The Vienna Circle cannot be assigned
one single philosophy. First, there existed a plurality of philosophical positions within the Circle, and second, members often changed their views fundamentally in the course of time and in reaction to discussions in the Circle. It thus seems more convenient to speak of "the philosophies (in the plural) of the Vienna Circle". However, some central topics and debates can be identified.
The Manifesto (1929) This states the scientific world-conception of the Vienna Circle, which is characterized "essentially by two features. First it is
empiricist 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." 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 statements; 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 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. "Ordinary language for instance uses the same
part of speech, the substantive, for
things ('apple') as well as for
qualities ('hardness'), relations ('friendship'), and processes ('sleep'); therefore it misleads one into a thing-like conception of functional
concepts". 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 from given states of affair".
Synthetic knowledge a priori is rejected by the Vienna Circle. Mathematics, which at first sight seems an example of necessarily valid synthetic knowledge derived from pure
reason alone, has instead a
tautological 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 (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 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". 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, upbringing,
architecture, 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. 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,
Jørgen Jørgensen (after Hahn's death) and
Charles W. Morris (from 1938), whose aim was to present a unified vision of science. After the publication in
Europe of seven monographs from 1933 to 1939, the collection was dismissed, because of the problems arising from the
World War II. In 1938 a new series of publications started in the United States. It was the
International Encyclopedia of 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's well known work,
The Structure of Scientific Revolutions, was published in this Encyclopedia in 1962, as the number two in the second volume.
Critique 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, i.e., a set of meaningful words, and a
syntax, 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): • What
sentences is
S deducible from, and what sentences are deducible from
S? • Under what conditions is
S supposed to be true, and under what conditions false? • How is
S verified? • What is the meaning of
S? (Carnap, "The Elimination of Metaphysics Through Logical Analysis of Language" in Sarkar, Sahotra 1996, p. 12) An example offered by Carnap concerns the word '
arthropod'. 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 \exists \;), which occurs only in statements such as \exists \;xP(x), 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. In a formal language, "Nothing" only means \lnot \;\exists \;x, such as "there is nothing which is outside"—i.e., \lnot \;\exists \;xO(x), and thus "Nothing" never occurs as a noun or as a predicate, but as a quantifier. According to Carnap, although metaphysics has no theoretical content, it does have content: metaphysical pseudo-statements express the attitude of a person towards life, and this is the role of metaphysics. He compares it to an art like lyrical poetry; the metaphysician 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". ==Institute Vienna Circle / Vienna Circle Society ==