Chapter 3

Logic and Language

Preview of 3.1 - 3.3

• Problem areas– 3.1• Proposition

– 3.2• Subtlety of definitional terms

– 3.3• Largely unproblematic

Chapter 3.1

• This chapter is about “What is actually meant by . . . .”• Which of these concepts/terms were difficult?– Proposition– Cognitive meaning– Emotive force

• For the concepts/terms that were confusing, can someone clarify it for us by defining and giving at least one example, or the range of examples, of it?

• Why is it important to understand these concepts/terms?• Review problematic exercises

Chapter 3.2• Which of these concepts/terms were difficult?

– Ambiguity versus vagueness– Extensional definition

• Ostensive• Enumerative• Subclassical

– Intensional definition• Lexical (genus & differentia)• Stipulative• Precising• Theoretical

• For the concepts/terms that were confusing, can someone clarify it for us by defining and giving at least one example, or the range of examples, of it?

• Why is it important to understand these concepts/terms?• Review problematic exercises

Why care about definitions?

• ‘Define’ literally means to put ‘limits around’ (fr. L. de ‘about’ + finis ‘limit’).

• So, definition limits meanings.–Minimizes • vagueness (meanings shading off into other areas)• ambiguity (more than one meaning)

–Minimizes complications of “It all depends on what you mean by __________.”

Definition by extension

• Pointing (a.k.a. ‘ostensive’)– actually showing one or more cases

• Enumeration– listing individual examples

• Subclass– listing types or categories

• Exhaustive v. non-exhaustive?

Intensional definition

• Stipulative: personal, ad hoc, coined or not• Lexical: positive, descriptive, dictionary-type, though

not necessarily exclusively so• Precising: minimizes vagueness & ambiguity, to “put

a fine point on it,” to distinguish precise meaning from popular meaning

• Theoretical: places a term in a particular context; may give meaning to both term and context

• Persuasive: affective, subjective, emotive

Definition by intension

• Synonym– Another word (lit. ‘similar’ + ‘name’)

• Etymology– Linguistic genealogy (lit. ‘true’ + s ‘account’)

• Test– Establishes criteria to be met

• Genus + difference/differentia– “garden variety” definition technique: ‘x is a y [that . . . .]’

Chapter 3.2, cont’d.• Which of these concepts/terms were difficult?

– Genus versus difference/differentia– Definiendum versus definiens– Counterexample

• For the concepts/terms that were confusing, can someone clarify it for us by defining and giving at least one example, or the range of examples, of it?

• Why is it important to understand these concepts/terms?• What are the criteria for producing a good definition?

– Not to wide– Not to narrow– Not obscure, ambiguous, figurative– Not circular– Not negative if it can be positive– Not use unsuitable criteria to determine extension

• Review problematic exercises

Ways of defining: terms

• ‘definiendum’: word to be defined• ‘definiens’: words doing the defining• ‘extension’: set of objects in defined class• ‘intension’: properties of objects in class

Rules

• What is meant by essential characteristics (necessary & sufficient)?

• How can the definiens be too broad or narrow?• What is meant by circularity?• Cite examples of ambiguity, obscurity,

figurative or emotive language.

Chapter 3.3• Which of these concepts/terms were difficult?– Equivocation versus merely verbal dispute– Persuasive definition

• For the concepts/terms that were confusing, can someone clarify it for us by defining and giving at least one example, or the range of examples, of it?

• Why is it important to understand these concepts/terms?• Review problematic exercises