IB Philosophy 3.1 Nature of Knowledge Key Definitions

The correspondence theory of truth holds that a statement or belief is true if and only if it accurately represents an independent reality. Truth, on this view, is a relation between language (or thought) and the world.

Deductive reasoning is a form of inference in which the conclusion follows necessarily from the premises. If the premises are true and the reasoning is valid, the conclusion must be true (e.g., "All humans are mortal; Socrates is human; therefore Socrates is mortal").

Epistemology is the branch of philosophy concerned with the nature, sources, and limits of knowledge, including the distinction between knowledge and opinion, the role of reason and experience, and the conditions under which beliefs count as justified.

Inductive reasoning is a form of inference in which the conclusion is supported by the premises but does not follow necessarily from them. Induction generalises from particular observations to broader claims (for example, "every swan I have seen is white, therefore all swans are white"), making it probabilistic rather than certain.

In Western philosophy, knowledge is traditionally defined as justified true belief, requiring that a claim be factually accurate, genuinely accepted by the person, and supported by adequate evidence or sound reasoning. This definition has been challenged by Gettier cases and alternative accounts from non-Western traditions.

Nyaya is a classical school of Indian philosophy that places logic and rigorous epistemological analysis at the centre of philosophical inquiry, recognising four valid means of knowledge: perception, inference, comparison, and testimony. The Nyaya tradition developed a sophisticated theistic argument contending that the orderly operation of karma and the structure of the universe require an omniscient, eternal God as their ultimate coordinator.

In the philosophy of the Indian thinker Bhartrhari, pratibha refers to a form of direct, intuitive understanding or flash of insight that grasps meaning holistically, prior to and distinct from propositional analysis. It challenges Western epistemology's focus on propositional knowledge ('knowing that').

Self-knowledge refers to an individual's awareness and understanding of their own mental states, character traits, and motivations, a form of introspective access that philosophers from Socrates to Descartes have regarded as epistemically privileged. Whether such knowledge is genuinely immediate or mediated by social and linguistic frameworks remains a central debate in philosophy of mind and epistemology.

Testimony is the acquisition of knowledge through the reports or statements of other people, making it a fundamentally social source of knowledge distinct from perception, reason, or memory. Philosophers debate whether testimony is a basic source of justification in its own right or whether it depends parasitically on the hearer's prior evidence about the speaker's reliability.

(literally ‘the Way’) the central concept of the Tao Te Ching and refers to the ultimate, underlying principle of reality that gives rise to all things, sustains them, and to which they return; it is characterised by its ineffability, formlessness, and its paradoxical nature as both the source of all being and beyond all categories of description. Ineffability in this context means that the Tao cannot be adequately captured in language, concepts, or rational definitions, because any attempt to name or describe it necessarily limits and distorts what is by nature unlimited and unconditioned.

a property of beliefs, propositions, or statements that indicates their agreement with reality, coherence with other beliefs, or practical effectiveness. The nature of truth is itself one of the most contested questions in philosophy, with correspondence, coherence, and pragmatist theories offering competing accounts.