Logical Fallacies

A fallacy is the application of invalid or otherwise faulty reasoning in the construction of an argument. Such reasoning may appear to be well-structured if the error remains unnoticed.

Logical fallacies are errors in the structure or content of arguments that render them logically unsound. These defects in reasoning are frequently employed in mass media, advertising, and political discourse to persuade an audience by creating a diversion from the actual point of debate.

While fallacies can be committed intentionally to manipulate or deceive, they may also occur unintentionally due to human limitations such as ignorance, carelessness, or cognitive bias.

Formal and Informal Classifications

Fallacies are generally divided into two major categories: - Formal
- Informal

A formal fallacy, also termed a deductive fallacy or non sequitur, is a structural flaw in a deductive argument that renders the entire inference invalid.

In these cases, the conclusion does not follow from the premises in the manner described. Examples include affirming the consequent and denying the antecedent. In propositional logic, a formal fallacy can be identified even if the content of the statements is composed of nonsense or made-up words.

An informal fallacy originates in an error of reasoning related to the content of the propositions rather than a structural flaw.

Arguments containing informal fallacies may be formally valid yet remain rationally unpersuasive. Identification of these errors requires an understanding of the concepts and meanings involved in the argument.

Informal fallacies include broad categories such as fallacies of relevance, fallacies of presumption, and linguistic fallacies. Within the context of measurement, these may manifest as unwarranted inferential leaps when raw data is extrapolated to value claims.

Common Informal Fallacies

• Ad Hominem (Against the Man): Attacking the messenger’s character or personal traits instead of addressing the substance of their argument.

• Straw Man: Misrepresenting, exaggerating, or fabricating an opponent’s argument to make it easier to attack.

• Slippery Slope: Asserting that a specific action will inevitably lead to a chain of (usually disastrous) events without providing evidence for the causal link.

• False Dilemma (False Dichotomy/False Binary): Presenting only two options as the only possibilities when, in reality, more exist.

• Circular Reasoning (Begging the Question): An argument where the conclusion is already included in the premise.

• Hasty Generalisation: Making a sweeping statement or statistical claim based on an inadequate or non-representative sample size.

• False Cause (Post Hoc Ergo Propter Hoc): Assuming that because one event followed another, the first event caused the second.

• Appeal to Authority (Argumentum ad Verecundiam): Claiming something is true solely because an authority figure said so, regardless of relevant expertise or evidence.

• Bandwagon (Argumentum ad Populum): Arguing that a claim is valid because it is popular or many people believe it.

• Appeal to Emotion: Using inflammatory or emotional language to persuade an audience in place of a valid or compelling argument.

• Tu Quoque (Appeal to Hypocrisy): Avoiding criticism by turning it back on the accuser, claiming that they have committed the same error.

• Genetic Fallacy: Judging an idea as good or bad based on its origin rather than its own merits.

Formal Fallacies

Formal fallacies are errors in the structure of a deductive argument that make the inference invalid.

• Affirming the Consequent: An invalid form where if p implies q, one incorrectly infers p from q.

• Denying the Antecedent: An invalid form where if p implies q, one incorrectly infers that not-p implies not-q.

• Fallacy of the Undistributed Middle: A structural error in a syllogism where the middle term is not distributed in at least one premise.

• Non Sequitur (It does not follow): A general term for an argument where the conclusion does not follow from the premises.

Probabilistic and Statistical Fallacies

These fallacies involve the misapplication of the laws of probability or the law of small numbers.

• Conjunction Fallacy: Incorrectly assuming that a specific combination of conditions is more probable than a single, more general condition.

• Base Rate Fallacy: Ignoring the underlying frequency of an event (the base rate) when assessing the probability of a specific outcome.

• Small Numbers Fallacy: Seeking a causal explanation for a phenomenon when it is merely a result of the statistical law that smaller samples yield more extreme results.

• Regression to the Mean Fallacy: Attributing a causal explanation to a phenomenon that is actually a natural statistical return to the average.

• Gambler’s Fallacy: Believing that independent, random events (like a coin flip) are influenced by previous outcomes.

• Misuse of Statistics: Expressing data in ways that bias reports, such as relative changes instead of absolute numbers.

Linguistic and Classical Fallacies

Aristotle first systematised logical errors into linguistic (verbal) and non-linguistic (material) fallacies.

• Equivocation: Using a single word or phrase in two different senses within the same argument.

• Amphiboly: Ambiguity resulting from the grammatical structure of a sentence.

• Accent: A fallacy where the meaning is changed by the way words are stressed or pronounced.

• Composition Fallacy: Incorrectly assuming that what is true for the parts must be true for the whole.

• Division Fallacy: Incorrectly assuming that what is true for the whole must be true for each individual part.

• Complex Question (Loaded Question): Asking a question with a built-in assumption that forces the answerer to admit guilt or a specific premise.

The David King Handbook List

The sources contain an extensive list from David King’s "A Handbook of Logical Fallacies":

• Ad Fidentia (Against Self-Confidence): Attacking a person's confidence in their principles rather than the principles themselves.

• Ambiguous Collective: Using collective terms like "we" or "the people" without defining the specific group being discussed.

• Anti-Conceptual Mentality: Treating abstract concepts as though they were self-contained perceptual concretes requiring no definition.

• Argument from Intimidation: Challenging someone's character or moral status to force acceptance of an argument.

• Assumption Correction Assumption: Implicitly assuming that the other party will correct your mistaken assumptions.

• Barefoot: Claiming that without government control of a service, society would lack it entirely.

• Barking Cat: Demanding a government or entity behave contrary to its established nature.

• Boolean Fallacy (Excluded Middle): Treating a continuum as if it were only represented by its extremities.

• Cherishing the Zombie: Continuing to tout an idea that has long been proven dead or ineffective.

• Context Imposition: Trying to force another person to share a manufactured intellectual or moral context.

• Determinism: Claiming that human states of consciousness are determined by factors beyond volitional control.

• Elephant Repellent: Using the absence of a problem as proof that a specific (often unnecessary) solution is working.

• Emphatic Fallacy: Reacting with disproportionate emotion to minor issues while ignoring serious ones.

• Flat Earth Navigation Syndrome: Devoting energy to solving problems that do not exist.

• Frozen Abstraction: Substituting a specific concrete example for the wider abstract class to which it belongs.

• Gravity Game: Demanding an idea be proven indefinitely before its validity is accepted.

• Greek Math: The inability to distinguish between positive/negative scales, often viewing a "lesser negative" as a positive.

• I-Cubed: Assuming an adversary is Ignorant, Incompetent, or Inexperienced.

• Megatrifle: Taking a small effect and magnifying it to appear all-encompassing.

• Moving Goalpost Syndrome: Continually changing the criteria for "proof" once an initial requirement is met.

• Relative Privation: Making a situation appear better or worse simply by comparing it to an extreme.

• Retrogressive Causation: Using the cause of a problem to eliminate the effect, thereby inducing further implementation of the cause.

• Shingle Speech: Grouping superficial aspects of a subject topically rather than hierarchically.

• Silence Implies Consent: Assuming that a lack of verbal opposition constitutes agreement.

• Wouldchuck: Using conditional probability ("would happen if") as though it were factual reality without evidence.

Other fallacies mentioned include Discarded Differentia, Donut, Eclectic, Exclusivity, Floating Abstraction, Government Absolutist/Solipotence, Gratuitous Inculpation, Homily Ad Hominem, Ignoring Historical Example/Proportionality, Instantiation of the Unsuccessful, Meatpoison, Misplaced Precision, Null Value, Pigeonholing, Pretentious Antecedent, Proving a Negative, Self Exclusion, Simplistic-Complexity, Spurious Causation/Superficiality, Stolen Concept, Suppression of the Agent, Thompson Invisibility Syndrome, Unknowables, Unintended Self-Inclusion, Variant Imagization, and Verbal Obliteration.