Fallacies of Logic

The authority fallacy is when:

• a large number of people have participated in something and the statistic is used to endorse the activity or product (example: a million Australians trying Oral B toothpaste)

• there are only two possible solutions to a problem and you must pick one (example: live where you can eat breakfast at McDonalds or live in a dictatorship)

• a celebrity or other source of authority is used to "endorse" your argument even though that celebrity/authority is not legitimately connected to the argument (example: Alex Trebek as a spokesperson for an insurance product)

What is an example of ad hominem?

• You can either eat what the cafeteria is serving or starve.

• Mrs. Moe's argument about how we are responsible for completing the assignment is invalid because she is wearing an ugly scarf.

• Mrs. Moe has a Starbucks drink today so that means she will not go to Caribou and then Caribou will go out of business.

A faulty analogy is when:

• you assume that because two things have characteristics in common that they have everything in common

• a large number of people are doing something so you feel you should do it, too

• a celebrity endorses a product so you feel you can trust that the product is good or reliable

America is the best place to live, because it's better than any other country.

• ad hominem

• red herring

• circular logic

• straw man

Russia has a terrible human rights record. Well, the United States has done plenty of bad things. -the President when confronted about Russia's human rights abuses.

• slippery slope

• red herring

• moral equivalence

• non sequitur

Because doctors smoke it must be a healthy choice.

• hasty generalization

• moral equivalence

• straw man

• slippery slope

We should stop using hairspray because it is snowing in New York.

• hasty generalization

• non sequitur

• ad hominem

• moral equivalence

It is warmer this year in Las Vegas as compared to last year; therefore, global warming is rapidly accelerating.

• slippery slope

• red herring

• circular reasoning

• hasty generalization

If we use just one more can of hairspray this month, earth as we know it will no longer exist.

• hasty generalization

• slippery slope

• red herring

• straw man

We either ban hairspray or the world will end.

• slippery slope

• non sequitur

• either/or (black/white) (binary)

• moral equivalence