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, the word's definition often implies an intension. For instance, intension of the word '[plant]' includes properties like "being composed of cellulose" and "alive" and "organism", among others. Comprehension is the collection of all such intensions.

The meaning of a word can be thought of as the bond between the idea the word means and the physical form of the word. Swiss linguist Ferdinand de Saussure (1857–1913) contrasts three concepts:

Without intension of some sort, a word has no meaning. For instance, the terms 'rantans' or 'brillig' have no intension and hence no meaning. Such terms may be suggestive, but a term can be suggestive without being meaningful. For instance, 'ran tan' is an archaic onomatopoeia for chaotic noise or din and may suggest to English speakers a din or meaningless noise, and 'brillig' though made up by Lewis Caroll may be suggestive of 'brilliant' or 'frigid'. Such terms, it may be argued, are always intensional since they connote the property 'meaningless term' but this paradox does not constitute a counterexample to the claim that without intension a word has no meaning.

Intension is analogous to the signified in the Saussurean system, extension to the referent.

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 and time.

A statement-form is simply a form obtained by putting blanks into a sentence where one or more expressions with extensions occur—for instance, "The quick brown ___ jumped over the lazy ___'s back." An instance of the form is a statement obtained by filling the blanks in.

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