View source for Ad hoc hypothesis

{{Short description|Addition to a theory to prevent falsification}}
{{other uses|Ad hoc (disambiguation)}}
{{DISPLAYTITLE:''Ad hoc'' hypothesis}}
In [[science]] and [[philosophy]], an '''''ad hoc'' hypothesis''' is a [[hypothesis]] added to a [[theory]] in order to save it from being [[falsified]].

For example, a person that wants to believe in [[leprechaun]]s can avoid ever being proven wrong by using ''ad hoc'' hypotheses (e.g., by adding "they are invisible", then "their motives are complex", and so on).<ref name=Stanovich2007>Stanovich, Keith E. (2007). How to Think Straight About Psychology. Boston: Pearson Education. Pages 19-33</ref>

Often, ''ad hoc'' hypothesizing is employed to compensate for anomalies not anticipated by the theory in its unmodified form.

==In the scientific community==
Scientists are often [[Scientific skepticism|skeptical]] of theories that rely on frequent, unsupported adjustments to sustain them. This is because, if a theorist so chooses, there is no limit to the number of ''ad hoc'' hypotheses that they could add. Thus the theory becomes more and more complex, but is never falsified. This is often at a cost to the theory's [[predictive power]], however.<ref name="Stanovich2007"/> ''Ad hoc'' hypotheses are often characteristic of [[pseudoscientific]] subjects.<ref>Carroll, Robert T. "Ad hoc hypothesis." ''The Skeptic's Dictionary''. 22 Jun. 2008 <http://skepdic.com/adhoc.html>.</ref>{{bettersource|date=November 2021}}

[[Albert Einstein]]'s addition of the [[cosmological constant]] to [[general relativity]] in order to allow a [[static universe]] was ''ad hoc''. Although he later referred to it as his "greatest blunder", it may correspond to theories of [[dark energy]].<ref>Texas A&M University. "Einstein's Biggest Blunder? Dark Energy May Be Consistent With Cosmological Constant." ''ScienceDaily'' 28 November 2007. 22 June 2008 <https://www.sciencedaily.com/releases/2007/11/071127142128.htm>.</ref>

== See also ==
* [[Ad hoc]]
* [[Fringe science]]
* [[Russell's teapot]]
* {{section link|Deferent and epicycle|Bad science}}
* [[No true Scotsman]]
* [[Special pleading]]
* ''[[The Structure of Scientific Revolutions]]''
* ''[[Proofs and Refutations]]''
* "[[The Demon-Haunted World#Dragon in the garage|The Dragon in My Garage]]"
* [[Paraconsistent logic]]
* [[Moving the goalposts]]

== References==
{{reflist}}

== External links ==
*{{PhilPapers|search|Ad_hoc_hypothesis}}

{{DEFAULTSORT:Ad Hoc Hypothesis}}
[[Category:Hypotheses]]
[[Category:Epistemology of science]]
[[Category:Scientific skepticism]]
[[Category:Razors (philosophy)]]
[[Category:Concepts in the philosophy of science]]


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