Fallacious Substitution in Argument¶

Abstractions that diagnose informal fallacies where a persuasive but irrelevant signal — threat, repetition, believability, age, or a curated evidence subset — is substituted for the genuine logical or evidential support a claim actually requires.

17 abstractions in this family — domain-specific abstractions that sit near one another in structural-signature space (k-means over structural-signature embeddings). Each is shown with its short description.

Ad Baculum (Appeal to Force) — The fallacy of securing acceptance of a claim by threatening the listener rather than giving reasons bearing on its truth — a relevance error in which a payoff-altering signal is substituted for a truth-bearing one, so compliant assent and warranted belief come apart.
Ad Nauseam (Argument from Repetition) — Diagnose the fallacy of treating a claim as established by bare repetition, where frequency raises felt credibility through processing fluency while adding zero new evidential warrant.
Begging the Question — Detect an argument whose premises presuppose the very conclusion they are offered to support — valid, even sound, yet dialectically empty — by testing whether the premises would survive an interlocutor who denies the conclusion.
Belief Bias — The tendency to judge an argument's logical validity by the believability of its conclusion rather than its form — a cheap plausibility check displacing an effortful logical-form check — exposed by crossing validity against believability in a 2×2.
Bulverism — Assume an opponent's conclusion is false, then explain the psychological or sociological cause of their 'error' — substituting a genetic account of the belief for the logical evaluation that was owed.
Chronological Snobbery — The fallacy of dismissing a belief solely because it is old — substituting a temporal fact for a content-specific reason — corrected by Lewis's question of whether the view was actually refuted or merely fell out of fashion, with an age-as-credit mirror in appeal to tradition.
Circular Reasoning — Diagnose an argument whose conclusion already appears among its premises by tracing its justification graph for a cycle that never touches a node the audience grants independently.
Epiphany — A discrete moment in which an unsolved problem suddenly reorganizes in the mind so the answer is manifest — not the acquisition of a new fact but a restructuring of the framing through which fixed facts are read, arriving abruptly across an impasse and seeming obvious in hindsight.
Invention (Rhetorical Canon) — Systematically canvass the arguments available in a case by visiting a fixed catalogue of topoi in turn, treating coverage of that space — not the quality of any one argument — as the standard of adequacy, before any choice of what to advance begins.
Irrelevant conclusion — Prove a sound argument for a proposition that is not the one at issue, then treat it as settling the contested claim — a relevance failure caught by restating the question before grading the answer.
Is-Ought Problem — Hume's principle that no purely descriptive premises can by themselves deductively entail a normative conclusion — so any move from 'is' to 'ought' requires an explicit, defensible bridging value premise, and its absence marks a category error.
Moralistic fallacy — Detect the inference that runs from normative undesirability straight to empirical falsity — 'this would be bad if true, therefore it is not so' — foreclosing a factual question on a moral ground without any evidence being weighed, the mirror of the naturalistic fallacy.
Null Ritual — The institutionalised practice of mechanically executing a null hypothesis significance test — nil-null, p-value, p < .05 verdict — severed from the alternatives, priors, effect sizes, and decision context inference requires, yet retaining full editorial authority as if it had not been.
Proof By Assertion
Red Herring — Deflect a discussion by introducing material irrelevant to the open question, so attention and the conversational floor shift to the new topic and the original question is left feeling-addressed-but-unanswered — the test being whether the new material does any work on the claim that was open.
Relative Privation — The informal fallacy of dismissing a concern by pointing to a worse problem elsewhere, conflating severity-ranking with action-licensing — since ranking governs how much total attention a problem warrants, not whether it is eligible for any, unless the worse problem's resources are genuinely exclusive.
Suppressed Evidence