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
