View source for Philosophy:Confirmation holism

{{Short description|Idea in the philosophy of science}}
In [[Philosophy:Philosophy of science|philosophy of science]], '''confirmation holism''', also called '''epistemological holism''', is the view that no individual statement can be confirmed or disconfirmed by an empirical test, but rather that only a set of statements (a whole theory) can be so. It is attributed to [[Biography:Willard Van Orman Quine|Willard Van Orman Quine]] who motivated his holism through extending [[Biography:Pierre Duhem|Pierre Duhem]]'s problem of [[Philosophy:Underdetermination|underdetermination]] in physical theory to all knowledge claims.<ref name="online text">W. V. O. Quine. '[[Philosophy:Two Dogmas of Empiricism|Two Dogmas of Empiricism]].' ''The Philosophical Review'', 60 (1951), pp. 20–43. [http://www.ditext.com/quine/quine.html online text]</ref><ref>Duhem, Pierre. ''The Aim and Structure of Physical Theory''. Princeton, New Jersey, Princeton University Press, 1954.</ref>

Duhem's idea was, roughly, that no [[Theory|theory]] of any type can be tested in isolation but only when embedded in a background of other hypotheses, e.g. hypotheses about initial conditions. Quine thought that this background involved not only such hypotheses but also our whole '''web of belief'''<!--boldface per WP:R#PLA-->, which, among other things, includes our mathematical and logical theories and our scientific theories. This last claim is sometimes known as the [[Philosophy:Duhem–Quine thesis|Duhem–Quine thesis]].<ref>Curd, M. and Cover, J.A. (Eds.) (1998). Philosophy of Science, Section 3, The Duhem-Quine Thesis and Underdetermination, W.W. Norton & Company.</ref>

A related claim made by Quine, though contested by some (see [[Biography:Adolf Grünbaum|Adolf Grünbaum]] 1962),<ref name=Grünbaum1962>Grünbaum, A. 1962. "The falsifiability of theories: total or partial? A contemporary evaluation of the Duhem-Quine thesis", ''Synthese'', vol. 14:17-34. {{doi|10.1007/BF02274802}}</ref> is that one can always protect one's theory against refutation by attributing failure to some other part of our web of belief. In his own words, "Any statement can be [[Philosophy:Hold come what may|held true come what may]], if we make drastic enough adjustments elsewhere in the system."<ref name="online text"/>

==Underdetermination in physical theory==

By 1845 astronomers found that the orbit of planet [[Astronomy:Uranus|Uranus]] around the Sun departed from expectations.  Not concluding that [[Physics:Newton's law of universal gravitation|Newton's law of universal gravitation]] was flawed, however, astronomers John Couch Adams as well as [[Biography:Urbain Le Verrier|Urbain Le Verrier]] independently predicted a new planet, eventually known as [[Astronomy:Neptune|Neptune]], and even calculated its weight and orbit through Newton's theory.{{efn |name= discOfNeptune|1= From wikipedia: ''[[Astronomy:Discovery of Neptune|Discovery of Neptune]]'' <ref name="Danjon, Prof. André Director of the Paris Observatory 1946">{{cite journal | last1=Danjon |first1=André | year=1946 | title=Le centenaire de la découverte de Neptune | journal=Ciel et Terre |volume=62 |page=369 | bibcode=1946C&T....62..369D}}</ref>}} And yet neither did this empirical success of Newton's theory verify Newton's theory.

Le Verrier soon reported that [[Astronomy:Mercury (planet)|Mercury]]'s perihelion—the peak of its orbital ellipse nearest to the Sun—advanced each time Mercury completed an orbit, a phenomenon not predicted by Newton's theory, which astrophysicists were so confident in that they predicted a new planet, named ''[[Astronomy:Vulcan (hypothetical planet)|Vulcan]]'', which a number of astronomers subsequently claimed to have seen.  In 1905, however, Einstein's [[Physics:Special theory of relativity|special theory of relativity]] claimed that space and time are both [[Physics:Spacetime|relative]], refuting the very framework of Newton's theory that claimed that space and time were both [[Philosophy:Absolute space and time|absolute]].

In 1915, Einstein's general theory of relativity newly explained gravitation while precisely predicting Mercury's orbit.  In 1919, astrophysicist [[Biography:Arthur Eddington|Arthur Eddington]] led an expedition to test Einstein's prediction of the Sun's mass reshaping [[Physics:Spacetime|spacetime]] in its vicinity.  The Royal Society announced confirmation—accepted by physicists as the fall of Newton's theory.  Yet few [[Physics:Theoretical physics|theoretical physicists]] believe general relativity is a fundamentally accurate description of gravitation, and instead seek a theory of [[Physics:Quantum gravity|quantum gravity]].<ref>{{Cite web|url=https://www.preposterousuniverse.com/podcast/2019/09/09/63-solo-finding-gravity-within-quantum-mechanics/|title=63 &#124; Solo: Finding Gravity within Quantum Mechanics – Sean Carroll}}</ref><ref>http://cgpg.gravity.psu.edu/people/Ashtekar/articles/rovelli03.pdf {{Bare URL PDF|date=March 2022}}</ref> {{citation needed|date=January 2014}}

==Total vs. partial holism==

Some scholars, like Quine, argue that if a prediction that a theory makes comes out true, then the corresponding piece of evidence confirms the whole theory and even the whole framework within which that theory is embedded. Some have questioned this radical or total form of confirmational holism. If total holism were true, they argue, that would lead to absurd consequences like the confirmation of arbitrary conjunctions. For example, if the general [[Physics:Theory of relativity|theory of relativity]] is confirmed by the perihelion of Mercury then, according to ''total'' holism, the conjunction of the general theory of relativity with the claim that the moon is made of cheese also gets confirmed. More controversially, the two conjuncts are meant to be confirmed in equal measure.

The critics of total holism do not deny that evidence may spread its support far and wide. Rather, they deny that it always spreads its support to the ''whole'' of any theory or theoretical framework that entails or probabilistically predicts the evidence. This view is known as partial holism. One early advocate of partial confirmational holism is [[Biography:Adolf Grünbaum|Adolf Grünbaum]] (1962).<ref name=Grünbaum1962/> Another is [[Biography:Ken Gemes|Ken Gemes]] (1993).<ref>Gemes, K. 1993. 'Hypothetico-Deductivism, Content, and the Natural Axiomatization of Theories', ''Philosophy of Science'', vol. 60:477-487. [http://sas-space.sas.ac.uk/762/1/K_Gemes_Hypothetico-Deductivsm.pdf online text]</ref> The latter provides refinements to the hypothetico-deductive account of confirmation, arguing that a piece of evidence may be confirmationally relevant only to some content parts of a hypothesis. A third critic is Elliott Sober (2004).<ref>Sober, E. 2004. 'Likelihood, Model Selection, and the Duhem-Quine Problem', ''Journal of Philosophy'', vol. 101:1-22.</ref> He considers likelihood comparisons and model selection ideas.   More recently, and in a similar vein, Ioannis Votsis (2014)<ref>{{cite journal|last1=Votsis|first1=Ioannis|year=2014|title=Objectivity in confirmation: Post hoc monsters and novel predictions|url=http://philsci-archive.pitt.edu/12928/1/Objectivity%20in%20Confirmation%20Penultimate%20Draft.pdf|journal=Studies in History and Philosophy of Science Part A|volume=45|pages=70–78|doi=10.1016/j.shpsa.2013.10.009|pmid=24984452|bibcode=2014SHPSA..45...70V }}<!--http://philsci-archive.pitt.edu/12928/1/Objectivity%20in%20Confirmation%20Penultimate%20Draft.pdf--></ref> argues for an objectivist account of confirmation, according to which, monstrous hypotheses, i.e. roughly hypotheses that are put together in an ''ad hoc'' or arbitrary way, have internal barriers that prevent the spread of confirmation between their parts. Thus even though the conjunction of the general theory of relativity with the claim that the moon is made of cheese gets confirmed by the perihelion of Mercury since the latter is entailed by the conjunction, the confirmation does not spread to the conjunct that the moon is made of cheese. In other words, it is not always the case that support spreads to all the parts of a hypotheses, and even when it does, it is not always the case that it spreads to the different parts in equal measure.

==See also==
* [[Philosophy:Coherence theory of truth|Coherence theory of truth]]
* [[Philosophy:No true Scotsman|No true Scotsman]]
* [[Semantic holism]]
* [[Philosophy:Theory-ladenness|Theory-ladenness]]
* Truth theory

==Notes and references==
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[[Category:Epistemology of science]]
[[Category:Metaphysics of science]]

{{Sourceattribution|Confirmation holism}}