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Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement in
Western philosophy Western philosophy encompasses the philosophical thought and work of the Western world. Historically, the term refers to the philosophical thinking of Western culture, beginning with the ancient Greek philosophy of the pre-Socratics. The word ' ...
whose central thesis was the verification principle (also known as the verifiability criterion of meaning). This
theory of knowledge Epistemology (; ), or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics. Ep ...
asserted that only statements verifiable through direct observation or logical proof are meaningful in terms of conveying truth value, information or factual content. Starting in the late 1920s, groups of philosophers, scientists, and mathematicians formed the
Berlin Circle The Berlin Circle (german: die Berliner Gruppe) was a group that maintained logical empiricist views about philosophy. History Berlin Circle was created in the late 1920s by Hans Reichenbach, Kurt Grelling and Walter Dubislav and composed o ...
and the
Vienna Circle The Vienna Circle (german: Wiener Kreis) of Logical Empiricism was a group of elite philosophers and scientists drawn from the natural and social sciences, logic and mathematics who met regularly from 1924 to 1936 at the University of Vienna, ch ...
, which, in these two cities, would propound the ideas of logical positivism. Flourishing in several European centres through the 1930s, the movement sought to prevent confusion rooted in unclear language and unverifiable claims by converting philosophy into "scientific philosophy", which, according to the logical positivists, ought to share the bases and structures of empirical sciences' best examples, such as Albert Einstein's
general theory of relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the differential geometry, geometric scientific theory, theory of gravitation published by Albert Einstein in 1915 and is the current descr ...
. Despite its ambition to overhaul philosophy by studying and mimicking the extant conduct of empirical science, logical positivism became erroneously stereotyped as a movement to regulate the scientific process and to place strict standards on it. After World War II, the movement shifted to a milder variant, logical empiricism, led mainly by Carl Hempel, who, during the rise of Nazism, had immigrated to the United States. In the ensuing years, the movement's central premises, still unresolved, were heavily criticised by leading philosophers, particularly
Willard van Orman Quine Willard Van Orman Quine (; known to his friends as "Van"; June 25, 1908 – December 25, 2000) was an American philosopher and logician in the analytic tradition, recognized as "one of the most influential philosophers of the twentieth century" ...
and Karl Popper, and even, within the movement itself, by Hempel. The 1962 publication of
Thomas Kuhn Thomas Samuel Kuhn (; July 18, 1922 – June 17, 1996) was an American philosopher of science whose 1962 book '' The Structure of Scientific Revolutions'' was influential in both academic and popular circles, introducing the term ''paradig ...
's landmark book ''
The Structure of Scientific Revolutions ''The Structure of Scientific Revolutions'' (1962; second edition 1970; third edition 1996; fourth edition 2012) is a book about the history of science by philosopher Thomas S. Kuhn. Its publication was a landmark event in the history, philoso ...
'' dramatically shifted academic philosophy's focus. In 1967 philosopher
John Passmore John Passmore AC (9 September 1914 – 25 July 2004) was an Australian philosopher. Life John Passmore was born on 9 September 1914 in Manly, Sydney, where he grew up. He was educated at Sydney Boys High School.Sydney High School Old Boys ...
pronounced logical positivism "dead, or as dead as a philosophical movement ever becomes".Passmore, John. 'Logical Positivism', ''The Encyclopedia of Philosophy'', Paul Edwards (ed.). New York: Macmillan, 1967, 1st edition
/ref>


Origins

Logical positivists picked from Ludwig Wittgenstein's early philosophy of language the verifiability principle or criterion of meaningfulness. As in Ernst Mach's
phenomenalism In metaphysics, phenomenalism is the view that physical objects cannot justifiably be said to exist in themselves, but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in ...
, whereby the mind knows only actual or potential sensory experience, verificationists took all sciences' basic content to be only sensory experience. And some influence came from
Percy Bridgman Percy Williams Bridgman (April 21, 1882 – August 20, 1961) was an American physicist who received the 1946 Nobel Prize in Physics for his work on the physics of high pressures. He also wrote extensively on the scientific method and on other as ...
's musings that others proclaimed as operationalism, whereby a physical theory is understood by what laboratory procedures scientists perform to test its predictions. In
verificationism Verificationism, also known as the verification principle or the verifiability criterion of meaning, is the philosophical doctrine which maintains that only statements that are empirically verifiable (i.e. verifiable through the senses) are cogniti ...
, only the ''verifiable'' was scientific, and thus meaningful (or ''cognitively meaningful''), whereas the unverifiable, being unscientific, were meaningless "pseudostatements" (just ''emotively meaningful''). Unscientific discourse, as in ethics and metaphysics, would be unfit for discourse by philosophers, newly tasked to organize knowledge, not develop new knowledge.


Definitions

Logical positivism is sometimes stereotyped as forbidding talk of
unobservable An unobservable (also called impalpable) is an entity whose existence, nature, properties, qualities or relations are not directly observable by humans. In philosophy of science, typical examples of "unobservables" are the force of gravity, causat ...
s, such as microscopic entities or such notions as causality and general principles, but that is an exaggeration. Rather, most neopositivists viewed talk of unobservables as
metaphor A metaphor is a figure of speech that, for rhetorical effect, directly refers to one thing by mentioning another. It may provide (or obscure) clarity or identify hidden similarities between two different ideas. Metaphors are often compared wi ...
ical or elliptical: direct observations phrased abstractly or indirectly. So ''
theoretical term Ramsey sentences are formal logical reconstructions of theoretical propositions attempting to draw a line between science and metaphysics. A Ramsey sentence aims at rendering propositions containing non-observable theoretical terms (terms employed ...
s'' would garner meaning from ''
observational term Ramsey sentences are formal logical reconstructions of theoretical propositions attempting to draw a line between science and metaphysics. A Ramsey sentence aims at rendering propositions containing non-observable theoretical terms (terms employed ...
s'' via ''correspondence rules'', and thereby ''theoretical laws'' would be reduced to ''empirical laws''. Via
Bertrand Russell Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ...
's
logicism In the philosophy of mathematics, logicism is a programme comprising one or more of the theses that — for some coherent meaning of 'logic' — mathematics is an extension of logic, some or all of mathematics is reducible to logic, or some or all ...
, reducing mathematics to logic, physics' mathematical formulas would be converted to symbolic logic. Via Russell's
logical atomism Logical atomism is a philosophical view that originated in the early 20th century with the development of analytic philosophy. Its principal exponent was the British philosopher Bertrand Russell. It is also widely held that the early works of his ...
,
ordinary language Ordinary language philosophy (OLP) is a philosophical methodology that sees traditional philosophical problems as rooted in misunderstandings philosophers develop by distorting or forgetting how words are ordinarily used to convey meaning in ...
would break into discrete units of meaning.
Rational reconstruction Rational reconstruction is a philosophical term with several distinct meanings. It is found in the work of Jürgen Habermas and Imre Lakatos. Habermas For Habermas, rational reconstruction is a philosophical and linguistic method that systemat ...
, then, would convert ordinary statements into standardized equivalents, all networked and united by a logical syntax. A scientific theory would be stated with its method of verification, whereby a logical calculus or empirical operation could
verify CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system's DOS BIOS (typically residing ...
its falsity or truth.


Development

In the late 1930s, logical positivists fled Germany and Austria for Britain and the United States. By then, many had replaced Mach's phenomenalism with
Otto Neurath Otto Karl Wilhelm Neurath (; 10 December 1882 – 22 December 1945) was an Austrian-born philosopher of science, sociologist, and political economist. He was also the inventor of the ISOTYPE method of pictorial statistics and an innovator in mu ...
's physicalism, whereby science's content is not actual or potential sensations, but instead is entities publicly observable. Rudolf Carnap, who had sparked logical positivism in the Vienna Circle, had sought to replace ''verification'' with simply ''confirmation''. With
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
's close in 1945, logical positivism became milder, ''logical empiricism'', led largely by Carl Hempel, in America, who expounded the covering law model of scientific explanation. Logical positivism became a major underpinning of analytic philosophy,Se
"Vienna Circle"
in ''Stanford Encyclopedia of Philosophy''.
and dominated philosophy in the
English-speaking world Speakers of English are also known as Anglophones, and the countries where English is natively spoken by the majority of the population are termed the '' Anglosphere''. Over two billion people speak English , making English the largest langua ...
, including
philosophy of science Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ult ...
, while influencing sciences, but especially social sciences, into the 1960s. Yet the movement failed to resolve its central problems, and its doctrines were increasingly criticized, most trenchantly by
Willard Van Orman Quine Willard Van Orman Quine (; known to his friends as "Van"; June 25, 1908 – December 25, 2000) was an American philosopher and logician in the analytic tradition, recognized as "one of the most influential philosophers of the twentieth century" ...
, Norwood Hanson, Karl Popper,
Thomas Kuhn Thomas Samuel Kuhn (; July 18, 1922 – June 17, 1996) was an American philosopher of science whose 1962 book '' The Structure of Scientific Revolutions'' was influential in both academic and popular circles, introducing the term ''paradig ...
, and Carl Hempel.


Roots


Language

''
Tractatus Logico-Philosophicus The ''Tractatus Logico-Philosophicus'' (widely abbreviated and cited as TLP) is a book-length philosophical work by the Austrian philosopher Ludwig Wittgenstein which deals with the relationship between language and reality and aims to define th ...
'', by the young
Ludwig Wittgenstein Ludwig Josef Johann Wittgenstein ( ; ; 26 April 1889 – 29 April 1951) was an Austrian-British philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He is con ...
, introduced the view of philosophy as "critique of language", offering the possibility of a theoretically principled distinction of intelligible versus nonsensical discourse. ''Tractatus'' adhered to a correspondence theory of truth (versus a
coherence theory of truth Coherence theories of truth characterize truth as a property of whole systems of propositions that can be ascribed to individual propositions only derivatively according to their coherence with the whole. While modern coherence theorists hold that ...
). Wittgenstein's influence also shows in some versions of the verifiability principle. In tractarian doctrine, truths of logic are tautologies, a view widely accepted by logical positivists who were also influenced by Wittgenstein's interpretation of
probability Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and 1, where, roughly speakin ...
although, according to Neurath, some logical positivists found ''Tractatus'' to contain too much metaphysics.


Logicism

Gottlob Frege Friedrich Ludwig Gottlob Frege (; ; 8 November 1848 – 26 July 1925) was a German philosopher, logician, and mathematician. He was a mathematics professor at the University of Jena, and is understood by many to be the father of analytic ph ...
began the program of reducing mathematics to logic, continued it with
Bertrand Russell Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ...
, but lost interest in this
logicism In the philosophy of mathematics, logicism is a programme comprising one or more of the theses that — for some coherent meaning of 'logic' — mathematics is an extension of logic, some or all of mathematics is reducible to logic, or some or all ...
, and Russell continued it with Alfred North Whitehead in their ''
Principia Mathematica The ''Principia Mathematica'' (often abbreviated ''PM'') is a three-volume work on the foundations of mathematics written by mathematician–philosophers Alfred North Whitehead and Bertrand Russell and published in 1910, 1912, and 1913. ...
'', inspiring some of the more mathematical logical positivists, such as Hans Hahn and Rudolf Carnap. Carnap's early anti-metaphysical works employed Russell's theory of types. Carnap envisioned a universal language that could reconstruct mathematics and thereby encode physics.Jaako Hintikka, "Logicism", in Andrew D Irvine, ed, ''Philosophy of Mathematics'' (Burlington MA: North Holland, 2009),
pp. 283–84
Yet Kurt Gödel's
incompleteness theorem Complete may refer to: Logic * Completeness (logic) * Completeness of a theory, the property of a theory that every formula in the theory's language or its negation is provable Mathematics * The completeness of the real numbers, which implies t ...
showed this impossible except in trivial cases, and
Alfred Tarski Alfred Tarski (, born Alfred Teitelbaum;School of Mathematics and Statistics, University of St Andrews ''School of Mathematics and Statistics, University of St Andrews''. January 14, 1901 – October 26, 1983) was a Polish-American logician a ...
's undefinability theorem shattered all hopes of reducing mathematics to logic. Thus, a universal language failed to stem from Carnap's 1934 work ''Logische Syntax der Sprache'' (''Logical Syntax of Language''). Still, some logical positivists, including Carl Hempel, continued support of logicism.


Empiricism

In Germany, Hegelian metaphysics was a dominant movement, and Hegelian successors such as F H Bradley explained reality by postulating metaphysical entities lacking empirical basis, drawing reaction in the form of positivism.Frederick Suppe, "The positivist model of scientific theories", in ''Scientific Inquiry'', Robert Klee, ed, (New York: Oxford University Press, 1999), pp. 16–24. Starting in the late 19th century, there was a "back to Kant" movement. Ernst Mach's positivism and
phenomenalism In metaphysics, phenomenalism is the view that physical objects cannot justifiably be said to exist in themselves, but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in ...
were a major influence.


Origins


Vienna

The
Vienna Circle The Vienna Circle (german: Wiener Kreis) of Logical Empiricism was a group of elite philosophers and scientists drawn from the natural and social sciences, logic and mathematics who met regularly from 1924 to 1936 at the University of Vienna, ch ...
, gathering around
University of Vienna The University of Vienna (german: Universität Wien) is a public research university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world. With its long and rich hist ...
and
Café Central Café Central is a traditional Viennese café located at Herrengasse 14 in the Innere Stadt first district of Vienna, Austria. The café occupies the ground floor of the former Bank and Stockmarket Building, today called the Palais Ferstel after i ...
, was led principally by
Moritz Schlick Friedrich Albert Moritz Schlick (; ; 14 April 1882 – 22 June 1936) was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle. Early life and works Schlick was born in Berlin to a wealthy Prussian f ...
. Schlick had held a
neo-Kantian In late modern continental philosophy, neo-Kantianism (german: Neukantianismus) was a revival of the 18th-century philosophy of Immanuel Kant. The Neo-Kantians sought to develop and clarify Kant's theories, particularly his concept of the "thi ...
position, but later converted, via Carnap's 1928 book ''Der logische Aufbau der Welt'', that is, ''The Logical Structure of the World''. A 1929 pamphlet written by
Otto Neurath Otto Karl Wilhelm Neurath (; 10 December 1882 – 22 December 1945) was an Austrian-born philosopher of science, sociologist, and political economist. He was also the inventor of the ISOTYPE method of pictorial statistics and an innovator in mu ...
, Hans Hahn, and Rudolf Carnap summarized the Vienna Circle's positions. Another member of Vienna Circle to later prove very influential was Carl Hempel. A friendly but tenacious critic of the Circle was Karl Popper, whom Neurath nicknamed the "Official Opposition". Carnap and other
Vienna Circle The Vienna Circle (german: Wiener Kreis) of Logical Empiricism was a group of elite philosophers and scientists drawn from the natural and social sciences, logic and mathematics who met regularly from 1924 to 1936 at the University of Vienna, ch ...
members, including Hahn and Neurath, saw need for a weaker criterion of meaningfulness than verifiability. A radical "left" wing—led by Neurath and Carnap—began the program of "liberalization of empiricism", and they also emphasized
fallibilism Originally, fallibilism (from Medieval Latin: ''fallibilis'', "liable to err") is the philosophical principle that propositions can be accepted even though they cannot be conclusively proven or justified,Haack, Susan (1979)"Fallibilism and Nece ...
and
pragmatics In linguistics and related fields, pragmatics is the study of how context contributes to meaning. The field of study evaluates how human language is utilized in social interactions, as well as the relationship between the interpreter and the in ...
, which latter Carnap even suggested as empiricism's basis. A conservative "right" wing—led by
Schlick Schlick or Schlicke may refer to: People * Moritz Schlick, German philosopher and the founding father of logical positivism and the Vienna Circle * Arnolt Schlick, German organist and composer of the Renaissance * Robert H. Von Schlick, German- ...
and Waismann—rejected both the liberalization of empiricism and the epistemological nonfoundationalism of a move from
phenomenalism In metaphysics, phenomenalism is the view that physical objects cannot justifiably be said to exist in themselves, but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in ...
to physicalism. As Neurath and somewhat Carnap posed science toward social reform, the split in Vienna Circle also reflected political views.


Berlin

The
Berlin Circle The Berlin Circle (german: die Berliner Gruppe) was a group that maintained logical empiricist views about philosophy. History Berlin Circle was created in the late 1920s by Hans Reichenbach, Kurt Grelling and Walter Dubislav and composed o ...
was led principally by Hans Reichenbach.


Rivals

Both
Moritz Schlick Friedrich Albert Moritz Schlick (; ; 14 April 1882 – 22 June 1936) was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle. Early life and works Schlick was born in Berlin to a wealthy Prussian f ...
and Rudolf Carnap had been influenced by and sought to define logical positivism versus the neo-Kantianism of
Ernst Cassirer Ernst Alfred Cassirer ( , ; July 28, 1874 – April 13, 1945) was a German philosopher. Trained within the Neo-Kantian Marburg School, he initially followed his mentor Hermann Cohen in attempting to supply an idealistic philosophy of science. A ...
—the then leading figure of
Marburg school In late modern philosophy, late modern continental philosophy, neo-Kantianism (german: Neukantianismus) was a revival of the 18th-century philosophy of Immanuel Kant. The Neo-Kantians sought to develop and clarify Kant's theories, particularly hi ...
, so called—and against
Edmund Husserl , thesis1_title = Beiträge zur Variationsrechnung (Contributions to the Calculus of Variations) , thesis1_url = https://fedora.phaidra.univie.ac.at/fedora/get/o:58535/bdef:Book/view , thesis1_year = 1883 , thesis2_title ...
's phenomenology. Logical positivists especially opposed
Martin Heidegger Martin Heidegger (; ; 26 September 188926 May 1976) was a German philosopher who is best known for contributions to phenomenology, hermeneutics, and existentialism. He is among the most important and influential philosophers of the 20th ce ...
's obscure metaphysics, the epitome of what logical positivism rejected. In the early 1930s, Carnap debated Heidegger over "metaphysical pseudosentences".Friedman, ''Reconsidering Logical Positivism'' (Cambridge UP, 1999)
p. xii
Despite its revolutionary aims, logical positivism was but one view among many vying within Europe, and logical positivists initially spoke their language.


Export

As the movement's first emissary to the
New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...
,
Moritz Schlick Friedrich Albert Moritz Schlick (; ; 14 April 1882 – 22 June 1936) was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle. Early life and works Schlick was born in Berlin to a wealthy Prussian f ...
visited Stanford University in 1929, yet otherwise remained in Vienna and was murdered in 1936 at the
University A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States ...
by a former student,
Johann Nelböck Johann "Hans" Nelböck (May 12, 1903 – February 3, 1954) was an Austrian former student and murderer of Moritz Schlick, the founder of the group of philosophers and scientists known as the Vienna Circle. After attending the gymnasium in Wels, ...
, who was reportedly deranged. That year, a British attendee at some Vienna Circle meetings since 1933, A. J. Ayer saw his ''
Language, Truth and Logic ''Language, Truth and Logic'' is a 1936 book about meaning by the philosopher Alfred Jules Ayer, in which the author defines, explains, and argues for the verification principle of logical positivism, sometimes referred to as the ''criterion of ...
'', written in English, import logical positivism to the
English-speaking world Speakers of English are also known as Anglophones, and the countries where English is natively spoken by the majority of the population are termed the '' Anglosphere''. Over two billion people speak English , making English the largest langua ...
. By then, the
Nazi Party The Nazi Party, officially the National Socialist German Workers' Party (german: Nationalsozialistische Deutsche Arbeiterpartei or NSDAP), was a far-right political party in Germany active between 1920 and 1945 that created and supported t ...
's 1933 rise to power in Germany had triggered flight of intellectuals. In exile in England,
Otto Neurath Otto Karl Wilhelm Neurath (; 10 December 1882 – 22 December 1945) was an Austrian-born philosopher of science, sociologist, and political economist. He was also the inventor of the ISOTYPE method of pictorial statistics and an innovator in mu ...
died in 1945. Rudolf Carnap, Hans Reichenbach, and Carl Hempel—Carnap's protégé who had studied in
Berlin Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...
with Reichenbach—settled permanently in America. Upon Germany's
annexation of Austria The (, or , ), also known as the (, en, Annexation of Austria), was the annexation of the Federal State of Austria into the German Reich on 13 March 1938. The idea of an (a united Austria and Germany that would form a " Greater Germany ...
in 1938, remaining logical positivists, many of whom were also Jewish, were targeted and continued flight. Logical positivism thus became dominant in the English-speaking world.


Principles


Analytic/synthetic gap

Concerning
reality Reality is the sum or aggregate of all that is real or existent within a system, as opposed to that which is only imaginary. The term is also used to refer to the ontological status of things, indicating their existence. In physical terms, r ...
, the necessary is a state true in all
possible worlds Possible Worlds may refer to: * Possible worlds, concept in philosophy * ''Possible Worlds'' (play), 1990 play by John Mighton ** ''Possible Worlds'' (film), 2000 film by Robert Lepage, based on the play * Possible Worlds (studio) * ''Possible Wo ...
—mere logical validity—whereas the contingent hinges on the way the particular world is. Concerning
knowledge Knowledge can be defined as Descriptive knowledge, awareness of facts or as Procedural knowledge, practical skills, and may also refer to Knowledge by acquaintance, familiarity with objects or situations. Knowledge of facts, also called pro ...
, the ''
a priori ("from the earlier") and ("from the later") are Latin phrases used in philosophy to distinguish types of knowledge, justification, or argument by their reliance on empirical evidence or experience. knowledge is independent from current ...
'' is knowable before or without, whereas the '' a posteriori'' is knowable only after or through, relevant experience. Concerning
statements Statement or statements may refer to: Common uses *Statement (computer science), the smallest standalone element of an imperative programming language *Statement (logic), declarative sentence that is either true or false *Statement, a declarative ...
, the '' analytic'' is true via terms' arrangement and meanings, thus a tautology—true by logical necessity but uninformative about the world—whereas the '' synthetic'' adds reference to a state of facts, a contingency. In 1739,
David Hume David Hume (; born David Home; 7 May 1711 NS (26 April 1711 OS) – 25 August 1776) Cranston, Maurice, and Thomas Edmund Jessop. 2020 999br>David Hume" ''Encyclopædia Britannica''. Retrieved 18 May 2020. was a Scottish Enlightenment phil ...
cast a
fork In cutlery or kitchenware, a fork (from la, furca 'pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tine (structural), tines with which one ...
aggressively dividing "relations of ideas" from "matters of fact and real existence", such that all truths are of one type or the other. By Hume's fork, truths by relations among ideas (abstract) all align on one side (analytic, necessary, ''a priori''), whereas truths by states of actualities (concrete) always align on the other side (synthetic, contingent, ''a posteriori''). Of any treatises containing neither, Hume orders, "Commit it then to the flames, for it can contain nothing but
sophistry A sophist ( el, σοφιστής, sophistes) was a teacher in ancient Greece in the fifth and fourth centuries BC. Sophists specialized in one or more subject areas, such as philosophy, rhetoric, music, athletics, and mathematics. They taught ' ...
and illusion". Thus awakened from "dogmatic slumber",
Immanuel Kant Immanuel Kant (, , ; 22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and ...
quested to answer Hume's challenge—but by explaining how
metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
is possible. Eventually, in his 1781 work, Kant crossed the tines of Hume's fork to identify another range of truths by necessity— synthetic ''a priori'', statements claiming states of facts but known true before experience—by arriving at
transcendental idealism Transcendental idealism is a philosophical system founded by German philosopher Immanuel Kant in the 18th century. Kant's epistemological program is found throughout his '' Critique of Pure Reason'' (1781). By ''transcendental'' (a term that dese ...
, attributing the mind a constructive role in phenomena by arranging
sense data The theory of sense data is a view in the philosophy of perception, popularly held in the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A. J. Ayer, and G. E. Moore. Sense data are taken to be mind-depend ...
into the very experience ''space'', ''time'', and ''substance''. Thus, Kant saved
Newton's law of universal gravitation Newton's law of universal gravitation is usually stated as that every particle attracts every other particle in the universe with a force that is proportional to the product of their masses and inversely proportional to the square of the distan ...
from Hume's problem of induction by finding uniformity of nature to be ''a priori'' knowledge. Logical positivists rejected Kant's synthetic ''a priori'', and adopted Hume's fork, whereby a statement is either analytic and ''a priori'' (thus necessary and verifiable logically) or synthetic and '' a posteriori'' (thus contingent and verifiable empirically).


Observation/theory gap

Early, most logical positivists proposed that all knowledge is based on logical inference from simple "protocol sentences" grounded in observable facts. In the 1936 and 1937 papers "Testability and meaning", individual terms replace sentences as the units of meaning. Further, theoretical terms no longer need to acquire meaning by explicit definition from observational terms: the connection may be indirect, through a system of implicit definitions. Carnap also provided an important, pioneering discussion of disposition predicates.


Cognitive meaningfulness


Verification

The logical positivists' initial stance was that a statement is "cognitively meaningful" in terms of conveying truth value, information or factual content only if some finite procedure conclusively determines its truth. By this verifiability principle, only statements verifiable either by their analyticity or by empiricism were ''cognitively meaningful''.
Metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
,
ontology In metaphysics, ontology is the philosophical study of being, as well as related concepts such as existence, becoming, and reality. Ontology addresses questions like how entities are grouped into categories and which of these entities exi ...
, as well as much of
ethics Ethics or moral philosophy is a branch of philosophy that "involves systematizing, defending, and recommending concepts of right and wrong behavior".''Internet Encyclopedia of Philosophy'' The field of ethics, along with aesthetics, concer ...
failed this criterion, and so were found ''cognitively meaningless''. Moritz Schlick, however, did not view ethical or aesthetic statements as cognitively meaningless. ''Cognitive meaningfulness'' was variously defined: having a
truth value In logic and mathematics, a truth value, sometimes called a logical value, is a value indicating the relation of a proposition to truth, which in classical logic has only two possible values ('' true'' or '' false''). Computing In some pro ...
; corresponding to a possible state of affairs; intelligible or understandable as are scientific statements.
Ethics Ethics or moral philosophy is a branch of philosophy that "involves systematizing, defending, and recommending concepts of right and wrong behavior".''Internet Encyclopedia of Philosophy'' The field of ethics, along with aesthetics, concer ...
and
aesthetics Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed t ...
were subjective preferences, while
theology Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...
and other
metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
contained "pseudostatements", neither true nor false. This meaningfulness was cognitive, although other types of meaningfulness—for instance, emotive, expressive, or figurative—occurred in metaphysical discourse, dismissed from further review. Thus, logical positivism indirectly asserted Hume's law, the principle that ''is'' statements cannot justify ''ought'' statements, but are separated by an unbridgeable gap. A. J. Ayer's 1936 book asserted an extreme variant—the boo/hooray doctrine—whereby all evaluative judgments are but emotional reactions.


Confirmation

In an important pair of papers in 1936 and 1937, "Testability and meaning", Carnap replaced ''verification'' with ''confirmation'', on the view that although universal laws cannot be verified they can be confirmed. Later, Carnap employed abundant logical and mathematical methods in researching inductive logic while seeking to provide an account of probability as "degree of confirmation", but was never able to formulate a model.Mauro Murz
"Rudolf Carnap (1891–1970)"
, ''Internet Encyclopedia of Philosophy'', 12 April 2001.
In Carnap's inductive logic, every universal law's degree of confirmation is always zero. In any event, the precise formulation of what came to be called the "criterion of cognitive significance" took three decades (Hempel 1950, Carnap 1956, Carnap 1961). Carl Hempel became a major critic within the logical positivism movement. Hempel criticized the positivist thesis that empirical knowledge is restricted to ''Basissätze''/''Beobachtungssätze''/''Protokollsätze'' (basic statements or observation statements or protocol statements). Hempel elucidated the paradox of confirmation.


Weak verification

The second edition of A. J. Ayer's book arrived in 1946, and discerned ''strong'' versus ''weak'' forms of verification. Ayer concluded, "A proposition is said to be verifiable, in the strong sense of the term, if, and only if, its truth could be conclusively established by experience", but is verifiable in the weak sense "if it is possible for experience to render it probable".Ayer, ''
Language, Truth and Logic ''Language, Truth and Logic'' is a 1936 book about meaning by the philosopher Alfred Jules Ayer, in which the author defines, explains, and argues for the verification principle of logical positivism, sometimes referred to as the ''criterion of ...
'', 1946, pp. 50–51.
And yet, "no proposition, other than a tautology, can possibly be anything more than a probable
hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...
". Thus, all are open to weak verification.


Philosophy of science

Upon the global defeat of
Nazism Nazism ( ; german: Nazismus), the common name in English for National Socialism (german: Nationalsozialismus, ), is the far-right totalitarian political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) i ...
, and the removal from philosophy of rivals for radical reform—
Marburg Marburg ( or ) is a university town in the German federal state (''Bundesland'') of Hesse, capital of the Marburg-Biedenkopf district (''Landkreis''). The town area spreads along the valley of the river Lahn and has a population of approxima ...
neo-Kantianism,
Husserlian , thesis1_title = Beiträge zur Variationsrechnung (Contributions to the Calculus of Variations) , thesis1_url = https://fedora.phaidra.univie.ac.at/fedora/get/o:58535/bdef:Book/view , thesis1_year = 1883 , thesis2_title ...
phenomenology,
Heidegger Martin Heidegger (; ; 26 September 188926 May 1976) was a German philosopher who is best known for contributions to phenomenology, hermeneutics, and existentialism. He is among the most important and influential philosophers of the 20th centur ...
's "existential hermeneutics"—and while hosted in the climate of American
pragmatism Pragmatism is a philosophical tradition that considers words and thought as tools and instruments for prediction, problem solving, and action, and rejects the idea that the function of thought is to describe, represent, or mirror reality. ...
and commonsense empiricism, the neopositivists shed much of their earlier, revolutionary zeal. No longer crusading to revise traditional philosophy into a new ''scientific philosophy'', they became respectable members of a new philosophy subdiscipline, ''
philosophy of science Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ult ...
''.Michael Friedman,
Reconsidering Logical Positivism
'' (New York: Cambridge University Press, 1999)
p. xiv
Receiving support from
Ernest Nagel Ernest Nagel (November 16, 1901 – September 20, 1985) was an American philosopher of science. Suppes, Patrick (1999)Biographical memoir of Ernest Nagel In '' American National Biograph''y (Vol. 16, pp. 216-218). New York: Oxford University Pr ...
, logical empiricists were especially influential in the social sciences.Novick, ''That Noble Dream'' (Cambridge UP, 1988)
p. 546


Explanation

Comtean positivism had viewed science as ''description'', whereas the
logical positivists Logical positivism, later called logical empiricism, and both of which together are also known as neopositivism, is a movement in Western philosophy whose central thesis was the verification principle (also known as the verifiability criterion of ...
posed science as ''explanation'', perhaps to better realize the envisioned
unity of science The unity of science is a thesis in philosophy of science that says that all the sciences form a unified whole. Overview The unity of science thesis was proposed by Ludwig von Bertalanffy in "General System Theory: A New Approach to Unity of Scie ...
by covering not only
fundamental science Basic research, also called pure research or fundamental research, is a type of scientific research with the aim of improving scientific theories for better understanding and prediction of natural or other phenomena. In contrast, applied resear ...
—that is, fundamental physics—but the special sciences, too, for instance
biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary i ...
,
anthropology Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, societies, and linguistics, in both the present and past, including past human species. Social anthropology studies patterns of be ...
,
psychology Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries between ...
,
sociology Sociology is a social science that focuses on society, human social behavior, patterns of social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of empirical investigation an ...
, and
economics Economics () is the social science that studies the production, distribution, and consumption of goods and services. Economics focuses on the behaviour and interactions of economic agents and how economies work. Microeconomics analyzes ...
.James Woodward
"Scientific explanation"
– sec 1 "Background and introduction", in Zalta EN, ed,''The Stanford Encyclopedia of Philosophy'', Winter 2011 edn
The most widely accepted concept of scientific explanation, held even by neopositivist critic Karl Popper, was the
deductive-nomological model The deductive-nomological model (DN model) of scientific explanation, also known as Hempel's model, the Hempel–Oppenheim model, the Popper–Hempel model, or the covering law model, is a formal view of scientifically answering questions asking, ...
(DN model).James Woodward
"Scientific explanation"
– Article overview, Zalta EN, ed, ''The Stanford Encyclopedia of Philosophy'', Winter 2011 edn
Yet DN model received its greatest explication by Carl Hempel, first in his 1942 article "The function of general laws in history", and more explicitly with
Paul Oppenheim Paul Oppenheim (June 17, 1885 – June 22, 1977) was a German chemist, philosopher, independent scholar and industrialist. Biography Oppenheim was born in Frankfurt am Main. After studying natural sciences and chemistry at the University of Freibur ...
in their 1948 article "Studies in the logic of explanation". In the DN model, the stated phenomenon to be explained is the ''explanandum''—which can be an event,
law Law is a set of rules that are created and are enforceable by social or governmental institutions to regulate behavior,Robertson, ''Crimes against humanity'', 90. with its precise definition a matter of longstanding debate. It has been vario ...
, or
theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be ...
—whereas premises stated to explain it are the ''explanans''.Suppe, ''Structure of Scientific Theories'' (U Illinois P, 1977)
pp. 619–21
Explanans must be true or highly confirmed, contain at least one law, and entail the explanandum. Thus, given initial conditions ''C1, C2 . . . Cn'' plus general laws ''L1, L2 . . . Ln'', event ''E'' is a deductive consequence and scientifically explained. In the DN model, a law is an unrestricted generalization by conditional proposition—''If A, then B''—and has empirical content testable. (Differing from a merely true regularity—for instance, ''George always carries only $1 bills in his wallet''—a law suggests what ''must'' be true, and is consequent of a scientific theory's axiomatic structure.) By the
Humean Humeanism refers to the philosophy of David Hume and to the tradition of thought inspired by him. Hume was an influential Scottish philosopher well known for his empirical approach, which he applied to various fields in philosophy. In the philosop ...
empiricist view that humans observe sequences of events, (not cause and effect, as causality and causal mechanisms are unobservable), the DN model neglects causality beyond mere constant conjunction, first event ''A'' and then always event ''B''. Hempel's explication of the DN model held
natural laws Natural law ( la, ius naturale, ''lex naturalis'') is a system of law based on a close observation of human nature, and based on values intrinsic to human nature that can be deduced and applied independently of positive law (the express enacted ...
—empirically confirmed regularities—as satisfactory and, if formulated realistically, approximating causal explanation. In later articles, Hempel defended the DN model and proposed a probabilistic explanation, inductive-statistical model (IS model). the DN and IS models together form the ''covering law model'', as named by a critic, William Dray. Derivation of statistical laws from other statistical laws goes to deductive-statistical model (DS model).Stuart Glennan
p. 276
in Sarkar S & Pfeifer J, eds, ''The Philosophy of Science: An Encyclopedia'', Volume 1: A–M (New York: Routledge, 2006).
Georg Henrik von Wright Georg Henrik von Wright (; 14 June 1916 – 16 June 2003) was a Finnish philosopher. Biography G. H. von Wright was born in Helsinki on 14 June 1916 to Tor von Wright and his wife Ragni Elisabeth Alfthan. On the retirement of Ludwig Wittgenste ...
, another critic, named it ''subsumption theory'',Manfred Riedel
pp. 3–4
in Manninen J & Tuomela R, eds, ''Essays on Explanation and Understanding: Studies in the Foundation of Humanities and Social Sciences'' (Dordrecht: D Reidel Publishing, 1976).
fitting the ambition of theory reduction.


Unity of science

Logical positivists were generally committed to " Unified Science", and sought a common language or, in Neurath's phrase, a "universal slang" whereby all scientific propositions could be expressed. The adequacy of proposals or fragments of proposals for such a language was often asserted on the basis of various "reductions" or "explications" of the terms of one special science to the terms of another, putatively more fundamental. Sometimes these reductions consisted of set-theoretic manipulations of a few logically primitive concepts (as in Carnap's ''Logical Structure of the World'', 1928). Sometimes, these reductions consisted of allegedly analytic or ''a priori'' deductive relationships (as in Carnap's "Testability and meaning"). A number of publications over a period of thirty years would attempt to elucidate this concept.


Theory reduction

As in Comtean positivism's envisioned
unity of science The unity of science is a thesis in philosophy of science that says that all the sciences form a unified whole. Overview The unity of science thesis was proposed by Ludwig von Bertalanffy in "General System Theory: A New Approach to Unity of Scie ...
, neopositivists aimed to network all special sciences through the covering law model of scientific explanation. And ultimately, by supplying
boundary condition In mathematics, in the field of differential equations, a boundary value problem is a differential equation together with a set of additional constraints, called the boundary conditions. A solution to a boundary value problem is a solution to th ...
s and supplying bridge laws within the covering law model, all the special sciences' laws would reduce to fundamental physics, the
fundamental science Basic research, also called pure research or fundamental research, is a type of scientific research with the aim of improving scientific theories for better understanding and prediction of natural or other phenomena. In contrast, applied resear ...
.


Critics

After
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
, key tenets of logical positivism, including its atomistic philosophy of science, the verifiability principle, and the fact/value gap, drew escalated criticism. The verifiability criterion made universal statements 'cognitively' meaningless, and even made statements beyond empiricism for technological but not conceptual reasons meaningless, which was taken to pose significant problems for the philosophy of science. These problems were recognized within the movement, which hosted attempted solutions—Carnap's move to ''confirmation'', Ayer's acceptance of ''weak verification''—but the program drew sustained criticism from a number of directions by the 1950s. Even philosophers disagreeing among themselves on which direction general
epistemology Epistemology (; ), or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics. Epis ...
ought to take, as well as on
philosophy of science Philosophy of science is a branch of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ult ...
, agreed that the logical empiricist program was untenable, and it became viewed as self-contradictory: the verifiability criterion of meaning was itself unverified. Notable critics included Popper, Quine,
Hanson Hanson or Hansson may refer to: People * Hanson (surname) * Hansson (surname) * Hanson (wrestler), ringname of an American professional wrestler Musical groups * Hanson (band), an American pop rock band * Hanson (UK band), an English rock ...
, Kuhn, Putnam, Austin, Strawson,
Goodman Goodman or Goodmans may refer to: Businesses and organizations * Goodman Games, American publisher. * Goodman Global, an American HVAC manufacturer. * Goodman Group, an Australian property company. * Goodmans Industries, a British electronic co ...
, and Rorty.


Popper

An early, tenacious critic was Karl Popper whose 1934 book ''Logik der Forschung'', arriving in English in 1959 as ''
The Logic of Scientific Discovery ''The Logic of Scientific Discovery'' is a 1959 book about the philosophy of science by the philosopher Karl Popper. Popper rewrote his book in English from the 1934 (imprint '1935') German original, titled ''Logik der Forschung. Zur Erkenntnisthe ...
'', directly answered verificationism. Popper considered the problem of induction as rendering empirical verification logically impossible, and the deductive fallacy of
affirming the consequent Affirming the consequent, sometimes called converse error, fallacy of the converse, or confusion of necessity and sufficiency, is a formal fallacy of taking a true conditional statement (e.g., "If the lamp were broken, then the room would be dar ...
reveals any phenomenon's capacity to host more than one logically possible explanation. Accepting
scientific method The scientific method is an empirical method for acquiring knowledge that has characterized the development of science since at least the 17th century (with notable practitioners in previous centuries; see the article history of scientific ...
as hypotheticodeduction, whose inference form is
denying the consequent In propositional logic, ''modus tollens'' () (MT), also known as ''modus tollendo tollens'' (Latin for "method of removing by taking away") and denying the consequent, is a deductive argument form and a rule of inference. ''Modus tollens'' ...
, Popper finds scientific method unable to proceed without
falsifiable Falsifiability is a standard of evaluation of scientific theories and hypotheses that was introduced by the philosopher of science Karl Popper in his book ''The Logic of Scientific Discovery'' (1934). He proposed it as the cornerstone of a so ...
predictions. Popper thus identifies
falsifiability Falsifiability is a standard of evaluation of scientific theories and hypotheses that was introduced by the philosopher of science Karl Popper in his book '' The Logic of Scientific Discovery'' (1934). He proposed it as the cornerstone of a s ...
to demarcate not ''meaningful'' from ''meaningless'' but simply ''scientific'' from ''unscientific''—a label not in itself unfavorable. Popper finds virtue in
metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
, required to develop new scientific theories. And an unfalsifiable—thus unscientific, perhaps metaphysical—concept in one era can later, through evolving knowledge or technology, become falsifiable, thus scientific. Popper also found science's quest for truth to rest on values. Popper disparages the '' pseudoscientific'', which occurs when an unscientific theory is proclaimed true and coupled with seemingly scientific method by "testing" the unfalsifiable theory—whose predictions are confirmed by necessity—or when a scientific theory's falsifiable predictions are strongly falsified but the theory is persistently protected by "immunizing stratagems", such as the appendage of ''
ad hoc Ad hoc is a Latin phrase meaning literally 'to this'. In English, it typically signifies a solution for a specific purpose, problem, or task rather than a generalized solution adaptable to collateral instances. (Compare with '' a priori''.) C ...
'' clauses saving the theory or the recourse to increasingly speculative hypotheses shielding the theory. Explicitly denying the positivist view of meaning and verification, Popper developed the epistemology of
critical rationalism Critical rationalism is an epistemological philosophy advanced by Karl Popper on the basis that, if a statement cannot be logically deduced (from what is known), it might nevertheless be possible to logically falsify it. Following Hume, Poppe ...
, which considers that human knowledge evolves by conjectures and refutations, and that no number, degree, and variety of empirical successes can either verify or confirm scientific theory. For Popper, science's aim is ''corroboration'' of scientific theory, which strives for
scientific realism Scientific realism is the view that the universe described by science is real regardless of how it may be interpreted. Within philosophy of science, this view is often an answer to the question "how is the success of science to be explained?" Th ...
but accepts the maximal status of strongly corroborated
verisimilitude In philosophy, verisimilitude (or truthlikeness) is the notion that some propositions are closer to being true than other propositions. The problem of verisimilitude is the problem of articulating what it takes for one false theory to be clo ...
("truthlikeness"). Popper thus acknowledged the value of the positivist movement's emphasis on science but claimed that he had "killed positivism".


Quine

Although an empiricist, American logician
Willard Van Orman Quine Willard Van Orman Quine (; known to his friends as "Van"; June 25, 1908 – December 25, 2000) was an American philosopher and logician in the analytic tradition, recognized as "one of the most influential philosophers of the twentieth century" ...
published the 1951 paper "
Two Dogmas of Empiricism "Two Dogmas of Empiricism" is a paper by analytic philosopher Willard Van Orman Quine published in 1951. According to University of Sydney professor of philosophy Peter Godfrey-Smith, this "paper ssometimes regarded as the most important in all o ...
", which challenged conventional empiricist presumptions. Quine attacked the analytic/synthetic division, which the verificationist program had been hinged upon in order to entail, by consequence of Hume's fork, both
necessity Necessary or necessity may refer to: * Need ** An action somebody may feel they must do ** An important task or essential thing to do at a particular time or by a particular moment * Necessary and sufficient condition, in logic, something that i ...
and aprioricity. Quine's
ontological relativity The inscrutability or indeterminacy of reference (also referential inscrutability) is a thesis by 20th century analytic philosopher Willard Van Orman Quine in his book '' Word and Object''. The main claim of this theory is that any given sentence ...
explained that every term in any statement has its meaning contingent on a vast network of knowledge and belief, the speaker's conception of the entire world. Quine later proposed
naturalized epistemology Naturalized epistemology (a term coined by W. V. O. Quine) is a collection of philosophic views concerned with the theory of knowledge that emphasize the role of natural scientific methods. This shared emphasis on scientific methods of studying k ...
.


Hanson

In 1958, Norwood Hanson's ''Patterns of Discovery'' undermined the division of observation versus
theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be ...
,Novick, ''That Noble Dream'' (Cambridge University Press, 1988)
p. 527
as one can predict, collect, prioritize, and assess data only via some horizon of expectation set by a theory. Thus, any
dataset A data set (or dataset) is a collection of data. In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record of the ...
—the direct observations, the scientific facts—is laden with theory.


Kuhn

With his landmark ''
The Structure of Scientific Revolutions ''The Structure of Scientific Revolutions'' (1962; second edition 1970; third edition 1996; fourth edition 2012) is a book about the history of science by philosopher Thomas S. Kuhn. Its publication was a landmark event in the history, philoso ...
'' (1962),
Thomas Kuhn Thomas Samuel Kuhn (; July 18, 1922 – June 17, 1996) was an American philosopher of science whose 1962 book '' The Structure of Scientific Revolutions'' was influential in both academic and popular circles, introducing the term ''paradig ...
critically destabilized the verificationist program, which was presumed to call for foundationalism. (But already in the 1930s,
Otto Neurath Otto Karl Wilhelm Neurath (; 10 December 1882 – 22 December 1945) was an Austrian-born philosopher of science, sociologist, and political economist. He was also the inventor of the ISOTYPE method of pictorial statistics and an innovator in mu ...
had argued for nonfoundationalism via
coherentism In philosophical epistemology, there are two types of coherentism: the coherence theory of truth; and the coherence theory of justification (also known as epistemic coherentism). Coherent truth is divided between an anthropological approach, wh ...
by likening science to a boat (
Neurath's boat Neurath's boat (or Neurath's ship) is a simile used in anti-foundational accounts of knowledge, especially in the philosophy of science. It was first formulated by Otto Neurath. It is based in part on the Ship of Theseus which, however, is standar ...
) that scientists must rebuild at sea.) Although Kuhn's thesis itself was attacked even by opponents of neopositivism, in the 1970 postscript to ''Structure'', Kuhn asserted, at least, that there was no
algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ...
to science—and, on that, even most of Kuhn's critics agreed. Powerful and persuasive, Kuhn's book, unlike the vocabulary and symbols of logic's
formal language In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules. The alphabet of a formal language consists of sy ...
, was written in natural language open to the layperson. Kuhn's book was first published in a volume of ''
International Encyclopedia of Unified Science International is an adjective (also used as a noun) meaning "between nations". International may also refer to: Music Albums * ''International'' (Kevin Michael album), 2011 * ''International'' (New Order album), 2002 * ''International'' (The T ...
''—a project begun by logical positivists but co-edited by Neurath whose view of science was already nonfoundationalist as mentioned above—and some sense unified science, indeed, but by bringing it into the realm of historical and social assessment, rather than fitting it to the model of physics. Kuhn's ideas were rapidly adopted by scholars in disciplines well outside natural sciences,Novick, ''That Noble Dream'' (Cambridge University Press, 1988)
pp. 526–27
.
and, as logical empiricists were extremely influential in the
social science Social science is one of the branches of science, devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of so ...
s, ushered academia into
postpositivism Postpositivism or postempiricism is a metatheoretical stance that critiques and amends positivism and has impacted theories and practices across philosophy, social sciences, and various models of scientific inquiry. While positivists emphasize ...
or postempiricism.


Putnam

The " received view" operates on the ''correspondence rule'' that states, "The observational terms are taken as referring to specified phenomena or phenomenal properties, and the only interpretation given to the theoretical terms is their explicit definition provided by the correspondence rules". According to Hilary Putnam, a former student of Reichenbach and of Carnap, the dichotomy of observational terms versus theoretical terms introduced a problem within scientific discussion that was nonexistent until this dichotomy was stated by logical positivists. Putnam's four objections: * Something is referred to as "observational" if it is observable directly with our senses. Then an observational term cannot be applied to something unobservable. If this is the case, there are no observational terms. * With Carnap's classification, some unobservable terms are not even theoretical and belong to neither observational terms nor theoretical terms. Some theoretical terms refer primarily to observational terms. * Reports of observational terms frequently contain theoretical terms. * A scientific theory may not contain any theoretical terms (an example of this is Darwin's original theory of evolution). Putnam also alleged that positivism was actually a form of metaphysical idealism by its rejecting scientific theory's ability to garner knowledge about nature's unobservable aspects. With his "no miracles" argument, posed in 1974, Putnam asserted
scientific realism Scientific realism is the view that the universe described by science is real regardless of how it may be interpreted. Within philosophy of science, this view is often an answer to the question "how is the success of science to be explained?" Th ...
, the stance that science achieves true—or approximately true—knowledge of the world as it exists independently of humans' sensory experience. In this, Putnam opposed not only the positivism but other
instrumentalism In philosophy of science and in epistemology, instrumentalism is a methodological view that ideas are useful instruments, and that the worth of an idea is based on how effective it is in explaining and predicting phenomena. According to instrumenta ...
—whereby scientific theory is but a human tool to predict human observations—filling the void left by positivism's decline.


Decline and legacy

By the late 1960s, logical positivism had become exhausted. In 1976, A. J. Ayer quipped that "the most important" defect of logical positivism "was that nearly all of it was false", though he maintained "it was true in spirit." Although logical positivism tends to be recalled as a pillar of scientism, Carl Hempel was key in establishing the philosophy subdiscipline philosophy of science where
Thomas Kuhn Thomas Samuel Kuhn (; July 18, 1922 – June 17, 1996) was an American philosopher of science whose 1962 book '' The Structure of Scientific Revolutions'' was influential in both academic and popular circles, introducing the term ''paradig ...
and Karl Popper brought in the era of
postpositivism Postpositivism or postempiricism is a metatheoretical stance that critiques and amends positivism and has impacted theories and practices across philosophy, social sciences, and various models of scientific inquiry. While positivists emphasize ...
.
John Passmore John Passmore AC (9 September 1914 – 25 July 2004) was an Australian philosopher. Life John Passmore was born on 9 September 1914 in Manly, Sydney, where he grew up. He was educated at Sydney Boys High School.Sydney High School Old Boys ...
found logical positivism to be "dead, or as dead as a philosophical movement ever becomes". Logical positivism's fall reopened debate over the metaphysical merit of scientific theory, whether it can offer knowledge of the world beyond human experience (scientific realism) versus whether it is but a human tool to predict human experience (instrumentalism).Ruth Lane
"Positivism, scientific realism and political science: Recent developments in the philosophy of science"
''Journal of Theoretical Politics'', 1996 Jul8(3):361–82, abstract.
Meanwhile, it became popular among philosophers to rehash the faults and failures of logical positivism without investigation of them.Friedman, ''Reconsidering Logical Positivism'' (Cambridge, 1999)
p. 1
Thereby, logical positivism has been generally misrepresented, sometimes severely. Arguing for their own views, often framed versus logical positivism, many philosophers have reduced logical positivism to simplisms and stereotypes, especially the notion of logical positivism as a type of foundationalism.Friedman, ''Reconsidering Logical Positivism'' (Cambridge, 1999)
p. 2
In any event, the movement helped anchor analytic philosophy in the English-speaking world, and returned Britain to empiricism. Without the logical positivists, who have been tremendously influential outside philosophy, especially in
psychology Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries between ...
and other
social science Social science is one of the branches of science, devoted to the study of societies and the relationships among individuals within those societies. The term was formerly used to refer to the field of sociology, the original "science of so ...
s, intellectual life of the 20th century would be unrecognizable.


See also

*
Anti-realism In analytic philosophy, anti-realism is a position which encompasses many varieties such as metaphysical, mathematical, semantic, scientific, moral and epistemic. The term was first articulated by British philosopher Michael Dummett in an argument ...
*
Definitions of philosophy Definitions of philosophy aim at determining what all forms of philosophy have in common and how to distinguish philosophy from other disciplines. Many different definitions have been proposed but there is very little agreement on which is the rig ...
*
Empirio-criticism Ernst Waldfried Josef Wenzel Mach ( , ; 18 February 1838 – 19 February 1916) was a Moravian-born Austrian physicist and philosopher, who contributed to the physics of shock waves. The ratio of one's speed to that of sound is named the Mach n ...
*
Moral panic A moral panic is a widespread feeling of fear, often an irrational one, that some evil person or thing threatens the values, interests, or well-being of a community or society. It is "the process of arousing social concern over an issue", us ...
*
Raven paradox The raven paradox, also known as Hempel's paradox, Hempel's ravens, or rarely the paradox of indoor ornithology, is a paradox arising from the question of what constitutes evidence for the truth of a statement. Observing objects that are neither ...
*
Sociological positivism Positivism is an empiricist philosophical theory that holds that all genuine knowledge is either true by definition or positive—meaning ''a posteriori'' facts derived by reason and logic from sensory experience.John J. Macionis, Linda M. G ...
*''
The Structure of Science ''The Structure of Science: Problems in the Logic of Scientific Explanation'' is a 1961 book about the philosophy of science by the philosopher Ernest Nagel, in which the author discusses the nature of scientific inquiry with reference to both na ...
'' *
Unobservable An unobservable (also called impalpable) is an entity whose existence, nature, properties, qualities or relations are not directly observable by humans. In philosophy of science, typical examples of "unobservables" are the force of gravity, causat ...


People

* Gustav Bergmann *
Herbert Feigl Herbert Feigl (; ; December 14, 1902 – June 1, 1988) was an Austrian-American philosopher and an early member of the Vienna Circle. He coined the term " nomological danglers". Biography The son of a trained weaver who became a textile designer, ...
*
Kurt Grelling Kurt Grelling (2 March 1886 – September 1942) was a German logician and philosopher, member of the Berlin Circle. Life and work Kurt Grelling was born on 2 March 1886 in Berlin. His father, the Doctor of Jurisprudence Richard Grelling, ...
* Friedrich Waismann * R. B. Braithwaite


Notes


References

*Bechtel, William,
Philosophy of Science: An Overview for Cognitive Science
' (Hillsdale NJ: Lawrence Erlbaum Assoc, 1988). *Friedman, Michael,
Reconsidering Logical Positivism
' (New York: Cambridge University Press, 1999). *Novick, Peter,
That Noble Dream: The 'Objectivity Question' and the American Historical Profession
' (Cambridge UK: Cambridge University Press, 1988). *Stahl, William A & Robert A Campbell, Yvonne Petry, Gary Diver,
Webs of Reality: Social Perspectives on Science and Religion
' (Piscataway NJ: Rutgers University Press, 2002). *Suppe, Frederick, ed,
The Structure of Scientific Theories
', 2nd edn (Urbana IL: University of Illinois Press, 1977).


Further reading

* Achinstein, Peter and Barker, Stephen F. ''The Legacy of Logical Positivism: Studies in the Philosophy of Science''. Baltimore: Johns Hopkins Press, 1969. *Ayer, Alfred Jules. ''Logical Positivism''. Glencoe, Ill: Free Press, 1959. *Barone, Francesco. ''Il neopositivismo logico''. Roma Bari: Laterza, 1986. *Bergmann, Gustav. ''The Metaphysics of Logical Positivism''. New York: Longmans Green, 1954. *Cirera, Ramon.
Carnap and the Vienna Circle: Empiricism and Logical Syntax
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External links

* Articles by logical positivists
The Scientific Conception of the World: The Vienna Circle

Carnap, Rudolf. 'The Elimination of Metaphysics Through Logical Analysis of Language'




* [https://web.archive.org/web/20110511191629/http://etext.lib.virginia.edu/cgi-local/DHI/dhicontrib2.cgi?id=dv3-69 Feigl, Herbert. 'Positivism in the Twentieth Century (Logical Empiricism)', ''Dictionary of the History of Ideas'', 1974, Gale Group (Electronic Edition)]
Hempel, Carl. 'Problems and Changes in the Empiricist Criterion of Meaning.'
Articles on logical positivism *


Murzi, Mauro. 'Logical Positivism', ''The New Encyclopedia of Unbelief'', Tom Flynn (ed.). Prometheus Books, 2007 (PDF version)



Passmore, John. 'Logical Positivism', ''The Encyclopedia of Philosophy'', Paul Edwards (ed.). New York: Macmillan, 1967, first edition
Articles on related philosophical topics
Hájek, Alan. 'Interpretations of Probability', ''The Stanford Encyclopedia of Philosophy (Summer 2003 Edition), Edward N. Zalta (ed.)''

Rey, Georges. 'The Analytic/Synthetic Distinction', ''The Stanford Encyclopedia of Philosophy (Fall 2003 Edition)'', Edward N. Zalta (ed.)

Ryckman, Thomas A., 'Early Philosophical Interpretations of General Relativity', ''The Stanford Encyclopedia of Philosophy (Winter 2001 Edition), Edward N. Zalta (ed.)''

Woleński, Jan. 'Lvov-Warsaw School', ''The Stanford Encyclopedia of Philosophy (Summer 2003 Edition), Edward N. Zalta (ed.)''

Woodward, James. 'Scientific Explanation', ''The Stanford Encyclopedia of Philosophy (Summer 2003 Edition), Edward N. Zalta (ed.)''
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