supervenire

Supervenience is a philosophical concept describing a dependency relation between two sets of properties or facts. A properties set A is said to supervene on a set of properties B if any change in A is necessarily accompanied by a change in B; equivalently, if two possible worlds are indistinguishable with respect to B, they must be indistinguishable with respect to A. In this sense, A depends on B, but B may vary without requiring a change in A.

Etymology and usage: The term derives from the Latin supervenire, meaning to come on top of or to occur as an addition. In philosophy, the notion is typically expressed in English as “A supervenes on B.” The corresponding verb exists in other languages as well, including Italian, where supervenire carries a similar sense.

Variants and scope: Two common formulations are weak and strong (or local/global) supervenience. Weak supervenience states that if two possible worlds share all B-properties, they must share all A-properties. Strong supervenience tightens the requirement, often interpreted as any difference in A across possible worlds being accompanied by a difference in B, sometimes across broader ranges of description or relational structure. In practice, philosophers apply the idea to domains such as mind–body (mental properties on physical brain states), ethics (m moral properties on natural properties), and science (higher-level phenomena on lower-level bases).

Examples and relevance: Classic examples include mental states supervening on brain states and moral properties supervening on natural properties. Supervenience is widely discussed in debates on reductionism, realism, and the nature of emergent properties, serving as a framework to express dependency without committing to full reduction.

Critique and status: While supervenience captures a robust form of dependence, it does not by itself explain why A depends on B or how such dependence arises. Critics argue about its applicability to certain emergent phenomena and its relationship to reduction and causation.