Intension

In linguistics, logic, philosophy, and other fields, an intension is any property or quality connoted by a word, phrase, or another symbol. In the case of a word, it is often implied by the word's definition. The term may also refer to all such intensions collectively, although the term comprehension is technically more correct for this.

The meaning of a word can be thought of as the bond between the idea or thing the word refers to and the word itself. Swiss linguist Ferdinand de Saussure contrasts three concepts:

• the signifier — the "sound image" or string of letters on a page that one recognizes as a sign.
• the signified — the concept or idea that a sign evokes.
• the referent — the actual thing or set of things a sign refers to. See Dyadic signs and Reference (semantics).

Intension is analogous to the signified, extension to the referent. The intension thus links the signifier to the sign's extension. Without intension of some sort, words can have no meaning.

In philosophical arguments about dualism versus monism, it is noted that thoughts have intensionality and physical objects do not (S.E. Palmer, 1999), but rather have extension in space.

Intension and intensionality (the state of having intension) should not be confused with intention and intentionality, which are pronounced the same and occasionally arise in the same philosophical context. Where this happens, the letter s or t is sometimes italicized to emphasize the distinction.