Editing Logical positivism (section)

==Philosophy of science==

The logical positivist movement shed much of its revolutionary zeal following the defeat of Nazism and the decline of rival philosophies that sought radical reform, notably [[Marburg school|Marburg]] [[neo-Kantianism]], [[Edmund Husserl|Husserlian]] [[Phenomenology (philosophy)|phenomenology]] and [[Martin Heidegger|Heidegger]]'s [[existentialism|existential]] [[hermeneutics]]. Hosted in the climate of American [[pragmatism]] and [[common sense]] [[empiricism]], its proponents no longer crusaded to revise traditional philosophy into a radical ''scientific philosophy'', but became respectable members of a new philosophical subdiscipline, ''[[philosophy of science]]''.<ref name=Friedman-pxiv/> Receiving support from [[Ernest Nagel]], they were especially influential in the [[social sciences]].<ref name=Novick-p546>{{cite book |last=Novick |first=Peter |title=That Noble Dream |publisher=Cambridge University Press |year=1988 |page=546}}</ref>

===Scientific explanation===

{{See also|Deductive-nomological model}}

[[Carl Hempel]] was prominent in the development of the [[deductive-nomological model|deductive-nomological]] (DN) model, then the foremost model of [[models of scientific inquiry|scientific explanation]] defended even among critics of neo-positivism such as [[Karl Popper|Popper]].<ref name=SEPWoodward>{{cite encyclopedia |first=James |last=Woodward |url=https://plato.stanford.edu/archives/win2011/entries/scientific-explanation |title=Scientific explanation |editor=Edward N. Zalta |encyclopedia=The Stanford Encyclopedia of Philosophy |edition=Winter 2011}}</ref> According to the DN model, a scientific explanation is valid only if it takes the form of a [[deductive reasoning|deductive inference]] from a set of explanatory [[premise]]s (''explanans'') to the observation or theory to be explained (''explanandum'').<ref name=Suppe>{{cite book |last=Frederick Suppe |first=Frederick |title=The Structure of Scientific Theories |publisher=University of Illinois Press |year=1977 |url=https://books.google.com/books?id=SpvZsxCA0TIC&pg=PA619 |edition=2nd |pages=619–21}}</ref> The model stipulates that the premises must refer to at least one [[scientific law|law]], which it defines as an [[enumerative induction|unrestricted generalization]] of the [[conditional sentence|conditional]] form: "If ''A'', then ''B''".<ref>{{cite book |first=Eleonora |last=Montuschi |title=Objects in Social Science |publisher=Continuum |year=2003 |url=https://books.google.com/books?id=bQ24-BV8WSAC&pg=PA62 |pages=61–62}}</ref> Laws therefore differ from mere ''regularities'' ("George always carries only $1 bills in his wallet") which do not necessarily support [[counterfactual]] claims.<ref>{{cite book| last=Bechtel |first=William |title=Philosophy of Science: An Overview for Cognitive Science |location=Hillsdale NJ |publisher=Lawrence Erlbaum Assoc. |year=1988 |pages=25-28}}</ref> Furthermore, laws must be empirically verifiable in compliance with the verification principle.<ref name=Suppe/>

The DN model ignores causal mechanisms beyond the principle of [[constant conjunction]] ("first event ''A'' and then always event ''B''") in accordance with the [[David Hume|Humean]] [[empiricism|empiricist]] postulate that, though sequences of events are observable, the underpinning [[causality|causal principles]] are not.<ref name=SEPWoodward/> Hempel stated that well-formulated natural laws (empirically confirmed regularities) are satisfactory in approximating causal explanation.<ref name=Suppe/>

Hempel later proposed a probabilistic model of scientific explanation: The inductive-statistical (IS) model. Derivation of statistical laws from other statistical laws would further be designated as the deductive-statistical (DS) model. The DN and IS models are collectively referred to as the "covering law model" or "subsumption theory", the latter referring to the movement's stated goals of "theory reduction".<ref name=Suppe/><ref>{{cite book |first=Manfred |last=Riedel |url=https://books.google.com/books?id=It3ji_AuO3sC&dq=Covering+subsumption&pg=PA3 |chapter=Causal and Historical Explanation |pages=3–4 |editor1=Manninen J |editor2=Tuomela R. |title=Essays on Explanation and Understanding: Studies in the Foundation of Humanities and Social Sciences |location=Dordrecht |publisher=D. Reidel Publishing |year=1976}}</ref>

===Unity of science===

{{See also|Unity of science}}

Logical positivists were committed to the vision of a [[unity of science|unified science]] encompassing all scientific fields (including the [[special sciences]], such as [[biology]], [[anthropology]], [[sociology]] and [[economics]], and ''the fundamental science'', or [[fundamental physics]]) which would be synthesised into a singular [[epistemology|epistemic]] entity.<ref>{{cite journal |first=Gregory |last=Frost-Arnold |url=https://philsci-archive.pitt.edu/archive/00002005/01/PSA2004Short.rtf |title=The Large Scale Structure of Logical Empiricism: Unity of Science and the Elimination of Metaphysics |journal=Philosophy of Science |volume=72 |issue=5 |year=2005 |pages=826-838 |doi=10.1086/508113}}</ref><ref name=Suppe/> Key to this concept was the doctrine of ''theory reduction'', according to which the covering law model would be used to interconnect the special sciences and, thereupon, to [[reductionism|reduce]] all laws in the special sciences to fundamental physics.<ref>{{cite book |last=Kuhn |first=Thomas S. |url=http://dx.doi.org/10.7208/chicago/9780226458106.001.0001 |title=The Structure of Scientific Revolutions |date=1996 |publisher=University of Chicago Press |isbn=978-0-226-45808-3}}</ref>

The movement envisioned a universal scientific language that could express statements with common [[semantics|meaning]] intelligible to all scientific fields. [[Rudolf Carnap|Carnap]] sought to realise this goal through the systematic reduction of the linguistic terms of more specialised fields to those of more fundamental fields. Various methods of reduction were proposed, referring to the use of [[set theory]] to manipulate logically [[primitive notion|primitive concepts]] (as in Carnap's ''Logical Structure of the World'', 1928) or via [[analytic and synthetic|analytic]] and ''a priori'' deductive operations (as described in ''Testability and Meaning'', 1936, 1937). A number of publications over a period of thirty years would attempt to elucidate this concept.<ref>{{cite book |last=Hinst |first=Peter |chapter=Carnap, Rudolf: Der logische Aufbau der Welt |date=2020 |title=Kindlers Literatur Lexikon (KLL) |pages=1–2 |doi=10.1007/978-3-476-05728-0_9509-1 |location=Stuttgart |publisher=J.B. Metzler |isbn=978-3-476-05728-0}}</ref><ref>{{cite book |last=Sarkar |first=Sahotra |chapter=Rudolf Carnap Testability and Meaning |year=2021 |title=Logical Empiricism at its Peak |pages=200–265 |doi=10.4324/9781003249573-13 |location=New York |publisher=Routledge |isbn=978-1-003-24957-3}}</ref>