logical fallacies

sweeping generalization

sweeping generalization

An argument based on the assumption that all people, situations, or events of a kind are the same 

All Southern Californians love In and Out.

sweeping generalization

non sequiter

no logical connection

People like walking on the beach. Beaches have sand. So, people should have sand floors in their homes.

non sequieter

red herring

Presents an irrelevant topic to divert attention away from the original issue (like a non-sequitur)

“we admit that this measure is popular, but we also urge you to note that there are so many bond issues on this ballot that the whole thing is getting ridiculous”

red herring

Weak analogy

Comparing  two situations, people, objects , etc. that aren’t quite alike

 Philosophy 101 is a philosophy class and has many discussions; logic is a philosophy class. So, it must also have many discussions

Weak analogy

False dichotomy

When only two choices are presented yet more exist, or a spectrum of possible choices exists between two extremes.  False dilemmas are usually characterized by “either this or that” language, but can also be characterized by omissions of choices. 

You love me, or you hate me

False dichotomy

Scare tactics

Exaggerated threats

if you don’t accept…is true, something bad will happen to you

Scare tactics

Slippery Slope

One small event has tremendously exaggerated consequences. 

take a small sip of alcohol in high school and you’ll be an alcoholic by 30

Slippery Slope

Appeal to Pity

Get you to accept something by making you feel sorry for someone

If I don’t get an A then I won’t be able to play baseball

Appeal to Pity

Ad Populum

Using the popularity of a premise or proposition as evidence for its truthfulness.  This is a fallacy which is very difficult to spot because our “common sense” tells us that if something is popular, it must be good/true/valid, but this is not so, especially in a society where clever marketing, social and political weight, and money can buy popularity.

Most people used to believe the earth was the center of the universe 

Ad Populum

Dogmatism 

Holding something as true without factual foundation or consideration for alternative views. Intolerant religious stances are often dogmatic. 

when a child asks why, the parent says “because I said so”

Dogmatism 

Ad Hominem 

Character attack. A person makes one mistake, and they are a bad person in every other area of their life. Also, attacking the person, not the issue.

we can’t support his proposal to improve mass transit because he is an immoral man

Ad Hominem 

Appeal to (doubtful) authority

The reference to an "expert" who actually is not qualified to speak with authority on the issue

My 5th grade teacher once told me that girls go crazy for boys who can dance. So, if you want to make girls go crazy for you, learn to dance. 

Appeal to (doubtful) authority

"Since 88% of people polled believe in UFOs, they must exist.”

ad populum 

"Andrea Dworkin has written several books arguing that the media harms women when it comes to body image. But Dworkin is an ugly, bitter person, so you shouldn't listen to her." 

ad hominem

"I know the exam is graded based on performance, but you should give me an A. My cat has been sick, my car broke down, and I've had a cold, so it was really hard for me to study!" 

appeal to pity

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." 

slippery slope

"Guns are like hammers—they're both tools with metal parts that could be used to kill someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on purchasing guns are equally ridiculous." 

weak analogy

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

appeal to doubtful authority

"Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we continue to risk students' safety. Obviously we shouldn't risk anyone's safety, so we must tear the building down."

false dichotomy

"My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard!" 

sweeping generalization 

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

non sequiter 

"Animal experimentation reduces our respect for life. If we don't respect life, we are likely to be more and more tolerant of violent acts like war and murder. Soon our society will become a battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent this terrible consequence, we should make animal experimentation illegal right now." 

scare tactics