Nonreductive

Nonreductive is an adjective used to describe theories, explanations, or systems that resist reduction to a simpler, more fundamental set of components or laws. In philosophy, the term is most often found in the expression nonreductive physicalism or nonreductive naturalism. These positions assert that while mental phenomena depend on physical substrates, they cannot be fully explained by reducing them to physical properties alone. They typically appeal to emergent properties, upward dependences, or downward causation, and they contrast with reductive explanations where higher-level states are fully analysable in terms of lower-level microphysics.

In social and human sciences, nonreductive approaches emphasize that social, psychological, or cultural phenomena cannot be fully captured by single-cause explanations (for example, biology or economics). Proponents argue for multi-level analyses and emergent explanations, sometimes invoking holism or critical realism.

In mathematics and related areas, nonreductive may describe objects or structures that are not reductive in the sense of a reductive decomposition, for example certain algebraic groups with nontrivial unipotent radicals. The term is less standardized here and is used to indicate deviation from a strictly reductive framework.

The term is sometimes encountered in other disciplines to mark a stance against simplistic reductionism, while debates over its merits often focus on issues of explanation, causation, and methodological pluralism.