supervenience a dependence relation between properties or facts of one type, and properties or facts of another type. Moore, for instance, held that the property intrinsic value is dependent in the relevant way on certain non-moral properties (although he did not employ the word ‘supervenience’). As he put it, ‘if a given thing possesses any kind of intrinsic value in a certain degree, then not only must that same thing possess it, under all circumstances, in the same degree, but also anything exactly like it, must, under all circumstances, possess it in exactly the same degree’ (Philosophical Studies, 1922). The concept of supervenience, as a relation between properties, is essentially this: Properties of type A are supervenient on properties of type B if and only if two objects cannot differ with respect to their A-properties without also differing with respect to their B-properties. Properties that allegedly are supervenient on others are often called consequential properties, especially in ethics; the idea is that if something instantiates a moral property, then it does so in virtue of, i.e., as a (non-causal) consequence of, instantiating some lower-level property on which the moral property supervenes.
In another, related sense, supervenience is a feature of discourse of one type, vis-à-vis discourse of another type. The term was so used, again in connection with morals, by Hare, who wrote:
First, let us take that characteristic of ‘good’ which has been called its supervenience. Suppose that we say, ‘St. Francis was a good man.’ It is logically impossible to say this and to maintain at the same time that there might have been another man placed exactly in the same circumstances as St. Francis, and who behaved in exactly the same way, but who differed from St. Francis in this respect only, that he was not a good man. (The Language of
Morals, 1952) Here the idea is that it would be a misuse of moral language, a violation of the ‘logic of moral discourse,’ to apply ‘good’ to one thing but not to something else exactly similar in all pertinent non-moral respects. Hare is a metaethical irrealist: he denies that there are moral properties or facts. So for him, moral supervenience is a feature of moral discourse and judgment, not a relation between properties or facts of two types. The notion of supervenience has come to be used quite widely in metaphysics and philosophy of mind, usually in the first sense explained above. This use was heralded by Davidson in articulating a position about the relation between physical and mental properties, or statetypes, that eschews the reducibility of mental properties to physical ones. He wrote: Although the position I describe denies there are psychophysical laws, it is consistent with the view that mental characteristics are in some sense dependent, or supervenient, on physical characteristics. Such supervenience might be taken to mean that there cannot be two events alike in all physical respects but differing in some mental respects, or that an object cannot alter in some mental respects without altering in some physical respects. Dependence or supervenience of this kind does not entail reducibility through law or definition. (‘Mental Events,’ 1970) A variety of supervenience theses have been propounded in metaphysics and philosophy of mind, usually (although not always) in conjunction with attempts to formulate metaphysical positions that are naturalistic, in some sense, without being strongly reductionistic. For instance, it is often asserted that mental properties and facts are supervenient on neurobiological properties, and/or on physicochemical properties and facts. And it is often claimed, more generally, that all properties and facts are supervenient on the properties and facts of the kind described by physics. Much attention has been directed at how to formulate the desired supervenience theses, and thus how to characterize supervenience itself. A distinction has been drawn between weak supervenience, asserting that in any single possible world w, any two individuals in w that differ in their A-properties also differ in their B-properties; and strong supervenience, asserting that for any two individuals i and j, either within a single possible world or in two distinct ones, if i and j differ in A-properties then they also differ in B- properties. It is sometimes alleged that traditional formulations of supervenience, like Moore’s or Hare’s, articulate only weak supervenience, whereas strong supervenience is needed to express the relevant kind of determination or dependence. It is sometimes replied, however, that the traditional natural-language formulations do in fact express strong supervenience – and that formalizations expressing mere weak supervenience are mistranslations.
Questions about how best to formulate supervenience theses also arise in connection with intrinsic and non-intrinsic properties. For instance, the property being a bank, instantiated by the brick building on Main Street, is not supervenient on intrinsic physical properties of the building itself; rather, the building’s having this social-institutional property depends on a considerably broader range of facts and features, some of which are involved in subserving the social practice of banking. The term ‘supervenience base’ is frequently used to denote the range of entities and happenings whose lowerlevel properties and relations jointly underlie the instantiation of some higher-level property (like being a bank) by some individual (like the brick building on Main Street).
Supervenience theses are sometimes formulated so as to smoothly accommodate properties and facts with broad supervenience bases. For instance, the idea that the physical facts determine all the facts is sometimes expressed as global supervenience, which asserts that any two physically possible worlds differing in some respect also differ in some physical respect. Or, sometimes this idea is expressed as the stronger thesis of regional supervenience, which asserts that for any two spatiotemporal regions r and s, either within a single physically possible world or in two distinct ones, if r and s differ in some intrinsic respect then they also differ in some intrinsic physical respect.
See also NATURALISM , PHILOSOPHY OF MIND , RESULTANC. T.E.H.