

Acquaintance KnowledgeKnowledge by direct experience or perception (e.g., 'I know what the colour red looks like' or 'I know the smell of coffee'). It does not involve propositions or facts; it is a direct, personal familiarity with a person, place, or sensation.

**Ability Knowledge (Know-How)**Knowledge of how to do something (e.g., 'I know how to ride a bike'). This is practical knowledge. Crucially, a person can possess ability knowledge without being able to articulate the theory behind it.

Propositional KnowledgeKnowledge that something is the case (e.g., 'I know that Paris is the capital of France'). This is the primary focus of epistemology. It is expressed as a proposition (a statement that can be true or false). Philosophers express this formally as: S knows that p (where S is the subject and p is the proposition).

The Tripartite Definition (JTB)

Traditionally, propositional knowledge is defined as Justified True Belief. This account argues that knowledge is composed of three conditions that are individually necessary and jointly sufficient:

1. Truth (p is true): You cannot know something that is false. The proposition must correspond to reality.
2. Belief (S believes p): You must mentally assent to the proposition. You cannot know something if you don't believe it.
3. Justification (S is justified in believing p): You must have adequate evidence or rational grounds for your belief. This separates knowledge from a lucky guess.

The Gettier Challenge (1963)

Edmund Gettier challenged the JTB account by providing counter-examples where a person has a justified true belief, but we would intuitively say they do not have knowledge.

The Core Argument: Gettier cases demonstrate that the three conditions of JTB are not jointly sufficient. You can meet all three conditions and still lack knowledge, usually because the connection between the justification and the truth is purely accidental (epistemic luck).

The Nature of Definition (Linda Zagzebski)

Philosopher Linda Zagzebski argued that the problem with JTB is structural. Any definition of knowledge that treats truth and justification as separate, independent components will always be vulnerable to Gettier-style counter-examples. Because justification doesn't guarantee truth, there will always be a gap where luck can intervene.

Podcast Episode

Listen to this 10-minute audio guide covering the core concepts, common mistakes, and a quick-fire recall quiz.