Argument Requires premises and conclusion Non-arguments : I dont like chocolates; Chocolates are makes you sick; I believe in God Arguments: Chocolates.

Argument

• Requires premises and conclusion• Non-arguments : I don’t like chocolates;

Chocolates are makes you sick; I believe in God

• Arguments: Chocolates are sweet- I do not enjoy sweets- Therefore I don’t like chocolates; I believe what my mother says- My mother says that God exists- Thus I believe in God

Valid Arguments

• Valid argument- Conclusion entailed from premises [logically follows the premises]

• If P then Q exists. Q exists. So P• Premises or conclusion don’t have to be true• Deductive logic

Valid and Invalid Arguments

• Jessica is a man- Men have beards-Jessica has a beard

• Jessica is a woman- Men are astronauts- Jessica is not an astronaut

• Andy is a boy- Boys are mammals-Andy is a mammal

• Andy is cute man- Cute babies can be naughty- Thus Andy is a naughty man

Valid and Invalid Arguments

• I believe what psychics say- A psychic said that I would die yesterday- I believe I died yesterday

• A psychic said that my dog is a ferret- I believe him- I am dumb

• White tablecloths are not blue- My table cloth is white- Thus it is not blue

• White skirts are not blue-My skirt is not blue- Thus it is white

Sound Arguments

• Valid arguments +• True premises• As premises are true, conclusion is always true• If P then Q. Q. So P. P and Q is true, thus sound argument• Sound Argument: Jessica is a girl- Girls are human

beings- Jessica is a human being• Unsound Argument: Jessica is a girl- Girls are pretty-

Jessica is pretty

Sound and Unsound Arguments

• Jessica is a girl- Girls are human beings- Jessica is a human being

• Jessica is a girl- Girls are pretty- Jessica is pretty

• Cakes are food- Food can be eaten- Cakes can be eaten

• Cakes are food- Food is always tasty- Cakes are always tasty

Syllogism

• Form of an argument• Proposition is proved or disproved in the

conclusion• Major premise is universal, minor premise and

conclusion are particulars

Aristotelian Syllogism

• 3 categorical propostions Major premise: All men are mortal.

Minor premise: All Greeks are men. Conclusion: All Greeks are mortal

Men are subject s, Greeks are predicate P and mortals is the middle term

• Types of categoricals: 1. Universal Affirmative All S are P – S a P2. Universal Negative- No S are P- S e P3. Particular Affirmative- Some S are P- S i P4. Particular Negative- Some S are not p- S o P

• Forms of syllogism

Conclusion is always S-P• 256 forms- 6 fallacies in each categories are

valid forms, some of them have an existential fallacy i.e. an empty category

Major Premise

M-P P-M M-P P-M

Minor Premise

S-M S-M M-S M-S

BARBARA

All men are mortal. (MaP) All Greeks are men. (SaM)All Greeks are mortal. (SaP)

CAMESTROS

All horses have hooves. (PaM) No humans have hooves. (SeM) Some humans are not horses. (SoP)

DARAPTIAll squares are rectangles. (MaP) All squares are rhombs. (MaS) Some rhombs are rectangles. (SiP)

DARII All rabbits have fur. (MaP) Some pets are rabbits. (SiM)

∴ Some pets have fur. (SiP)

FESAPO FRESISON

FALLACIES

• Fallacy is an error in argument or reasoning• Formal fallacies can be spotted by invalidty in its

syllogistic form. Fallacies of Accident• Verbal fallacies can be classified as: Fallacy of false cause Begging the Question Red Herring Fallacies Equivocation Informal fallacies

FALLACY OF ACCIDENT

• Post hoc [post hoc ergo poster hoc]: after this therefore because of this

President Jones raised taxes, and then the rate of violent crime went up. Jones is responsible for the rise in crime.

• False dichotomy: either 2+2=5 or God exists. God exists, thus 2+2 is not 5

RED HERRING FALLACIES

• Going off the tangentGrading this exam on a curve would be the most

fair thing to do. After all, classes go more smoothly when the students and the professor are getting along well

RED HERRING FALLACIES

• Slippery Slope: slide down the bottom when we stop halfway downhill

If I fail English 101, I won't be able to graduate. If I don't graduate, I probably won't be able to get a good job, and I may very well end up doing temp work or flipping burgers for the next year.

RED HERRING FALLACIES

• Ad hominem tu quoque [against someone-you too] Failure to act consistently

Dia Mirza: I believe in ethical treatment of all living beings; I’m a PETA member and I endorse The Body Shop

Ms.X: The Body Shop may be vegan but it owned by L’oreal which tests its products on animals, thus you are cruel

RED HERRING FALLACIES

• Straw man fallacy: Wimpy version of opponent’s argument and knock it down

Person A: Sunny days are good.Person B: If all days were sunny, we'd never have

rain, and without rain, we'd have famine and death. Therefore, you are wrong

BEGGING THE QUESTION

• Circular reasoning to prompt a question, the answer is what you argue for

We know that God exists, because it says so in the Bible. And we can trust the Bible on this matter because it's the Word of God, and so must be correct

INFORMAL FALLACIES

• Appeal to Ignorance One cant prove that God doesn’t exist therefore

he exists• Undistributed Middle/ EquivocationUse of metaphor, middle term has more than

one implication All polticians are snakes- Snakes have no legs-

Polticians have no legs

INFORMAL FALLACIES

• Appeal to authority: We should abolish the death penalty. Many respected people, such as actor Guy Handsome, have publicly stated their opposition to it.

• Hasty generalization: My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard

INFORMAL FALLACIES

• Missing the Point: The seriousness of a punishment should match the seriousness of the crime. Right now, the punishment for drunk driving may simply be a fine. But drunk driving is a very serious crime that can kill innocent people. So the death penalty should be the punishment for drunk driving

INFORMAL FALLACIES

• Ad populum [to the people]: Gay marriages are just immoral because 70% of Americans think so.

• Reductio ad absurdumIf P, then Q. But not-Q. So not-P

[Unbeatable computer game]