Understanding Logical Fallacies

By Mario Sikora

Part of an ongoing series of articles on clear-thinking skills, excerpted from “How to Think Well, and Why: The Awareness to Action Guide to Clear Thinking” by Mario Sikora (available at www.awarenesstoactionbooks.com).

Learning to recognize logical fallacies in the arguments of others makes us more disciplined in being logical ourselves.

Informal logical fallacies, like those below, do not necessarily invalidate an argument, but they are fallacious because they cannot serve alone as sufficient justification for a point of view. Skillful thinkers learn these fallacies and watch for them in the arguments of others.

Common Logical Fallacies

• Ad hominem: attacking the person rather than the merit of the idea they are proposing.
• Appeal to antiquity or custom: giving undue validity to an argument because it is old or part of a tradition.
• Appeal to authority: giving undue validity to an argument because an important or famous person made it.
• Appeal to emotion: encouraging people to focus on their feelings rather than the facts when evaluating an argument.
• Appeal to popularity: claiming that an argument is valid because a lot of people believe it.
• Appeal to the stone: dismissing a claim as absurd without providing proof for its absurdity.
• Argument from ignorance: assuming that a claim is true because it has not been or cannot be proven false, or vice versa.
• Argument from incredulity: “I cannot imagine how this could be true; therefore, it must be false.”
• Begging the question: providing the conclusion of the argument as a premise.
• Shifting the burden of proof: claiming, I need not prove my claim, you must prove it is false.
• Circular reasoning: when the reasoner begins with what he or she is trying to end up with; sometimes called assuming the conclusion.
• Circular cause and consequence: when the consequence of the phenomenon is claimed to be its root cause.
• Correlation proves causation (also known as post hoc ergo propter hoc, “after the thing, therefore because of the thing”): a flawed assumption that because there is a correlation between two variables that one caused the other.
• False authority: elevating an expert of dubious credentials or using only one opinion to promote a product or idea.
• False choice: when two contrasting statements are held to be the only possible options when in reality there are more.
• False equivalence: assuming logical and apparent equivalence when in fact there is none.
• Fallacy of the single cause: assuming there is one simple cause of an outcome when in it may have actually been caused by a number of interrelated causes.
• Inflation of conflict: assuming that if experts disagree on a certain point, the scholars of a whole field must not know anything.
• McNamara fallacy (quantitative fallacy): making a decision based only on quantitative observations and discounting all other considerations.
• Moving the goalposts: an argument in which the evidence presented in response to a specific claim is dismissed with a demand for some other (often greater) evidence.
• Naturalistic fallacy: inferring the something is good because it is the way it is now or it is the way it was in the past.
• Shifting the burden of proof: assuming that the person questioning a claim is responsible for proving the validity of the claim, rather than assuming the burden is on the person making the claim.
• Proof by assertion: repeatedly restating a proposition regardless of contradiction.
• Proof by verbosity: overwhelming others with an argument too complex and verbose to reasonably deal with in all its details.
• Prosecutor’s fallacy: a low probability of false matches does not mean a low probability of some false match being found.
• Psychologist’s fallacy: presupposes the objectivity of one’s own perspective when analyzing a behavioral event.
• Red herring: an attempt to distract an audience by deviating from the topic at hand with a separate argument the speaker believes is easier to address.
• Reification: when an abstraction is treated as if it were a concrete, real event or physical entity.
• Shotgun argumentation: the arguer offers such a large number of arguments for a position that the opponent can’t possibly respond to all of them.
• Special pleading: when an advocate of a position attempts to cite an exemption to a generally accepted rule or principle without justifying the exemption.
• Straw Man: Misrepresenting another’s claim and then attacking the misrepresentation rather than the actual point being made.
• Tu quoque: “You did it too.” Pointing out another person’s error or transgression rather than addressing your own. Also known as “What about-ism.”