Logical Fallacies

Invalid Arguments

Slippery Slope• If A happens, then through small steps more

things will happen (B, C, D…. X, Y) all the way to Z. So if we don’t want Z to happen then we can’t do A.

Example: If we ban Hummers because they are bad for the environment eventually the government will ban all cars, so we should not ban Hummers.

Hasty Generalization

Vocab: Hasty = quick, generalization = conclusion

• Rushing to a conclusion before you have all the relevant facts.

Example: Even though it's only the first day, I can tell this is going to be a boring course.

Example: Fred, the Australian, stole my wallet. Thus, all Australians are thieves

Circular Argument/Begging the Question

• Restates the argument rather than actually proving it.

Example: John is a good communicator because he speaks effectively.

Example: You can’t give me a C, I’m an A student

Ad Hominem (personal attack)

• This is an attack on the character of a person rather than her/his opinions or arguments.

Example: Green Peace's strategies aren't effective because they are all dirty, lazy hippies.

Example: We should discount what Steve Forbes says about cutting taxes because he stands to benefit from a lower tax rate.

Example: I don’t care what you think- you’re too young

Ad Populum/Bandwagon/Appeal to Populartity

• Emotional appeal to positive (such as patriotism, religion, democracy) or negative (such as terrorism or fascism) concepts rather than the real issue at hand.

• “Everyone knows that ______ so this must be true”

Example: If you were a true American you would support the rights of people to choose whatever vehicle they want.

Example: Since 88% of the people polled believed in UFOs, they must exist

Red Herring• Distraction tactic that avoids the key issues,

often by avoiding opposing arguments rather than addressing them.

Example: The level of mercury in seafood may be unsafe, but what will fishers do to support their families?

Example: Girlfriend asks, “Honey, does this dress make me look fat?” Boyfriend replies, “Say, babe, your hair is really gorgeous! And those earrings are a knock-out!”

Straw Man• Oversimplifies/ignores the other side’s viewpoint

and then attacks it.(Creates a man made of straw that can easily be

knocked down)

Example: People who don't support the proposed state minimum wage increase hate the poor.

Example: “Senator Jones says that we should not fund the attack submarine program. I disagree entirely. I can’t understand why he wants to leave us defenseless like that.”

Post Hoc, Ergo Propter Hoc:

Vocab: Latin, "after this, therefore because of this"

• Assumes that if 'A' occurred after 'B' then 'B' must have caused 'A.’ (mistake of thinking correlation implies causation)

Example: I drank bottled water and now I am sick, so the water must have made me sick.

Example: Michelle’s mother is an English teacher, so that’s why Michelle got an A in Language Arts

• Post Hoc, Ergo Propter Hoc: If A then B, then B must have caused A

• Straw Man: Oversimplifying the argument• Red Herring: Talking about something unrelated• Ad Populum/Bandwagon/Appeal to Populartity:

Appeal to the masses• Ad Hominem: Attacking the person• Circular Argument/Begging the Question:

Restating the question rather than proving• Hasty Generalization: Jumping to conclusions• Slippery Slope: If this happens all these other

things will happen