1. LANGUAGE AND DEFINITION
CHAPTER 3

2. LANGUAGE AND DEFINITION
Language can be divided into three basic categories according to its function.
1) Informative discourse is language used to convey information.
2) Expressive discourse is used to convey or invoke feelings.
3) Directive discourse is language used to cause or prevent certain
action.
Two less common functions include ceremonial language (can combine expressive and other functions as in How do you do?) and performative language. ( words that perform the function that they announce; i.e. “ I apologize for such a foolish remark.”)
Often, declarative sentences function directively or expressively; and questions may be directive rather than interrogative. Therefore, grammatical forms cannot be taken as the determining factor for language function.
Excercises p 73-79
LANGUAGE AND DEFINITION

3. LANGUAGE AND DEFINITION
On the level of the word, language is likewise complex.
Words have many different meaning to many different people, they can be used intentionally or not, some words cause reactions
Words can have both literal meanings and emotional impacts—and the literal and emotive meanings of words are largely independent of one another.
Although emotionally colored language may be appropriate in some contexts, in logic we strive, so far as possible, to be free from the distortions of emotive language. Good for poetry but bad for research.
Exercises p 81-84
LANGUAGE AND DEFINITION

4. LANGUAGE AND DEFINITION
Disputes are often not really disputes. Sometimes, because of the misunderstanding or misuse of words, we think we disagree when, in fact, we do not.
Therefore, we must make a distinction between obviously genuine disputes, in which people really explicitly disagree, and what we call merely verbal disputes.
These “disputes” occur when some word or phrase in an argument is ambiguous or misused.
Disputants may find themselves defending the same proposition with different words, or different propositions with the same words.
Exer. P 85-87
LANGUAGE AND DEFINITION

5. LANGUAGE AND DEFINITION
Definitions, since they can expose and thus eliminate ambiguity, are indispensable. They come in five different forms:
1 ) Stipulative—a definition that arises from the deliberate assignment of a meaning to a definiendum (A WORD OR PHRASE THAT IS BEING DEFINED). Eg. Zeta can be stipulated to mean a billion trillions.
2) Lexical—a definition that, like a dictionary, reports a meaning that a definiendum has already. Eg. A fish is a vertebrate with scales and gills.
3) Precising—definitions that reduce vagueness; the definiendum is not a new term, but the definition is not merely lexical. Eg. Used to further define an already accepted term to be more precise.
4) Theoretical—a definition that attempts to formulate a theoretically adequate or scientifically useful description of the objects to which the term applies. Eg. Used in philosophy and science to describe an entire set of words to help define a term.
5) Persuasive—definitions that are formulated to influence attitudes or emotions in order to persuade and/or resolve disputes.
Exerc. p 95-96
LANGUAGE AND DEFINITION

6. LANGUAGE AND DEFINITION
In defining general terms, logicians are careful to distinguish between the extension of a term (which is the collection of objects to which a term applies) and its intension (or the shared attributes of those objects).
Though the extension of a term is determined by its intension, the opposite is not true.
Moreover, when attributes are added to the intension of a term, the intension increases—though extension decreases.
Terms may, therefore, have intension but no extension.
Exerc. P 99
LANGUAGE AND DEFINITION

7. LANGUAGE AND DEFINITION
Denotative definitions use techniques that identify the extension of the term being defined
Terms may be defined extensionally by the collection of objects to which the term being defined applies. (i.e. for megaliths, one could say like Stonehenge, Newgrange or Skara brae.)
Such definitions have limitations, since two terms with different intensions may have the same extension.
Moreover, any given object has many different attributes, and thus is included in the extensions of many different general terms.
These difficulties are not cleared up by ostensive definition, (pointing at an object to define or demonstrating it) though quasi-ostensive definition, (pointing at the object and adding a qualifier) which includes a descriptive phrase, sometimes resolves the ambiguity. Obvious problems exist as you can be very limited as to what you can point at or demonstrate.
Ex. P 101
LANGUAGE AND DEFINITION

8. LANGUAGE AND DEFINITION
Intensional definitions, which refer to the attributes of the denoted objects, can be either subjective, objective, or conventional.
Subjective intension is the set of all attributes that the speaker/writer believes to be possessed by objects denoted by a certain term.
Objective intension is the total set of characteristics shared by all objects in the extension of a term.
Conventional intension is the commonly accepted intension of a term; the criteria generally agreed upon for deciding, with respect to any object, whether it is part of the extension of that term.
LANGUAGE AND DEFINITION

9. LANGUAGE AND DEFINITION
The technique of actually defining a word is, most frequently, using a synonym.
Synonymous definition is giving a definition using a word that means the same thing as the term being defined. Excellent for learning foreign languages.
But for strange or unfamiliar words, we must use other techniques.
Operational definition states that the term being defined can be explained by the performance of an operation that yields a specific result.
LANGUAGE AND DEFINITION

10. LANGUAGE AND DEFINITION
We might give an operational definition of a word or, if that does not work, we might try a definition by genus and difference.
Definition by genus and difference is the most applicable type of defining terms. It refers to identifying the larger class (genus) of which the term being defined is a species or sub-class of, and then identifies the attribute (the difference) that distinguishes the members of that species from members of all other species in the same genus.
A class is a collection of entities that share a common characteristic. Eg. All members of the genus (class) polygon share the fact that they are closed plane figures bounded by straight lines. Sub-classes (differences) would include triangles, hexagons, squares, etc.
If we use this last technique, we must follow the five rules for definition.
LANGUAGE AND DEFINITION

11. LANGUAGE AND DEFINITION
5 Rules for Definition
Rule 1 – A definition should state the essential attributes of the species (a definition should state the conventional intension of the term being defined).
Rule 2 – A definition must not be circular. i.e. The Bible is the word of God because the Bible says so.
Rule 3 – A definition must be neither too broad nor too narrow.
Rule 4 – Ambiguous, obscure, or figurative language must not be used in a definition.
Rule 5 – A definition should not be negative when it can be affirmative. Eg. Say what a term does mean, rather than to define it by what it does not mean.
Ex. P
LANGUAGE AND DEFINITION