Copyright, 1996 © Dale Carnegie & Associates, Inc. Classification and Definition Morris Cohen and Ernest Nagel An Introduction to logic and scientific method, pp ©Harcourt, Brace & World, Inc. 1934

Natural and Artificial Classes “Natural” classes –classifying traits according to facts “Artificial” classes –classifying traits through arbitrary selection

Natural and Artificial Classes “Artificial” classes aren’t artificial at all? All classes are artificial?

The Significance of Classification Classification is useful as a principle of organizing knowledge It should be determined by traits that have the highest logical value –i.e. whale = classified with pickerel or with horse?

Summary of Classification Science is supposed to gather facts, then classify them We often have to classify items before we can determine how to gather facts about them.

Conclusion of Classification Traits should be classified according to the most significant information about an item’s nature Who are qualified to make these decision? –Experts –Formal logic

The Purpose of Definition Psychological motivation –desire to learn the meanings of new words –desire to economize speech –desire to understand a word’s meaning better To produce accurate thinking and communication by reducing vagueness and ambiguity in language use

The Nature of Definition Vagueness –problems with shared denotations i.e., “genius” = –Isaac Newton, for his contributions to physics –any person with a high IQ –a baby to his mother –nonspecific, needs context i.e., “there’s moss on the log” (Linguistics 401, Dr. Andrea Wilhelm, January 2005) –…on top of the log. –…on the side of the log. –…on the back of the log.

The Nature of Definition Ambiguity –One word, two meanings i.e., “desirable” - John Stuart Mills (225) –attractive (desirable woman) –worth seeking (desirable legislation) –One phrase, two meanings i.e., “Lisa met the new French teacher” (Linguistics 401, Dr. Andrea Wilhelm, January 2005) –…the new teacher from France. –…the new teacher of French.

Nominal Definition Agreement or resolution regarding the use of verbal symbols (228) –Definiendum - new symbol to replace known symbol/word (definiens) i.e., Algebraic exponents: a 2 = a. a. Df.

Nominal Definition Neither true nor false Not a proposition Aids in scientific inquiry –It economizes language use –It adds clarity

Definition by Denotation Dictionary meaning / real-world symbol Core information that fixes/symbolizes reference (224) –i.e. ‘city’ denotes individual places such as Edmonton. –i.e., M. Jourdain uses specific examples to denote prose (226)

Definition by Denotation A symbolic representation of a word form is not a definition –i.e., Euthyphro’s definition of ‘piety’ (227)

Real Definition Analysis of the symbolized reference Genuine and universal proposition –may be either true or false i.e., Euthyphro’s second attempt at defining piety –Piety. =. that which is dear to the gods. Df. (230)