Supervenience

Examples of supervenience, in which case the truth values of some propositions cannot vary unless the truth values of some other propositions vary, include: Supervenience is of interest to philosophers because it differs from other nearby relations, for example entailment.

It is by and large agreed that some form of supervenience holds in these cases: Pain happens when the appropriate neurons fire.

In the 1970s, Donald Davidson was the first to use the term to describe a broadly physicalist (and non-reductive) approach to the philosophy of mind, called anomalous monism.

"[3] In subsequent years Terence ("Terry") Horgan, David Lewis, and especially Jaegwon Kim formalized the concept and began applying it to many issues in the philosophy of mind.

In the contemporary literature, there are two primary (and non-equivalent) formulations of supervenience (for both definitions let A and B be sets of properties).

[citation needed] (1) A-properties supervene on B-properties if and only if all things that are B-indiscernible are A-indiscernible.

Some points of clarification: first, the definitions above involve quantification over properties and hence higher-order logic.

Thus, (1) can be understood more intuitively as the claim that all objects that are indiscernible with respect to a base set of properties are indiscernible with respect to a supervenient set of properties, or, as it is also sometimes said, that B-twins are A-twins.

Also, note that in the early literature properties were not always central, and there remain some who prefer to frame the relation in terms of predicates, facts, or entities instead, for example.

Beginning in the 1980s, inspired largely by Jaegwon Kim's work, philosophers proposed many varieties of supervenience, which David Lewis called the "unlovely proliferation".

For example, something's being a dollar bill depends not only on the paper and the inks it is made out of, but also on a widely dispersed variety of features of the world it occupies.

There are also several kinds of global supervenience relations, which were introduced to handle cases in which worlds are the same at the base level and also at the supervenient level, but where the ways the properties are connected and distributed in the worlds differ.

For example, it is consistent with global mental–physical supervenience on the simple formulation described above for two worlds to have the same number of people in the same physical states, but for the mental states to be distributed over those people in different ways (e.g.

In philosophy of mind, many philosophers make the general claim that the mental supervenes on the physical.

This weak global thesis is particularly important in the light of direct reference theories, and semantic externalism with regard to the content both of words and (more relevant to our concerns here) of thoughts.

In this case, the arrangement of bytes in that packet supervenes on the physical properties of the phone signal.

When we see a letter "a" in a page of print, for example, the meaning Latin lowercase "a" supervenes on the geometry of the boundary of the printed glyph, which in turn supervenes on the ink deposition on the paper.

[7][8] Another example of convergent evolution is the loss of sight that almost universally occurs in cave fish living in lightless pools.

This may not seem to provide much of a problem, but because Jackson's solution refers only to minimal physical duplicates, this allows for the mental properties of W to be vastly different from those in the actual world.

[citation needed] Suppose that the supervenience thesis for physicalism is stated as a nomological constraint, rather than a metaphysical one; this avoids any objection based on the thesis ruling out metaphysical possibilities which a physicalist would leave open.

But the thesis would not rule out the metaphysical possibility of philosophical zombies, although their impossibility is a clear consequence of physicalism.

This however is paradoxical, based on the fact that physicalism both permits and prevents the existence of such beings.