## 1. Biographical sketch



Otto Neurath was born on 10 December 1882 in Vienna. He was the son of
Gertrud Kaempffert and Wilhelm Neurath, a Hungarian Jewish political
economist and social reformer, and was born Roman Catholic. Initially
studying in Vienna philosophy, mathematics and physics and then
history, philosophy and economics (he formally enrolled for classes at
the University of Vienna only for two semesters in 1902-3), he
followed the social scientist Ferdinand Tonnies's advice to
move to Berlin, where he received a doctoral degree in history of
economics in 1906. He studied under Eduard Meyer and Gustav Schmoller
and he was awarded the degree for two studies of economic history of
antiquity, one on Cicero's *De Officiis* and the other
with an emphasis on the non-monetary economy of Egypt. In his
biographical precis at the end his doctoral dissertation on
Cicero, he mentioned having studied mathematics, natural science and
philosophy in Vienna with von Escherich, Haberda, Haffner, Hartl,
Jodl, Kohn, Kretschmer, von Lang, Lieben, Mertens, Much,
Mullner, Oberhummer, Penck, Schindler and von Schroeder, and that
in Berlin, he studied national economy, history and philosophy with
von Bortkiewicz, Breysig, Brunner, Eberstadt, Hintze, Jastrow, Landau,
Menzer, Meyer, Paulsen, Schmoller, Simmel, and Wagner. He also
acknowledged that he had studied the ideas of the logician Gregor
Itelson, Wilhelm Neurath's colleague and mathematician Oskar
Simony, and the social scientist Ferdinand Tonnies.



His first publications were in logic, a subject he had formally
learned at the University of Vienna from Laurenz Mullner and
possibly Friedrich Jodl, and in the history of political economy, on
which his father had also written. The papers on logic (see below)
examined different kinds of identities and the principle of duality
stimulated by Schroder; they included one paper co-authored with
his friend and second wife, Olga Hahn, sister of the mathematician
Hans Hahn. In the history of political economy, topics included the
history of money and economic organizations in antiquity, and his
publications included textbooks and readers either co-authored or
co-edited with his first wife Anna Schapire-Neurath. Not surprisingly,
his subsequent theorizing on the social sciences and his contributions
to debates in logical empiricism integrated both disciplines. With the
mathematician Hans Hahn and the physicist Philip Frank, around 1910
Neurath formed in Vienna a philosophical discussion group devoted to
the philosophical ideas about science of Vienna's
phenomenologist Ernst Mach and the French conventionalists Pierre
Duhem, Abel Rey and Henri Poincare. A great deal of
philosophical and scientific concerns and insight were already in
place in Neurath's thinking and projects. With a grant from the
Carnegie Endowment for International Peace, a subsequent study of the
Balkan wars before World War I led to his theory of war economy as a
natural (non-monetary) economy, or economy in kind.



In 1919 the short-lived Bavarian socialist government (November
1918-April 1919) appointed him head of the Central Planning Office.
The fall of the subsequent Bavarian Soviet Republic in May 1919 got
him expelled from his junior post teaching economic theory at
Heidelberg University, where he had received his *Habilitation*
in 1917. His program for full socialization was inspired by his
studies of war economics and based on his theory of natural economy
and a holistic requirement to bring different institutions and kinds
of knowledge together in order to understand, predict and control the
complex phenomena of the social world. From 1921 until 1934 Neurath
participated actively in the development of Vienna's socialist
politics, especially in housing and adult education (on his political
life, see Sandner 2014). He established the Social and Economic Museum
of Vienna, where he developed and applied the 'Vienna
method' of picture statistics and the ISOTYPE language
(International System of Typographic Picture Education) (see the
supplementary document on
 Visual Education).
 Like the thought of other Viennese philosophers such as Wittgenstein
and Popper, Neurath's philosophy was inextricably linked to
pedagogical theory, critique of language and, in Popper's case,
political thought. In 1928, with members of the Austrian Freethinkers
Association and the Vienna City Council and the scientifically-trained
members of the informal circle around the current holder of
Mach's University Chair, the philosopher Moritz Schlick
(1924-29), Neurath helped found the *Verein Ernst Mach*, the
Ernst Mach Association for the Promotion of Science Education. The
publication in 1929 of an intellectual manifesto gave way to the
formation of the Vienna Circle, whose narrower goal was the
articulation and promotion of a scientific world-conception and
logical empiricism (on the Viennese intellectual landscape, see
Stadler 2001).



Subsequently, when in 1934 the Austrian government allied itself with
the Nazi government in Germany, Neurath fled to the Netherlands. As a
result, his local, Viennese, socialist Enlightenment project turned
into an internationalist, intellectual and social-political project.
He created the International Foundation for Visual Education in The
Hague, with his assistants from Vienna, and spearheaded the
International Unity of Science movement. The latter, inspired by a
tradition culminating in the Enlightenment's French
Encyclopedists, launched the project of an Encyclopedia of Unified
Science. Together with the pictorial languages, the scientific
encyclopedia would promote scientific and social cooperation and
progress at an international level. After Austria became part of the
German Reich in 1938, even though living in the Netherlands, Neurath
was considered a German citizen and a 'half-Jew' and he
was not allowed to marry his 'Aryan' assistant Marie
Reidemeister--after his second wife, Olga, had died in 1937.
During this period, he travelled abroad, including the United States,
where logical empiricism had become entangled with the Cold War
political and intellectual debates and witch hunts (on the Cold War
phase, see Reich 2005). Carnap and Charles Morris at the University of
Chicago acted as his co-editors of the International Encyclopedia of
Unified Science. New York leftist intellectuals hosted him as an
intellectual and political ally. And his maternal first cousin
Waldemar Kaempffert, influential editor for *The New York
Times* and *Popular Science*, introduced him as an
international reformer and visionary, praising his science-oriented
intellectual, social and educational ideas, especially his
contribution to unity of science and visual language (see Reisch
2019). After the Nazi invasion of the Netherlands in 1940, Otto
Neurath and Marie Reidemeister fled to England, on the small
*Seaman's Hope*. After nine months in an internment camp
they resumed activities related to the Isotype language and the unity
of science. He died in Oxford on 22 December 1945 (on activities in
the camp see Henning 2019; on activities after see Korber 2019
and Tuboly 2019).


## 2. From economic theory to scientific epistemology



During the Vienna Circle years, Neurath introduced in the new context
views which he developed and generalized from his earlier social
theory, only now in terms of the debates on scientific epistemology
that came to characterize logical empiricism: (1) a notion of
theorizing in natural and social sciences, including history, based on
the exploration of combinatorial possibilities and models; (2) the
logical under-determination and conventional and pragmatic aspect of
decision-making in the methodology of evaluation and choice of data
and hypotheses; (3) the social, cooperative dimension of scientific
research ('the republic of scientists'); and, connectedly,
(4) an argument for a holistic approach to scientific knowledge in the
form of unified science as a tool for successful prediction and
engineering (mechanical, electrical and social) of events and their
evolution in a world understood as a complex of factors (Cat *et
al*. 1991 and 1996)--where an alternative model of
unification would replace the standard set by the reductive, precise
and abstract monetary units of the market model (Nemeth 1991).



This engineering value of unity applied equally to political
governance and scientific action, since both are collective and
pragmatic endeavors. According to Neurath, 'scientific theories
are sociological events' (Neurath 1932a/1983, 88), and, since
'our thinking is a tool', in this case the 'modern
scientific world-conception' aims to 'create a unified
science that can successfully serve all transforming activity'
(Neurath 1930/1983, 42). In both cases, Neurath noted, 'common
planned action is possible only if the participants make common
predictions' and group predictions yield more reliable results;
therefore, he concluded, 'common action presses us toward
unified science' (Neurath 1931/1973, 407). Indeed, all along,
for Neurath scientific attitude and solidarity (and socialism) go
together (Neurath 1928/1973, 252).



During the 1910s Neurath engaged the intellectual issues of holism and
conventionalism raised both by the models of economies in kind
--the Balkan war economies and socialization of the Bavarian
economy--and by Duhem's philosophy of scientific testing.
Not surprisingly, his intellectual attitude led him to the recurrent
dismissal of the myth of the fundamental epistemological and political
value of isolated statements (hypotheses) and isolated individuals
(citizens, scholars). The problem of unity of the sciences would
become another problem of coordination and cooperation, social and
intellectual (see above), of scholars and statements, and Neurath
presented it in just those terms (Neurath 1936/1983).



Neurath developed and generalized his early practical, theoretical and
meta-theoretical concerns about social theory (with his talk of a
'universal science' in 1910, a 'unified construction
of economic science' in 1917 and a 'unified program'
for socialization in 1919) as a philosophy of the human sciences.
These included psychology and sociology, which he treated in contrast
with the natural sciences. His study of the foundations of the social
sciences extended to import normative constraints set by logical
empiricism, e.g., the emphasis on foundations and the logical and
empiricist considerations with respect to physicalism. This
contribution determined his qualifications to ideals of unity of the
sciences, especially involving the relation between the natural and
the human sciences, and to ideals of shared scientific
methodology.



The new framework for philosophy, and meta-theory, was characterized
by an anti-metaphysical attitude towards linguistic and otherwise
formal, rather than material, entities. For Neurath, social theory
points not only to the contingent historical and social nature of
language; it also points to a more naturalistic attitude towards
language--and knowledge--in connection with its social roots
and uses. As a result, his early considerations of social theory and
values yielded a model of language of theory and observation that were
meant to do justice to the social and voluntaristic dimensions of
unity, rationality, and objectivity in the language and methodology of
the sciences. Next, in the rest of this section, I provide details of
the connection I have indicated. 



In the early 1930s Neurath would point to weakness and incompleteness
of the logical and linguistic relations between different kinds of
scientific statements--mainly due to the unavoidable presence of
vague cluster-concepts, or congestions (*Ballungen*). They
consisted in linguistic manifestation of the ineliminable social,
everyday, non-theoretical vague elements of language and of the
intrinsic complexity of the world discussed in the German metaphysical
literature and the later socialist debates (Cat 1995 and Cartwright
*et al*. 1996). Since then his notion of unity is phrased in
terms of an anti-reductionistic and
anti-systematic--anti-axiomatic--'encyclopedia
model', by establishing cross-connections among disciplines, as
in a Crusonian archipelago: a 'great, rather badly coordinated
mass of statements' in which at best 'systems develop like
little islands, which we must try to enlarge' (Neurath
1936/1983, 153).



The connection between the arguments and positions in 1930s scientific
epistemology or philosophy of science and the arguments in the debates
in the history of economics points to a kind of unity and continuity
in Neurath's thinking in which specific claims in epistemology
and social thought are historically as well as conceptually connected.
This unity is moreover an instance of Neurath's persistent
views: his pragmatic and conventionalist epistemology and his view of
the unity of science.



The historical and conceptual link is suggested by two elements that
appear in Neurath's arguments. One is the notion of control, the
other is the reference to the scenario illustrated by the fiction of
Robinson Crusoe. They are both a common feature of discussions of
central planning. In Neurath's writings on that subject they
appear together at least once, in 1935 in his essay 'What is
Meant by a Rational Economic Theory?' There, Neurath protests
that



> 
> 
> 'quite a few political economists advocate the thesis that a
> Robinson Crusoe--or what amounts to the same thing, a controlled
> economy--calculates in terms of profits and losses.'
> (Neurath 1935/1987, 95)
> 
> 
> 



The two references appear also in the formulations of his private
language argument, this time with epistemological meaning. A reference
to controlling and an indirect mention of Crusoe appear in 1931 in his
essay 'Physicalism' and an explicit reference to Crusoe
appears in 1932 in 'On Protocol Statements'. Thus in
'Physicalism' Neurath put the argument as follows:



> 
> 
> Carnap...distinguished two languages: a
> 'monologizing' one (phenomenalist) and an
> 'intersubjective' (physicalist) one. (...) only one
> language comes into question from the start, and that is the
> physicalist. One can learn the physicalist language from earliest
> childhood. If someone makes predictions and wants to check them
> himself, he must count on changes in the system of his senses, he must
> use clocks and rulers, in short, the person supposedly in isolation
> already makes use of the 'intersensual' and
> 'intersubjective' language. The forecaster of yesterday
> and the controller of today are, so to speak, two persons. (Neurath
> 1931/1983, 54-55)
> 
> 
> 



In 'On Protocol Statements' Neurath refers to Robinson
Crusoe explicitly:



> 
> 
> The universal jargon...is the same for the child and for the
> adult. It is the same for a Robinson Crusoe as for a human society. If
> Robinson wants to join what is in a protocol of yesterday with what is
> in his protocol today, that is, if he wants to make use of language at
> all, he must make use of the 'intersubjective' language.
> The Robinson of yesterday and the Robinson of today stand precisely in
> the same relation in which Robinson stands to Friday...In other
> words, every language as such is intersubjective. (Neurath 1932b/1983,
> 96)
> 
> 
> 



Objectivity features prominently in the private language argument.
Both Neurath's argument and Wittgenstein's earlier one are
laid out for the case of an individual epistemic agent understanding
himself before he needs to understand others (Uebel 1995b). For both,
the constancy and consistency of language use is paramount. It can
only be ensured by an intersubjective, that is, objective and social,
language, namely the language of physicalism, about
'spatio-temporal structures'. For Wittgenstein, especially
in the *Philosophical Investigations*, the social dimension of
language is a key element of its extrinsic character and therefore its
proper justification, the normative condition of possibility and
intelligibility of success, and likewise for the more general case of
rule-following. The scope of Neurath's argument is more
particularly directed to the case of scientific language in the
scientific community.



The notion of private language argument is typically associated with
the later argument by Wittgenstein in *Philosophical
Investigations* to the effect that a private language is logically
impossible for an individual to use consistently and for others to
understand. By private language, Wittgenstein means a language with
words whose meaning is essentially constituted by and for the inner
experience or individual consciousness of a subject. In a previous
version from 1929 (see the Bergen electronic edition), Wittgenstein
refers to the primacy of our public everyday language about physical
things over a language of immediate sensations. In the 1951 version
(2009, 203, 242ff) such language is impossible to coherently make
sense of, the language is being shown to be dependent on the public
social institutions of language-games and their rules as embedded in
actual forms of life. A private language would be a language which
could be generated wholly through individual acts of unsharable
self-consciousness and understood, in principle, only by that
individual speaker, by means of his or her self-consciousness. This is
an incoherent notion. 



To follow a rule privately means to assume that thinking that one is
following a rule is the same as following it (*Philosophical
Investigations*, art. 202). But this assumption is based on a
subjective internal notion of justification, dependent on intrinsic
individual consciousness. And this is incorrect. For according to
Wittgenstein 'justification consists in appealing to something
independent' (*ibid*., art. 265). The independence is
provided by a notion of language use and rule following with
reference, actual or potential, to membership in a wider external
community and to intersubjective, that is, public and social,
interaction.



For Wittgenstein as well the external, pragmatic and independent
notion of calculation and rule following applies to the circulation of
money as economic practice. In Wittgenstein's own words:



> 
> 
> Why can't the right hand give my left hand money? My right hand
> can put it into my left hand. My right hand can write a deed of gift
> and my left hand a receipt. But the further practical consequences
> would not be those of a gift. When the left hand has taken money from
> the right, etc., we shall ask, "Well, what of it?"
> (*ibid*., art. 268)
> 
> 
> 



This intersubjective or objective constraint provides a normative,
even if conventional, distinction between consistent and inconsistent
language use, or between correct and incorrect rule following. Kripke
and David Bloor correctly point out that this condition is not
incompatible with Robinson Crusoe's physical isolation (Kripke
1989, 112, n. 89; Bloor 1997). Now we can see the point of
Kripke's analogy between the impossibility of a private language
and the impossibility of central planning. If, as in Mises's
argument, an economic agent has no extrinsic range of intersubjective
and commensurable values--that is, the numerical market prices
which are set independently by others--, then he has no rational
and objective justification for choosing between alternative courses
of action. Here exact numerical commensurability and explicit
calculation rules are the basis for both objectivity and rationality.
In contrast with Kripke's analogy there is a strong opposing
analogy between Neurath's argument against private language and
his defense of central planning. The analogy, as explained in
connection with Neurath's position towards Mises, above, reveals
a common set of values that are coherent yet different from the ones
involved in Mises's argument.



The issue of the connection between social models of society and
scientific methodology might have been encouraged by the social and
political turmoils of the first half of the twentieth century.
Neurath's case was not unique. The issue persists in the works
of Neurath's contemporaries, the philosophers of science Michael
Polanyi (1958) and Karl Popper (1950, 1957). Their epistemology of
science is also radically social and linked to political and economic
thought. A recurring thought experiment that provides guidance through
these discussions is the story of Robinson Crusoe.


## 3. Neurath's place in logical empiricism: physicalism, anti-foundationalism, holism, naturalism, externalism, pragmatism


### 3.1 On Language



Neurath's later views on the language and method of science
expressed his simultaneous response to problems in the social sciences
and to philosophical issues addressed by the Vienna Circle between
1928 and 1934 and by Karl Popper. A primary aim of the Vienna Circle
was to account for the objectivity and intelligibility of scientific
method and concepts. Their philosophical approach was to adopt what
the Circle member Gustav Bergmann called the linguistic turn, namely,
to investigate the formal or structural, logical and linguistic
framework of scientific knowledge. The formal approach encompassed
logicism and logical analysis as views about the formation and
justification of theoretical statements. The problem of empiricism
became then the problem of coordination between the formal theoretical
structures and the records of observations in such a way that it also
offered an explication of how scientific knowledge can be formally
constructed (especially logic and mathematics), empirically grounded
(except logic and mathematics), rational and objective.



Besides his own early interest in logic and classical and ancient
languages, the value of attention to language was familiar to Neurath
from the Austrian fin-de-siecle culture of critique of language
(Janik and Toulmin 1973), his interest (and his first wife's) in
literature, especially in Goethe (Zemplen 2006, see above), the
internationalist and utopianists efforts at introducing new universal
languages such as Volapuk and Esperanto, the emphasis on signs
and universal languages - to be known as pasigraphy - in
the scholastic and rationalist philosophical traditions, in the
traditions of empirical taxonomies and in the interest in universal
language as instrument of knowledge and social order in the
Enlightenment, a semiotic tradition in scientific epistemology
including Helmholtz, Mach, Duhem and Peirce (Cat 2019) and the
sociologist Ferdinand Tonnies's formal approach to
sociology and social signs (Tonnies 1899-1900 and
Cartwright *et al*. 1996, 121-24). The significance of
the internationalist and philosophical projects of pasigraphy were
acknowledged also by Carnap. More "scientific" sources
were recent technical developments in logic, philosophy of science and
the foundation of mathematics often claiming Leibniz as a precursor
(Leibniz's logic and project of a universal characteristic had
become widely recognized by the late nineteenth century (Peckhaus
2012)). Leading figures in such developments were Frege, Hilbert,
Whitehead, Russell and Wittgenstein.



David Hilbert placed the axiomatic tradition in mathematics on a
formalist footing by eliminating the requirement of a fixed meaning
for primitive terms such as 'points' and
'lines' except holistically and implicitly, in the set of
axioms or definitions in which they appear. Hilbert extended the
application of his program of axiomatics from geometry and arithmetic
to physics. Gottlob Frege, followed by A.N. Whitehead and Bertrand
Russell, sought to place mathematics, or at least arithmetic, on firm
and rational principles of logic, which now included a theory of
relations and was to provide a comprehensive and unifying foundation.
The reductionist ideal was fatally criticized by Kurt Godel.
Russell, having replaced idealist monism with perceptual atomism, next
put the new logical framework to epistemological use in the scientific
program of logical construction of objects of experience and thought.
His student Wittgenstein, in turn, introduced a linguistic philosophy
that limited the world to the scope of the application of an ideal
symbolic languages, or calculus. As a result, the sole task of
philosophy was, according to Wittgenstein, the critique of language in
the form of an activity of clarification, without yielding a
distinctive philosophical body of knowledge or set of
propositions.



Looking to the rationalist traditions of Descartes and Leibniz, Jean
van Heijenoort and Jaakko Hintikka have distinguished between two views
of language that are relevant to the new linguistic turn (Mormann
1999): language as calculus (LC) and language as universal medium
(LUM). The LC tradition, illustrated by Tarski's views, aligned
itself with the Cartesian ideal of a transparent language, with clear
and distinctive meaning and explicit, mechanical combination and
rule-following that extended to its use in reasoning. There are many
possible constructed languages and each is an interpreted calculus
with different possible semantics. The LUM tradition adopted the idea
of a single actual or ideal language and one semantic or
interpretation, to be elucidated, with no possibility of representing
its relation to the world from outside. Views by Frege, who pointed to
Leibniz on language and reasoning, and Wittgenstein illustrate this
tradition, which in turn accommodates two versions, a Cartesian one
(Frege and Russell) and a non-Cartesian one (Wittgenstein).
Carnap's conversion to semantics in the early 1930s took him to
the LC Cartesian tradition seeking a universal language of rational
reconstruction he had previously recognized in the language of
physics. Neurath, by contrast, modeled his unification of the sciences
in the LUM tradition, on a universal mixed language he called a
universal jargon, with descriptions of spatio-temporal arrangements
and connections he called physicalism, historically contingent use of
vague and ordinary terms (see below). In this context Neurath adopted
a militant syntacticism that opposed Carnap's defense of
semantics as metaphysical (Anderson 2019) and engaged in heated
terminological disputes that ignored Carnap's commitment to
ontological neutrality (Carus 2019).



The Circle's projects shared the aforementioned focus on
language and experience. The 'linguistic turn', as it is
known, was adopted as a philosophical tool in order to explicate the
rationality and the objectivity--that is,
inter-subjectivity--and communicability of thought. Lacking the
transcendental dimension of Kant's metaphysical apparatus,
attention to language extended to non-scientific cases such as
'ordinary language philosophy' in Oxford. In the context
of logical empiricism, the formal dimension of knowledge was thought
to be manifest particularly in the exactness of scientific statements.
For Schlick, knowledge proper, whether of experience or transcendent
reality, was such only by virtue of form or
structure--'only structure is knowable'. For Carnap,
in addition, the formal dimension possessed distinct methodological
values: it served the purpose of logical analysis and rational
reconstruction of knowledge and helped expose and circumvent
'pseudo-philosophical' problems around metaphysical
questions about reality (his objections to Heidegger appealed to
failures of proper logical formulation and not just empirical
verification). In 1934 he proposed as the task of philosophy the
metalinguistic analysis of logical and linguistic features of
scientific method and knowledge (the 'thesis of
metalogic'). For Neurath, this approach helped purge philosophy
of deleterious metaphysical nonsense and dogmatism, and acknowledged
the radically social nature of language and science.


### 3.2 From language to logic and its broader relevance



Neurath enjoyed early attention and recognition for his logic work
also reflected in early reminiscences of figures such as Popper and
the mathematician Karl Menger. Perhaps now surprisingly, mentions of
Neurath's and Olga Hahn's papers, including a joint one,
were included by the logicians C.I. Lewis, in 1918, and Alonzo Church,
in 1936, in their canonical bibliographies on symbolic logic (Lewis
1918 and Church 1936).Neurath kept algebraic logic and its symbolic
dimension as a recurrent standard and resource, first in his earlier
work on the social sciences and pictorial language, and subsequently
in related contributions to the discussions that informed logical
empiricism (for a detailed discussion, see Cat 2019). The relevance to
his interest in political economy concerned the rational and
scientific character of economic theory, the possibility of
qualitative measurement and the limits of quantification and univocal
determination, and, as a result, also of decision-making and
prediction. Contrary to predominant accounts using attention to formal
languages and logic to pit against each other wings and members of the
logical empiricist movement, the symbolic logical standard may be
considered a unifying framework that distinguished Neurath with it and
not from it. It a unifying reference he willingly adopted when he
coined the term 'logical empiricism' (Mormann 1999 and Cat
2019). The differentiating role in Neurath's positions can be
identified in his shifting and progressively skeptical and critical
attention to the standard and the his attention to algebraic logic
rather than the newer logic familiar to Carnap at work in Frege and
Russell's logicism. 



Leibniz had given modern philosophical currency to the pasigraphic
notion of a universal characteristic or Alphabet of Thought that both
expressed reality and operated as a logical calculus of reasoning. In
the Cartesian spirit, language and reason were inseparable instruments
of knowledge and mathematical, logical and philosophical methods were
identical. In the late nineteenth century and the early twentieth,
Leibniz's project became a common reference in works in
mathematical logic. Not only did Frege see his philosophy of language
and mathematical logic within this tradition, as did Peano; Russell
penned a landmark study and logicians such as Ernst Schroder and
Louis Couturat associated it distinctively with the development of
algebraic logic since Boole, especially with Schroder's own
(Peckhaus 2012 and Cat 2019). In this tradition the logician and
political economist Stanley Jevons recovered the combinatorial element
in Leibniz's method.



Neurath's logic writings focused on Schroder's
axiomatic systematization of algebraic logic, mainly in the monumental
*Vorlesungen uber die Algebra der Logik (exakte Logik)*
(1890-95). There and in earlier writings, Schroder geve a
fundamental role to the relation of subsumption and a law of duality.
Subsumption was a part-whole relation defined over domains of objects
and it was expressed with a symbol, EUR, which denoted both
inclusion and equality (with a corresponding algebraic expression,
following Hermann Grassmann, in terms of partial inequality [?]) so
that if a EUR b and b EUR a, then a=b. The law of duality
established a systematic correspondence between theorems in terms of 1
and operation + and theorems in terms of 0 and operation x. The
methodological role of duality organizing and deriving theorems was
expressed in a dual-column presentation. The latter was adopted in a
more general spirit by Neurath and subsequently also by Carnap in his
presentation of the systematic correspondence between formal and
material modes (see Cat 2019).



By the late nineteenth century, in Austria as well as Germany,
algebraic logic had found a central place in the raging controversies
over the relationship between science and philosophy and, in
particular, between mathematics, logic and psychology. Neurath and
Olga Hahn became acquainted with algebraic logic at the University of
Vienna sometime around 1902-3, but it wasn't until 1909, after
Olga had become blind and Neurath was back in Vienna providing
assistance, that she started working on algebraic logic for her
doctorate in philosophy. In 1909 Wilhelm Wundt had published a third
volume of his *Logik*; in 1909, part 1 of Schroder's
synthetic treatment, *Abriss der Algebra der Logik* appeared
posthumously; and in 1910 part 2 was published, as well as Olha
Hahn's thesis director Adolph Stohr's *Lehrbuch
der Logik in Psychologisiender Darstellung* (see Cat 2019 for
details and references).



Neurath published four papers, one with Hahn (Neurath 1909a, 1909b and
1910a, and Hahn and Neurath 1909). Hahn separately published two
others, the second submitted as her doctoral thesis (Hahn 1909 and
1910).In the joint paper, Hahn and Neurath proved the dependence of
the principle of duality on the algebraic complementarity of domains
of objects to which symbols and operations are applied.
Neurath's own three papers addressed mainly
Schroder's symbolic relation of equality and the property
of commutativity of operations sum and product over symbols standing
for classes of objects. It included a classification of applications
of symbolic equalities and a discussion of univocality, or
determinateness, noting its fundamental role in Schroder's
system and following the positivist philosopher Joseph
Petzoldt's discussion of causality, determinism and the
interpretation of equality signs in mathematical equations. Neurath
distinguished between (quantitative) equality, definitional equality
and symbolic equality (Neurath 1910a). with the notational dimension
of the latter equality and the lack of cognitive significance Neurath
associated with differences in symbolic expression, his linguistic
perspective differed markedly from Frege's. Besides attention to
the relativity of notational convention, the significance of the
commutation law was, according to Neurath, relative to the axiomatic
system (echoing Poincare's conventionalist treatment of
geometry).



The issues Neurath addressed resonated with ongoing philosophical
debates over equality in mathematical equations, identity,
definitions, analyticity, axiomatization and conceptual analysis. In
addition to the theme of univocality, a second enduring theme that
appeared first in the logic writings was the semiotic, or notational,
and typographic approach to the conventional introduction and
organization of symbols, especially the linear, one-dimensional
character of typographic arrangements. The ideas and perspectives he
developed in the logic writings played a role in his subsequent
discussions of economics, decision-making, scientific theorizing
through combinatorial classifications and the epistemological and
methodological contributions to logical empiricism.



For instance, he cast the scientific character of political economy in
terms of a modal criterion according to which true science consists in
systematically examining all possible cases and historical methods
provided a laboratory for the exploration of such possibilities
(Neurath 1910b, 277). Moreover, this scientific character was also
expressed by the aims of systematicity, rationality and exactness, but
not quantitative measurability. Exact relations, he declared, were
possible between non-measurable quantities. Such qualitative
measurements involved logical (and topological) relations such as the
ordinal standard based on the algebraic relation of inequality
(ibid.). Poincare had introduced the same ordering relations
between 'non-measurable quantities' such as Gustav
Fechner's psycho-physical sensations to draw attention to the
gap between the phenomenological and mathematical ideas of the spatial
continuum (Poincare 1906, 28; Turk 2018). Neurath, following
also Poincare and Fechner by analogy with the case of
subjective utility measures, applied this approach to study of the
limitations in the method of determination of decisions over
collective distributions of satisfaction based on aggregations of
individual attributions (Uebel 2004, 37 and Turk 2018, 136).
Comparisons between individual pleasure attributions for the same
individual or the same object did not determine the comparative order
between aggregations: for individuals a and b and objects a and b, we
may have determined (Aa)>(Ab) and (Ba)>(Bb), and yet,
(Aa)+(Bb)?(Ab)+(Ba) (Neurath 1912/1973, 115). Methodological and
epistemological consequences for the formulation of logical empiricist
included acknowledging the technical formal contributions to modern
science protecting it from metaphysics and meaninglessness, a role
captured by the term 'logical empiricism,' while
acknowledging only a limited value for the empirical application
formal logical standard (with the risk of pseudorationalism),
defending syntacticism about language and unification only through a
universal mixed jargon and local logical systematization.


### 3.3 Scientific and linguistic epistemology



Kant had delivered the latest grand attempt to address the relation
between science and philosophy, by taking the former to provide
objective empirical knowledge (exact, universal and necessary) and
giving to the latter knowledge the task of laying out the conditions
of intelligibility and possibility of such knowledge as the sole,
critical scope of metaphysics and legitimate exercise of reason.
Kant's standard of *a priori*, an expression of
rationality, was challenged and relativized by the Frege, Russell and
Whitehead's notions of mathematical numbers grounded in logic
and by the new notions of space and time in Einstein's
relativity theories. Neither mathematics was synthetic, nor physics
seemed a priori; and the synthetic *a priori* was dismissed as
empty of content in the new scientific landscape.



With the scientific world-conception, logical empiricists followed in
the footsteps and Helmholtz and Mach and considered a new post-Kantian
problematic: investigating the possibility of objective empirical
knowledge with a role for intellectual construction without
universality or necessity, neither Kantian apriorism nor radical
positivism. Logic, with scientific status linked to technical
symbolism and the possibility of mathematics, was the sole last refuge
for philosophy. The new problematic suggested a demarcation project
with two inseparable tasks that were both descriptive and normative: a
positive, unifying task to establish and promote the marks of
scientific knowledge and the negative task to distinguish it from
philosophy.



The *a priori* kind of knowledge claims expressed in exact
theory was circumscribed to the analytic, voided of universality and
necessity and deflated by Schlick and Reichenbach to the character of
definitions and conventions (following Poincare). The synthetic
kind of knowledge claim was exclusively *a posteriori*,
grounded in experience. The dominating, and later popularized,
position was that revisable theoretical scientific statements should
stand in appropriate logical relations to unrevisable statements about
elementary observations (data), called 'control sentences'
or 'protocol sentences'. Such relations would provide
theoretical terms with cognitive meaning or sense, and theoretical
statements with verification. The form, role and status of protocol
statements thus became the topic of an important philosophical debate
in the early 1930s involving logical-empiricist philosophers such as
Carnap, Moritz Schlick, Edgar Zilsel and Otto Neurath, and others such
as Karl Popper. At stake in the debate was precisely the very
articulation of a philosophy of scientific knowledge, hence its
importance and also the diversity of positions that animated it.



The philosophical discussion that developed around the members of the
Vienna Circle was associated with the formulation of logical
empiricism and the banner of 'unity of science against
metaphysics', but it cannot be adequately understood without
taking into account the diversity of evolving projects it
accommodated. Carnap (much influenced by the neo-Kantian tradition,
Einstein's theories of relativity, Husserl's
phenomenology, Frege's logic and, i.e., Hilbertian axiomatic
approach to mathematics as well as Russell's own logicism and
his philosophical project of logical constructions) was concerned with
the conditions of the possibility of objective knowledge, which he
considered especially manifest in the formal exactness of scientific
claims (Carnap 1928). Schlick (inspired by turn-of-the-century French
conventionalists such as Rey, Duhem and Poincare,
Wittgenstein's philosophy of representation of facts, as well as
Einstein's relativity theories and Hilbert's implicit
definitions and axiomatic approach to mathematics) was interested in
the meaning of terms in which actual scientific knowledge of reality
is expressed, as well as its foundation on true and certain beliefs
about reality (Schlick 1918, 1934). Neurath (influenced by Mach,
varieties of French conventionalism, especially Duhem's, and
Marxism) sought to explore the empirical and historical conditions of
scientific practice in both the natural and social sciences (Neurath
1931/1973, 1932a/1983). Outside the Vienna Circle, Popper (influenced
by Hume, Kant and Austrian child psychology) was interested in
addressing the logical and normative issues of justification and
demarcation of objective and empirical scientific knowledge, without
relying on descriptive discussions of the psychology of subjective
experience and meaning (Popper 1935/1951). 



The linguistic turn framed the examination of the controversial role
of experience. In that respect the discussions of protocol sentences,
the so-called protocol sentence debate, addressed their linguistic
characteristics and their epistemological status (Uebel 1992). It was
another dimension of their examination of both the source of human
knowledge and the rejection of metaphysics as nonsense--often
dangerous nonsense (Carnap, Hahn and Neurath 1929/1973, and Stadler
2007).



In his classic work *Der Logische Aufbau der Welt* (1928)
(known as the *Aufbau* and translated as *The Logical
Structure of the World*), Carnap investigated the logical
'construction' of objects of inter-subjective knowledge
out of the simplest starting point or basic types of fundamental
entities (Russell had urged in his late solution to the problem of the
external world to substitute logical constructions for inferred
entities). He introduced several possible domains of objects, one of
which being the psychological objects of private sense
experience--analysed as 'elementary experiences'.
These provided the simplest but also the 'natural starting point
in the epistemic order of objects'. This specific construction
captures the fact that knowledge is someone's private knowledge,
while it raises Carnap's (and Kant's) main problem,
namely, how then objective knowledge is possible. In the
*Aufbau* and especially in *Pseudoproblems in
Philosophy*, also here the inclusion of terms and statements in
the system of science by this method was intended to exclude all
nonsensical speculative statements. It provided a verification
criterion not only of testing but also of cognitive significance, or
meaning. Carnap stated in that vein that 'science is a system of
statements based on direct experience' (Carnap 1932/1934).



In spite of the range of alternatives considered, the
*Aufbau*'s main focus on an empiricist, or
phenomenological, model of knowledge in terms of the immediate
experiential basis was quickly understood by fellow members of the
Vienna Circle as manifesting three philosophical positions:
*reductionism*, *atomism* and *foundationalism*.
*Reductionism* took one set of terms to be fundamental or
primitive; the rest would be logically connected to them. The
objectivity, rationality and empirical content and justification of
scientific knowledge depended on the resulting vertical integration.
*Atomism*, especially in Neurath's reading, was manifest
semantically and syntactically: semantically, in the analyzability of
a term; syntactically or structurally, in the elementary structure of
protocols in terms of a single experiential term--'red
circle here now'--; it also appeared in the possibility of
an individual testing relation of a theoretical statement to one of
more experiential statements. Note that this version of atomism
differs from the atomistic positivism about the form of elementary
experience that Carnap attributed to Mach, in contrast with his own,
scientifically updated and preferred *Gestalt*-doctrine of a
unified field of experience at a given time. The 'atomic'
concepts of the experiential basis are the result of a
'quasi-analysis'.



*Foundationalism*, in the Cartesian tradition of secure basis,
took the beliefs in these terms held by the subject to be infallible,
or not requiring verification, as well as the sole empirical source of
epistemic warrant--or credibility--for all other beliefs.
Descartes's foundationalism is based on *a priori*
knowledge; Carnap's presentation of the empirical basis
instantiates a more modest version. Still a controversial issue among
Carnap scholars, Carnap's kind of foundationalism would be
characterized within one structure as a relation to its basis rather
than foundationalism, as in Hume or Descartes, regarding one
privileged basis over others. In 1932 Carnap acknowledged that he had
adopted a 'refined form of absolutism of the
*ur*-sentence ("elementary sentence", "atomic
sentence")' (1932/1987, 469).



Neurath first confronted Carnap on yet another alleged feature of his
system, namely, subjectivism. He immediately rejected Carnap's
proposals on the grounds that if the language and the system of
statements that constitute scientific knowledge are intersubjective,
then phenomenalist talk of immediate subjective, private experiences
should have no place. More generally, Neurath offered a private
language argument to the effect that languages are necessarily
intersubjective. In order to use experience reports to test and verify
even one individual's own beliefs over time, private
instantaneous statements of the form 'red here now' will
not do. To replace Carnap's phenomenalist language Neurath
introduced in 1931 the language of physicalism (Neurath 1931/1983 and
1932a/1983). This is the controversial *Thesis of Physicalism*:
the unity, intelligibility and objectivity of science rests on
statements in a language of public things, events and processes in
space and time --including behavior and physiological events,
hence not necessarily in the technical terms of physical theory. While
inspired by materialism, for Neurath this was a methodological and
linguistic rule, and not an ontological thesis. (As is the case in
Carnap's methodological solipsism, given Neurath's
anti-metaphysical attitude it would not have been meant as an
expression of an objectivist metaphysics in the form of either
materialism or social idealism). That physicalism was to avoid
metaphysical connotations can be seen further in that, in the spirit
of Carnap's *Thesis of Metalogic*, its linguistic nature
was also central to its applications:



> 
> 
> statements are compared with statements, certainly not with some
> "reality", nor with "things", as the Vienna
> Circle also thought up until now. (Neurath 1931/1983, 53)
> 
> 
> 



Following Neurath, Carnap explicitly opposed to the language of
experience a narrower conception of intersubjective physicalist
language which was to be found in the exact quantitative determination
of physics-language realized in the readings of measurement
instruments. Remember that for Carnap only the structural or formal
features, in this case, of exact mathematical relations (manifested in
the topological and metric characteristics of scales), can guarantee
objectivity. Now the unity, objectivity and cognitive significance of
science rested on the universal possibility of the translation of any
scientific statement into physical language--which in the long
run might lead to the reduction of all scientific knowledge to the
laws and concepts of physics.



Neurath responded with a new doctrine of protocol statements that
considered their distinctive linguistic form, contents and
methodological status (Neurath 1932b/1983). This doctrine was meant to
explicate the idea of scientific evidence in the framework of
empiricism, and it did so by specifying conditions of acceptance of a
statement as empirical scientific evidence. It was meant also to
circumvent the pitfalls of the alleged subjectivism, atomism,
reductionism and foundationalism attributed to Carnap's earlier
discussion of the experiential constitution, or construction system of
concepts and knowledge. Neurath's informal but paradigmatic
example of a protocol was:



> 
> 
> Otto's protocol at 3:17 o'clock: [Otto's
> speech-thinking at 3:16 was: (at 3:15 o'clock there was a table
> in the room perceived by Otto)].
> 
> 
> 



Far from Carnap's atomic sort of protocol statements,
Neurath's model manifested a distinctive complexity of terms and
structure ("aggregations"). The protocol contains a
factual physicalist core in terms about the table and its location. It
also contains the experiential term that provides the linguistic
recording of the empirical character of protocols, that is, their
experiential origin. Neurath was mindful to caution here that
perception terms only admitted physicalistic meaning in terms, for
instance, of physiological mechanisms of perception. It also contains
the declarative level, marked with 'Otto says', which
distinguishes the protocol as a linguistic statement. Neurath
insisted, again, that the statement had a dual nature, linguistic
(propositional and communicative) and physicalist in the form of a
physical and physiological process. Finally, the other distinctive
elements were the name of the protocolist and the times and locations
of the experience and the reports, which provided an intersubjective ,
physicalist, public alternative to Carnap's subjective
'*I* see a red circle *here* *now*'.
(Note, however, that for Carnap, the idea of self itself is a
constituted concept.)



The general attention to language turned the project of logical
empiricism into the problem of the acceptable universal language.
Science must be characterized by its proper scientific language.
Neurath's plan was for a unified science against metaphysics,
and this involved a plan to police the proper unifying,
metaphysics-free language. The negative track of the plan was
effectively carried out by the development and adoption of a list of
'dangerous terms', which he sometimes referred to,
semi-jokingly, as an *index verborum prohibitorum*: a list of
forbidden terms such as 'I', 'ego',
'substance', etc. (Neurath 1933, Neurath 1940/1984, 217).
The positive track was the adoption of the universal language of
physicalism: '*metaphysical terms
divide*--*scientific terms unite*' (1935, 23,
orig. ital.).



Unlike Carnap's ideal of basic statement, whether protocol or
physicalist, Neurath's protocols were not 'clean',
precise or pure in their terms. For Neurath physicalist language, and
hence science in turn, is inseparable from ordinary language of any
time and place. In particular, it is muddled with imprecise,
unanalyzed, cluster-like terms (*Ballungen*) that appear
especially in the protocols: the name of the protocolist,
'seeing', 'microscope', etc. They were often
to be further analyzed into more precise terms or mathematical
co-ordinations, but they often would not be eliminated. Even the
empirical character of protocol statements could not be pure and
primitive, as physicalism allowed the introduction of
theoretical--non-perception--terms. Carnap himself, in
*The Logical Syntax of Language* (1934), declared the
distinction between analytic and synthetic (protocol-based) statements
arbitrary. Physicalism, and thus unified science, were based on a
universal 'jargon'.



The empirical genealogy expressed by protocols was the linguistic
expression of empiricism that identified protocol statements as
epistemological special units in the system of statements that would
constitute objective scientific knowledge. This was Neurath's
attempt to express the empiricist sentiment also behind Carnap's
appeal to experience. A difference from Carnap's model of
protocol appears in the second aspect of their empiricist character,
their testing function.



Neurath's protocols didn't have the atomic structure and
the atomic testing role of Carnap's. Their methodological role
reflected Duhem's *holism*: hypotheses are not tested
individually; only clusters of statements confront empirical data. But
their methodological value in the testing of other statements
didn't make them unrevisable. This is Neurath's
*anti-foundationalism*: Insofar as they were genuinely
scientific statements, consistency with the spirit that opposed
science to dogmatic speculation and, no less importantly, opposed
naturalistic attention to actual practice, required that protocols too
be testable. This is the so-called *Neurath Principle*: in the
face of conflict between a protocol and theoretical statements, the
cancellation of a protocol statement is a methodological possibility
as well (Neurath 1932b/1983, 95, Haller 1982). The role of
indeterminacy in the protocol language points to a distinction between
a *special Neurath Principle* and a *general Neurath
Principle* (Cartwright *et al*. 1996, 202-6). In the
former, and earlier, Neurath assumed a determinate logical relation of
inconsistency. In the latter, subsequent version, the scope of
relations between hypotheses and protocol statements extended to
indeterminate relations such that the principle behind the epistemic
status of protocol statements is simply grounded on the voluntarisitic
and conventionalist doctrine that '[a]ll content statements of
science, and also their protocol statements that are used for
verification, are selected on the basis of decisions and can be
altered in principle' (Neurath 1934/1983, 102). Carnap adopted a
similar conventionalist and pragmatic attitude in 'On Protocol
Sentences' (1932/1987) and in *Logical Syntax* (1934).
The complex structure of the explicitly laid out protocol would serve,
in the holistic Duhemian spirit, the purpose of testing it by making
explicit as many circumstances as possible which are relevant to the
experience, especially as sources of its fallibility (was Otto
hallucinating? were all the parts of the experimental instrument
working reliably? etc.). Neurath's dictum was meant to do
justice to actual scientific practice with regard to the role of
experimental data.



This problematic was only made more challenging by the presence of
*Ballung*-type terms. The method of testing could not be
carried out in a logically precise, determinate and conclusive manner,
expecting calculability, determinism, omniscience and certainty, as
the prevailing ideal of rationality required (Neurath 1913/1983,
Neurath 1934/1983 and Cat 1995). Protocol sentences, by virtue of
perception terms, could provide certain stability in the permanence of
information necessary for the generation of new expressions. But
methodologically they could only bolster or shake our confidence. To
acknowledge these limitations is a mark of proper
rationality--which he opposed to *pseudorationality*. A
loose coherentist view of justification and unification is the only
logical criterion available: 'a statement is called correct if
it can be incorporated in this totality' of 'existing
statements that have already been harmonized with each other'
(Neurath 1931/1984, 66). Reasons underdetermine our actions and thus
pragmatic extra-logical factors are required to make decisions about
what hypotheses to accept. Thinking requires provisional rules, or
auxiliary motives, that fix a conclusion by decision (Neurath
1913/1983). Scientific rationality is situated, contextually
constrained by, practical rationality. The system of knowledge is
constrained by historically, methodologically and theoretically
accepted terms and beliefs, with limited stability, and cannot be
rebuilt on pure, secure, infallible empirical foundations. This is the
anti-Cartesian naturalism, non-foundationalism, fallibilism and holism
of Neurath's model. This is also the basis for its corresponding
conventionalist, constructivist normativity (Uebel 1996 and 2007 and
Cartwright *et al*. 1996). Without the conventions there is no
possibility of rationality or objectivity of knowledge. Neurath
captured the main features of his doctrine of scientific knowledge in
the image of a boat:



> 
> 
> There is no way to establish fully secured, neat protocol statements
> as starting points of the sciences. There is no *tabula rasa*.
> We are like sailors who have to rebuild their ship on the open sea,
> without ever being able to dismantle it in dry-dock and reconstruct it
> from its best components. Only metaphysics can disappear without a
> trace. Imprecise 'verbal clusters' [*Ballungen*]
> are somehow always part of the ship. If imprecision is diminished at
> one place, it may well re-appear at another place to a stronger
> degree. (Neurath 1932b/1983, 92)
> 
> 
> 



By 1934, the year of the completion of his *Logic of Scientific
Discovery* (*Logik der Forschung*), Popper had adopted an
approach to scientific knowledge based on the logic of method, not on
meaning, so that any talk of individual experience would have no
linguistic expression (Popper 1935/1951). He unfairly criticized
Neurath and also Carnap for allowing with such expressions the
introduction of psychologism in a theory of knowledge. For Popper a
theory of scientific knowledge was to be not a subjective or
descriptive account, but a normative logic of justification and
demarcation. He also criticized Neurath's antifoundationalism
about protocols as a form of anti-empiricism that merely opened the
door to dogmatism or arbitrariness.



Instead of protocols, Popper proposed to speak about basic
statements--a term more attuned to their logical and functional
role. They are basic relative to a theory under test. Their empirical
character would invisibly reside in the requirement that basic
statements be singular existential ones describing material objects in
space and time--much like Neurath's physicalism--which
would be observable, in a further unspecified logical not
psychological sense. Their components would not themselves be purely
empirical terms since many would be understood in terms of
dispositional properties, which, in turn, involved reference to
law-like generalizations. But their 'basic' role was
methodological 'with no direct function of demarcation from
metaphysics in terms of meaning, sense or cognitive
significance' and only provisional. They would be brought to
methodological use for the purpose of falsifying theories and
hypotheses 'individually and conclusively' only once they
were conventionally and communally accepted by decision in order to
stop infinite regress and further theoretical research.



But such acceptance, much as in Neurath's model, could be in
principle revoked. It is a contingent fact that scientists will stop
at easily testable statements simply because it will be easier to
reach an agreement. It is important that basic statements satisfy
explicit conditions of testability or else they could not be rightful
part of science. Popper could offer no rational theory of their
acceptance on pain of having to have recourse to theories of
psychology of perception and thereby weakening his normative criterion
of demarcation. In his view, his method, unlike Neurath's,
didn't lead to either arbitrariness or dogmatism or the
abandonment of empiricism. As he had argued against Spengler in 1921,
historical contingency provides the rich constraints that establish
communities and communication and the possibility of knowledge and, in
this holistic form, preclude radical relativism in practice; in
historically situated practice, inherited or constructed stable
Archimedean points always come into place; there is no *tabula
rasa* (Neurath 1921/1973). Neurath rejected Popper's
approach for its stealth empiricism and its pseudorationalism: its
misplaced emphasis on and faith in the normative uniqueness, precision
and conclusiveness of a logical method--at the expense of its own
limitations and pragmatic character (Zolo 1989, Cat 1995, Hacohen
2000).



Finally, the most radical empiricist attitude toward protocol
sentences within the Vienna Circle came from Schlick. Schlick
endorsed, following Hilbert, a formal, structural notion of
communicable, objective knowledge and meaning as well as a
correspondence theory of truth. His realism opposed Neurath's
coherentism, and also the pragmatism and conventionalism of
Carnap's *Principle of Tolerance* in logical matters as
well as his Thesis of Metalogic. But like Carnap's latter thesis
and his syntactic approach of 1934, Schlick was concerned with both
the Cartesian ideal of foundational certainty and Wittgenstein's
metalinguistic problem of how language represents the reality it is
about; such relation could only be shown, not said. In 1934 Schlick
proposed to treat the claims motivating protocol statements, left by
Neurath with the status of little more than mere hypotheses, as key to
the foundation of knowledge. They would be physicalistic statements
that, albeit being fallible, could be subjectively linked to
statements about immediate private experiences of reality such as
'blue here now' he called affirmations
(*Konstatierungen*) (Schlick 1934). Affirmations carried
certainty and elucidated what could be showed but not said, they
provided the elusive confrontation or correspondence between
theoretical propositions and facts of reality. In this sense they
afforded, according to Schlick, the fixed starting points and
foundation of all knowledge. But the foundation raised a psychological
and semantic problem about the acceptance of a protocol. Affirmations,
as acts of verification or giving meaning, lacked logical inferential
force; in Schlick's words, they 'do not occur within
science itself, and can neither be derived from scientific
propositions, nor the latter from them' (Schlick 1934, 95).
Schlick's empiricism regarding the role of protocol sentences
suggests but does not support strong epistemological foundationalism.
Schlick's occasional references to a correspondence theory of
truth were just as unacceptable and were felt to be even more of a
philosophical betrayal within the framework of empiricism.
Predictably, Neurath rejected Schlick's doctrines as
metaphysical, manifesting the pseudorationalist attitude (Neurath
1934/1983).


## 4. Unity of Science and the Encyclopedia Model



Early in his intellectual life, at the turn of the twentieth century,
Neurath was acquainted with at least four recent images and projects
of unification of the sciences: (1) The scholastic (Llull) and
rationalist (Leibniz) tradition of an ideal universal language and
calculus of reasoning; (2) the Neo-Kantians'distinction between
the *Naturwissenschaften* and the
*Geisteswissenschaften*; (3) Wundt's comprehensive
logical viewpoints associated with different sciences, or perspectival
monism; and (4) the Monist movement more generally, with figures such
as Ernst Haeckel and Wilhelm Ostwald that included the project of
energetics, with Mach's related bio-economic, neutral monism of
elementary sensations. Subsequently, throughout the 1910s, Neurath
engaged four connected debates: (1) The debate over the Neo-Kantian
divide between natural and human, or cultural, sciences; (2) the
debate over the distinctive role of value judgment in the social
sciences; (3) the debate over the scope and validity of concepts and
laws in economics; and (4) the debate over the possibility of history
as a positive science.



In the Vienna Circle's manifesto (1929), Neurath ushered in and
extolled a scientistic turn in philosophy he labelled the scientific
world-conception. Beyond the intellectual, he added, '*the
scientific world-conception serves life and life receives
it*' (Carnap, Hahn and Neurath 1929/1973, 306, orig. ital.).
Here the project of logical empiricism gets its Enlightenment
dimension, with the old reforming, constructive and universalist
ambitions, but with new and revised ideas and ideals of society,
science and rationality (Uebel 1998). Neurath continued to maintain
the view that, as predictive tools, all sciences are 'aids to
creative life' (Neurath 1931/1973, 319), alongside his view of
the complexity of life, e.g., the earthly plane of the empirical world
that includes the human, private and social. It cannot surprise, then,
that in this new transformative joint philosophical-social project he
would urge that 'the goal ahead is *unified
science*' (Carnap, Hahn and Neurath 1929/1973, 306, orig.
ital.). Like science itself, unified science straddles any divide
between theory and action, the world of physical objects and the world
of social objectives, past and future, empirical reality and human
realization. It is unity of science at the point of action (Cartwright
et al 1991, Cartwright *et al*. 1996 and Cat *et al*.
1996, O'Neill 2003).



Neurath illustrated the fact that the holistic argument for
unification from the complexity of life generalizes Duhem's
holistic argument about prediction and testing with the example of a
forest fire:



> 
> 
> Certainly, different kinds of laws can be distinguished from each
> other: for example, chemical, biological or sociological laws;
> however, it can *not be said of a prediction of a concrete
> individual process that it depend on one definite kind of law
> only*. For example, whether a forest will burn down at a certain
> location on earth depends as much on the weather as on whether human
> intervention takes place or not. This intervention, however, can only
> be predicted if one knows the laws of human behaviour. *That is,
> under certain circumstances, it must be possible to connect all kinds
> of laws with each other*. Therefore all laws, whether chemical,
> climatological or sociological, must be conceived as parts of a
> system, namely of unified science. (Neurath 1931/1983, 59, orig.
> itals.)
> 
> 
> 



Laws of one kind may apply nicely to systems, phenomena or events
purely of one kind, but such things are not concrete individuals in
the real world. We may think of them as useful models or abstractions;
reality behaves more like them only in controlled settings, the
outcome of engineering, of planned design and construction, that is,
the materialized form of abstraction. Idealizations, like ideal types,
dangerously assume real separability between properties (Neurath
1941/1983, 225). In this sense, necessary experimentation for the
purpose of prediction and testing that control is key to observation
and in turn observation controls theory. In general, from that point
of view, exactness and scope requires the possibility of composing
models, laws and sciences of different kinds. Science at the point of
action is unified science.



Neurath's philosophical contributions to logical empiricism
appear now more distinctly motivated and more clearly understood: It
is to serve the valuable goal of unified science, within science,
philosophy and society, that Neurath conceived the stress on two
further epistemological aims, namely, the role of collective efforts
and finally, by implication, intersubjectivity (*ibid*.). The
argument from holism would in turn meet the requirements of the
demarcation against metaphysics, since metaphysical terms and
metaphysicians divide, whereas scientific terms and scientists unite.
The boat images further illustrated Neurath's aim of unity,
within its proper epistemological framework: as a historically
situated, non-foundational and collective enterprise. Science is a
model and a resource for society and society is in turn a model and
resource for science.



In the context and the phase of the rise of logical empiricism,
Neurath's arguments took a general intellectual formulation and
application, with references to precedents from intellectual history
such as Leibniz and L'Encyclopedie (see SCIENTIFIC
UNITY), and an institutional expression in the form of the planned
unity of science movement, with its different institutions (Institute
of Unified Science), events (International Congresses for the Unity of
Science) and publications (International Encyclopedia of Unified
Science) (Neurath 1937a/1983, Reisch 1994, Symons et al. 2011).



What are the model and mode of unity? What is the alternative they
oppose? Despite popular approaches suggesting a hierarchical, or
pyramidal, structure, which he associated with, among others, Comte,
Ostwald and then Carnap (in the *Aufbau* and in his subsequent
doctrine of physicalism), Neurath opposed the ideal of
'pyramidism' and a 'system-model': an
axiomatic, precisely and deductively closed and complete hierarchy of
conceptually pure, distinct and fixed sciences. He also dismissed the
idea of ONE method and ONE ideal language, for instance, mathematics
or physics, followed by all the other sciences (Neurath 1936/1983 and
Neurath 1937b/1983). Since 1910 Neurath's approach to the issue
was thoroughly antireductionist: cognitively, logically and
pragmatically. Each science would fail to deal with the connections to
others (Neurath 1910/2004). In particular, electron talk, Neurath
insisted, is irrelevant to understanding and predicting the complex
behavior of social groups.



The imperative of unity required that 'it must be possible to
connect each law with every other law under certain circumstances, in
order to obtain new formulations' (Neurath 1931/1983, 59).
Instead of the system-model, he proposed a weaker, dynamical and local
model of integration he called the 'encyclopedia-model': a
more or less coherent totality of scientific statements at a given
time, in flux, incomplete, with linguistic imprecisions and logical
indeterminacy and gaps, unified linguistically by the universal jargon
of physicalist language (not Carnap's physicalism)--a
mixture of 'cluster' and 'formula'--, the
cooperative and empiricist spirit, and the acceptance of a number of
methods or techniques (probability, statistics, etc), all providing
'cross-connections' (Neurath 1936/1983, 145-158 and
213-229). The evolution of the sciences could be said to proceed
from encyclopedias to encyclopedias (a model weaker and more
pluralistic than those based on Kuhn's paradigms and
Foucault's *epistemes*, but closer to
Carnap's later notion of linguistic frameworks; from this
perspective, it seems less paradoxical that Carnap published
Kuhn's *The Structure of Scientific Revolutions* in the
last volume of the International Encyclopedia of Unified Science).
Neurath spoke of a 'mosaic', an 'aggregation',
an interdisciplinary 'orchestration' of the sciences as
'systematisation from below' rather than a 'system
from above', especially, after World War II, carefully excluding
any form of 'authoritative integration', even favoring
'cooperation in fruitful discussion' to a socialist, Nazi
or totalitarian-sounding talk of a 'programme' (Neurath
1936/1983 and Neurath 1946/1983, 230-242). Correspondingly, his
later political writings emphasized internationalism, democracy and
plurality of institutional loyalties.



The disciplinary dismissal of philosophy, especially its talk of
transcendental entities that make up metaphysical doctrines, hardly
recommend calling Neurath's views a philosophy. At the same
time, his emphasis on science was coached in a framework that
connected thought and action. One may speak of a program.
Neurath's program was intended to be and was pluralistic and
'aggregational' through and through, semantically,
theoretically, disciplinarily, educationally, socially,
politically.


## 5. Philosophy of psychology, education, and the social sciences


### 5.1 Philosophy of psychology



Vienna became an international capital of psychological research while
logical empiricism started to develop a scientific epistemology and an
epistemology of science with normative demarcation goals.
Freud's psychoanalysis was more popular than J.B. Watson's
American behaviorism and Gestalt psychology was dominant neither in
psychology nor scientific philosophy. The members of the Vienna Circle
collectively adopted its framework of scientism and anti-metaphysics,
of logic and empiricism, and aimed to select their intellectual allies
and targets accordingly. Yet, individually, they tailored their
considerations of the different sciences to their respective agendas,
shifting projects and development. In the Vienna Circle manifesto, the
official programmatic position was to point to the defects of much
contemporary psychological language, plagued by metaphysical burden,
conceptual imprecision and logical inconsistency. The emphasis on
perception selected behaviorist psychology as intellectual ally
consistent with the Circle's scientific world-conception
(Carnap, Hahn and Neurath 1929/1973, 314-5, Hardcastle 2007).



Hans Reichenbach, Carnap and Schlick's ally in Berlin, was the
leader of the Berlin Society for Scientific Philosophy, also known as
the Berlin Circle, and hence was in personal and intellectual
interaction with Wolfgang Kohler in Berlin. Eventually he would
mention Gestalt theory in his writings in 1931, in 'Aims of
Modern Philosophy of Nature'. There he raised the question of
the philosophical problems of psychology and focused on Gestalt theory
as 'a recent development' that 'subsumes
psychological events under the concept of Gestalt (...) an
organized arrangement of experiences' (Reichenbach 1931/1959,
88).



Like Kant, Popper was interested in a transcendental and regulative
philosophy, and, more so than Kant, he hailed science as the paradigm
of intellectual activity. But by 1928 he was still holding a
commitment to inductivism. In 1928 Popper finished his doctoral
dissertation, 'On the Methodological Problem of Cognitive
Psychology'. There, Popper set out to understand the relations
between logic, biology and psychology in the production of knowledge
and, to that effect, to outline the methodological preconditions of
cognitive psychology. Two alternative views of psychology were
available to Popper through his two doctoral examiners, Karl
Buhler and Moritz Schlick.



Schlick represented Gestalt theory as psychology within the reductive
framework of physicalism, that is, rejecting the existence of
autonomous entities, laws and methods of psychology.
Buhler's career was central to Austrian psychology and to
Red Vienna culture. After an assistantship with Stumpf in his
Berlin's laboratory, Buhler had emerged, along with Otto
Selz and Max Wertheimer, from the research laboratory of Ostwald
Kulpe in Wurtzburg. With Kulpe he had engaged in
empirical research on thought processes--contra Wundt's
atomistic psychology-, with special attention to imageless thought and
the importance of language. He subsequently moved with Kulpe to
Bonn and eventually replaced him in Munich in 1915. In 1912
Buhler had originally contributed to Gestalt psychology with the
discussion of simple Gestalt forms involved in the perception of
proportions of geometrical figures and ended concentrating on his
cognitive phenomenon of the 'aha experience', a sudden
insight in problem solving. Interested in the same phenomenon,
Charlotte Malachowski was encouraged by Stumpf to join Buhler in
Munich, where she became his wife. They collaborated on a project to
study the mental development of children, ending with intelligent
learning through language. The results appeared in his *The Mental
Development of the Child* (1918), which immediately became the
standard reference on the subject.



In Vienna, Otto Glockel, founder of the world-renowned Vienna
School Reform movement and president of the Vienna School Board,
offered to fund for the Buhlers a psychological laboratory. After
Karl Buhler had lost to Kohler the appointment to the Berlin
posts, he ended up assuming in 1923 the directorship of the newly
funded Psychological Institute of Vienna. From the Institute the
Buhlers became central to Red Vienna culture. They taught at the
Pedagogical Academy of Vienna. In addition, she focused on children
education and psychological welfare. His interest in language and
philosophy brought him closer to Schlick (Wittgenstein's sister
Margaret organized social occasions for Wittgenstein, the Buhlers
and the Schlicks to meet) and he encouraged his students to attend
Vienna Circle seminars (Egon Brunswick, Elsa Frankel, Marie Jahoda,
Paul Lazersfeld, Rudolf Ekstein and Edith Weisskopf). Then in 1927 he
published *Die Krise der Psychologie* (*The Crisis of
Psychology*). In the book, Buhler argued that the problem of
explaining the social significance of language showed that psychology
has lost the complexity and richness required to synthesize three
levels of psychology: experience, behavior and intellectual structure
(Buhler 1927, Hacohen 2000 and Humphrey 1951). A framework was
needed for unifying the different narrow 'schools' of
psychology: Behaviorism, Gestalt theory, psychoanalysis,
associationism, and humanistic psychology. They were deficient in
their narrow domain of application. The unity of psychology demanded
methodological pluralism at the point of cooperation.



Around this time, Popper's interest in the scientific character
of psychology was still bound to the notion that induction is the
empirical method of the natural sciences (ter Hark 2002, and Gattei
2004, 453). He developed his interest in psychology in his second
thesis, on the method of cognitive psychology, of 1928 (the first was
on the inductive basis of pedagogy). Popper argued against
Schlick's views rejecting the reciprocal interaction between
body and mind: physicalism was impractical and psychophysical
parallelism empirically unverifiable. The choice between
Schlick's physicalism and Buhler's pluralism was not
logically decidable. Psychology was better off autonomous, discovering
empirically new laws and phenomena that only subsequently might or
might not prove reducible to material interpretation. Moreover, he was
primarily concerned with his own epistemological project, descriptive
and regulative, regarding the production of scientific knowledge.
Popper reasoned by analogy with Buhler's problem regarding
language: Gestalt psychology was too narrow to establish the
conditions of possibility of cognitive psychology and the logic of
intellectual structures. He was further interested in the Viennese
Otto Selz's holistic and functional notion of 'total
task', based on a psychological mechanism of trial and error
(this notion would inspire not only Popper's pedagogy, but
elements of his scientific methodology of hypotheses and
falsification, conjectures and refutations). His heart and mind were
set against the sufficiency of Gestalt psychology.



In the *Aufbau* Carnap associated Watson's behaviorism
with a physicalist basis for a construction system, whereas Gestalt
psychology was better suited to provide an empirical basis for the
epistemological system (which was to reflect the origin of the
concepts in our system of knowledge) (Carnap 1928). Carnap was
concerned, in a neo-Kantian fashion, with the question of the
constitution of the world; and he tried to combine the strengths of
empiricist and Kantian epistemologies in a system that was
metaphysically neutral. One of the many possible logical constructions
--borrowing Russell's terminology--or constitution
systems of knowledge was to accommodate the epistemic value of
individual experience while preserving the objective form of
scientific knowledge (Friedman 1999). It is there that in order to
represent experience scientifically, he chose, following Schlick,
Gestalt theory. Experience contributed a complex holistic
stream--a 'true', 'organic'
whole--out of which the elementary empirical concepts must be
abstracted, by the process he called quasi-analysis. Unlike for
Stumpf, but like for Wertheimer and Kohler, for Carnap elementary
sensations were only abstractions--he wrote of quasi-analysis
through classes of recollected experiences--from experiential
Gestalts. In the book he explicitly referred to Kohler's
article 'Gestaltprobleme und Anfange einer Gestalttheorie,
Ubersichtsreferat' (1925) and Wertheimer's survey
*Ueber Gestalttheorie* (1925) (Carnap (1928), sects. 62 and
109; besides Husserl's, the influence of Meinong's
Gestalt-based philosophy deserves careful exploration).



Like Wittgenstein and Popper, both prior to but especially during the
Red Vienna period, Neurath was interested in education and cognitive
psychology (like Popper, also in connection with socialist political
and social goals). He quickly gained notoriety with his visual method
of communication, known as ISOTYPE or Vienna Method. Neurath's
crusade for unified science against speculative metaphysics and the
connected challenge of understanding the social and objective nature
of scientific knowledge drove him in 1931 to adopt physicalism as the
chief constraint on scientific concepts and theories. Physicalism, in
a sense broader than Carnap and Schlick's doctrine of the same
term, was the materialist view that science speaks only of observable
events, things and processes in space and time. This view set a
(normative) bridge intended to unify the truly scientific natural and
the social sciences, yet it did not require any reduction to physics.
Radical empiricism, by contrast, would only impose the primacy of the
subjective, the source of contentiousness, dogmatism and
arbitrariness, which he abhorred in speculative metaphysical
doctrines. Neurath rejected, along these lines, the language of the
unconscious and the ego, subjective mental states devoid of material
-physiological-, perceptual or operational correlates. 



The metaphysical or semantic policing of psychological vocabulary took
place at two levels: as a science integrated within the unity of the
sciences according to principles of physicalism, and as part of the
scientific representation of relevant perception in the form of
protocol sentences. As a matter of psychology of perception and
language, all events and processes, all perceptual, speech and thought
terms involved in the production of empirical data were to be taken
physicalistically, e.g., as descriptions of spatio-temporal structures
involving behavior or bodily--anatomical and physiological-
changes under given observed conditions (Neurath 1931/1983, 55).



From the point of view of Neurath's physicalism or enlightened
empiricism, the goal was to achieve a unity of empirical formulations
in psychology. The only acceptable psychological positions were the
kinds of behaviorism championed by J.B. Watson, E.C. Tolman, and F.B.
Skinner and physiological theories (Neurath 1931a/1983, 50;
1931b/1983, 55; 1932a/1983, 63, 67, and 73). Yet he also drew some
distance between physicalism and behaviorism by declaring the latter
both too narrow and too broad, and containing non-physicalist notions
(Neurath 1936/1983, 164). He came to distinguish behaviorism, in this
narrow sense, from 'behavioristics', the emphasis on
perceptual considerations of behavior within the framework of
physicalism (Neurath 1933/1987, 13). Neurath mentioned Gestalt theory
as one of the schools of psychology alongside behaviorism and
psychoanalysis disrupting the unity of psychology as a discipline
(implicitly echoing Buhler's earlier lamentations; Neurath
1937/1983, 172-3, and 1933/1987, 15), but he did not mention
Gestalt as an example of scientific psychology (a few statements on
this point in Cat 2005 are regrettably mistaken or else misleading).
He merely pointed to the promise of its empirical contributions to
scientific behaviorism with a rejection of its talk of holistic
properties as metaphysical danglers (Neurath 1933/1987, 17-8).



### 5.2 Philosophy of education



As mentioned above, psychology and pedagogy were inseparable in
Vienna's intellectual, scientific and political culture of the
1920s. Glockel's school reform movement of 1922 onwards
advocated empirical research in pedagogy, it separated school from
church and promoted social equality. Child welfare became a central
concern and attracted the pedagogical interest for intellectual and or
political reasons of Popper, Wittgenstein and Neurath (on Popper see
Hacohen 2002; Wittgenstein see Bartley 1974 and Peters 2001). In their
pedagogical activities one can find the roots of some of their
epistemological views. Popper and Wittgenstein became school-teachers
and Wittgenstein even published in 1925 a spelling dictionary,
*Worterbuch fur Volksschullen*. Lili Roubiczek, a
student of Maria Montessori in London and Karl Buhler in Vienna
established a Montessori school in 1923 and soon Montessori ideas
attracted educators and psychologists alike (from Charlotte
Buhler to Anna Freud) (Kramer 1988). Montessori stressed the idea
of the child's capacity for active self-directed learning
through sensory and motor interaction with the environment with
guidance and error-correcting feedback. Gestalt psychologists,
psychoanalysts and others defended similarly active models of the
child's mind. 



In 1927, after Vienna's city council had unified the
psychological and pedagogical institutes into a Pedagogic Institute,
Popper wrote his first thesis, '"Habit" and
"Experience of Law" in Education'. There, he
justified the scientific status of pedagogy on inductivist grounds.
And he raised the fateful philosophical problems of the
'objective-scientific decidability of pedagogical
problems' and 'the delimitation of the empirical part of
pedagogy from its non-empirical part' (ter Hark 2002, 88 and
Gattei 2004, 454). Selz's holistic and functional notion of
'total task', based on a psychological mechanism of trial
and error would inspire Popper's pedagogy as well as his
scientific methodology. Moreover, his awareness of Montessori methods
was secured in the 1920s by his teaching education, his friendship
with a carpenter who made toys for a Montessori orphanage and turned
him to cabinet-making and the Montessori-inspired 'Socratic
method' of his admired Kantian critical philosopher Leonard
Nelson (Hacohen 2000, 90 and 122).



Neurath's views on education, as did his scientific
epistemology, integrated social, political, scientific and empiricist
elements in a mutually reinforcing manner. Equally, his synthetic
attitude integrated attention to different specific dimensions such as
conceptual information, material, linguistic and graphic
representation, and cognitive and social attitudes, capacities,
values, goals and institutions. The most influential example and
outcome of his views were the development and application of ISOTYPE
method of visual education (See the supplementary document
 Visual Education.).



Education involves *argument* and *discussion*. It is in
this sense dialogical. The term 'argument' was used by
Neurath broadly, to include the case or point being made and
communicated, both senses of demonstration. Neurath wrote that to
argue requires one to distinguish between essentials and incidentals
(Neurath 1945/1973, 239). So a visual argument is 'a combination
of verbal and visual aids leading to the essentials'
(*ibid*., 240). 



Under the aegis of the values of neutrality and universality that
characterized his economic theory, social views and scientific
epistemology, Neurath sought also the universal media of communication
of knowledge: visual perception and scientific information. Science is
'the typical species of arguing which human beings of all
nations, rich and poor, have in common' (*ibid*., 229),
allowing for discussions in any civilization, which other disciplines
or discourses render local. As in the doctrines of the objective
(intersubjective), universal, unifying value of observation language,
Neurath claimed that simple visual representations were theoretically-
and value-neutral, eliminating judgment, at least compared to verbal
expressions (and theoretical statements) (*ibid*., 234).



The interest in cognitive psychology, child psychology and child
welfare, and the anti-metaphysical and epistemological value of
empiricism led him to defend the value of visual education. Quoting
from the Victorian self-improvement author Samuel Smiles, he declared
that 'all persons are more or less apt to learn through the eyes
rather than the ear... especially the case in early youth, when
the eye is the chief inlet of knowledge' (Neurath 1946, 100).
This approach was consistent with Montessori's and other
contemporary educational theories as well as with scientific
education. He repeatedly pointed to another Victorian hero of his,
Britain's foremost experimental scientist and popular science
educator, Michael Faraday, and his *Course of Six* *Lectures
on the Chemical History of a Candle* (1861), which was intended
primarily for children. Given the importance he placed on scientific
information, also socially, the main challenge he routinely took up
became the concretization of abstract information, especially the
visual communication of statistical information. More generally, he
believed that visual education provided a unifying framework that
bridged the gap between science and the humanities (Neurath 1945/1973,
234). 



Education requires *simplification*, that is, the empiricist
notion of *abstraction* in the face of the complexity of facts.
Teaching requires knowing what to leave out, what counts as
superfluous detail and accuracy: 'he who knows best what to omit
is the best teacher' and so 'to remember simplified
pictures is better than to forget accurate figures' (Neurath
1933/1973, 220 and 1945a, 440). The graphic, visual counterpart of
this point constitutes the basis for his design of ISOTYPE icons, by
analogy with the method of silhouettes, so popular in Austrian art, as
a form of visual abstraction for the communication of information
about types or general concepts. The approach was consistent with the
empiricist anti-metaphysical spirit and Bauhaus and modernist
aesthetic of the rejection of ornament famously advocated by the
Viennese architect Adolf Loos in *Ornament and Crime* (1908)
also echoed by Neurath in 1926: 'the time of ornaments is
over' (recounted by Ernst Niekisch in Neurath 1973, 22).



Reinforced by the Viennese School Reform movement led by Glockel,
his scientific attitude, and the philosophy of logical empiricism, was
the scientific and empirical attitude towards models of education.
This applied to the methods and tools of visual education in two ways:
by applying accepted recent ideas from empirical disciplines such as
developmental psychology, anthropology, art history, even ideas by his
Encyclopedia co-editor Charles Morris in his *Foundations of a
Theory of Signs* (Morris 1938); and by testing the end-products,
albeit with different degrees of rigor (see the supplementary document
on
 Visual Education).



Neurath was aware of the values and limitations of the elements of
visual education (see below), and admitted the diversity of tools and
values with the same kind of *pluralism*, *holism* and
*pragmatism* he adopted in his economic theory and more general
scientific epistemology: each educational media had educational
characteristics of each own that are incomparable and non-additive,
cannot be ranked and serve different purposes (Neurath 1944, 56,
Neurath 1945/1973, 238 and Neurath 1946, 99).



The sensual dimension of education is part of the larger goal of
*humanization*: the elimination of secret knowledge and
exclusive communities. Education involves the language of daily life
and the avoidance of unnecessary technical terms, and thereby enables
organized humanity, including international cooperation (Neurath
1945/1973, 231). 



More intellectually, education involves *comparison* (Neurath
1945/1973, 238). But the comparative analysis, which Hume made a
staple of empiricist methodology, does not exhaust the gamut of
intellectual values. The exploration of incomparable or alternative
possibilities, as was illustrated by the cases of economic and social
theory, practical rationality and scientific method (see the
supplementary document
 Political Economy),
 is a key cognitive goal of education that was to make the other
specific practices possible (logically and psychologically). He called
this *meditation*: besides handing out knowledge, education
involves a transfer of criticism, a meditative mood and atmosphere,
and the ability to consider matter under discussion from all sides
(possible and actual perspectives within the pluralistic attitude)
(*ibid*., 233).



Education should discourage narrow specialization. Since the holistic
and synthetic model of socialization, epistemology and science
requires the consideration of alternative perspectives and the
integration of different kinds of knowledge. Neurath praised the
Danish pedagogical model of university education, a Philosophy Faculty
in the medieval comprehensive, universalist spirit of the scholastic
meaning of 'university'. In the setting of one of the
Congresses of the Unity of Science Movement, he praised the
requirement at University of Copenhagen of mandatory science and
philosophy courses for students of all specialties, and Joerg
Joergensen's lectures on scientific thinking based on historical
explanation and logical reasoning (Neurath 1938).



Education depends on *intellectual ethos and social values* as
well. Education includes what he called also the habits of scientific
attitude: habits of '*sincerity* of research and
*integrity* of arguing' (Neurath 1946/1973, 233).
Education involves also *tolerance*: the transfer of tradition
is a preference within one community, not an expression of an absolute
higher point of view above other communities, also a preference among
others within that community independent of that tradition
(*ibid*., 229). 



The social dimension was a recurring theme even though with changing
connotations or emphasis, from post-WWI socialism to post-WWII
internationalism. Public education was dependent on an institutional
basis consisting of a number of institutions: schools, museums and
other places holding public exhibitions, and periodicals (Neurath
1931/1973, 222). Neurath was director of the Social and Economic
Museum in Vienna from 1924 until 1934. Not coincidently, his cousin
Waldemar Kaempffert planned and proceeded along lines similar to
Neurath's during his tenure as director of the Museum for
Science and Industry of Chicago from 1928 until 1931.



The social dimension extended to groups, generations and nations
related by education as the process of *group* *transfer of
traditions*: 'Education may be regarded as the transfer of
certain traditions in a more or less systematized way, from one person
to another person, from one group of persons to another group,
particularly from one generation to the next. It is also the transfer
of tradition from one nation to another' (Neurath 1945/1973,
228).



It also extended to political arrangements, from *socialism*
and *democracy* to ideals of *international
cooperation*. The earlier views emphasized the socialist
significance of education as condition of democracy in the form of
informed participation and of cooperation, since 'successful
collaboration is possible only when those who act fix on one
possibility, whether by agreement or by propaganda' (Neurath
1928/1973, 293). Education as spreading of knowledge is required for
everyone involved in taking common decisions and hence for the working
of democracy (Neurath 1945/1973, 230). Democratic society, Neurath
concluded, requires a common language (*ibid*., 247). Post-WWII
internationalism became a motivation for visual education
(*ibid*., 234, 247). Common language without common laws and
common language for common knowledge and cooperation, rendered visual
language a socio-political tool, as the non-dictatorial basis for a
potential human brotherhood (*ibid*., 248). In both contexts,
Neurath offered a criticism of elitist individualistic teaching with a
contrast between Anglo-Saxon education methods linked to empiricism
and utilitarianism and Nazi education linked to German romanticism and
transcendentalism (Neurath 1945b, 370-1).



The social and political valence of education provided the framework
for linking education to social structures such as entrenched
institutions, techniques and habits involving advertising and
entertainment that supported the relevant cognitive models such as
visual media: 'Modern man is conditioned by the cinema and a
wealth of illustrations. He gets much of his knowledge during leisure
hours in the most pleasing way through his eyes. If one wants to
spread social knowledge, one should use means similar to modern
advertisement' (Neurath 1925/1973, 214). In the latter context,
Neurath stressed the superiority of visual education to verbal
education as the basis for international or general education:
'words divide, pictures unite' (Neurath 1931/1973, 217).



### 5.3 Philosophy of the social sciences



As in the case of philosophy of psychology, Neurath's
philosophical theory of the social sciences was his attempt at a
paradigmatic application of the logical empiricist framework that
replaced philosophy as a speculative and autonomous source of
knowledge. Philosophy was now the reflexive perspective of unified
science and it was constituted by two meta-theoretical approaches to
science: logical analysis and empirical theory, that is, the
'logic of science'--emphasized by Carnap-- and
the 'behavioristics of science'--emphasized by
Neurath. The non-formal, empirical, perspective, allied to the
'scientific attitude', became in 1931 Neurath's
physicalism, his compromise between empiricism and
materialism--Mach and Marx--; this was also his attempt at a
resolution of the conflict between experience and objectivity (of
scientific knowledge), which Carnap attempted through the formal
aspect of structural descriptions and logical relations. 



Work on the foundation of the social sciences, a critical
meta-theoretical discussion, was of special importance to Neurath as a
core motivation behind the very program of logical empiricism. Because
knowledge is a tool (whether propaganda or reform), only the best
possible tool would help transform society. Science was precisely the
antidote to the speculative, metaphysical, philosophical discourses
behind much racist, classist, nationalistic and oppressive ideology,
politics and social theory. In this sense, Neurath's exposition
of his own social and economic views was from the beginning of his
career inseparable from an element of meta-theoretical or
philosophical discussion and motivation (elicited by the opposition
from the more dominant, orthodox doctrines and their proponents).
Neurath's views on the social sciences are also the source of
much of his distinctive, non-reductionistic, views on physicalism and
unity within the movement of logical empiricism (Cartwright *et
al*. 1996).



Physicalism encompasses psychology, history, economics and sociology
without reducing them to physics. Social sciences are scientific
within the framework of physicalism, namely, insofar as they describe
concrete spatially and temporally ordered events and processes and
make predictions about them (Neurath 1931b/1973, 325). Social behavior
is itself a complex and its prediction requires that sociology
incorporate various sources such as history, ethics, jurisprudence,
economics, ethnography, etc. (*ibid*., 328). For Neurath,
Marx's study of capital is important first and foremost as an
instance of empirical research that brings together history and
economics, and the most complete case of physicalist sociology
(*ibid*., 349). Sociology is a synthetic effort part of in turn
a larger synthetic effort that is unified science, the set of all
connectible languages and laws required to describe and predict order.
The synthetic dimension is inseparable from the empirical one: It is
the formal, linguistic and conceptual, expression of the totalistic,
holist approach required by the conception of empirical reality as a
complex, including the phenomena of 'concrete ways of
life'. Empirically determinable behaviors are partial
descriptions, separations, for instance 'peoples' are
'loosely separable sections of the mass of men'
(*ibid*., 332). In general, concreteness and complexity are
characteristics of reality that language expresses, especially
unanalyzed and imprecise cluster (*Ballung*)-type terms.



The alliance between unity and empiricism, or physicalism, is thrown
into further relief by contrast with the post-Diltheyan German
sociology of Windelband, Rickert, Sombart and especially Weber. They
distinguished between the natural and the social sciences and, as
distinctive feature of the latter, in Weber's sociology there
appear non-scientific, non-behavioristic entities and activities such
as the spirit of the age (*Zeitgeist*), and empathy or
understanding, poetic activity that grounds what he calls
'*Verstehende* sociology' (*ibid*., 353).
Neurath's was willing to accept the use of such concepts
provided they could be given a physicalistic meaning. 



Neurath emphasized attention to individuals and groups, individuated
in terms of stimulus/response interrelationship and clusters of shared
customs and habits, and, for instance, the transfer of such habits or
traditions (*ibid*., 371), which is how he defined education
(see above). The empirical conceptualization of the social units is
Gestalt-like and holistic, like the silhouettes, patterns or profiles
of total life plans: 'Peoples, states, age groups, religious
communities, all are complexes built up of single individuals. Such
composite groups have certain interconnections which are ruled by
laws, and they have a definite 'physiognomy'. The separate
features of these complexes are not independent of each other but are
related' (*ibid*., 387). Decisions and predictions, as in
the case of social planning, often involved the 'comparison of
total complexes' (*ibid*.).



Citing Mill, Neurath noted that empiricism brings the natural and the
social sciences together, but so do some of its *limits*. The
markers of empirical science are the practices of observation,
experimentation and prediction. Laws are merely vehicles for taking us
from the concrete and unique to the concrete and unique, whether in
biology or history. Sociology is like geology and biology in that the
possibility of many *experiments* is prevented by certain
constraints of ethical values or scale (*ibid*., 365).
*Predictability* is characterized by nine conditions. It is
based on (1) the availability of generalizations about groups and (2)
stable conditions, or control, and for a limited period. Control is a
key notion that connects empiricism and engineering, mechanical and
social. Neurath didn't think that laws of physics, for instance,
are in that sense more universal or unconditioned:
'Mariotte's law in physics holds only within certain
limits' (*ibid*., 331). (3) Correlations on which
predictions are based are the product of induction, and inductive
conclusions, in sociology as elsewhere, are based on a decision
(Neurath 1931b/1973, 407). (4) Moreover, sociology, like the natural
sciences, often has recourse to information, including laws, from
other disciplines, in a local synthetic effort of predictive value
(*ibid*., 364). (5) Holism prevents sociology from the
'ideal forecast' associated with the fiction of the
Laplacean mind and the availability of molecular descriptions of
individuals free from instabilities (in a symposium on Pasqual
Jordan's quantum mechanics, Neurath addressed the new
perspective from quantum mechanics on the problem of free will and its
conflict with the determinism (causality) of natural laws as riddled
with metaphysics (Neurath 1935)). One may not expect, however, that
aggregations or complexes will be always more predictable than
individuals, since the evolution of the complex might depend on the
interaction with individuals and the environment in a way affected by
chance. Instead, it has to make do with 'rough facts of a
complex character' (*ibid*., 405) in a 'system of
entangled habits' (*ibid*., 371 and 374), and most social
types of behavior in a group are not 'autonomously
computable' and have to be regarded as 'parts of the
complex that is being investigated at the time', considering
'the whole of life' of the group, since each
'historical period = non-analysed complex of conditions'
(Neurath 1932a/1983, 76 and 85); he would subsequently speak of
aggregations (Neurath 1944a). Any resulting prediction or explanation
(retrodiction) of individual behavior is an approximation to a
'world history without names'. (6) A linguistic
implication is that empiricism in general and the social sciences in
particular are dependent on non-univocal, indistinct
terms--'a "clot" (German *Ballung*,
French *gregat*)'--, in both protocol
statements (see above) and theories insofar as they are sensitive to
cultural phenomena and historically inherited concepts that cannot be
usefully replaced with precise technical terms of the 'modern
international folklore' (Neurath 1944a, 5-7, 18). (7) The
'multivocality' of the relation between phenomena and
theoretical interpretations is more pervasive than the sort of
pluralism Duhem noted in physics, and leads Neurath to speak of
'pluri-items' (*ibid*., 14). (8) Certain phenomena
or entities such as inventions can only be predicted provided one has
also the means to create them (Neurath 1931b/1973, 405); this insight
is typically attributed to the critic of Neurath Popper, who published
it much later. (9) Sociological predictions are co-determinants in the
occurrence of the predicted event, for instance a position in the
stock market or a political revolution (*ibid*., 405); the
prediction may have a reinforcing or a preventive character (he wrote
about self-fulfilling prophecies as early as 1921, in his polemic
against Spengler; Neurath 1921). Theory becomes part of practice;
scientist becomes part of the social scene (*ibid*., 406).



A related issue is Max Weber's issue of *value-freedom*,
and objectivity, in the social sciences. Neurath noted that all
sciences are based on values that determine the choice of relevant
aspects, phenomena, quantities, etc. This is not just consistent with,
but an implication of his voluntarism and his
'rationalism'. Value-free methods are not essential for
scientific practice. The formulation of a question or the choice of a
quantity might be value-dependent but their respective answer or
measurement will not be so in the same sense (*ibid*.,
364-5). Neurath formulated the same idea in terms of
theory-dependence: the putting right questions and making the right
observations require a 'meta-concept' or an
'approximate theory' (*ibid*., 388-89).



In spite of these caveats, the value of the social sciences remains
attached to the value of empirical knowledge and the scientific
attitude in the social roots of our life: 'Even where
sociologists cannot make predictions, they may provide men of action
or meditation with empiricist material. (...) We argue
differently and act differently when we know the material provided by
the social sciences. (...) altering our scientific language is
cohesive with altering out social and private life' (Neurath
1944a, 46).



Finally, we should address the reflexive value of the social sciences
insofar as science plays the meta-theoretical and critical role of
philosophy, displacing any alternative, autonomous and speculative
source of insight. History of science, for instance, will require
adequate classifications for the purposes of advancing correlations.
In that regard, it will benefit from avoiding narrow dichotomies of
classification and adopt, instead, the notion of theory -
applied in economic planning - that aims at exploring all
possibilities in the form of a matrix of combinations, realized and
unrealized (in the tradition of encyclopedic and symbolic calculus of
Llull and Leibniz). Neurath himself provided an application to the
case of optics (Neurath 1916/1983 and Neurath 1944a, 42). Similarly
for sociology, the search of an adequate classification of hypotheses
in the first step. Notice, however, that the epistemological
relativism associated with logical empiricism is not the outcome
solely of such external sociological perspective or naturalistic and
empirical considerations about scientific practice, but the
philosophical rejection of Kant's synthetic a priori and, as
alternative to Kant's approach to apriorism, the development of
conventionalism by Carnap, Reichenbach and others inherited from
Duhem, Poincare and others concerning the exact sciences
(Nemeth 2007, 283-4). Otherwise, Neurath pointed to the
reflexivity of the social character of science itself and declared
that sociologists argued, decided and acted in science as they
themselves and others do in society. They are on the same boat with
us; the boat of social sciences is just like that of the unified
science and of social planning itself. This notion of social
scientists, thinking up and putting in place possibilities under
conditions of uncertainty, prompted Neurath's final version of
the boat analogy:



> 
> 
> Imagine sailors, who, far out at sea, transform the shape of their
> clumsy vessel from a more circular to a more fishlike one. They make
> use of some drifting timber, besides the timber of the old structure,
> to modify the skeleton and the hull of their vessel. But they cannot
> put the ship in dock in order to start from scratch. During their work
> they stay on the old structure and deal with heavy gales and
> thundering waves. In transforming their ship they take care that
> dangerous leakages do not occur. A new ship grows out of the old one,
> step by step--and while they are still building, the sailors may
> already be thinking of a new structure, and they will not always agree
> with one another. The whole business will go on in a way that we
> cannot even anticipate today. That is our fate. (Neurath 1944a,
> 47)
> 
> 
> 



Criticisms came from Viennese social scientists such as Karl Menger,
Edgar Zilsel and Felix Kaufmann. Zilsel, an ally of the Circle,
objected to the programmatic nature of Neurath's foundational
work, namely, that it was empiricism without empirical research. They
all objected to the narrow strictures on the relation between the
natural and the human sciences imposed by physicalism. Kaufmann, in
particular, defended a phenomenological sociology, following Husserl
much more closely than Carnap especially did, based on the value of
introspective experience, although without the scientifically
mysterious Weberian method of empathy (Uebel 2007, 255-57).



Zilsel, Frank and Neurath had learned from Mach the value of history
as a creative source of theoretical possibilities and critical
perspective. Mach had called his approach 'historical-critical
method' which echoed in his heirs' ears with relevant
references to Kant and Marx, and was understood to support the
rejection of superhuman metaphysical inevitability. Like Reichenbach,
Zilsel replaced the Kantian inquiry into the preconditions of the
possibility scientific knowledge with more modest and
anti-metaphysical projects, in his case, centered on the
empirical--social political, economic-preconditions. Later on,
Philip Frank advocated the empirical historical studies of science as
part of the more complete answer to the question of the choice of
hypotheses raised by Duhem and Poincare, and the insufficiency
of the logical inference that grounded their conventionalism. These
are important sources and precedents of modern empirical studies of
science.