Logical positivism
Encyclopedia
Logical positivism is a philosophy that combines empiricism
—the idea that observational evidence is indispensable for knowledge—with a version of rationalism
incorporating mathematical and logico-linguistic constructs and deductions of epistemology.
It may be considered as a type of analytic philosophy
.See, e.g., : "Vienna Circle" in Stanford Encyclopedia of Philosophy
Logical positivism, in the formal sense, began from discussions of a group known as the "First Vienna Circle
" which gathered during the earliest years of the 20th century in Vienna at the Café Central
. After World War I, Hans Hahn
, a member of that early group, helped bring Moritz Schlick
to Vienna. Schlick's Vienna Circle
, along with Hans Reichenbach
's "Berlin Circle
", propagated the new doctrines more widely during the 1920s and early 1930s. It was Otto Neurath
's advocacy that made the movement self-conscious and more widely known. A 1929 pamphlet written by Neurath, Hahn, and Rudolf Carnap
summarized the doctrines of the Vienna Circle at that time. The doctrines included the opposition to all metaphysics
, especially ontology
and synthetic a priori propositions; the rejection of metaphysics not as wrong but as having no meaning; a criterion of meaning based on Ludwig Wittgenstein
's early work; the idea that all knowledge should be codifiable by a single standard language of science; and above all the project of "rational reconstruction," in which ordinary-language concepts were gradually to be replaced by more precise equivalents in that standard language.
During the early 1930s, the Vienna Circle dispersed, mainly because of political upheaval and the untimely deaths of Hahn and Schlick. The most prominent proponents of logical positivism emigrated to the United Kingdom and the United States, where they influenced American philosophy considerably. Until the 1950s, logical positivism was the leading school in the philosophy of science. During this period, Carnap proposed a replacement for the earlier doctrines in his "Logical Syntax of Language". This change of emphasis and the somewhat different opinions of Reichenbach and others resulted in a consensus that the English name for the shared doctrine, in its American exile from the late 1930s, should be "logical empiricism."
and Ludwig Wittgenstein
's formalism was developed by a group of philosophers in Vienna and Berlin, who formed the Vienna Circle
and Berlin Circle into a doctrine known as logical positivism (or logical empiricism). Logical positivism used formal logic to underpin an empiricist account of our knowledge of the world. Philosophers such as Rudolf Carnap
and Hans Reichenbach
, along with other members of the Vienna Circle
, claimed that the truths of logic and mathematics were tautologies
, and those of science were verifiable empirical claims. These two constituted the entire universe of meaningful judgements; anything else was nonsense.
The claims of ethics and aesthetics were subjective preferences. Theology and other metaphysics were pseudo-statements, neither true nor false, simply meaningless nonsense. Karl Popper
's insistence upon the role of falsification in the philosophy of science was a reaction to the logical positivists. With the rise of Adolf Hitler
and National Socialism in Germany and Austria, some members of the Vienna and Berlin Circles fled Germany
, mainly to Britain and the USA, which helped to reinforce the dominance of logical positivism and analytic philosophy in the Anglophone world.
Logical positivists typically considered philosophy as having a very limited function. For them, philosophy concerned the organization of thoughts, rather than having distinct topics of its own. The positivists adopted the principle of verificationism, according to which every meaningful statement is either analytic or is capable of being verified by experience. This caused the logical positivists to reject many traditional problems of philosophy, especially those of metaphysics
or ontology
, as meaningless.
Ernst Mach
, Gottlob Frege
, Bertrand Russell
and the young Ludwig Wittgenstein
.
Mach's influence is most apparent in the logical positivists' persistent concern with metaphysics
, the unity of science, and the interpretation of the theoretical terms of science, as well as the doctrines of reductionism
and phenomenalism
, later abandoned by many positivists.
Wittgenstein's Tractatus Logico-Philosophicus
was a text of great importance for the positivists. The Tractatus introduced many doctrines which later influenced logical positivism, including the concept of philosophy as a "critique of language," and the possibility of making a theoretically principled distinction between intelligible and nonsensical discourse. The Tractatus also adhered to a correspondence theory of truth
which the positivists adopted, although some, like Otto Neurath
, preferred a form of coherentism
. Wittgenstein's influence is also evident in certain formulations of the verification principle. Compare, for example, Proposition 4.024 of the Tractatus, where Wittgenstein asserts that we understand a proposition when we know what happens if it is true, with Schlick's assertion that "To state the circumstances under which a proposition is true is the same as stating its meaning." The tractarian doctrine that the truths of logic are tautologies was widely believed among the logical positivists. Wittgenstein also influenced the logical positivists' interpretation of probability
. According to Neurath, some logical positivists disliked the Tractatus, since they thought it included a great deal of metaphysics.
Contemporary developments in logic and the foundations of mathematics, especially Bertrand Russell
and Alfred North Whitehead
's monumental Principia Mathematica
, impressed the more mathematically minded logical positivists such as Hans Hahn
and Rudolf Carnap
. "Language-planning" and syntactical techniques derived from these developments were used to defend logicism
in the philosophy of mathematics and various reductionist theses. Russell's theory of types
was employed to great effect in Carnap's early anti-metaphysical polemics.
Immanuel Kant
also had an important influence on the positivists, both positive and negative. Negatively, Kant was often scorned by the positivists in their early debates, and Kant's doctrine of synthetic a priori truths was the doctrine they most wished to discredit. However, Kant's opinions about the nature of physical objects pervaded the "protocol sentence" debate, and Kantian opinions of the relationship between philosophy and science were shared by the positivists to some degree.
in Germany is thought to have developed in response to Hegelian and neo-Hegelian metaphysics, which was a famous philosophy in Germany. Hegelian "successors" such as F.H. Bradley attempted to explain reality by postulating metaphysical entities that did not have any empirical basis. Logical positivists in response wanted to stop such metaphysical entities from being used as an explanation.
Another, less well-known factor that encouraged logical positivism was the urgency of solving new philosophical problems raised by new scientific developments. The Vienna Circle
under the influence of Moritz Schlick
and the Berlin Circle
under the influence of Hans Reichenbach
consisted of scientists, mathematicians, and scientists turned philosophers, who shared a common goal of solving new problems in the philosophy of science.
and metaphysics
. Early, most logical positivists proposed that all knowledge is based on logical inference from simple "protocol sentences" grounded in observable facts. Many logical positivists endorsed forms of materialism
, metaphysical naturalism
, and empiricism
. (See James Ladyman, Understanding Philosophy of Science, p. 147)
Perhaps the view for which the logical positivists are best known is the verifiability criterion of meaning, or verificationism. In one of its earlier and stronger formulations, this is the doctrine that a proposition is "cognitively meaningful" only if there is a finite procedure for conclusively determining its truth. An intended consequence of this opinion, for most logical positivists, is that metaphysical, theological, and ethical statements fail this criterion, and so are not cognitively meaningful. They distinguished cognitive from other varieties of meaningfulness (e.g. emotive, expressive, figurative), and most authors concede that the non-cognitive statements of the history of philosophy possess some other kind of meaningfulness. The positive characterization of cognitive meaningfulness varies from author to author. It has been described as the property of having a truth value, corresponding to a possible state of affairs, naming a proposition, or being intelligible or understandable in the sense in which scientific statements are intelligible or understandable.
Another characteristic feature of logical positivism is the commitment to "Unified Science
"; that is, the development of a common language or, in Neurath's phrase, a "universal slang" in which all scientific propositions can be expressed. The adequacy of proposals or fragments of proposals for such a language was often asserted on the basis of various "reductions" or "explications" of the terms of one special science to the terms of another, putatively more fundamental one. Sometimes these reductions consisted of set-theoretic manipulations of a few logically primitive concepts (as in Carnap's (1928) Logical Structure of the World); sometimes these reductions consisted of allegedly analytic or a priori deductive relationships (as in Carnap's Testability and Meaning). A number of publications over a period of thirty years would attempt to elucidate this concept.
. The term subsequently came to be almost interchangeable with "analytic philosophy" during the first half of the twentieth century. Logical positivism was immensely influential in the philosophy of language
and represented the dominant philosophy of science
between World War I
and the Cold War
.
, since it had implications for the practice of science and the empirical truth of other statements. This presented severe problems for the logical consistency of the theory. Another problem was that, while positive existential claims
("there is at least one human being") and negated universal claims ("not all ravens are black") allow for obvious methods of verification (find a human or a non-black raven), negative existential claims and positive universal claims do not allow for verification.
Universal claims could apparently never be verified: How can you tell that all ravens are black, unless you've hunted down every raven, including those of the past and future? This resulted in a great deal of work on induction, probability, and "confirmation," which combined verification and falsification
.
Logical positivists' response to the first criticism was that logical positivism is a philosophy of science, not an axiomatic system
that can prove its own consistency (see Godel's incompleteness theorem). Secondly, a theory of language
and mathematical logic
were created to answer what it really means to make statements like "all ravens are black."
Many commentators (including those of the preceding section) on logical positivism have attributed to its proponents a greater unity of purpose and creed than they actually shared, ignoring the complex disagreements among the logical positivists themselves.
, who published the book Logik der Forschung in 1934 (translated by himself as The Logic of Scientific Discovery
, published 1959). In it he argued that the positivists' criterion of verifiability was too strong a criterion for science, and should be replaced by a criterion of falsifiability
. Popper thought that falsifiability was a better criterion because it did not invite the philosophical problems inherent in verifying an inductive inference, and it allowed statements from the physical sciences which seemed scientific but which did not satisfy the verification criterion.
Popper's concern was not with distinguishing meaningful from meaningless statements, but distinguishing scientific from metaphysical statements. Unlike the positivists, he did not claim that metaphysical statements must be meaningless; he also claimed that a statement which was "metaphysical" and unfalsifiable in one century (like the ancient Greek philosophy about atom
s) could, in another century, be developed into falsifiable theories that have the metaphysical views as a consequence, and thus become scientific.
Popper denied that science need rely on inductive reasoning, or that inductive reasoning actually exists, although most philosophers think it obvious that science does rely on it.
, can possibly be anything more than a probable hypothesis
" (Ayer 1946:51), and therefore can only be subject to weak verification. This defense was controversial among logical positivists, some of whom touted strong verification, and claimed that general propositions were indeed nonsense.
, a former student of Hans Reichenbach
and Rudolf Carnap
, making an observational/theoretical distinction is meaningless. The "received view
" operates on the correspondence rule that states "The observational terms are taken as referring to specified phenomena or phenomenal properties, and the only interpretation given to the theoretical terms is their explicit definition provided by the correspondence rules." Putnam argues that introducing this dichotomy of observational terms and theoretical terms is the problem from which to start. Putnam demonstrates this with four objections:
has claimed that it is not possible to provide truth conditions for science independent of its historical paradigm. But even this criticism was not unknown to the logical positivists: Otto Neurath compared science to a boat which we must rebuild on the open sea.
expressed it, "dead, or as dead as a philosophical movement ever becomes." By the late 1970s, its ideas were so generally recognized to be seriously defective that one of its own main proponents, A. J. Ayer, could say in a interview: "I suppose the most important [defect]...was that nearly all of it was false." It retains an important place in the history of Analytic philosophy
as the antecedent of philosophies which continue now, such as Constructive empiricism
, Positivism
and Postpositivism
.
Articles on logical positivism
Articles on related philosophical topics
Empiricism
Empiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...
—the idea that observational evidence is indispensable for knowledge—with a version of rationalism
Rationalism
In epistemology and in its modern sense, rationalism is "any view appealing to reason as a source of knowledge or justification" . In more technical terms, it is a method or a theory "in which the criterion of the truth is not sensory but intellectual and deductive"...
incorporating mathematical and logico-linguistic constructs and deductions of epistemology.
It may be considered as a type of analytic philosophy
Analytic philosophy
Analytic philosophy is a generic term for a style of philosophy that came to dominate English-speaking countries in the 20th century...
.See, e.g., : "Vienna Circle" in Stanford Encyclopedia of Philosophy
Logical positivism, in the formal sense, began from discussions of a group known as the "First Vienna Circle
Vienna Circle
The Vienna Circle was an association of philosophers gathered around the University of Vienna in 1922, chaired by Moritz Schlick, also known as the Ernst Mach Society in honour of Ernst Mach...
" which gathered during the earliest years of the 20th century in Vienna at the Café Central
Café Central
Café Central is a coffeehouse in Vienna. It is located in the Innere Stadt district at Herrengasse 14 in the former Bank and Stockmarket Building , today called the Palais Ferstel after its architect Heinrich von Ferstel....
. After World War I, Hans Hahn
Hans Hahn
Hans Hahn was an Austrian mathematician who made contributions to functional analysis, topology, set theory, the calculus of variations, real analysis, and order theory.-Biography:...
, a member of that early group, helped bring Moritz Schlick
Moritz Schlick
Friedrich Albert Moritz Schlick was a German philosopher, physicist and the founding father of logical positivism and the Vienna Circle.-Early life and works:...
to Vienna. Schlick's Vienna Circle
Vienna Circle
The Vienna Circle was an association of philosophers gathered around the University of Vienna in 1922, chaired by Moritz Schlick, also known as the Ernst Mach Society in honour of Ernst Mach...
, along with Hans Reichenbach
Hans Reichenbach
Hans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...
's "Berlin Circle
Berlin Circle (philosophy)
The Berlin Circle was a group that maintained logical empiricist views about philosophy.It was created in the late 1920s by Hans Reichenbach, Kurt Grelling and Walter Dubislav and composed of philosophers and scientists such as Carl Gustav Hempel, David Hilbert and Richard von Mises...
", propagated the new doctrines more widely during the 1920s and early 1930s. It was Otto Neurath
Otto Neurath
Otto Neurath was an Austrian philosopher of science, sociologist, and political economist...
's advocacy that made the movement self-conscious and more widely known. A 1929 pamphlet written by Neurath, Hahn, and Rudolf Carnap
Rudolf Carnap
Rudolf Carnap was an influential German-born philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism....
summarized the doctrines of the Vienna Circle at that time. The doctrines included the opposition to all metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
, especially ontology
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
and synthetic a priori propositions; the rejection of metaphysics not as wrong but as having no meaning; a criterion of meaning based on Ludwig Wittgenstein
Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He was professor in philosophy at the University of Cambridge from 1939 until 1947...
's early work; the idea that all knowledge should be codifiable by a single standard language of science; and above all the project of "rational reconstruction," in which ordinary-language concepts were gradually to be replaced by more precise equivalents in that standard language.
During the early 1930s, the Vienna Circle dispersed, mainly because of political upheaval and the untimely deaths of Hahn and Schlick. The most prominent proponents of logical positivism emigrated to the United Kingdom and the United States, where they influenced American philosophy considerably. Until the 1950s, logical positivism was the leading school in the philosophy of science. During this period, Carnap proposed a replacement for the earlier doctrines in his "Logical Syntax of Language". This change of emphasis and the somewhat different opinions of Reichenbach and others resulted in a consensus that the English name for the shared doctrine, in its American exile from the late 1930s, should be "logical empiricism."
Summary
During the late 1920s, '30s, and '40s, Bertrand RussellBertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...
and Ludwig Wittgenstein
Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He was professor in philosophy at the University of Cambridge from 1939 until 1947...
's formalism was developed by a group of philosophers in Vienna and Berlin, who formed the Vienna Circle
Vienna Circle
The Vienna Circle was an association of philosophers gathered around the University of Vienna in 1922, chaired by Moritz Schlick, also known as the Ernst Mach Society in honour of Ernst Mach...
and Berlin Circle into a doctrine known as logical positivism (or logical empiricism). Logical positivism used formal logic to underpin an empiricist account of our knowledge of the world. Philosophers such as Rudolf Carnap
Rudolf Carnap
Rudolf Carnap was an influential German-born philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism....
and Hans Reichenbach
Hans Reichenbach
Hans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...
, along with other members of the Vienna Circle
Vienna Circle
The Vienna Circle was an association of philosophers gathered around the University of Vienna in 1922, chaired by Moritz Schlick, also known as the Ernst Mach Society in honour of Ernst Mach...
, claimed that the truths of logic and mathematics were tautologies
Tautology (logic)
In logic, a tautology is a formula which is true in every possible interpretation. Philosopher Ludwig Wittgenstein first applied the term to redundancies of propositional logic in 1921; it had been used earlier to refer to rhetorical tautologies, and continues to be used in that alternate sense...
, and those of science were verifiable empirical claims. These two constituted the entire universe of meaningful judgements; anything else was nonsense.
The claims of ethics and aesthetics were subjective preferences. Theology and other metaphysics were pseudo-statements, neither true nor false, simply meaningless nonsense. Karl Popper
Karl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...
's insistence upon the role of falsification in the philosophy of science was a reaction to the logical positivists. With the rise of Adolf Hitler
Adolf Hitler
Adolf Hitler was an Austrian-born German politician and the leader of the National Socialist German Workers Party , commonly referred to as the Nazi Party). He was Chancellor of Germany from 1933 to 1945, and head of state from 1934 to 1945...
and National Socialism in Germany and Austria, some members of the Vienna and Berlin Circles fled Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, mainly to Britain and the USA, which helped to reinforce the dominance of logical positivism and analytic philosophy in the Anglophone world.
Logical positivists typically considered philosophy as having a very limited function. For them, philosophy concerned the organization of thoughts, rather than having distinct topics of its own. The positivists adopted the principle of verificationism, according to which every meaningful statement is either analytic or is capable of being verified by experience. This caused the logical positivists to reject many traditional problems of philosophy, especially those of metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
or ontology
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
, as meaningless.
Origins
The main influences on the early logical positivists were the positivistPositivism
Positivism is a a view of scientific methods and a philosophical approach, theory, or system based on the view that, in the social as well as natural sciences, sensory experiences and their logical and mathematical treatment are together the exclusive source of all worthwhile information....
Ernst Mach
Ernst Mach
Ernst Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as the Mach number and the study of shock waves...
, Gottlob Frege
Gottlob Frege
Friedrich Ludwig Gottlob Frege was a German mathematician, logician and philosopher. He is considered to be one of the founders of modern logic, and made major contributions to the foundations of mathematics. He is generally considered to be the father of analytic philosophy, for his writings on...
, Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...
and the young Ludwig Wittgenstein
Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He was professor in philosophy at the University of Cambridge from 1939 until 1947...
.
Mach's influence is most apparent in the logical positivists' persistent concern with metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
, the unity of science, and the interpretation of the theoretical terms of science, as well as the doctrines of reductionism
Reductionism
Reductionism can mean either an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things or a philosophical position that a complex system is nothing but the sum of its parts, and that an account of it can...
and phenomenalism
Phenomenalism
Phenomenalism is the view that physical objects do not exist as things in themselves but only as perceptual phenomena or sensory stimuli situated in time and in space...
, later abandoned by many positivists.
Wittgenstein's Tractatus Logico-Philosophicus
Tractatus Logico-Philosophicus
The Tractatus Logico-Philosophicus is the only book-length philosophical work published by the Austrian philosopher Ludwig Wittgenstein in his lifetime. It was an ambitious project: to identify the relationship between language and reality and to define the limits of science...
was a text of great importance for the positivists. The Tractatus introduced many doctrines which later influenced logical positivism, including the concept of philosophy as a "critique of language," and the possibility of making a theoretically principled distinction between intelligible and nonsensical discourse. The Tractatus also adhered to a correspondence theory of truth
Correspondence theory of truth
The correspondence theory of truth states that the truth or falsity of a statement is determined only by how it relates to the world, and whether it accurately describes that world...
which the positivists adopted, although some, like Otto Neurath
Otto Neurath
Otto Neurath was an Austrian philosopher of science, sociologist, and political economist...
, preferred a form of coherentism
Coherence theory of truth
Coherence theory of truth regards truth as coherence with some specified set of sentences, propositions or beliefs. There is no single coherence theory of truth, but rather an assortment of perspectives that are commonly collected under this title...
. Wittgenstein's influence is also evident in certain formulations of the verification principle. Compare, for example, Proposition 4.024 of the Tractatus, where Wittgenstein asserts that we understand a proposition when we know what happens if it is true, with Schlick's assertion that "To state the circumstances under which a proposition is true is the same as stating its meaning." The tractarian doctrine that the truths of logic are tautologies was widely believed among the logical positivists. Wittgenstein also influenced the logical positivists' interpretation of probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...
. According to Neurath, some logical positivists disliked the Tractatus, since they thought it included a great deal of metaphysics.
Contemporary developments in logic and the foundations of mathematics, especially Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...
and Alfred North Whitehead
Alfred North Whitehead
Alfred North Whitehead, OM FRS was an English mathematician who became a philosopher. He wrote on algebra, logic, foundations of mathematics, philosophy of science, physics, metaphysics, and education...
's monumental Principia Mathematica
Principia Mathematica
The Principia Mathematica is a three-volume work on the foundations of mathematics, written by Alfred North Whitehead and Bertrand Russell and published in 1910, 1912, and 1913...
, impressed the more mathematically minded logical positivists such as Hans Hahn
Hans Hahn
Hans Hahn was an Austrian mathematician who made contributions to functional analysis, topology, set theory, the calculus of variations, real analysis, and order theory.-Biography:...
and Rudolf Carnap
Rudolf Carnap
Rudolf Carnap was an influential German-born philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism....
. "Language-planning" and syntactical techniques derived from these developments were used to defend logicism
Logicism
Logicism is one of the schools of thought in the philosophy of mathematics, putting forth the theory that mathematics is an extension of logic and therefore some or all mathematics is reducible to logic. Bertrand Russell and Alfred North Whitehead championed this theory fathered by Richard Dedekind...
in the philosophy of mathematics and various reductionist theses. Russell's theory of types
Type theory
In mathematics, logic and computer science, type theory is any of several formal systems that can serve as alternatives to naive set theory, or the study of such formalisms in general...
was employed to great effect in Carnap's early anti-metaphysical polemics.
Immanuel Kant
Immanuel Kant
Immanuel Kant was a German philosopher from Königsberg , researching, lecturing and writing on philosophy and anthropology at the end of the 18th Century Enlightenment....
also had an important influence on the positivists, both positive and negative. Negatively, Kant was often scorned by the positivists in their early debates, and Kant's doctrine of synthetic a priori truths was the doctrine they most wished to discredit. However, Kant's opinions about the nature of physical objects pervaded the "protocol sentence" debate, and Kantian opinions of the relationship between philosophy and science were shared by the positivists to some degree.
Logical positivism in Germany
PositivismPositivism
Positivism is a a view of scientific methods and a philosophical approach, theory, or system based on the view that, in the social as well as natural sciences, sensory experiences and their logical and mathematical treatment are together the exclusive source of all worthwhile information....
in Germany is thought to have developed in response to Hegelian and neo-Hegelian metaphysics, which was a famous philosophy in Germany. Hegelian "successors" such as F.H. Bradley attempted to explain reality by postulating metaphysical entities that did not have any empirical basis. Logical positivists in response wanted to stop such metaphysical entities from being used as an explanation.
Another, less well-known factor that encouraged logical positivism was the urgency of solving new philosophical problems raised by new scientific developments. The Vienna Circle
Vienna Circle
The Vienna Circle was an association of philosophers gathered around the University of Vienna in 1922, chaired by Moritz Schlick, also known as the Ernst Mach Society in honour of Ernst Mach...
under the influence of Moritz Schlick
Moritz Schlick
Friedrich Albert Moritz Schlick was a German philosopher, physicist and the founding father of logical positivism and the Vienna Circle.-Early life and works:...
and the Berlin Circle
Berlin Circle (philosophy)
The Berlin Circle was a group that maintained logical empiricist views about philosophy.It was created in the late 1920s by Hans Reichenbach, Kurt Grelling and Walter Dubislav and composed of philosophers and scientists such as Carl Gustav Hempel, David Hilbert and Richard von Mises...
under the influence of Hans Reichenbach
Hans Reichenbach
Hans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...
consisted of scientists, mathematicians, and scientists turned philosophers, who shared a common goal of solving new problems in the philosophy of science.
Basic tenets
Although the logical positivists held a wide range of views on many matters, they were all interested in science and skeptical of theologyTheology
Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...
and metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
. Early, most logical positivists proposed that all knowledge is based on logical inference from simple "protocol sentences" grounded in observable facts. Many logical positivists endorsed forms of materialism
Materialism
In philosophy, the theory of materialism holds that the only thing that exists is matter; that all things are composed of material and all phenomena are the result of material interactions. In other words, matter is the only substance...
, metaphysical naturalism
Metaphysical naturalism
Metaphysical naturalism, also called ontological naturalism and philosophical naturalism, or just naturalism, is a philosophical worldview and belief system that holds that there is nothing but natural elements, principles, and relations of the kind studied by the natural sciences, i.e., those...
, and empiricism
Empiricism
Empiricism is a theory of knowledge that asserts that knowledge comes only or primarily via sensory experience. One of several views of epistemology, the study of human knowledge, along with rationalism, idealism and historicism, empiricism emphasizes the role of experience and evidence,...
. (See James Ladyman, Understanding Philosophy of Science, p. 147)
Perhaps the view for which the logical positivists are best known is the verifiability criterion of meaning, or verificationism. In one of its earlier and stronger formulations, this is the doctrine that a proposition is "cognitively meaningful" only if there is a finite procedure for conclusively determining its truth. An intended consequence of this opinion, for most logical positivists, is that metaphysical, theological, and ethical statements fail this criterion, and so are not cognitively meaningful. They distinguished cognitive from other varieties of meaningfulness (e.g. emotive, expressive, figurative), and most authors concede that the non-cognitive statements of the history of philosophy possess some other kind of meaningfulness. The positive characterization of cognitive meaningfulness varies from author to author. It has been described as the property of having a truth value, corresponding to a possible state of affairs, naming a proposition, or being intelligible or understandable in the sense in which scientific statements are intelligible or understandable.
Another characteristic feature of logical positivism is the commitment to "Unified Science
Unified Science
"Unified Science" can refer to any of three related strands in contemporary thought.* Belief in the unity of science was a central tenet of logical positivism. Different logical positivists construed this doctrine in several different ways, e.g...
"; that is, the development of a common language or, in Neurath's phrase, a "universal slang" in which all scientific propositions can be expressed. The adequacy of proposals or fragments of proposals for such a language was often asserted on the basis of various "reductions" or "explications" of the terms of one special science to the terms of another, putatively more fundamental one. Sometimes these reductions consisted of set-theoretic manipulations of a few logically primitive concepts (as in Carnap's (1928) Logical Structure of the World); sometimes these reductions consisted of allegedly analytic or a priori deductive relationships (as in Carnap's Testability and Meaning). A number of publications over a period of thirty years would attempt to elucidate this concept.
Influence
Logical positivism spread throughout almost the entire western world. It was disseminated throughout the European continent. It was spread to Britain by the influence of A. J. Ayer. And later, it was brought to American universities by members of the Vienna Circle after they fled Europe and settled in the United States during and after WWII. Logical positivism was essential to the development of early analytic philosophyAnalytic philosophy
Analytic philosophy is a generic term for a style of philosophy that came to dominate English-speaking countries in the 20th century...
. The term subsequently came to be almost interchangeable with "analytic philosophy" during the first half of the twentieth century. Logical positivism was immensely influential in the philosophy of language
Philosophy of language
Philosophy of language is the reasoned inquiry into the nature, origins, and usage of language. As a topic, the philosophy of language for analytic philosophers is concerned with four central problems: the nature of meaning, language use, language cognition, and the relationship between language...
and represented the dominant philosophy of science
Philosophy of science
The philosophy of science is concerned with the assumptions, foundations, methods and implications of science. It is also concerned with the use and merit of science and sometimes overlaps metaphysics and epistemology by exploring whether scientific results are actually a study of truth...
between World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
and the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
.
Criticisms
Early critics of logical positivism said that its fundamental tenets could not themselves be formulated consistently. The verifiability criterion of meaning did not seem verifiable; but neither was it simply a logical tautologyTautology (logic)
In logic, a tautology is a formula which is true in every possible interpretation. Philosopher Ludwig Wittgenstein first applied the term to redundancies of propositional logic in 1921; it had been used earlier to refer to rhetorical tautologies, and continues to be used in that alternate sense...
, since it had implications for the practice of science and the empirical truth of other statements. This presented severe problems for the logical consistency of the theory. Another problem was that, while positive existential claims
Term logic
In philosophy, term logic, also known as traditional logic or aristotelian logic, is a loose name for the way of doing logic that began with Aristotle and that was dominant until the advent of modern predicate logic in the late nineteenth century...
("there is at least one human being") and negated universal claims ("not all ravens are black") allow for obvious methods of verification (find a human or a non-black raven), negative existential claims and positive universal claims do not allow for verification.
Universal claims could apparently never be verified: How can you tell that all ravens are black, unless you've hunted down every raven, including those of the past and future? This resulted in a great deal of work on induction, probability, and "confirmation," which combined verification and falsification
Falsification
Falsification may refer to:* The act of disproving a proposition, hypothesis, or theory: see Falsifiability* Mathematical proof* Falsified evidence...
.
Logical positivists' response to the first criticism was that logical positivism is a philosophy of science, not an axiomatic system
Axiomatic system
In mathematics, an axiomatic system is any set of axioms from which some or all axioms can be used in conjunction to logically derive theorems. A mathematical theory consists of an axiomatic system and all its derived theorems...
that can prove its own consistency (see Godel's incompleteness theorem). Secondly, a theory of language
Philosophy of language
Philosophy of language is the reasoned inquiry into the nature, origins, and usage of language. As a topic, the philosophy of language for analytic philosophers is concerned with four central problems: the nature of meaning, language use, language cognition, and the relationship between language...
and mathematical logic
Mathematical logic
Mathematical logic is a subfield of mathematics with close connections to foundations of mathematics, theoretical computer science and philosophical logic. The field includes both the mathematical study of logic and the applications of formal logic to other areas of mathematics...
were created to answer what it really means to make statements like "all ravens are black."
Many commentators (including those of the preceding section) on logical positivism have attributed to its proponents a greater unity of purpose and creed than they actually shared, ignoring the complex disagreements among the logical positivists themselves.
Karl Popper's objection
A well-known critic of logical positivism was Karl PopperKarl Popper
Sir Karl Raimund Popper, CH FRS FBA was an Austro-British philosopher and a professor at the London School of Economics...
, who published the book Logik der Forschung in 1934 (translated by himself as The Logic of Scientific Discovery
The Logic of Scientific Discovery
The Logic of Scientific Discovery is a 1934 book by Karl Popper. It was originally written in German and titled Logik der Forschung. Then Popper reformulated his book in English and republished it in 1959. This forms the rare case of a major work to appear in two languages, both written and one...
, published 1959). In it he argued that the positivists' criterion of verifiability was too strong a criterion for science, and should be replaced by a criterion of falsifiability
Falsifiability
Falsifiability or refutability of an assertion, hypothesis or theory is the logical possibility that it can be contradicted by an observation or the outcome of a physical experiment...
. Popper thought that falsifiability was a better criterion because it did not invite the philosophical problems inherent in verifying an inductive inference, and it allowed statements from the physical sciences which seemed scientific but which did not satisfy the verification criterion.
Popper's concern was not with distinguishing meaningful from meaningless statements, but distinguishing scientific from metaphysical statements. Unlike the positivists, he did not claim that metaphysical statements must be meaningless; he also claimed that a statement which was "metaphysical" and unfalsifiable in one century (like the ancient Greek philosophy about atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s) could, in another century, be developed into falsifiable theories that have the metaphysical views as a consequence, and thus become scientific.
Popper denied that science need rely on inductive reasoning, or that inductive reasoning actually exists, although most philosophers think it obvious that science does rely on it.
A.J. Ayer's objection
A response to the second criticism was provided by A. J. Ayer in Language, Truth and Logic, in which he defines the distinction between "strong" and "weak" verification. "A proposition is said to be verifiable, in the strong sense of the term, if, and only if, its truth could be conclusively established by experience." (Ayer 1946:50) It is this sense of verifiable that causes the problem of verification with negative existential claims and positive universal claims. However, the weak sense of verification states that a proposition is "verifiable... if it is possible for experience to render it probable" (ibid.). After establishing this distinction, Ayer claims that "no proposition, other than a tautologyTautology (logic)
In logic, a tautology is a formula which is true in every possible interpretation. Philosopher Ludwig Wittgenstein first applied the term to redundancies of propositional logic in 1921; it had been used earlier to refer to rhetorical tautologies, and continues to be used in that alternate sense...
, can possibly be anything more than a probable hypothesis
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
" (Ayer 1946:51), and therefore can only be subject to weak verification. This defense was controversial among logical positivists, some of whom touted strong verification, and claimed that general propositions were indeed nonsense.
Hilary Putnam's objection
According to Hilary PutnamHilary Putnam
Hilary Whitehall Putnam is an American philosopher, mathematician and computer scientist, who has been a central figure in analytic philosophy since the 1960s, especially in philosophy of mind, philosophy of language, philosophy of mathematics, and philosophy of science...
, a former student of Hans Reichenbach
Hans Reichenbach
Hans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...
and Rudolf Carnap
Rudolf Carnap
Rudolf Carnap was an influential German-born philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism....
, making an observational/theoretical distinction is meaningless. The "received view
Received view of theories
The received view of theories is a position in the philosophy of science that identifies a scientific theory with a set of propositions which are considered to be linguistic objects, such as axioms...
" operates on the correspondence rule that states "The observational terms are taken as referring to specified phenomena or phenomenal properties, and the only interpretation given to the theoretical terms is their explicit definition provided by the correspondence rules." Putnam argues that introducing this dichotomy of observational terms and theoretical terms is the problem from which to start. Putnam demonstrates this with four objections:
- Something is referred to as "observational" if it is observable directly with our senses. Then an observation term cannot be applied to something unobservable. If this is the case, there are no observation terms.
- With Carnap's classification, some unobservable terms are not even theoretical and belong to neither observation terms nor theoretical terms. Some theoretical terms refer primarily to observation terms.
- Reports of observation terms frequently contain theoretical terms.
- A scientific theory may not contain any theoretical terms (an example of this is the original Darwin's theory of evolution).
Subsequent objections from Quine and Kuhn
Subsequent philosophy of science tends to use certain aspects of both of these approaches. W. V. O. Quine criticized the distinction between analytic and synthetic statements and the reduction of meaningful statements to immediate experience. Work by Thomas KuhnThomas Kuhn
Thomas Samuel Kuhn was an American historian and philosopher of science whose controversial 1962 book The Structure of Scientific Revolutions was deeply influential in both academic and popular circles, introducing the term "paradigm shift," which has since become an English-language staple.Kuhn...
has claimed that it is not possible to provide truth conditions for science independent of its historical paradigm. But even this criticism was not unknown to the logical positivists: Otto Neurath compared science to a boat which we must rebuild on the open sea.
Contemporary status within philosophy
Most philosophers consider logical positivism to be, as John PassmoreJohn Passmore
John Passmore AC was an Australian philosopher.Passmore was born in Manly, Sydney. He graduated from the University of Sydney with first-class honours in English literature and philosophy, and went on to study to become a secondary-school teacher...
expressed it, "dead, or as dead as a philosophical movement ever becomes." By the late 1970s, its ideas were so generally recognized to be seriously defective that one of its own main proponents, A. J. Ayer, could say in a interview: "I suppose the most important [defect]...was that nearly all of it was false." It retains an important place in the history of Analytic philosophy
Analytic philosophy
Analytic philosophy is a generic term for a style of philosophy that came to dominate English-speaking countries in the 20th century...
as the antecedent of philosophies which continue now, such as Constructive empiricism
Constructive empiricism
In philosophy, constructive empiricism is a form of empiricism. Bas van Fraassen is nearly solely responsible for the initial development of constructive empiricism; its historically most important presentation appears in his The Scientific Image...
, Positivism
Positivism
Positivism is a a view of scientific methods and a philosophical approach, theory, or system based on the view that, in the social as well as natural sciences, sensory experiences and their logical and mathematical treatment are together the exclusive source of all worthwhile information....
and Postpositivism
Postpositivism
In philosophy and models of scientific inquiry, postpositivism is a metatheoretical stance that critiques and amends positivism. Postpositivists believe that human knowledge is based not on unchallengeable, rock-solid foundations, but rather upon human conjectures...
.
People
- Alfred Jules Ayer
- Gustav BergmannGustav BergmannGustav Bergmann was a philosopher born in Vienna, Austria. He studied at the University of Vienna and was a member of the Vienna Circle. In the United States, he was a professor of philosophy and psychology at the University of Iowa.- Biography :Bergmann earned his Ph.D. in mathematics at the...
- Rudolf CarnapRudolf CarnapRudolf Carnap was an influential German-born philosopher who was active in Europe before 1935 and in the United States thereafter. He was a major member of the Vienna Circle and an advocate of logical positivism....
- Herbert FeiglHerbert FeiglHerbert Feigl was an Austrian philosopher and a member of the Vienna Circle.-Biography:The son of a weaver, Feigl was born in Reichenberg , Bohemia, and matriculated at the University of Vienna in 1922...
- Philipp FrankPhilipp FrankPhilipp Frank was a physicist, mathematician and also an influential philosopher during the first half of the 20th century. He was a logical-positivist, and a member of the Vienna Circle.He was born on 20 March 1884 in Vienna, Austria, and died on 21 July 1966 in Cambridge, Massachusetts, USA...
- Kurt GrellingKurt GrellingKurt Grelling was a logician, philosopher and member of the Berlin Circle.- Life and work :Shortly after his arrival in 1905 at University of Göttingen, Grelling began a collaboration with philosopher Leonard Nelson, with whom he tried to solve Russell's paradox, which had shaken the foundations...
- Hans HahnHans HahnHans Hahn was an Austrian mathematician who made contributions to functional analysis, topology, set theory, the calculus of variations, real analysis, and order theory.-Biography:...
- Carl Gustav HempelCarl Gustav HempelCarl Gustav "Peter" Hempel was a philosopher of science and a major figure in 20th-century logical empiricism...
- Ernest NagelErnest NagelErnest Nagel was a Czech-American philosopher of science. Along with Rudolf Carnap, Hans Reichenbach, and Carl Hempel, he is sometimes seen as one of the major figures of the logical positivist movement....
- Otto NeurathOtto NeurathOtto Neurath was an Austrian philosopher of science, sociologist, and political economist...
- Hans ReichenbachHans ReichenbachHans Reichenbach was a leading philosopher of science, educator and proponent of logical empiricism...
- David RyninDavid RyninDavid Rynin was an American philosopher. He is known mostly as an exponent of logical positivism. He served as president of the Pacific division of the American Philosophical Association in the years 1956-7...
- Moritz SchlickMoritz SchlickFriedrich Albert Moritz Schlick was a German philosopher, physicist and the founding father of logical positivism and the Vienna Circle.-Early life and works:...
- Friedrich WaismannFriedrich WaismannFriedrich Waismann was an Austrian mathematician, physicist, and philosopher. He is best known for being a member of the Vienna Circle and one of the key theorists in logical positivism.-Birth & Early Interest in Philosophy:...
- R. B. BraithwaiteR. B. BraithwaiteRichard Bevan Braithwaite was an English philosopher who specialized in the philosophy of science, ethics, and the philosophy of religion. He was a lecturer in moral science at the University of Cambridge from 1934 to 1953, then Knightbridge Professor of Moral Philosophy there from 1953 to 1967...
Other philosophical movements
- Analytic philosophyAnalytic philosophyAnalytic philosophy is a generic term for a style of philosophy that came to dominate English-speaking countries in the 20th century...
- PositivismPositivismPositivism is a a view of scientific methods and a philosophical approach, theory, or system based on the view that, in the social as well as natural sciences, sensory experiences and their logical and mathematical treatment are together the exclusive source of all worthwhile information....
- Scientific realismScientific realismScientific realism is, at the most general level, the view that the world described by science is the real world, as it is, independent of what we might take it to be...
- Sociological positivism
- Australian realism
Further reading
- Achinstein, PeterPeter AchinsteinPeter Achinstein is a distinguished American Philosopher of Science. He is the author of numerous influential books and articles. He is the Jay and Jeanie Schottenstein University Professor of Philosophy at Yeshiva University, director of the Yeshiva Center for History and Philosophy of Science,...
and Barker, Stephen F.Stephen Francis BarkerStephen Francis Barker is an American philosopher of mathematics, a professor emeritus of philosophy at Johns Hopkins University and a former faculty member at the University of Virginia and Ohio State University....
The Legacy of Logical Positivism: Studies in the Philosophy of Science. Baltimore: Johns Hopkins Press, 1969. - Ayer, Alfred Jules. Logical Positivism. Glencoe, Ill: Free Press, 1959.
- Barone, Francesco. Il neopositivismo logico. Roma Bari: Laterza, 1986.
- Bergmann, Gustav. The Metaphysics of Logical Positivism. New York: Longmans Green, 1954.
- Cirera, Ramon. Carnap and the Vienna Circle: Empiricism and Logical Syntax. Atlanta, GA: Rodopi, 1994.
- Edmonds, David & Eidinow, John; Wittgenstein's Poker, ISBN 0-06-621244-8
- Friedman, Michael. Reconsidering Logical Positivism. Cambridge, UK: Cambridge University Press, 1999
- Gadol, Eugene T. Rationality and Science: A Memorial Volume for Moritz Schlick in Celebration of the Centennial of his Birth. Wien: Springer, 1982.
- Geymonat, Ludovico. La nuova filosofia della natura in Germania. Torino, 1934.
- Giere, Ronald N. and Richardson, Alan W. Origins of Logical Empiricism. Minneapolis: University of Minnesota Press, 1997.
- Hanfling, Oswald. Logical Positivism. Oxford: B. Blackwell, 1981.
- Jangam, R. T. Logical Positivism and Politics. Delhi: Sterling Publishers, 1970.
- Janik, Allan and Toulmin, StephenStephen ToulminStephen Edelston Toulmin was a British philosopher, author, and educator. Influenced by Ludwig Wittgenstein, Toulmin devoted his works to the analysis of moral reasoning. Throughout his writings, he sought to develop practical arguments which can be used effectively in evaluating the ethics behind...
. Wittgenstein's Vienna. London: Weidenfeld and Nicolson, 1973. - Kraft, Victor. The Vienna Circle: The Origin of Neo-positivism, a Chapter in the History of Recent Philosophy. New York: Greenwood Press, 1953.
- McGuinness, Brian. Wittgenstein and the Vienna Circle: Conversations Recorded by Friedrich Waismann. Trans. by Joachim Schulte and Brian McGuinness. New York: Barnes & Noble Books, 1979.
- Mises von, Richard. Positivism: A Study in Human Understanding. Cambridge: Harvard University Press, 1951.
- Parrini, Paolo. Empirismo logico e convenzionalismo: saggio di storia della filosofia della scienza. Milano: F. Angeli, 1983.
- Parrini, Paolo; Salmon, Wesley C.; Salmon, Merrilee H. (ed.) Logical Empiricism - Historical and Contemporary Perspectives, Pittsburgh: University of Pittsburgh Press, 2003.
- Reisch, George. How the Cold War Transformed Philosophy of Science : To the Icy Slopes of Logic. New York: Cambridge University Press, 2005.
- Rescher, Nicholas. The Heritage of Logical Positivism. Lanham, MD: University Press of America, 1985.
- Richardson, Alan and Thomas Uebel (eds.) The Cambridge Companion to Logical Positivism. New York: Cambridge University Press, 2007.
- Salmon, Wesley and Wolters, Gereon (ed.) Logic, Language, and the Structure of Scientific Theories: Proceedings of the Carnap-Reichenbach Centennial, University of Konstanz, 21–24 May 1991, Pittsburgh: University of Pittsburgh Press, 1994.
- Sarkar, Sahotra (ed.) The Emergence of Logical Empiricism: From 1900 to the Vienna Circle. New York: Garland Publishing, 1996.
- Sarkar, Sahotra (ed.) Logical Empiricism at its Peak: Schlick, Carnap, and Neurath. New York: Garland Pub., 1996.
- Sarkar, Sahotra (ed.) Logical Empiricism and the Special Sciences: Reichenbach, Feigl, and Nagel. New York: Garland Pub., 1996.
- Sarkar, Sahotra (ed.) Decline and Obsolescence of Logical Empiricism: Carnap vs. Quine and the Critics. New York: Garland Pub., 1996.
- Sarkar, Sahotra (ed.) The Legacy of the Vienna Circle: Modern Reappraisals. New York: Garland Pub., 1996.
- Spohn, Wolfgang (ed.) Erkenntnis Orientated: A Centennial Volume for Rudolf Carnap and Hans Reichenbach, Boston: Kluwer Academic Publishers, 1991.
External links
Articles by logical positivists- Carnap, Rudolf. 'Empiricism, Semantics, and Ontology.'
- Excerpt from Carnap, Rudolf. Philosophy and Logical Syntax.
- Feigl, Herbert. 'Positivism in the Twentieth Century (Logical Empiricism)', Dictionary of the History of Ideas, 1974, Gale Group (Electronic Edition)
- Hempel, Carl. 'Problems and Changes in the Empiricist Criterion of Meaning.'
Articles on logical positivism
- Kemerling, Garth. 'Logical Positivism', Philosophy Pages
- Murzi, Mauro. 'Logical Positivism', The New Encyclopedia of Unbelief, Tom Flynn (ed.). Prometheus Books, 2007 (PDF version)
- Murzi, Mauro. 'The Philosophy of Logical Positivism.'
- Passmore, John. 'Logical Positivism', The Encyclopedia of Philosophy, Paul Edwards (ed.). New York: Macmillan, 1967, first edition
Articles on related philosophical topics
- Hájek, Alan. 'Interpretations of Probability', The Stanford Encyclopedia of Philosophy (Summer 2003 Edition), Edward N. Zalta (ed.)
- Rey, Georges. 'The Analytic/Synthetic Distinction', The Stanford Encyclopedia of Philosophy (Fall 2003 Edition), Edward N. Zalta (ed.)
- Ryckman, Thomas A., 'Early Philosophical Interpretations of General Relativity', The Stanford Encyclopedia of Philosophy (Winter 2001 Edition), Edward N. Zalta (ed.)
- Woleński, Jan. 'Lvov-Warsaw School', The Stanford Encyclopedia of Philosophy (Summer 2003 Edition), Edward N. Zalta (ed.)
- Woodward, James. 'Scientific Explanation', The Stanford Encyclopedia of Philosophy (Summer 2003 Edition), Edward N. Zalta (ed.)