Philosophical Arguments

Philosophical Arguments

What is an Argument?• A philosophical argument is not a disagreement.• A philosophical argument is not a dispute.• A philosophical argument is not a quarrel.• A philosophical argument is not an opinion.

Philosophical Arguments• A philosophical argument consists of one or more statements

set out in support of some other statement.• Premises: the statements set out in support of some other

statement.• Conclusion: the statement that other statements are set out to

support.

Examples of Arguments

All human beings are mortal.Socrates is a human being.Therefore, Socrates is mortal.

Premises

Conclusion

Scrabble is not exciting, for Scrabble is safe, and nothing is both safe and exciting.

Although all men are created equal, because Batman is fictional, and

fictional men are not the same as other men.

Batman is not equal to other men,

More Examples

Poetry cannot be translated; and, therefore, it is the poets that preserve the languages; for we would not be at the trouble to learn a language if we could have all that is written in it just as well in a translation. But as the beauties of poetry cannot be preserved in any language except that in which it was originally written, we learn the language.

-- Ben Johnson

• Poetry cannot be translated.• We would not be at the trouble to learn a language if we could

have all that is written in it just as well in a translation.• The beauties of poetry cannot be preserved in any language

except that in which it was originally written.• Therefore, it is the poets that preserve the languages.

More Examples

It is impossible to make people understand their ignorance; for it requires knowledge to perceive it and therefore he that can perceive it hath it not.

-- Jeremy Taylor

• Understanding ignorance requires knowledge to perceive it.

• Therefore, he that can perceive ignorance hath it not.• Therefore, it is impossible to make people understand their

ignorance.

Deductive and Inductive Arguments

Deductive Arguments• Deductive arguments are arguments in which the conclusion

is presented as following from the premises with necessity.

Inductive Arguments• Inductive arguments are arguments in which the conclusion is

presented as following from the premises with a high degree of probability.

Examples

Deductive Argument:I own every Dario Argento film.Suspiria is a Dario Argento film.Therefore, I own a copy of Suspiria.

Inductive Argument:Every Keanu Reeves movie ever

made has been awful.The Night Watchman will be a Keanu

Reeves movie.So The Night Watchman will be awful.

Logical Validity & Soundnessin Deductive Arguments

In constructing and evaluating an argument, we need to consider two things:

• Does its conclusion follow necessarily from its premises?• Are its premises true?

Philosophers use the answers to these questions to classify arguments.

Deductive Validity

A deductive argument is valid just in case the truth of its premises would absolutely guarantee the truth of its conclusion.• In other words, it is valid just in case there is no possible way

the premises could all be true but the conclusion false.

Deductive Soundness

A deductive argument is sound just in case it is valid and all of its premises are true.

So an argument can only be sound if it is also valid.

Evaluating Arguments for Soundness & Validity

Mike is older than Wes.Wes is older than Lisa.Therefore, Mike is older than Lisa.

To be a Canadian citizen, one has to be born in Canada.Darren was born in Canada.Therefore, Darren is a Canadian citizen.

All cats chase mice.Tigers do not chase mice.Therefore, tigers are not cats.

More Arguments

Everyone likes Phil100.All Phil100 exams are easy.Therefore, everyone will receive a high grade in Phil100.

All books are printed in multiples of 16 pages.Introduction to Philosophy has 819 pages.819 is not divisible by 16.Therefore, Introduction to Philosophy is not a book.

Some tests are multiple choice.Some exams are multiple choice.Therefore, some tests are exams.

All Tests

All MC Things

All Exams

MCTests

Exam-Tests

MCExams

MCExams

Some Common FallaciesEquivocation

In the fallacy of equivocation, the meaning of a key term shifts during the course of an argument.

Man is the only rational creature.No woman is a man.Therefore, no woman is a rational creature.

Any person with a handicap is at a disadvantage.Raymond has a handicap in golf.Raymond is at a disadvantage in golf.

Circularity and “Begging the Question”In a circular argument, something (A) is asserted to be true just in case something else (B) is true. But B turns out to be true just in case A is true.

The Bible is the infallible Word of God.The Bible says that God exists.Therefore, God exists.

My essays always deserve at least a “B”.This is one of my essays.Therefore, this essay did not deserve a “C”.

To “beg the question” is to prove what is not self-evident by means of itself.

Some Common Fallacies

Necessary & Sufficient Conditions

Necessary ConditionIf A is a necessary condition for B, then if not-A then not-B.

Sufficient ConditionIf A is a sufficient condition for B, then if A, then B.

Sleeping is a necessary condition for dreaming.• If you are not sleeping, then you are not dreaming.

Dreaming is a sufficient condition for sleeping.• If you are dreaming, then you are sleeping.