nondefinition

Nondefinition is a term used in philosophy of language and logic to describe a statement or proposal that does not supply a clear definition of a term. The concept can refer to two related ideas: the absence of a precise definition for a term due to complexity, vagueness, or normative content; or a device in which a term is introduced without an explicit criterion, relying instead on examples, usage, or context (such as ostensive or performative definitions). In critical discussions, nondefinition is contrasted with well-formed definitions that specify necessary and sufficient conditions.

Usage and interpretations vary. Some theorists treat nondefinition as a methodological acknowledgment of the limits of definitions, signaling that certain terms resist reduction to a single set of criteria. Others view nondefinition as a diagnostic label for terms that defy standard definitional strategies, suggesting that alternative approaches—such as family resemblance, prototype theory, or multi-definition frameworks—are more appropriate. The term can also function descriptively to indicate that a term is ambiguous, contested, or context-dependent.

Examples commonly cited in discussions include terms like art, love, and consciousness, which many argue resist simple essential definitions. In these cases, speakers may treat the term as nondefinitional in the sense that no universally accepted, exhaustive criteria exist.

Relation to broader topics includes vagueness, polysemy, and definitional pluralism, as well as debates about whether language can capture the essence of complex phenomena through singular definitions. Critics warn that overusing nondefinition may hinder progress, while proponents argue it highlights genuine limits and motivates more nuanced analyses. See also vagueness, definability, necessary and sufficient conditions, ostensive definition, and stipulative definitions.