logical fallacies

Hasty generalization

Making assumptions about a whole group or range of cases based on a sample that is inadequate (usually because it is atypical or just too small).

• Type of stereotype

Missing the point

The premises of an argument support a particular conclusion--but not the conclusion that the arguer actually draws.

• Same topic, different premise

Post hoc, ergo propter hoc

A faulty assumption that the cause of a relationship is the result of what preceded it. 

• Also known as Faulty Causality

• “after this, therefore because of this”

Slippery slope

The arguer claims that some form of chain reaction, usually ending in some dire consequence, will take place, but there's really not enough evidence for that assumption.

• Also called “The camel’s nose”

• Assumption that if we take one step onto the slippery slope, we’ll go all the way down (without having an option to stop)

Faulty/weak analogy

Many arguments rely on an analogy between two or more objects, ideas, or situations. If the two things that are being compared aren't really alike in the relevant respects, the analogy is a weak one, and the argument that relies on it commits the fallacy of weak analogy.

Appeal to authority

If we try to get readers to agree with us simply by impressing them with a famous name or by appealing to a supposed authority who really isn't much of an expert on the issue being discussed, we commit the fallacy of appeal to authority.

• Misuse of ethos

Appeal to pity/ad misericordiam

The appeal to pity takes place when an arguer tries to get people to accept a conclusion by making them feel sorry for someone.

• Misuse of pathos

• Can work for other emotions (pride, sadness, etc.)

Appeal to ignorance

An appeal to ignorance lacks conclusive evidence (data, facts, statistics) about the issue being discussed. The arguer states that one should accept his or her conclusion on the presented issue despite this.

Straw man

The arguer sets up a wimpy, distorted, or misrepresented version of the opponent’s position (counterargument) and tries to score points by knocking it down.

Red herring

Partway through an argument, the arguer goes off on a tangent, raising a side issue that distracts the audience from what's really being discussed.

• Often, the arguer never returns to the original issue.

False dichotomy

In false dichotomy, the arguer sets up the situation so it looks like there are only two choices. The arguer then eliminates one of the choices, so it seems that we are left with only one option: the one the arguer wanted us to pick in the first place.

Begging the question

An argument that begs the question asks the reader to simply accept the conclusion without providing real evidence by saying the same point in different words.

Equivocation

Equivocation is sliding between two or more different meanings of a single word or phrase that is important to the argument.

Circular reasoning

One statement is true because of the other statement, and the other statement is true because of the previous statement. A claim is supported by its reasoning; the argument begins where it ends. 

• X is true because of Y and Y is true because of X

Non sequitur

A gap in the sequence of your logic. The writer leaps from points A to B and then jumps to D, leaving out step C of an argument.

Reductio ad absurdum

Involves extending someone’s arguments to ridiculous proportions then criticizing the result that no reasonable person would take such a position.

• Also known as "reducing to an absurdity”

Poisoning the well

Attacking an argument by attacking the opponent (discrediting them) before they can present their argument.

Appeal to tradition

Because something has always been done a particular way, it should continue to be done that way.

Stacking the deck

Any evidence that supports an opposing argument is rejected, omitted, or ignored.

Hypothesis contrary to the fact

Offering poorly supported claims about what might have happened in the past or future if (the hypothetical part) circumstances or conditions were different.  The fallacy also entails treating future hypothetical situations as if they are fact.

Moving the goalposts

Demanding from an opponent that he or she address more and more points after the initial counter-argument has been satisfied, refusing to concede or accept the opponent’s argument.

Fallacies of relevance

These fallacies appeal to evidence or examples irrelevant to the argument at hand.

Component fallacies

Component fallacies are errors in inductive and deductive reasoning or in syllogistic terms that fail to overlap.

Occam’s razor

Occam's Razor is the principle that, if two competing hypotheses deal with a single phenomenon + reach the same conclusion + equally persuasive and convincing + explain the problem or situation satisfactorily, the logician should always pick the less complex one.