Vienna Circle
Encyclopedia
The Vienna Circle was an association of philosophers gathered around the University of Vienna
University of Vienna
The University of Vienna is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world...

 in 1922, chaired by Moritz Schlick
Moritz Schlick
Friedrich Albert Moritz Schlick was a German philosopher, physicist and the founding father of logical positivism and the Vienna Circle.-Early life and works:...

, also known as the Ernst Mach Society (Verein Ernst Mach) in honour of Ernst Mach
Ernst Mach
Ernst Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as the Mach number and the study of shock waves...

. Among its members were Gustav Bergmann
Gustav Bergmann
Gustav Bergmann was a philosopher born in Vienna, Austria. He studied at the University of Vienna and was a member of the Vienna Circle. In the United States, he was a professor of philosophy and psychology at the University of Iowa.- Biography :Bergmann earned his Ph.D. in mathematics at the...

, Rudolf Carnap
Rudolf Carnap
Rudolf Carnap was an influential German-born philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism....

, Herbert Feigl
Herbert Feigl
Herbert Feigl was an Austrian philosopher and a member of the Vienna Circle.-Biography:The son of a weaver, Feigl was born in Reichenberg , Bohemia, and matriculated at the University of Vienna in 1922...

, Philipp Frank
Philipp Frank
Philipp Frank was a physicist, mathematician and also an influential philosopher during the first half of the 20th century. He was a logical-positivist, and a member of the Vienna Circle.He was born on 20 March 1884 in Vienna, Austria, and died on 21 July 1966 in Cambridge, Massachusetts, USA...

, Kurt Gödel
Kurt Gödel
Kurt Friedrich Gödel was an Austrian logician, mathematician and philosopher. Later in his life he emigrated to the United States to escape the effects of World War II. One of the most significant logicians of all time, Gödel made an immense impact upon scientific and philosophical thinking in the...

, Hans Hahn
Hans Hahn
Hans Hahn was an Austrian mathematician who made contributions to functional analysis, topology, set theory, the calculus of variations, real analysis, and order theory.-Biography:...

, Tscha Hung, Victor Kraft
Victor Kraft
Victor Kraft was an Austrian philosopher, best known for being a member of the Vienna Circle.-Biography:Kraft studied philosophy, geography and history at the University of Vienna...

, Karl Menger
Karl Menger
Karl Menger was a mathematician. He was the son of the famous economist Carl Menger. He is credited with Menger's theorem. He worked on mathematics of algebras, algebra of geometries, curve and dimension theory, etc...

, Richard von Mises, Marcel Natkin, Otto Neurath
Otto Neurath
Otto Neurath was an Austrian philosopher of science, sociologist, and political economist...

, Olga Hahn-Neurath
Olga Hahn-Neurath
Olga Hahn-Neurath was an Austrian mathematician and philosopher. She is best known for being a member of the Vienna Circle. She was sister of the mathematician Hans Hahn....

, Theodor Radakovic, Rose Rand
Rose Rand
Rose Rand A logician and a Philosopher. A member of the Vienna Circle.- Life and work :Rand was born in Lemberg . After her family moved to Austria she studied at the Polish Gymnasium in Vienna. In 1924 she enrolled in Vienna University, her teachers included Heinrich Gomperz, Moritz Schlick,...

 and Friedrich Waismann
Friedrich Waismann
Friedrich Waismann was an Austrian mathematician, physicist, and philosopher. He is best known for being a member of the Vienna Circle and one of the key theorists in logical positivism.-Birth & Early Interest in Philosophy:...

. With the exception of Gödel, members of the Vienna Circle had a common attitude towards philosophy, consisting of an applied logical positivism
Logical positivism
Logical positivism is a philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge—with a version of rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology.It may be considered as a type of analytic...

 drawn from Ludwig Wittgenstein
Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He was professor in philosophy at the University of Cambridge from 1939 until 1947...

, whose Tractatus Logico-Philosophicus
Tractatus Logico-Philosophicus
The Tractatus Logico-Philosophicus is the only book-length philosophical work published by the Austrian philosopher Ludwig Wittgenstein in his lifetime. It was an ambitious project: to identify the relationship between language and reality and to define the limits of science...

formed the basis for the group's philosophy (although Wittgenstein himself insisted that logical positivism was a gross misreading of his thinking, and took to reading poetry during meetings of the Vienna Circle). The Vienna Circle's influence on 20th century philosophy was immense, and much later work, such as that of Willard Van Orman Quine
Willard Van Orman Quine
Willard Van Orman Quine was an American philosopher and logician in the analytic tradition...

, was in response to the Circle's thought.

History of the Vienna Circle

The pre-history of the Vienna Circle began with meetings on the philosophy of science
Philosophy of science
The philosophy of science is concerned with the assumptions, foundations, methods and implications of science. It is also concerned with the use and merit of science and sometimes overlaps metaphysics and epistemology by exploring whether scientific results are actually a study of truth...

 and epistemology from 1908 on, promoted by Philipp Frank, Hans Hahn and Otto Neurath.

Hans Hahn, the oldest of the three (1879–1934), was a mathematician. He received his degree in mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 in 1902. Afterwards he studied under the direction of Ludwig Boltzmann
Ludwig Boltzmann
Ludwig Eduard Boltzmann was an Austrian physicist famous for his founding contributions in the fields of statistical mechanics and statistical thermodynamics...

 in Vienna and David Hilbert
David Hilbert
David Hilbert was a German mathematician. He is recognized as one of the most influential and universal mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas in many areas, including invariant theory and the axiomatization of...

, Felix Klein
Felix Klein
Christian Felix Klein was a German mathematician, known for his work in group theory, function theory, non-Euclidean geometry, and on the connections between geometry and group theory...

 and Hermann Minkowski
Hermann Minkowski
Hermann Minkowski was a German mathematician of Ashkenazi Jewish descent, who created and developed the geometry of numbers and who used geometrical methods to solve difficult problems in number theory, mathematical physics, and the theory of relativity.- Life and work :Hermann Minkowski was born...

 in Göttingen
Göttingen
Göttingen is a university town in Lower Saxony, Germany. It is the capital of the district of Göttingen. The Leine river runs through the town. In 2006 the population was 129,686.-General information:...

. In 1905 he received the Habilitation
Habilitation
Habilitation is the highest academic qualification a scholar can achieve by his or her own pursuit in several European and Asian countries. Earned after obtaining a research doctorate, such as a PhD, habilitation requires the candidate to write a professorial thesis based on independent...

 in mathematics. He taught at Innsbruck
Innsbruck
- Main sights :- Buildings :*Golden Roof*Kaiserliche Hofburg *Hofkirche with the cenotaph of Maximilian I, Holy Roman Emperor*Altes Landhaus...

 (1905–1906) and Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

 (from 1909).

Otto Neurath (1882–1945) studied sociology
Sociology
Sociology is the study of society. It is a social science—a term with which it is sometimes synonymous—which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity...

, economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

 and philosophy
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

 in Vienna and Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

. From 1907 to 1914 he taught in Vienna at the Neuen Wiener Handelsakademie (Viennese Commercial Academy). Neurath married Olga, Hahn’s sister, in 1911.

Philipp Frank, the youngest of the group (1884–1966), studied physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 at Göttingen and Vienna with Ludwig Boltzmann, David Hilbert and Felix Klein
Felix Klein
Christian Felix Klein was a German mathematician, known for his work in group theory, function theory, non-Euclidean geometry, and on the connections between geometry and group theory...

. From 1912, he held the chair of theoretical physics
Theoretical physics
Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...

 in the German University in Prague
Prague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...

.

Their meetings were held in Viennese coffeehouses from 1907 onward. Frank remembered:
Presumably the meetings stopped in 1912, when Frank went to Prague, to hold the chair of theoretical physics left vacant by Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

. Hahn left Vienna during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

 and returned in 1921. The following year Hahn, with the collaboration of Frank, arranged to bring into the group Moritz Schlick, who held the chair of philosophy of the inductive sciences at the University of Vienna
University of Vienna
The University of Vienna is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world...

. Schlick had already published his two main works Raum und Zeit in die gegenwärtigen Physik (Space and Time in contemporary Physics) in 1917 and Allgemeine Erkenntnislehre (General Theory of Knowledge) in 1918. A central work for the newly founded discussion group was the Logisch-Philosophische Abhandlung (Tractatus Logico-Philosophicus
Tractatus Logico-Philosophicus
The Tractatus Logico-Philosophicus is the only book-length philosophical work published by the Austrian philosopher Ludwig Wittgenstein in his lifetime. It was an ambitious project: to identify the relationship between language and reality and to define the limits of science...

), published by Ludwig Wittgenstein
Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He was professor in philosophy at the University of Cambridge from 1939 until 1947...

 in 1921 (in 1922 in German-English version).

Under the direction of Schlick, a new regular series of meetings began. In 1926 Schlick and Hahn arranged to bring in Rudolf Carnap at the University of Vienna. In 1928 the Verein Ernst Mach (Ernst Mach Society) was founded, with Schlick as chairman. In 1929 the Vienna Circle manifesto Wissenschaftliche Weltauffassung. Der Wiener Kreis (The Scientific Conception of the World. The Vienna Circle) was published. The pamphlet is dedicated to Schlick, and its preface was signed by Hahn, Neurath and Carnap. In the appendix is a list of the members of the Vienna Circle.

The Vienna Circle was dispersed when the Nazi
Nazism
Nazism, the common short form name of National Socialism was the ideology and practice of the Nazi Party and of Nazi Germany...

 party came to power in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

; many of its members emigrated to USA, where they taught in several universities. Schlick remained in Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

, but in 1936 he was killed by a Nazi sympathizer student in the University of Vienna.

The Kraft Circle
Kraft Circle
The Kraft Circle was a student society of philosophers at the Institut für Österreichische Geschichtsforschung of the University of Vienna devoted to "considering philosophical problems in a nonmetaphysical manner and with special reference to the findings of the sciences"...

, a successor to the Vienna Circle, arose in 1949 under the leadership of Viktor Kraft. Its philosophical programme was continued long after its demise (1952/3) by Paul Feyerabend
Paul Feyerabend
Paul Karl Feyerabend was an Austrian-born philosopher of science best known for his work as a professor of philosophy at the University of California, Berkeley, where he worked for three decades . He lived a peripatetic life, living at various times in England, the United States, New Zealand,...

.

The Vienna Circle manifesto

It states the scientific world-conception of the Vienna Circle, which is characterized “essentially by two features. First it is empiricist
Empiricism
Empiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...

 and positivist
: there is knowledge only from experience […] Second, the scientific world-conception is marked by the application of a certain method, namely logical analysis
Logic
In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

.”

Logical analysis is the method of clarification of philosophical problems; it makes an extensive use of symbolic logic and distinguishes the Vienna Circle empiricism from earlier versions. The task of philosophy lies in the clarification—through the method of logical analysis—of problems and assertions.

Logical analysis shows that there are two different kinds of statement
Statement
Statement may refer to:* A kind of expression in language *Statement , declarative sentence that is either true or false*Statement , the smallest standalone element of an imperative programming language...

s; one kind includes statements reducible to simpler statements about the empirically given; the other kind includes statements which cannot be reduced to statements about experience
Experience
Experience as a general concept comprises knowledge of or skill in or observation of some thing or some event gained through involvement in or exposure to that thing or event....

 and thus they are devoid of meaning. Metaphysical statements belong to this second kind and therefore they are meaningless. Hence many philosophical problems are rejected as pseudo-problems which arise from logical mistakes, while others are re-interpreted as empirical statements and thus become the subject of scientific inquiries.

One source of the logical mistakes that are at the origins of metaphysics is the ambiguity of natural language
Language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

. “Ordinary language for instance uses the same part of speech, the substantive, for thing
Object (philosophy)
An object in philosophy is a technical term often used in contrast to the term subject. Consciousness is a state of cognition that includes the subject, which can never be doubted as only it can be the one who doubts, and some object or objects that may or may not have real existence without...

s (‘apple’) as well as for qualities
Quality (philosophy)
A quality is an attribute or a property. Attributes are ascribable, by a subject, whereas properties are possessible. In contemporary philosophy, the idea of qualities and especially how to distinguish certain kinds of qualities from one another remains controversial.-Background:Aristotle analyzed...

 (‘hardness’), relations (‘friendship’), and processes (‘sleep’); therefore it misleads one into a thing-like conception of functional concept
Concept
The word concept is used in ordinary language as well as in almost all academic disciplines. Particularly in philosophy, psychology and cognitive sciences the term is much used and much discussed. WordNet defines concept: "conception, construct ". However, the meaning of the term concept is much...

s”. Another source of mistakes is “the notion that thinking can either lead to knowledge out of its own resources without using any empirical material, or at least arrive at new contents by an inference
Inference
Inference is the act or process of deriving logical conclusions from premises known or assumed to be true. The conclusion drawn is also called an idiomatic. The laws of valid inference are studied in the field of logic.Human inference Inference is the act or process of deriving logical conclusions...

 from given states of affair”. The latter notion is typical in Kantian philosophy
Immanuel Kant
Immanuel Kant was a German philosopher from Königsberg , researching, lecturing and writing on philosophy and anthropology at the end of the 18th Century Enlightenment....

, according to which there are synthetic statements a priori
A priori and a posteriori (philosophy)
The terms a priori and a posteriori are used in philosophy to distinguish two types of knowledge, justifications or arguments...

 that expand knowledge without using the experience
Experience
Experience as a general concept comprises knowledge of or skill in or observation of some thing or some event gained through involvement in or exposure to that thing or event....

. Synthetic knowledge a priori is rejected by the Vienna Circle. Mathematics, which at a first sight seems an example of necessarily valid synthetic knowledge derived from pure reason
Reason
Reason is a term that refers to the capacity human beings have to make sense of things, to establish and verify facts, and to change or justify practices, institutions, and beliefs. It is closely associated with such characteristically human activities as philosophy, science, language, ...

 alone, has instead a tautological
Tautology (logic)
In logic, a tautology is a formula which is true in every possible interpretation. Philosopher Ludwig Wittgenstein first applied the term to redundancies of propositional logic in 1921; it had been used earlier to refer to rhetorical tautologies, and continues to be used in that alternate sense...

 character, that is its statements are analytical statements, thus very different from Kantian synthetic statements. The only two kinds of statements accepted by the Vienna Circle are synthetic statements a posteriori
A Posteriori
Apart from the album, some additional remixes were released exclusively through the iTunes Store. They are:*"Eppur si muove"  – 6:39*"Dreaming of Andromeda" Apart from the album, some additional remixes were released exclusively through the iTunes Store. They are:*"Eppur si muove" (Tocadisco...

 (i.e. scientific statements) and analytic statements a priori (i.e. logical and mathematical statements).

However, the persistence of metaphysics is connected not only with logical mistakes but also with “social and economical struggles”. Metaphysics and theology
Theology
Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...

 are allied to traditional social forms, while the group of people who “faces modern times, rejects these views and takes its stand on the ground of empirical sciences”. Thus the struggle between metaphysics and scientific world-conception
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

 is not only a struggle between different kinds of philosophies, but it is also—and perhaps primarily—a struggle between different political, social and economical attitudes. Of course, as the manifesto itself acknowledged, “not every adherent of the scientific world-conception will be a fighter”. Many historians of the Vienna Circle see in the latter sentence an implicit reference to a contrast between the so called ‘left wing’ of the Vienna Circle, mainly represented by Neurath and Carnap, and Moritz Schlick. The aim of the left wing was to facilitate the penetration of the scientific world-conception in “the forms of personal and public life, in education
Education
Education in its broadest, general sense is the means through which the aims and habits of a group of people lives on from one generation to the next. Generally, it occurs through any experience that has a formative effect on the way one thinks, feels, or acts...

, upbringing, architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

, and the shaping of economic and social life”. In contrast, Schlick was primarily interested in the theoretical study of science and philosophy. Perhaps the sentence “Some, glad of solitude, will lead a withdrawn existence on the icy slopes of logic” is an ironic reference to Schlick.

The manifesto lists Walter Dubislav
Walter Dubislav
Walter Dubislav was a German logician and philosopher of science...

, Josef Frank
Josef Frank (architect)
Josef Frank was an Austrian-born architect, artist, and designer who adopted Swedish citizenship in the latter half of his life. Together with Oskar Strnad, he created the Vienna School of Architecture, and its concept of Modern houses, housing and interiors.- Life :Josef Frank was of Jewish...

, Kurt Grelling
Kurt Grelling
Kurt Grelling was a logician, philosopher and member of the Berlin Circle.- Life and work :Shortly after his arrival in 1905 at University of Göttingen, Grelling began a collaboration with philosopher Leonard Nelson, with whom he tried to solve Russell's paradox, which had shaken the foundations...

, Hasso Härlen, Eino Kaila
Eino Kaila
Eino Sakari Kaila was a Finnish philosopher, critic and teacher. He worked in numerous fields including psychology , physics and theater, and attempted to find unifying principles behind various branches of human and natural sciences.- Life :Eino Kaila was born in Alajärvi, Finland...

, Heinrich Loewy, F. P. Ramsey, Hans Reichenbach
Hans Reichenbach
Hans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...

, Kurt Reidemeister
Kurt Reidemeister
Kurt Werner Friedrich Reidemeister was a mathematician born in Braunschweig , Germany.He received his doctorate in 1921 with a thesis in algebraic number theory at the University of Hamburg under the supervision of Erich Hecke. In 1923 he was appointed assistant professor at the University of Vienna...

, and Edgar Zilsel
Edgar Zilsel
Edgar Zilsel was an Austrian historian and philosopher of science. He is considered to be among the modern "pioneers of the sociology of science".- Life :...

 as "Those sympathetic to the
Vienna Circle" and Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

, Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...

 and Ludwig Wittgenstein
Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He was professor in philosophy at the University of Cambridge from 1939 until 1947...

 as "Leading representatives of the
scientific world-conception".

Unified science

The final goal pursued by the Vienna Circle was unified science
Unified Science
"Unified Science" can refer to any of three related strands in contemporary thought.* Belief in the unity of science was a central tenet of logical positivism. Different logical positivists construed this doctrine in several different ways, e.g...

, that is the construction of a "constitutive system" in which every legitimate statement is reduced to the concepts of lower level which refer directly to the given experience
Experience
Experience as a general concept comprises knowledge of or skill in or observation of some thing or some event gained through involvement in or exposure to that thing or event....

. "The endeavour is to link and harmonise the achievements of individual investigators in their various fields of science". From this aim follows the search for clarity, neatness, and for a symbolic language that eliminates the problems arising from the ambiguity of natural language. The Vienna Circle published a collection, called Einheitswissenschaft (Unified science), edited by Rudolf Carnap, Philipp Frank, Hans Hahn, Otto Neurath, Joergen Joergensen (after Hahn's death) and Charles W. Morris
Charles W. Morris
Charles W. Morris was an American semiotician and philosopher.-Background:A son of Charles William and Laura Morris, Charles William Morris was born on May 23, 1901...

 (from 1938), whose aim was to present an unified vision of science. After the publication in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 of seven monographs from 1933 to 1939, the collection was dismissed, because of the problems arising from the World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. In 1938 a new series of publications started in USA. It was the International Encyclopedia of Unified Science
International Encyclopedia of Unified Science
In 1938 a new series of publications started in USA. It was the International Encyclopedia of Unified Science . An ambitious project never completed devoted to unified science...

, an ambitious project never completed devoted to unified science. Only the first section Foundations of the Unity of Sciences was published; it contains two volumes for a total of twenty monographs published from 1938 to 1969. As remembered by Rudolf Carnap and Charles Morris in the Preface to the 1969 edition of the International Encyclopedia of Unified Science:
Thomas Kuhn
Thomas Kuhn
Thomas Samuel Kuhn was an American historian and philosopher of science whose controversial 1962 book The Structure of Scientific Revolutions was deeply influential in both academic and popular circles, introducing the term "paradigm shift," which has since become an English-language staple.Kuhn...

’s well known work, The Structure of Scientific Revolutions, was published in this Encyclopedia in 1962, as the number two in the second volume.

The elimination of metaphysics

The attitude of Vienna Circle towards metaphysics is well expressed by Carnap in the article 'Überwindung der Metaphysik durch Logische Analyse der Sprache' in Erkenntnis, vol. 2, 1932 (English translation 'The Elimination of Metaphysics Through Logical Analysis of Language' in Sarkar, Sahotra, ed., Logical empiricism at its peak: Schlick, Carnap, and Neurath, New York : Garland Pub., 1996, pp. 10–31). A language—says Carnap—consists of a vocabulary
Vocabulary
A person's vocabulary is the set of words within a language that are familiar to that person. A vocabulary usually develops with age, and serves as a useful and fundamental tool for communication and acquiring knowledge...

, i.e. a set of meaningful words, and a syntax
Syntax
In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....

, i.e. a set of rules governing the formation of sentences from the words of the vocabulary. Pseudo-statements, i.e. sequences of words that at first sight resemble statements but in reality have no meaning, are formed in two ways: either meaningless words occur in them, or they are formed in an invalid syntactical way. According to Carnap, pseudo-statements of both kinds occur in metaphysics.

A word W has a meaning if two conditions are satisfied. First, the mode of the occurrence of W in its elementary sentence form (i.e. the simplest sentence form in which W is capable of occurring) must be fixed. Secondly, if W occurs in an elementary sentence S, it is necessary to give an answer to the following questions (that are—according to Carnap—equivalent formulation of the same question):
  1. What sentence
    Sentence (linguistics)
    In the field of linguistics, a sentence is an expression in natural language, and often defined to indicate a grammatical unit consisting of one or more words that generally bear minimal syntactic relation to the words that precede or follow it...

    s is S deducible from, and what sentences are deducible from S?
  2. Under what conditions is S supposed to be true, and under what conditions false?
  3. How is S verified?
  4. What is the meaning of S?

(Carnap, 'The Elimination of Metaphysics Through Logical Analysis of Language' in Sarkar, Sahotra, cit., pp. 12)

An example offered by Carnap concerns the word 'arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

'. The sentence form "the thing x is an arthropod" is an elementary sentence form that is derivable from "x is an animal", "x has a segmented body" and "x has jointed legs". Conversely, these sentences are derivable from "the thing x is an arthropod". Thus the meaning of the word 'arthropod' is determined.

According to Carnap, many words of metaphysics do not fulfill these requirements and thus they are meaningless. As an example, Carnap considers the word 'principle'. This word has a definite meaning, if the sentence "x is the principle of y" is supposed to be equivalent to the sentence "y exists by virtue of x" or "y arises out of x". The latter sentence is perfectly clear: y arises out of x when x is invariably followed by y, and the invariable association between x and y is empirically verifiable. But—says Carnap—metaphysicians are not satisfied with this interpretation of the meaning of 'principle'. They assert that no empirical relation between x and y can completely explain the meaning of "x is the principle of y", because there is something that cannot be grasped by means of the experience, something for which no empirical criterion can be specified. It is the lacking of any empirical criterion—says Carnap—that deprives of meaning the word 'principle' when it occurs in metaphysics. Therefore, metaphysical pseudo-statements such as "water is the principle of the world" or "the spirit is the principle of the world" are void of meaning because a meaningless word occurs in them.

However, there are pseudo-statements in which occur only meaningful words; these pseudo-statements are formed in a counter-syntactical way. An example is the word sequence "Caesar is a prime number"; every word has a definite meaning, but the sequence has no meaning. The problem is that "prime number" is a predicate of numbers, not a predicate of human beings. In the example the nonsense is evident; however, in natural language the rules of grammar do not prohibit the formation of analogous meaningless word sequences that are not so easily detectable. In the grammar of natural languages, every sequence of the kind "x is y", where x is a noun and y is a predicate, is acceptable. In fact, in the grammar there is no distinction between predicate which can be affirmed of human beings and predicate which can be affirmed of numbers. So "Caesar is a general" and "Caesar is a prime number" are both well-formed, in contrast for example with "Caesar is and", which is ill-formed. In a logically constructed language—says Carnap—a distinction between the various kinds of predicate is specified, and pseudo-statements as "Caesar is a prime number" are ill-formed. Now, and this is the main point of Carnap's argument, metaphysical statements in which meaningless words do not occur, are indeed meaningless because they are formed in a way which is admissible in natural languages, but not in logically constructed languages. Carnap attempts to indicate the most frequent sources of errors from which metaphysical pseudo-statements can arise. One source of mistakes is the ambiguity of the verb 'to be', which is sometimes used as a copula ("I am hungry") and sometimes to designate existence ("I am"). The latter statement incorrectly suggests a predicative form, and thus it suggests that existence is a predicate. Only modern logic, with the introduction of an explicit sign to designate existence (the sign ), which occurs only in statements such as , never as a predicate, has shown that existence is not a predicate, and thus has revealed the logical error from which pseudo-statements such as "cogito, ergo sum" has arisen.

Another source of mistakes is type confusions, in which a predicate of a kind is used as a predicate of another kind. For example the pseudo-statements "we know the Nothing" is analogous to "we know the rain", but while the latter is well-formed, the former is ill-formed, at least in a logically constructed language, because 'Nothing' is incorrectly used as a noun
Noun
In linguistics, a noun is a member of a large, open lexical category whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition .Lexical categories are defined in terms of how their members combine with other kinds of...

. In a formal language, 'Nothing' only means , such as "there is nothing which is outside", i.e. , and thus 'Nothing' never occurs as a noun or as a predicate.

What is the role of metaphysics? According to Carnap, although metaphysics has no theoretical content, it has content indeed: metaphysical pseudo-statements express the attitude of a person towards life. Metaphysics is an art like lyrical poetry. The metaphysician, instead of using the medium of art, works with the medium of the theoretical; he confuses art with science, attitude towards life with knowledge, and thus produces an unsatisfactory and inadequate work. "Metaphysicians are musicians without musical ability".

Congresses and publications

The Vienna Circle was very active in advertising their new philosophical ideas. Several congresses on epistemology and philosophy of science were organized, with the help of the Berlin Circle. There were some preparatory congresses: Prague (1929), Königsberg
Königsberg
Königsberg was the capital of East Prussia from the Late Middle Ages until 1945 as well as the northernmost and easternmost German city with 286,666 inhabitants . Due to the multicultural society in and around the city, there are several local names for it...

 (1930), Prague (1934) and then the first congress on scientific philosophy held in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

 (1935), followed by congresses in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...

 (1936), Paris (1937), Cambridge, UK (1938), Cambridge, Mass
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...

. (1939). The Königsberg congress (1930) was very important, for Kurt Gödel announced that he had proven the completeness
Gödel's completeness theorem
Gödel's completeness theorem is a fundamental theorem in mathematical logic that establishes a correspondence between semantic truth and syntactic provability in first-order logic. It was first proved by Kurt Gödel in 1929....

 of first-order logic
First-order logic
First-order logic is a formal logical system used in mathematics, philosophy, linguistics, and computer science. It goes by many names, including: first-order predicate calculus, the lower predicate calculus, quantification theory, and predicate logic...

 and the incompleteness of formal arithmetic
Arithmetic
Arithmetic or arithmetics is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple day-to-day counting to advanced science and business calculations. It involves the study of quantity, especially as the result of combining numbers...

. Another very interesting congress was the one held in Copenhagen (1936), which was dedicated to quantum physics and causality
Causality
Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....

.

Between 1928 and 1937, the Vienna Circle published ten books in a collection named Schriften zur wissenschaftlichen Weltauffassung (Monographs on the Scientific World-Conception), edited by Schlick and Frank. Karl Raimund Popper’s book Logik der Forschung was published in this collection. Seven works were published in another collection, called Einheitswissenschaft (Unified Science). In 1930 Rudolf Carnap and Hans Reichenbach
Hans Reichenbach
Hans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...

 undertook the editorship of the journal Erkenntnis, which was published between 1930 and 1940 (from 1939 the editors were Otto Neurath, Rudolf Carnap and Charles Morris).

The following is the list of works published in the two collections edited by the Vienna Circle.

Schriften zur wissenschaftlichen Weltauffassung (Monographs on the Scientific World-Conception), edited by Schlick and Frank:
  • Richard von Mises, Wahrscheinlichkeit, Statistik und Wahrheit, 1928 (Probability, Statistics, and Truth, New York : Macmillan company, 1939)
  • Rudolf Carnap, Abriss der Logistik, 1929
  • Moritz Schlick, Fragen der Ethik, 1930 (Problems of Ethics, New York : Prentice-Hall, 1939)
  • Otto Neurath, Empirische Soziologie, 1931
  • Philipp Frank, Das Kausalgesetz und seine Grenzen, 1932 (The Law of Causality and its Limits, Dordrecth ; Boston : Kluwer, 1997)
  • Otto Kant, Zur Biologie der Ethik, 1932
  • Rudolf Carnap, Logische Syntax der Sprache, 1934 (The Logical Syntax of Language, New York : Humanities, 1937)
  • Karl Raimund Popper, Logik der Forschung, 1934 (The Logic of Scientific Discovery, New York : Basic Books, 1959)
  • Josef Schächeter, Prolegomena zu einer kritischen Grammatik, 1935 (Prolegomena to a Critical Grammar, Dordrecth ; Boston : D. Reidel Pub. Co., 1973)
  • Victor Kraft, Die Grundlagen einer wissenschaftliche Wertlehre, 1937 (Foundations for a Scientific Analysis of Value, Dordrecth ; Boston : D. Reidel Pub. Co., 1981)


Einheitswissenschaft (Unified Science), edited by Carnap, Frank, Hahn, Neurath, Joergensen (after Hahn's death), Morris (from 1938):
  • Hans Hahn, Logik, Mathematik und Naturerkennen, 1933
  • Otto Neurath, Einheitswissenschaft und Psychologie, 1933
  • Rudolf Carnap, Die Aufgabe der Wissenschaftlogik, 1934
  • Philipp Frank, Das Ende der mechanistischen Physik, 1935
  • Otto Neurath, Was bedeutet rationale Wirtschaftsbetrachtung, 1935
  • Otto Neurath, E. Brunswik
    Egon Brunswik
    Egon Brunswik was a psychologist who made contributions to functionalism and the history of psychology.-Early life and career:...

    , C. Hull, G. Mannoury, J. Woodger, Zur Enzyklopädie der Einheitswissenschaft. Vorträge, 1938
  • Richard von Mises, Ernst Mach und die empiristische Wissenschaftauffassung, 1939


These works are translated in Unified Science: The Vienna Circle Monograph Series Originally Edited by Otto Neurath, Kluwer, 1987.

Monographs, arranged in chronological order, published in the International Encyclopedia of Unified Science:
  • Otto Neurath, Niels Bohr, John Dewey
    John Dewey
    John Dewey was an American philosopher, psychologist and educational reformer whose ideas have been influential in education and social reform. Dewey was an important early developer of the philosophy of pragmatism and one of the founders of functional psychology...

    , Bertrand Russell
    Bertrand Russell
    Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...

    , Rudolf Carnap, Charles Morris, Encyclopedia and unified science, 1938, vol.1 n.1
  • Charles Morris, Foundations of the theory of signs, 1938, vol.1 n.2
  • Victor Lenzen, Procedures of empirical sciences, 1938, vol.1 n.5
  • Rudolf Carnap, Foundations of logic and mathematics, 1939, vol.1 n.3
  • Leonard Bloomfield
    Leonard Bloomfield
    Leonard Bloomfield was an American linguist who led the development of structural linguistics in the United States during the 1930s and the 1940s. His influential textbook Language, published in 1933, presented a comprehensive description of American structural linguistics...

    , Linguistic aspects of science, 1939, vol.1 n.4
  • Ernest Nagel
    Ernest Nagel
    Ernest Nagel was a Czech-American philosopher of science. Along with Rudolf Carnap, Hans Reichenbach, and Carl Hempel, he is sometimes seen as one of the major figures of the logical positivist movement....

    , Principles of the theory of probability, 1939, vol.1 n.6
  • John Dewey
    John Dewey
    John Dewey was an American philosopher, psychologist and educational reformer whose ideas have been influential in education and social reform. Dewey was an important early developer of the philosophy of pragmatism and one of the founders of functional psychology...

    , Theory of valuation, 1939, vol.2 n.4
  • Giorgio de Santillana
    Giorgio de Santillana
    Giorgio Diaz de Santillana was an Italian-American philosopher of science and historian of science, and professor at MIT....

     and Edgar Zilsel
    Edgar Zilsel
    Edgar Zilsel was an Austrian historian and philosopher of science. He is considered to be among the modern "pioneers of the sociology of science".- Life :...

    , The development of rationalism and empiricism, 1941, vol.2 n.8
  • Otto Neurath, Foundations of social sciences, 1944, vol.2 n.1
  • Joseph Henri Woodger, The technique of theory construction, 1949, vol.2 n.5
  • Philipp Frank, Foundations of physics, 1946, vol.1 n.7
  • Erwin Frinlay-Freundlich, Cosmology, 1951, vol.1 n.8
  • Joergen Joergensen, The development of logical empiricism, 1951, vol.2 n.9
  • Egon Brunswik
    Egon Brunswik
    Egon Brunswik was a psychologist who made contributions to functionalism and the history of psychology.-Early life and career:...

    , The conceptual framework of psychology, 1952, vol.1 n.10
  • Carl Hempel, Fundamentals of concept formation in empirical science, 1952, vol.2 n.7
  • Felix Mainx, Foundations of biology, 1955, vol.1 n.9
  • Abraham Edel
    Abraham Edel
    Abraham Edel was a North American philosopher and ethicist. He was the younger brother of North American literary critic and biographer Leon Edel, the uncle of composer Joel Mandelbaum. He was married three times; the first two were fellow academics and co-authors.Born in Pittsburgh, Pennsylvania,...

    , Science and the structure of ethics, 1961, vol.2 n.3
  • Thomas Kuhn
    Thomas Kuhn
    Thomas Samuel Kuhn was an American historian and philosopher of science whose controversial 1962 book The Structure of Scientific Revolutions was deeply influential in both academic and popular circles, introducing the term "paradigm shift," which has since become an English-language staple.Kuhn...

    , The structure of scientific revolutions, 1962, vol.2 n.2
  • Gherard Tintner, Methodology of mathematical economics and econometrics, 1968, vol.2 n.6
  • Herbert Feigl and Charles Morris, Bibliography and index, 1969, vol.2 n.10

Quoted works

  • Foundations of the Unity of Sciences, vol. 1, Chicago : The University of Chicago Press, 1969
  • Uebel, Thomas, "On the Austrian Roots of Logical Empiricism" in Logical Empiricism - Historical and contemporary Perspectives, ed. Paolo Parrini, Wesley C. Salmon, Merrilee H. Salmon, Pittsburgh : University of Pittsburgh Press, 2003, pp. 76–93
  • Wissenschaftliche Weltauffassung. Der Wiener Kreis, 1929. English translation The Scientific Conception of the World. The Vienna Circle in Sarkar, Sahotra, ed., The Emergence of Logical Empiricism: from 1900 to the Vienna Circle, New York : Garland Publishing, 1996, pp. 321–340
  • Rudolf Carnap, "Überwindung der Metaphysik durch Logische Analyse der Sprache" in Erkenntnis, vol. 2, 1932 (English translation "The Elimination of Metaphysics Through Logical Analysis of Language" in Sarkar, Sahotra, ed., Logical empiricism at its peak: Schlick, Carnap, and Neurath, New York : Garland Pub., 1996, pp. 10–31)

Reception in the U.S.

The spread of logical positivism
Logical positivism
Logical positivism is a philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge—with a version of rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology.It may be considered as a type of analytic...

 in the USA occurred throughout the 1920s–1930s. In 1929 and in 1932 Schlick was a Visiting Professor at Stanford, while Feigl, who immigrated to the USA in 1930, became lecturer (1931) and professor (1933) at the University of Iowa. The definite diffusion of logical positivism in the U.S. was due to Carl Hempel, Hans Reichenbach, Rudolf Carnap, Philipp Frank and Herbert Feigl, who emigrated and taught in the U.S. 
Another link to the U.S. is Willard Van Orman Quine
Willard Van Orman Quine
Willard Van Orman Quine was an American philosopher and logician in the analytic tradition...

 who traveled in 1932–1933 as Sheldon Traveling Fellow to Vienna, Prague, and Warsaw
Warsaw
Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...

. Moreover, American semiotician and philosopher Charles W. Morris
Charles W. Morris
Charles W. Morris was an American semiotician and philosopher.-Background:A son of Charles William and Laura Morris, Charles William Morris was born on May 23, 1901...

 helped many German and Austrian philosophers emigrate to the United States including Rudolf Carnap in 1936.

Reception in the UK

Alfred Jules Ayer acquainted the British academia with the work of the Vienna Circle. Also Karl Popper
Karl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...

was important for the reception and critique of their work, even though he never participated in the meetings of the Vienna Circle.

External links

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