I. Origins

A. Vienna between the wars

B. Scientific Common Interest
    1. aversion to metaphysics
    2. aversion to marxism, psychoanalysis
    3. Ernst Mach's positivism
    4. lessons of Einstein's theory of relativity (quantum mechanics?)

C. Members:
    1. Vienna: Moritz Schlick, Hans Hahn, Rudolph Carnap, Otto Neurath, Friedrich Weismann, Kurt Gödel, Viktor Kraft,
        Karl Menger,  Herbert Feigl
    2. Berlin: Hans Reichenbach, Carl Hempel
    3. England: A.J.Ayer, Susan Stebbing
    4. America: Philipp Frank, Percy W. Bridgman, Ernest Nagel, Charles Stevenson
    5. relation to Karl Popper

D. Influence of Frege-Russell tradition
    1. logicism
    2. linguistic turn - ideal artificial language theory
    3. foundationalism

E. Influence of Wittgenstein
    1. nature of interaction between L.W. and Vienna circle members
    2. Wittgenstein's Tractatian views
        a) what can be said = the facts = the sciences
        b) laws of logic are tautologies
        c) philosophical problems arise from nonsensical use of language
    3. Wittgenstein's later views

F. Humean influence - empiricism

G. Disbursement of group
    1. reception elsewhere
    2. influence on academic philosophy in America

A. prior statements of positivism
    1. identification of knowledge with science
    2. Comtean aims in positivism
    3. Mach's phenomenalism and anti-realism

B. The logical and the positive
    1. Acceptance of analytic/synthetic distinction
        a) Kantian heritage
        b) Quine's first dogma
    2. The dilemma for mathematics/logic posed by the analytic/synthetic distinction
        a) empiricism makes all synthetic knowledge based on experience
        b) but if logic/math are based on experience, they are not universal and
            necessary
        c) if logic and math are analytic, they are not about the world
    3. Logic and math are tautologies (following the Tractatus)
        a) logicism
        b) describe the structure of any possible world

C. The Verifiability criterion of meaning
    1. The function of a concept of meaning
        a) confusion with a theory of truth
        b) difference from the pragmatists' conception of "meaning"
    2. What is meant by "verifiable"
        a) direct vs. indirect verifiability
        b) verifiability in principle
        c) what is meant by "unverifiable in principle"
    3. What is directly verifiable
        a) basic statements (Protocol sentences)
        b) what are basic statements about
        c) Russellian sense data theory
        d) later physicalism of Carnap
        e) status of memory reports
    4. What is indirectly verifiable
        a) hypotheses
        b) reductionism: all indirectly verifiable (ergo meaningful) statements can be
            analyzed into truth functions of verifiable propositions (Quine's second dogma)
        c) problems with universal statements
            i) laws are subjunctive conditionals - counterfactuals
            ii) confirmation replaces verification
            iii) confirmation and truth conditions
        d) partial reduction sentences
    4. Operationalism - Bridgman
    5. The status of the Verifiability criterion itself

D. The Unity of Science
    1. Philosophy as the logic of science
    2. Unity of reference of basic statements = the (one and only) world
    3. Methodological unity

E. Anti-Metaphysical campaign
    1. statements of metaphysics are unverifiable in principle, hence
        a) they are cognitively meaningless
        b) any possible function is emotive (non-cognitive) = bad poetry
    2. descriptive epistemology (process of belief formation, mental process) reduced to
        empirical science of psychology
    3. anti-metaphysical campaign stands or falls with principle of verifiability
    4. ontological commitments in doctrine of direct verification of basic statements

F. Ethics and value claims (axiology)
    1. normative/descriptive dichotomy
    2. descriptive ethics reduces to social sciences, empirical psychology
    3. normative ethics is emotive
    4. performatory ethics
 

A. Amendments to Verificationism
    1. what are verifiers
        a) sensory states of affairs, sense data, brain states
        b) other sentences
            i) Neurath's Protokollsatze
                a) only a sentence can verify another sentence
                b) an indirectly verifiable statement can be analyzed only into other statements
                c) behaviorism
            ii) Carnap's position in the Aufbau - subjectivism
    2. Carnap's move to physicalism and testability
        a) basis of unity of science
        b) abandons foundationalism for a quasi-conventionalism
        c) the relativism implicit in Logical Syntax of Language
        d) attempts to avoid problems of semantics

B. Problems with reductionism
    1. dispositions and contrary to fact conditionals
    2. Carnap's move from testability to partial reduction
    3. move from "verifiability" to "testability"
        a) the minimal criterion for meaningfulness becomes in effect having empirical
            consequences, but since such a set is inevitably partial, it cannot be identified
            with "the" meaning of the sentence
        b) all non-directly verifiable statements are "hypotheses"
        c) in effect the logic of science becomes the attempt to develop a logic of
            epistemic probability in the relationship between evidence (directly verified) and
            hypotheses

C. The move from Foundationalism towards Conventionalism
    1. the status of the verifiability criterion
        a) Carnap's view that it is a logical statement concerned purely with syntax
        b) Ayer's "prescriptivist" position
    2. the move from empiricism to physicalism
        a) troubles with sense data epistemology
        b) finding a "basic" vocabulary
    3. the ultimate collapse of Quine's two dogmas: analytic/synthetic dichotomy and reductionism
    4. the move to system ("webs") of belief as basic epistemic units