Fallacy

A fallacy is the use of invalid or otherwise faulty reasoning in the construction of an argument. All forms of human communication can contain fallacies.

The use of fallacies is common when the speaker's goal of achieving common agreement is more important to them than utilizing sound reasoning. When fallacies are used, the premise should be recognized as not well-grounded, the conclusion as unproven (but not necessarily false), and the argument as unsound.

Red Herring

Introducing a second argument in response to the first argument that is irrelevant and draws attention away from the original topic (e.g.: saying "If you want to complain about the dishes I leave in the sink, what about the dirty clothes you leave in the bathroom?")

Informal Fallacy

A type of incorrect argument in natural language. Arguments that are logically unsound for lack of well-grounded premises

Formal Fallacy

A formal fallacy is an error in the argument's form. All formal fallacies are types of non sequitur.

Ad Hominem

Attacking the arguer instead of the argument. Ad hominem is a type of a [[#Red Herring]] fallacy.

Appeal to Motive

A subtype of [[#Ad Hominem]], so by association a [[#Red Herring]], dismissing an idea by questioning the motives of its proposer.

Poisoning the well

A subtype of [[#Ad Hominem]], so by association a [[#Red Herring]], presenting adverse information about a target person with the intention of discrediting everything that the target person says.

Appeal to Authority

A subtype of [[#Red Herring]], an assertion is deemed true because of the position or authority of the person asserting it.

Appeal to Emotion

A subtype of [[#Red Herring]], manipulating the emotions of the listener rather than using valid reasoning to obtain common agreement. Has common subtypes in appeals to fear, flattery, pity, ridicule, and spite.

Appeal to Nature

A subtype of [[#Red Herring]], judgment is based solely on whether the subject of judgment is 'natural' or 'unnatural'.

Straw Man

A subtype of [[#Red Herring]], refuting an argument different from the one actually under discussion, while not recognizing or acknowledging the distinction.

Sunk Cost

A statistical fallacy, refusal to leave a situation because you have already put large amounts of time or effort into it.

Example: Trying to jump over a wall you physically cannot jump over because you have already spent an hour trying to jump over it.

Gambler's Fallacy

A statistical fallacy, the incorrect belief that separate, independent events can affect the likelihood of another random event.

Example: If a fair coin lands on heads 10 times in a row, the belief that it is "due to the number of times it had previously landed on tails" is incorrect.

Cherry Picking

A faulty generalization, using individual cases or data that confirm a particular position, while ignoring related cases or data that may contradict that position.

Begging the Question

An improper premise, using the conclusion of the argument in support of itself in a premise

Example: Saying smoking cigarettes is deadly because cigarettes can kill you; something that kills is deadly.

Circular Reasoning

An improper premise, the reasoner begins with what they are trying to end up with. Circular reasoning is often of the form: "A is true because B is true; B is true because A is true." Circularity can be difficult to detect if it involves a longer chain of propositions.

Example: "This statement is correct because it says it is correct"

False Authority

An [[#Informal Fallacy]], using an expert of dubious credentials or using only one opinion to promote a product or idea. Related to [[#Appeal to Authority]].

False Equivalence

An [[#Informal Fallacy]], describes two or more statements as virtually equal when they are not.

Moving the Goalposts

An [[#Informal Fallacy]], an argument in which evidence presented in response to a specific claimed is dismissed and some other (often greater) evidence is demanded.

Slippery Slope

An [[#Informal Fallacy]], asserting that a proposed, relatively small, first action will inevitably lead to a chain of related events resulting in a significant and negative event and, therefore, should not be permitted.