Chapter Two: 2.2 The Intension and Extension of Terms

Term

Any word or arrangement of words that may serve as the subject of a statement Proper names - Napoleon Common names - animal Descriptive phrases - author of Hamlet

Increasing extension

Class size gets larger with each successive term Tiger, feline, mammal, animal Decreasing extension is opposite Nd same as increasing intension Animal, mammal, feline, tiger

Extensional meaning or Extension

Consist of the members of the class that the term denotes Denotation Ex: "inventor" Thomas Edison Alexander G. Bell Wright brothers

Intensional meaning or Intension

Consist of the qualities or attributes that the term connotes Connotation Ex: "inventor" Clever Intuitive Creative Imaginative

Increasing Intension

Each term in the series after the first is more specific than the one preceding it Animal, mammal, feline, tiger Decreasing intension is opposite and same as increasing extension Tiger, feline, mammal, animal

Cognitive Meaning of Words: Two kinds

International and extensional

Proper names: Intension determines Extension

Names are shorthand symbols for descriptions Proper names have some kind of intension

Conventional connotation

Of a term includes the attributes that the term commonly calls forth in the minds of competent speakers of the language To fix problem of different connotations that stem from different emotions

Empty Extension

Sometimes the denotation of a term can change radically with the passage of time Denote the empty or "null" class - class that has not members "Current king of France" "Unicorn" Terms do not have empty Intension

Main task of logic

The evaluation of arguments Task usually leads to observation Study of meaning and definition

Intension determines Extension

The intentional meaning of a term serves as the criterion for deciding what the extension consists of Problems occur with proper terms

Words that are not terms

Verbs Nonsubstantive adjs Adverbs Prepositions Conjunctions And all non-syntactic arrangement of words

Use vs mention of a word

Wherever is not a term but if it is in quotes it can serve as the subject of a sentence - not the word itself but the quoted word (mentioned) Without quotations it is used in the sentence