logical fallacies

False authority

borrowing the authority of someone who is not an expert on the topic you’re writing on. e.g. quoting a professor of medieval studies, Dr. Smith, on a medical question is using a false authority

False quotation

misquote an authority so that the
quotation fits your argument. For instance, while writing an essay that asserts a person’s freedom to
have sex with anyone, you neglect the “Thou Shalt Not” and declare that God commands, “Commit adultery” in the Bible.

Hasty generalization

stating a generalization without the evidence to back it up. Be careful throwing out words such as “everyone,” “all,” “many,” and “most.” Example – “Everyone hates Manser’s pizza.” (Did you really
ask everyone?)

Over simplification

People who ignore the complexity of an issue or disregard possible
exceptions or variations commit the fallacy of oversimplification. Example — A rock and roll song
about suicide made a teenager kill himself. (The teen may have been upset about a number of
things besides the song he was listening to.

False dilemma

sets up an untrue “either-or” argument. You commit this error if you set up a problem with only two solutions when, in fact, there may be other, unstated alternatives. Example – “Either I get a loan, or I’ll have to drop out of school.” (alternative—get a job and work your way through school)

False analogy

compares two things that
are not similar in any meaningful way. Example — Today's youth, like savages on the warpath, are
attacking the morals of our nation. (This sentence is a vivid insult, but it's not a valid analogy unless
you can explain a number of significant similarities between the two groups.)

Begging the question

assumes a definition that may not be true, begging the reader
to go along with the stated opinion. Example – “This UNFAIR policy will hurt the city.” (According to
whom? Have you given any evidence to prove this statement?

Circular reasoning

restating the argument instead of
proving that it is true. Example – “Drinking beer is wrong because it is immoral.” (which is like
saying, “drinking beer is wrong because it is wrong.)

False cause (POST HOC OR CASALITY)

wrongly attributing an effect to an event that happened before the effect. (This happened before that, so this must’ve caused that)

Nono sequitur (false assumption)

predicts effects or states conclusions that do not follow from the premises. This sounds similar to post hoc, so try not
to confuse them. Remember, the post hoc argument looks at two events that have already happened and assumes the first caused the second, but the non sequitur looks at one fact and predicts a false conclusion. Example – Harold is from California. He probably knows how to surf. (hint: it helps to think of the non sequitur as an “if . . . then” statement where the “then” is in question)

Ad hominem

name calling, stereotyping, and other ways in which someone may attack a persons character instead of talking about the issue.

Slippery slope

argues that one event will certainly cause another (and another) until a chain reaction happens, when, in fact, there may not be a connection between the imagined events.
This is also known as the Domino Effect

Bandwagon

If a majority of people want a particular thing then it must be the best choice. “If all of your friends jumped off a cliff would you?”
said to you, "If all your friends jumped off a cliff, would you jump too?"

Red herring

Bringing up an issue that is irrelevant to the current issue. Term comes from the practice of rubbing a smoked herring across a trail to distract hunting dogs.