Editing Logical positivism (section)

===Karl Popper===
[[Karl Popper]], a graduate of the [[University of Vienna]], was an outspoken critic of the logical positivist movement from its inception. In ''Logik der Forschung'' (1934, published in English in 1959 as ''[[The Logic of Scientific Discovery]]'') he attacked [[verificationism]] directly, contending that the [[problem of induction]] renders it impossible for [[hypothesis|scientific hypotheses]] and other [[universal generalization|universal statements]] to be verified conclusively. Any attempt to do so, he argued, would commit the fallacy of [[affirming the consequent]], given that verification cannot—in itself—exclude alternative valid explanations for a specific phenomenon or instance of observation.<ref>{{cite book|first=Samir |last=Okasha |title=The Philosophy of Science: A Very Short Introduction |location=New York |publisher=Oxford University Press |year=2002 |page=23}}</ref> He would later affirm that the content of the verifiability criterion cannot be empirically verified, thus is meaningless by its own proposition and ultimately [[self-refuting idea|self-defeating]] as a principle.<ref name=Piep>{{cite encyclopedia |url=https://www.iep.utm.edu/pop-sci/#H3 |title=Karl Popper: Philosophy of Science |last=Shea |first=Brendan |encyclopedia=Internet Encyclopedia of Philosophy |access-date=May 12, 2019}}</ref>

In the same book, Popper proposed ''[[falsifiability]]'', which he presented, not as a criterion of ''cognitive meaning'' like verificationism (as commonly misunderstood),<ref name="Hacohen">{{cite book |title=Karl Popper: The Formative Years, 1902–1945: Politics and Philosophy in Interwar Vienna |last=Hacohen |first=Malachi Haim |year=2000 |publisher=Cambridge University Press |location=Cambridge |pages=212-13}}</ref> but as a criterion to distinguish scientific from non-scientific statements, thereby to [[demarcation problem|demarcate the boundaries of science]]. Popper observed that, though universal statements cannot be verified, they can be falsified, and that the most productive scientific theories were apparently those that carried the greatest 'predictive risks' of being falsified by observation.<ref name=PopperAE>{{cite book |title=Conjectures and Refutations: The Growth of Scientific Knowledge |last=Popper |first=Karl |year=1962 |publisher=Routledge |edition=2nd |pages=34-37}}</ref> He would conclude that the [[scientific method]] should be a [[hypothetico-deductive model]], wherein scientific hypotheses must be falsifiable (per his criterion), held as provisionally true until proven false by observation, and are ''corroborated'' by supporting evidence rather than verified or confirmed.<ref name=Popper>{{cite book |last=Popper |first=Karl |title=The Logic of Scientific Discovery |doi=10.4324/9780203994627 |publisher=Routledge |location=London |year=2005 |edition=2nd}}</ref>

In rejecting neo-positivist views of cognitive meaningfulness, Popper considered [[metaphysics]] to be rich in meaning and important in the origination of scientific theories and [[value system]]s to be integral to science's quest for truth. At the same time, he disparaged [[pseudoscience]], referring to the [[confirmation bias]]es that embolden support for unfalsifiable conjectures (notably those in [[psychology]] and [[psychoanalysis]]) and ''[[ad hoc]]'' arguments used to entrench predictive theories that have been proven conclusively false.<ref name=PopperAE/>