Ad hoc

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'''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.

==Argumentation==
Ad hoc is a [[logical fallacy|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 [[rationalization]]s 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===
Many [[creationism|creationists]] and [[woo]]-pushers use ''ad hoc'' explanations to explain away evidence that contradicts [[A priori and a posteriori#A priori|their underlying beliefs]], [[cognitive dissonance|rather than revising those beliefs]]. For example, many [[alternative medicine]]s have been disproven or shown to be mere [[placebo]]s, but believers will make up excuses as to why the controlled and properly conducted experiment was wrong. Some [[homeopathy|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:

{{cquote|
'''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==

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==
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==
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==
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==
''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 [[experiment|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 [[black swan|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==
*[[Escape hatch]]
*[[Logical fallacy]]
*[[Special pleading]]
*[[Moving the goalposts]]

==External links==
*[http://atheism.about.com/library/FAQs/skepticism/blfaq_fall_adhoc.htm "Ad Hoc"], Atheism.about.com
*[http://www.logicallyfallacious.com/index.php/logical-fallacies/9-ad-hoc-rescue "Ad Hoc Rescue"], Logically Fallacious
*[http://www.iep.utm.edu/fallacy/#AdHocRescue "Ad Hoc Rescue"], Internet Encyclopedia of Philosophy
*[http://skepdic.com/adhoc.html "Ad hoc hypothesis"], [[Skeptic's Dictionary]]
*[http://infidels.org/library/modern/mathew/logic.html#adhoc "Ad hoc (for this purpose only)"], [[Secular Web]]

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[[Category:Ad hoc| ]]
[[Category:Latin phrases]]
[[Category:Political terms]]

Categories: Ad hoc, Latin phrases, Political terms