See also the old text of this article Physicalism/Larry's text.

Physicalism is the metaphysical position that everything is physical; that is, that there are no kinds of things other than physical things. Likewise, physicalism about the mental is a position in philosophy of mind which holds that the mind is a physical thing in some sense. This position is also called "materialism", but the term "physicalism" is preferable because it does not have any misleading connotations, and because it carries an emphasis on the physical, meaning whatever is described ultimately by physics -- that is, matter and energy.

Because it claims that only physical things exist, physicalism is a form of monism. Physicalism about the mental contrasts with dualism, which claims that the physical and the mental are two different sorts of things and thus that the mind is non-physical, and exists in a different metaphysical category and realm.

The opposite of physicalism is subjective idealism, such as the metaphysics proposed by George Berkeley, which holds that there is no physical reality at all. In this view, all that exists is mental or spiritual.

Type and token physicalism

Physicalism identifies the mental with the physical; that is, it makes the claim that the mental simply is the physical. This identity often takes one of two different forms:

• Token physicalism holds that for every mental particular there is a physical particular with which it is identical
• Type physicalism holds that every mental property is identical with a physical property.

Supervenience

Underlying every form of physicalism is the claim that everything there is supervenes on the physical; that is, that every particular or property is at root a physical property or particular. In effect, this means that any change in a physical particular or property will cause a change in the corresponding supervening particular or property, just as any alteration of the physical properties of a painting will have an effect on its artistic properties. We can therefore be reasonably sure that every physicalist will agree with the following conclusion of physicalism:

No two worlds could be identical in every physical respect yet differ in some other respect.

The corresponding conclusion about the mental would be as follows:

No two people (or beings, or things) could be identical in every physical respect yet differ in some mental respect.

In modern physicalism these propositions might be based on the idea of a person as a space-time path. The claim that everything supervenes on the physical is thus the minimal commitment of physicalism.

Reductive physicalism

One form of physicalism claims that the mental is reducible to the physical. To claim that one thing (X) is reducible to another (Y) is to hold that whenever one discusses X, one can be understood to be talking about Y instead. Thus, the claim of reductive physicalism is that when we talk about mental events, we can be understood to be talking about events that are made up entirely of matter and energy.

See also

• Philosophy of mind
• Presentism

Sources and further reading

• The Stanford Encyclopedia of Philosophy's entry on physicalism.