Philosophy 6: Logic in Practice

Los Angeles Pierce College

Department of History, Philosophy, & Sociology

 

 

 

 

 

Lecture Notes for "Chapter One" and "Chapter Two" of Porter's The Voice of Reason

 

 

 

 

 

 

 

Lecture Notes for "Chapter One" of Porter's The Voice of Reason

 

 

 

 

 

 

 

 

Contradictory Statements      

 

"'All generalizations are false.'" 

 

"'There's an exception to every rule'" 

 

"The French novelist Albert Camus once remarked that the minute we declare 'Everything is absurd' we contradict ourselves, for we have said something meaningful" 

 

"No one goes to that club anymore, it's too crowded"

 

 

 

 

 

 

 

 

 

 

 

Seeming Contradictions

 

Contradiction ­ Paradox

 

"Paradoxes are statements that appear to be inconsistent, absurd, or opposed to common sense but may be true in a special or deeper sense"

 

 

 

 

 

 

 

 

 

 

Contradiction ­ Oxymoron

 

 

"An oxymoron is a figure of speech in which opposite or incongruous words are put together to express a point more pungently" 

 

 

 

 

 

 

 

 

 

 

 

 

 

Trying it Out       

 

I. 2

 

II. 3

 

II. 5

 

IV. 2

 

V. 1

 

V. 8 

 

VI. 1

 

VI. 3

 

VII. 6

 

VII. 10

 

 

 

 

 

 

 

 

 

 

 

Using vs. Mentioning Terms

 

Referring to what words (may) represent, using those words

 

               ­

 

Referring to words themselves

 

 

 

 

 

 

 

 

 

 

Use

 

  ­

 

Mention

 

 

"a map is not the land itself"

 

"if 'strawberries' were mentioned as something found in a dictionary, it would be a waste of time trying to find them there to eat with cream and sugar." 

 

 

 

 

 

 

 

 

 

 

Quotation

Marks        

 

"To avoid miscommunication we must use quotation marks to signal that we are mentioning a word"

 

"otherwise people will assume we are using it in the customary way"

 

 

 

 

 

 

 

 

 

 

Trying it Out       

 

IV. 2

 

IV. 4

 

 

 

 

 

 

Lecture Notes for "Chapter Two" of Porter's The Voice of Reason

 

 

Part One of Chapter Two

 

 

 

 

 

Why Words       

Logical analysis demands the clear use of words 

 

Understanding the "basic elements that make up words" will help us in our future logical analyses.

 

 

 

 

 

 

 

 

 

The Basic Ingredients       

 

Intension ­ Extension ­ Connotation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Intension

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Extension

 

 

 

 

 

 

 

 

 

 

 

The See-Saw    

Intension varies inversely with extension

        

Larger and Smaller

The larger the intension, the smaller the extension, and vice versa

 

 

 

 

 

Small intension: 

      a herbivorous mammal

      four legged

Large extension:  cows, gazelles, horses, etc. 

 

 

 

 

 

 

 

Larger intension: 

       a herbivorous mammal

       four legged

       solid hoofed

Smaller extension:  cows, gazelles, horses, etc. 

 

 

 

 

 

 

 

 

What's What    

"knowing the distinction between intension and extension helps us understand such phrases as 'business is business,' 'boys will be boys,' [etc.]" 

 

 

 

 

 

 

 

 

 

 

Business E.G.

E.G.   "Business is business"

 

Extensional-business (commerce, competition, exchange, etc.) is intensional-business (money-making activity aimed at profit)

 

 

 

 

 

 

 

 

 

Trying it Out       

 

I. 9

 

I. 10

 

II. 1

 

II. 9

 

III. 3

 

III. 4

 

IV. 3

 

IV. 7

 

IV. 10

 

 

 

 

 

 

 

 

 

 

 

 

Connotation

Emotional associations connected to a word ­ explicit meaning of a word

 

 

 

 

"When you hear me on those other stations that's just industry businessÐbut when you hear me on Fake 93.2Ðnow that's family." 

 

 

 

 

 

Trying it Out       

 

V. 1

 

V. 2 

 

V. 6

 

VI. 3

 

VII. 3

 

VII. 5

 

VIII.

 

XI. 1. d

 

XI. 2. a

 

XI. 2. c

 

 

 

 

 

 

Part Two of Chapter Two

 

 

 

 

 

Vagueness

"Vague words or expressions lack clarity and distinctness, so that we don't know whether they apply in a given case." 

 

 

 

 

 

 

 

 

 

 

 

 

        

Acceptable Vagueness

         Aristotle:  "We must not expect more precision than the subject-matter admits"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

        

 

Vagueness as a Charge     

Word use that is unnecessarily vague is to be avoided

 

The charge of vagueness comes from using unnecessarily vague words

        

 

 

 

 

 

 

 

 

 

 

 

 

 

Charge

E.G.   "suppose we ask a used car salesman how much a car costs and we are told it's a bargain, a very good deal, less expensive than we might think, priced to move, sure to save us money, and so forth." 

        

 

 

 

 

 

 

 

 

 

 

 

 

        

The Ought for Vagueness  

Avoid vagueness as much as possible for the sake of clarity, even when vagueness is unavoidable

        

 

 

 

 

 

 

 

 

 

Trying it Out     

 

I. 3

 

I. 4

 

II. 2

 

II. 3

        

 

 

 

 

 

 

 

 

 

 

 

 

 

Ambiguity         

"In ambiguity a word contains several meanings, and we are uncertain which one is meant." 

 

In ambiguity, "[w]e are confused about the word, phrase, sentence, or passage because it can be understood in more than one sense." 

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Multiple Meanings of Words       

Many words have more than one meaning

 

"Go to the bank"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ambiguity as a Fact of Language        

In context, not a problem

 

"Go to he bank and deposit money into your savings account"

 

"Go to the bank and cast your line in" 

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ambiguities Semantic & Ambiguities Syntactic   

Semantic ­ syntactic

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Neutral Semantic Ambiguity      

"Semantic ambiguity has to do with the multiple meanings of a word as it appears in a sentence, either once or twice." 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

        

Single Use Semantic Ambiguity

"Bikinis now sold for a ridiculous figure"

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Double Use Semantic Ambiguity        

"'Time flies like an arrow, but fruit flies like a banana (and fireflies like the wind)'"

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ambiguity as a Positive Tool      

Ambiguity is not necessarily bad, and necessarily a mere fact of language, it can be a tool

 

"In philosophy, I am a tool too!" 

 

My favorite ambiguity: 

 

"I confuse easily"Ðcopyright me! 

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ambiguity as a Charge      

When the context does not settle the meaning, and you're not trying to tell a joke, you are open to being (negatively) charge with being ambiguous

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Negative Semantic Ambiguity    

 

"'All committed people will get out the vote,

 

'John has just been committed,

 

'therefore John will get out the vote'" 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

        

Pernicious Semantic Ambiguity

The right to bear arms extends to whom? 

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Semi-Neutral Semantic Ambiguity

 

Accent      

"Under the broad category of semantic ambiguity the phenomenon of accent should also be mentioned." 

 

"Here ambiguity occurs because it is unclear which word in the sentence is being accented or emphasized." 

        

 

 

 

 

 

 

 

 

 

 

 

 

Accent E.G. Banks     

"The bank robber Willie Sutton was asked, 'Why do you rob banks?' and he answered, 'Because that's where they keep the money.'" 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

        

Accent E.G. Harm      

"'You should not harm someone who has harmed you' might mean be taken to mean that you ought not return injury for injury (we should turn the other cheek), or maybe that we should harm someone who has not harmed us." 

        

 

 

 

 

 

 

 

 

 

 

 

 

 

Syntactic Ambiguity  

"Syntactic ambiguity occurs when the grammatical arrangement of words makes the meaning of a sentence unclear." 

 

"The meaning of each word may be plain but we cannot understand the overall sense." 

 

        

"Eat here and get gas" 

 

"Hospitals Are Sued by Seven Foot Doctors"

 

"Save soap and waste paper" 

 

"In 'Save soap and waste paper,' we do not know whether 'waste' is an adjective or a verb"

        

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Negative Syntactic Ambiguity

 

Amphiboly        

 

"'If John loves his family more than his mistress, then he is a good man,

 

'but John's mistress loves his family more than he does,

 

'therefore John is not a good man.'" 

        

Instead      

 

"'If John's mistress loves his family more than he does then he is a good not a man,

 

'but John loves his family more than his mistress,

 

'therefore John is a good man.'" 

        

Take Away Be aware of these differences and don't let them get in the way of your use of language

        

 

 

Trying it Out     

 

IV. 4

 

IV. 6

 

V. 7

 

VI. 3

 

VI. 5