Ad hoc

Cogito ergo sum
Logic and rhetoric

Key articles

* Logical fallacy
* Syllogism
* Argument

General logic

* Association fallacy
* Appeal to tradition
* Proof
* Informal fallacy
* SeekFind
* Appeal to accomplishment

Bad logic

* Gish Gallop
* Red herring
* Bulverism
* Fallacy of amphiboly
* Argumentum ad lunam
* Rapoport's Rules

v \- t \- e

Ad hoc is a phrase (literally, "to this") that describes ideas which are created solely for a specific task and not intended to be generalizable in any way.

## Contents

* 1 Argumentation
* 1.1 Examples
* 2 Piecemeal rebuttal
* 3 Politics
* 4 Depression and anxiety
* 5 Fiction
* 6 Legitimate uses
* 7 See also
* 8 External links

## Argumentation[edit]

Ad hoc is a fallacious debating tactic (also called a "just so story" or an "ad hoc rescue") in which an explanation of why a particular thing may be is substituted for an argument as to why it is; since it is therefore not an argument, it is not technically a fallacy, but is usually listed as one because it is a substitution for a valid argument. It is similar in form to moving the goalposts, but protects the argument by adding additional speculative terms rather than changing the meaning of existing ones.

Users of ad hoc claims generally believe that the excuses and rationalizations serve to shore up the original hypothesis, but in fact each additional speculative term weakens it. This is both due to the speculations being based simply on the faith that there might be an explanation, and because each additional term makes the hypothesis weaker according to the principle of parsimony.

"Possibly", "probably", "maybe", "might", and "could" are all good markers of ad hoc claims.

### Examples[edit]

Many creationists and woo-pushers use ad hoc explanations to explain away evidence that contradicts their underlying beliefs, rather than revising those beliefs. For example, many alternative medicines have been disproven or shown to be mere placebos, but believers will make up excuses as to why the controlled and properly conducted experiment was wrong. Some homeopaths, for instance, will cry that the succussion process was carried out incorrectly (as if 9 bangs rather than 10 makes all the difference), or that (inexplicably) it is impossible to do a "double-blind" test on homeopathy. Creationist explanations for how the Grand Canyon is explained via the global flood while similar canyons aren't seen everywhere are varied and ad hoc.

For example:

Alice: "It is clearly said in the Bible that the Ark was 450 feet long, 75 feet wide and 45 feet high."

Bob: "A purely wooden vessel of that size could not be constructed; the largest real wooden vessels were Chinese treasure ships which required iron hoops to build their keels. Even the Wyoming, which was built in 1909 and had iron braces, had problems with her hull flexing and opening up and needed constant mechanical pumping to stop her hold flooding."

Alice: "It's possible that God intervened and allowed the Ark to float, and since we don't know what gopher wood is, it is possible that it is a much stronger form of wood than any that comes from a modern tree."

Here, Alice has merely offered hypothetical explanations for how the Ark could have existed, rather than offering explicit proof that it could have.

## Piecemeal rebuttal[edit]

A piecemeal rebuttal is a strategy in which a person tries to refute all individual claims of the opponent ad hoc, with the goal to shift the burden of proof back to the opponent. This leads to a set of arguments that lack coherence or logical consistency, and the rebuttal fails to follow a unified framework or model.

## Politics[edit]

In politics, ad hoc refers to the creation of "temporary" committees or processes to handle new situations — similar to the valid uses of ad hoc arrangements described below, the situations are new, so can't really be dealt with in any other way. In some cases, notably due to laziness, these temporary creations end up becoming permanent. The constant "ad hoc tinkering" often creates solutions that work well in the short term, but end up creating a system that no one would have intentionally devised, given the time to work it out properly at the beginning. However, due to path dependency, it's basically impossible to go back and redesign the whole system from scratch. Instead, people make small ad hoc changes to the system again, and the process continues, with each new implementation causing a sort of partially-directed evolution of government.

## Depression and anxiety[edit]

A particularly pernicious form of anxiety called "imposter syndrome" is effectively ad hoc as applied to the self: the sufferer's sense of self-criticism is such that they cannot internalise their own successes, instead inventing an endless stream of justifications for why these successes somehow do not count. Note that both imposter syndrome and the suffering that it can cause are real; it's the process of creating negative delusions about the self which is ad hoc.

## Fiction[edit]

In fiction writing, the term "plot spackle" is used to describe the same method, where additional terms/characters/scenes/etc. are made up to pave over the cracks in a plot.

## Legitimate uses[edit]

Ad hoc explanations are not always an illegitimate exercise; if a new phenomenon is discovered, early explanations are likely to be technically ad hoc until experimentation or study can be conducted on it. In this sort of use and more general use, ad hoc arrangements are unavoidable because no one can predict the unpredictable (except maybe Derren Brown) — e.g., examiners putting ad hoc arrangements on exam marks because they didn't predict a spelling error, or role-players making up rules as they go along because the source book never said what to do if a Level 12 Sorceress cast that spell from that location while this rule was in effect under those rules in that building, which just produces a silly result. In science or when investigating pseudoscience, it is important to make sure that ad hoc claims are falsifiable and repeatable. Ad hoc algorithms are used in competitive programming and computing.

## See also[edit]

* Escape hatch
* Logical fallacy
* Special pleading
* Moving the goalposts

## External links[edit]

* "Ad Hoc", Atheism.about.com
* "Ad Hoc Rescue", Logically Fallacious
* "Ad Hoc Rescue", Internet Encyclopedia of Philosophy
* "Ad hoc hypothesis", Skeptic's Dictionary
* "Ad hoc (for this purpose only)", Secular Web

v \- t \- e

Articles about logical fallacies

Informal fallacies: |  Appeal to tradition • Appeal to novelty • Appeal to nature • Argument from morality • Argumentum ad martyrdom • Big words • Certum est quia impossibile est • Morton's fork • Friend argument • Exception that proves the rule • Extended analogy • Hindsight bias • Race card • Moralistic fallacy • Release the data • Gish Gallop • Terrorism-baiting • Uncertainty tactic • Greece-baiting • Ham Hightail • Red-baiting • Gore's Law • Nazi analogies • Mistaking the map for the territory • Red herring • Quidquid latine dictum sit, altum videtur • Presentism • Sunk cost • Two wrongs make a right • Flying carpet fallacy • My enemy's enemy • Appeal to ancient wisdom • Danth's Law • Argumentum ad lunam • Balance fallacy • Golden hammer • Loaded question • Escape to the future • Word magic • Spider-Man fallacy • Sanctioning the devil • Appeal to mystery • Informal fallacy • Common sense • Post-designation • Hyperbole • Relativist fallacy • Due diligence • Straw man • Good old days • Appeal to probability • Infinite regress • Circular reasoning • Media was wrong before • Is–ought problem • Ad iram • Just asking questions • Pink-baiting • Appeal to faith • Appeal to fear • Appeal to bias • Appeal to confidence • Appeal to consequences • Appeal to emotion • Appeal to flattery • Appeal to gravity • Appeal to hate • Argument from omniscience • Argument from silence • Argumentum ad baculum • Argumentum ad fastidium • Association fallacy • Broken window fallacy • Category mistake • Confounding factor • Counterfactual fallacy • Courtier's Reply • Damning with faint praise • Definitional fallacies • Equivocation • Fallacy of accent • Fallacy of accident • Fallacy of amphiboly • Gambler's fallacy • Imprecision fallacy • Moving the goalposts • Nirvana fallacy • Overprecision • Pathos gambit • Pragmatic fallacy • Quote mining • Argumentum ad sarcina inserta • Science doesn't know everything • Slothful induction • Spotlight fallacy • Style over substance • Toupee fallacy • Genuine but insignificant cause • Argument from incredulity • Appeal to age • Argumentum ad nauseam • Phantom distinction • Appeal to common sense • Argumentum ad hysteria • Omnipotence paradox • Argument from etymology • Appeal to trauma • Countless counterfeits fallacy •
| Ad hoc: |  No True Scotsman • Moving the goalposts • Escape hatch • Handwave • Special pleading • Slothful induction • Nirvana fallacy • God of the gaps • PIDOOMA • Tone argument •
| Arguments from ignorance: |  Science doesn't know everything • Argument from incredulity • Argument from silence • Toupee fallacy • Appeal to censorship • Science was wrong before • Holmesian fallacy • Argument from omniscience • Willful ignorance • Argument from ignorance •
| Causation fallacies: |  Post hoc, ergo propter hoc • Correlation does not imply causation • Wrong direction • Counterfactual fallacy • Regression fallacy • Gambler's fallacy • Denying the antecedent • Genuine but insignificant cause •
| Circular reasoning: |  Infinite regress • Argument by assertion • Argumentum ad dictionarium • Appeal to faith • Circular reasoning • Self-refuting idea •
| Emotional appeals: |  Appeal to fear • Appeal to emotion • Appeal to confidence • Deepity • Argumentum ad baculum • Appeal to shame • Appeal to flattery • Tone argument • Appeal to money • Argumentum ad fastidium • Appeal to gravity • Appeal to consequences • Loaded language • Style over substance • Appeal to pity • Appeal to hate • Pathos gambit • Shaming • Degenerate • Abomination •
| Fallacies of ambiguity: |  Fallacy of accent • Equivocation • Fallacy of amphiboly • Quote mining • Fallacy of ambiguity • Moral equivalence • Scope fallacy • Suppressed correlative • Not as bad as • Etymology • Continuum fallacy • Wronger than wrong • Definitional fallacies • Code word • Phantom distinction •
Formal fallacies: |  Confusion of the inverse • Denying the antecedent • Non sequitur • Affirmative conclusion from a negative premise • Not even wrong • Chewbacca Defense • Affirming a disjunct • Illicit process • Four-term fallacy • Negative conclusion from affirmative premises • Fallacy fallacy • Substituting explanation for premise • Enthymeme • Syllogism • Formal fallacy • Existential assumption • Masked man fallacy • Self-refuting idea • Argument by gibberish • One single proof • Affirming the consequent • False dilemma • Conjunction fallacy •
Fallacious arguments: |  Bumblebee argument • Fatwa envy • Gotcha argument • Hoyle's fallacy • Intuition pump • Logic and Creation • Not Circular Reasoning • Peanut butter argument • Great Beethoven fallacy • Fallacy of unique founding conditions • Evil is the absence of God • Argument from first cause • How do you know? Were you there? • Argument from design • Argument from beauty • Appeal to nature • Solferino fallacy • Religious scientists • Nothing to hide • Argument from fine tuning • Creep shaming • "I used to be an atheist" • Atheism as a religion • Argumentum ad populum • Argument from morality • Anti-environmentalism • Appeal to bias • Apophasis • Argumentum ad nauseam • Appeal to censorship • Argumentum ad sarcina inserta • Blaming the victim • Bait-and-switch • Danth's Law • Chewbacca Defense • Canard • DARVO • Demonization • Escape hatch • Friend argument • Everyone is racist • Gish Gallop • Greece-baiting • Gore's Law • Ham Hightail • Just asking questions • Leading question • Loaded language • Linking to authority • Loaded question • Lying by omission • Motte and bailey • Nazi analogies • Moving the goalposts • One single proof • Pink-baiting • One-way hash argument • Pathos gambit • Quote mining • Poisoning the well • Quidquid latine dictum sit, altum videtur • Race card • Red-baiting • Red herring • Release the data • Science was wrong before • Shill gambit • Straw man • Silent Majority • Uncertainty tactic • Style over substance • Terrorism-baiting • Weasel word • What's the harm (logical fallacy) • Whataboutism • Bullshit • Logical fallacy • Banana argument • Scapegoat • How come there are still monkeys? • Anti-racist is a code word for anti-white • Ontological argument • Omnipotence paradox • Presuppositionalism • Just a joke • Countless counterfeits fallacy •
Conditional fallacies: |  Slippery slope • What's the harm (logical fallacy) • Special pleading • Conditional fallacy • On the spot fallacy • Appeal to the minority • Argumentum ad populum • Galileo gambit • Professor of nothing •
| Genetic fallacies: |  Genetic fallacy •
|  | Appeals to authority: |  Ipse dixit • Appeal to confidence • Argumentum ad populum • Argument from authority • Linking to authority • Silent Majority • Invincible authority • Appeal to celebrity • Ultracrepidarianism • Appeal to the minority • Galileo gambit • Appeal to identity • Weasel word • Professor of nothing • Euthyphro dilemma • Divine command theory •
|  | Ad hominem: |  Ad iram • Argumentum ad cellarium • Bulverism • Poisoning the well • Blaming the victim • Tu quoque • Whataboutism • Nutpicking • Jonanism • Demonization • Shill gambit • Appeal to bias • Fallacy of opposition • Association fallacy • Damning with faint praise • Pathos gambit • Appeal to identity • Argumentum ad hominem • Nazi analogies • Not an argument • Nothing to hide • Scapegoat • 地下室论证 •
| Imprecision fallacies: |  Apex fallacy • Overprecision • Cherry picking • Overgeneralization • Texas sharpshooter fallacy • False analogy • Appeal to fiction • Spotlight fallacy • Pragmatic fallacy • Selection bias • Anecdotal evidence • Category mistake • Nutpicking • Imprecision fallacy • Confounding factor • Fallacy of accident • Neyman's bias •
Valid logical methods: |  Rapoport's Rules • Negative evidence • Reductio ad absurdum •
Fallacy collections: |  SeekFind • Nizkor Project • Fallacy Files • Your Logical Fallacy Is • Logically Fallacious •