¹ I do not like to refer to intellectuals associated with the Vienna Circle as ‘neo-positivists’ or ‘logical-positivists’ or any similar term. I find that although logical positivism characterised an aspect, if not the defining aspect of their work, such a definition undermines the breadth, depth and richness of the thought of the members of the Vienna Circle. Where I have used such expressions, it is merely to avoid confusion by keeping with the conventions in which philosophers have traditionally spoken of them. The use of such names also reflects the way in which Popper himself referred to its members in his published works and is thus keeping with Popper's public story, which often differed from the actual story of Popper's interaction with those in his close circle of associates.

² Popper, Karl, Unended Quest: An Intellectual Autobiography, (London: Routledge. 1993, [1974])Google Scholar, 84 Also see: Hacohen, Malachi H.Karl Popper – The Formative Years, 1902–1945, Politics and Philosophy in Interwar Vienna. (Cambridge: Cambridge University Press, 2000), 186–195Google Scholar.

³ Kołakowski, Leszek, Positivist Philosophy: From Hume to the Vienna Circle (Pelican Books, 1972), 209Google Scholar. It is not the case as Kołakowski asserted that in regards to falsificationism as a criterion for meaningfulness that ‘…such a view dismisses all metaphysical doctrines and religious beliefs as meaningless’. Such doctrines and beliefs may not be scientific, but they are also far from being meaningless.

⁴ Feyerabend, Paul, Against Method (London: Verso, 1975), 112Google Scholar.

⁵ Popper, Karl, ‘Memories of Otto Neurath’, After The Open Society: Selected Social and Political Writings (London and New York: Routledge, 2008), 29Google Scholar.

⁶ Popper, op. cit. note 2, 88.

⁷ Popper, op. cit. note 2, 107.

⁸ Popper, Karl, ‘Correspondence with Carnap on Social Philosophy (1940–50)’, After The Open Society: Selected Social and Political Writings, (London and New York: Routledge, 2008), 85–108Google Scholar. Also see Karl-Popper-Sammlung, University of Klagenfurt Library, Box 282–24.

⁹ Letter of correspondence: Carnap to Popper, January 29^th, 1943. See: Karl Popper After the Open Society, 88.

¹⁰ Letters of correspondence: Popper to Carnap, 25^th April 1946. Carnap to Popper, 17^th November, 1946.

¹¹ Letters of correspondence: Carnap to Popper, January 29^th, 1943. Popper to Carnap, 31^st March 1943. See: Karl Popper, After The Open Society, 88–107.

¹² It should be noted that by 1935 Carnap rarely took part in the meetings of the Vienna Circle. See Miller, David, Out of Error: Further Essays on Critical Rationalism, (Aldershot, Burlington: Ashgate, 2006), 9Google Scholar.

¹³ David Frisby in Adorno, Theodor et al. , The Positivist Dispute in German Sociology, (London: Heinemann Educational Books, 1976), xxvi–xxviiGoogle Scholar.

¹⁴ Ibid. xxvi–xxvii.

¹⁵ Adorno et al., op. cit. note 13, xxvii–xxviii.

¹⁶ Ibid. xxvii–xxviii.

¹⁷ Ibid. xx.

¹⁸ Adorno et al., op. cit. note 13, xx.

¹⁹ Stadler, Friedrich, Studien zum Wiener Kreis. Ursprung, Entwicklung und Wiurkung des Logischen Empirismus im Kontext (Frankfurt am Main: Suhrkamp Verlag, 1997), 472Google Scholar.

²⁰ Stadler, op. cit. note 19, 489–545. However, Popper's relationship with the members of the circle was not all positive. After criticising Reichenbach in a conference in Prague 1934, upon their first meeting at which Carnap was present, Reichenbach refused to shake Popper's hand (Ibid. 541).

²¹ For example, Ryckman argued that the logical empiricists division between ‘factual’ and ‘conventional’ aspects of scientific knowledge reflects a ‘lingering residue of a Neo-Kantian interpretation of the theory of relativity’. See Ryckman, Thomas, ‘P(oint) – C(oincidence) – Thinking: The Ironical Attachment of Logical Empiricism to General Relativity (and Some Lingering Consequences)’, Studies in History and Philosophy of Science, 23. 3, (1992), 471–497CrossRefGoogle Scholar.

²² Friedman, Michael, Foundations of Space-Time Theories. (Princeton: Princeton University Press, 1983), 7Google Scholar.

²³ Burdman-Feferman, Anita and Feferman, Solomon, Alfred Tarski: Life and Logic, (Cambridge: Cambridge University Press, 2004)Google Scholar, Ch. 4, 5.

²⁴ For instance, Popper wrote inside the front cover of Jan Łukasiewicz's Aristotle's Syllogistic, that ‘This is the first competent book in English on Aristotle's Syllogistic’. See Karl-Popper-Sammlung, University of Klagenfurt Library.

²⁵ For inter-subjective requirements for objectivity see Popper's Knowledge and the Body-Mind Problem (1994), where Popper wrote of ‘a genetically based instinct to acquire, by imitation, a specifically human language which is fit to be the carrier of objective knowledge’. Karl Popper, (1994), 84. For standards of rationality and testability see Popper's discussion of ‘corroboration’ in The Logic of Scientific Discovery, (New York: Harper and Row, 1968, [1959]), 273–276. Also see Anthony O'Hear's edition (Karl Popper: Philosophy and Problems, Cambridge: Cambridge University Press, 1995, [1980]), 20) for a discussion on the role of deduction and standards of rationality in Popper's thought. Also see David Miller's, Out of Error (op. cit. note 12), 13): ‘There is… the explanation of scientific objectivity in terms of inter-subjectivity… which acknowledges that individual scientists are not objective, but maintains that in a milieu of free critical discussion, possible only in an open society, subjectivity, where it is dangerous, may be largely neutralized.’

²⁶ For Twardowski's understanding of the role and method of philosophy see Wolenski, Jan, Logic and Philosophy in the Lvov-Warsaw School (Dordrecht/Boston/London: Kluwer, 1989), 36–41CrossRefGoogle Scholar. Twardowski like Popper rejected the unscientific treatment of metaphysical problems not the problems themselves. Twardowski developed the distinction between metaphysics (which is reflective of Popper's attitude towards the importance of metaphysics for scientific theory formation) and metaphysicism. The latter is defined by Wolenski as any manner of investigating philosophical problems which in advance assumes a definite metaphysical solution (Ibid. 38).Twardowski's doctrine of Metaphysicism can also be seen to accurately describe Popper's major criticisms of Hegel and the German idealist system builders. Also according to Wolenski, the separation of philosophy as a science from philosophical world-views was a central element of Twardowski's thought and led to a special duty within the Lvov-Warsaw School for philosophers to be critical and self-critical (Ibid. 40–41).

²⁷ For Feyerabend's criticism of Popper's formalism or methodological idealism see op. cit. note 4, ch. 17, 18.

²⁸ These arguments are found in Popper's writings on ‘evolutionary epistemology’ in the essay ‘Evolution and the Tree of Knowledge’ in Objective Knowledge (Clarendan Press, Oxford, 1972). Similar arguments concerning the praxiological or concrete problem solving can be found in All Life is Problemsolving (Routledge: New York, 1999), particularly in the lecture titled ‘All Life is Problem Solving’. Also see Diego Rosende's discussion Popper's distinction between methodological and logical falsifiability in Cohen, Robert and Parusniková's, Zuzana edition, Rethinking Popper (Boston Studies in the Philosophy of Science), (Springer Science, 2009), 144–151Google Scholar.

²⁹ Ajdukiewicz, Kazimierz, Problems and Theories of Philosophy (Cambridge: Cambridge University Press, 1973), xiGoogle Scholar. For an account of Kortabiński's ontology see: Wolenski's Logic and Philosophy in the Lvov-Warsaw School (op. cit. note 26), 224–242.

³⁰ Popper, op. cit. note 25, 444.

³¹ Kraft, Victor, The Vienna Circle. (Westport, Connecticut: Greenwood Press, 1953), 15Google Scholar. Rosende mentions the conventionalist and positivist remnants of Popper's philosophy of science in Logik der Forschung which he replaced with realist and objectivists interpretations of scientific theories. However, it is important to understand that the realist and objectivist aspects of Popper's thought were there from the beginning in a broad philosophical sense, yet did not, as is argued in this thesis, receive methodological prominence until after Popper changed his stance on transcendental criticism and rational arguability. See Cohen and Parusniková, op. cit. note 28, 150.

³² Popper, op. cit. note 2, 10–19.

³³ The following chapter of this thesis is devoted to Popper's change in attitude regarding transcendental criticisms and non-falsifiable theories.

³⁴ Popper, Karl, Frühe Schriften. (Tübingen: Mohr Siebeck, 2006), 87Google Scholar.

³⁵ ‘Die vorliegende Arbeit, obwohl in ihren Hauptteilen im hohen Grade theoretisch, ist dennoch ganz aus praktischer Erfahrung heraus entstanden und soll letzten Endes wieder der Praxis dienen. Ihre Methode ist daher im wesentlichen induktiv’ (Ibid. 87).

³⁶ Popper, op. cit. note 34, 118, 120, 122, 139, 141.

³⁷ Ibid. 118.

³⁸ Ibid. 124.

³⁹ Ibid. 123–124.

⁴⁰ Ibid. 190. Also see: Bühler, Karl. Foundations of Semiotics. Goodwin, Donald Fraser, trans. (Amsterdam; Philadelphia: John Benjamins Publishing Company, 1990 [1927]), 29Google Scholar.

⁴¹ Popper, op. cit. note 34, 255. Research by Michel Ter Hark has also shown how similar positions by Otto Selz also contributed to Popper's linking of biology and cognitive psychology with methodology. For example see Hark, Michael Ter ‘The Psychology of Thinking, Animal Psychology, and the Young Karl Popper’, Journal of the History of the Behavioural Sciences, 40. 4 (2004), 375–392CrossRefGoogle Scholar.

⁴² Popper, op. cit. note 34, 130.

⁴³ Letter of Correspondence. Popper to Victor Kraft. 9^th June 1967. Karl-Popper-Sammlung 3.16, 24 Victor Kraft 1945–74.

⁴⁴ This point was made to me by Arne F. Petersen in response to a question about Popper's pre-deductivist methodology, Friday, 29^th May, 2009. Also see Petersen, Arne F., ‘Popper's Gewöhnungstheorie Assembled and Faced with other Theories of Learning’, Series Humanistica, 6 (2008), 283Google Scholar. For ‘Axiome, Definitionen and Postulate der Geometrie’ see Popper, op. cit. note 34, 263–390.

⁴⁵ Popper, op. cit. note 2, 88.

⁴⁶ Rojszczak, Artur, ‘Philosophical Background and Philosophical content of the Semantic Definition of Truth’, Erkenntnis, 56. (2002), 37CrossRefGoogle Scholar.

⁴⁷ It is further stated by Tarski in his 1936 letter to Neurath that: ‘This agrees also with what Gödel told me in Vienna a year ago; he told me namely about the general mistrust which all investigations and considerations concerning language encountered before my lectures’. (Ibid. 37).

⁴⁸ Popper, op. cit. note 2, 90.

⁴⁹ Burdman-Feferman, A. & S. Feferman, op. cit. note 23, 96. Also see Unended Quest where Popper stated that the positivism developed by the Vienna Circle became influenced by Wittgenstein's Tractatus in ‘a very dogmatic form’. Popper, op. cit. note 2, 97.

⁵⁰ Miller, op. cit. note 12, 5.

⁵¹ Popper, op. cit. note 5, 16.

⁵² Ibid. 16.

⁵³ Ibid. 17.

⁵⁴ Popper, (Op. cit. note 5), 19. Also see Kraft, Julius. Von Husserl zu Heidegger. (Frankfurt: Öffentliches Leben, 1957)Google Scholar.

⁵⁵ See Chapter 5 of my unpublished doctoral thesis for a discussion on Popper's anti-intuitionism. Naraniecki, Alexander, Popper Re-appraised: New Perspectives on Karl Popper's Method and its Applications, (unpublished doctorate) Griffith University, School of Humanities, 2009Google Scholar.

⁵⁶ M.H. Hacohen, op cit. note 2, 123–124.

⁵⁷ See: Letters of correspondence, Popper to Julius Kraft, 25^th May 1933, 11^th July 1933, Karl-Popper-Sammlung. Box 316–23. Also see Popper, Karl, Die beiden Grundprobleme der Erkenntnistheorie (Tübingen: J. C. B. Mohr (Paul Siebeck) 1979)Google Scholar, Ch. 5.

⁵⁸ Popper, op. cit. note 5, 17.

⁵⁹ Ibid. 18.

⁶⁰ Salamun, Kurt, (ed.) Moral und Politik aus der Sicht des Kritischen Rationalismus (Amsterdam: Rodopi B. V., 1991), 95Google Scholar.

⁶¹ Karl Popper, The Myth of the Framework: In defence of science and rationality, M. A. Notturno, (ed.) (London and New York: Routledge), 82–111. Also see Noretta Koertge in Robert Cohen and Zuzana Parusniková, op. cit. note 28, 323–338.

⁶² Letter of Correspondence: Hayek to Popper, 17^th February 1963. Karl-Popper-Sammlung. Box 305. 15.

⁶³ Ibid.

⁶⁴ The ‘Bucket Theory’ for Popper is the theory that ‘our mind is a bucket which is originally empty, or more or less so, and into this bucket material enters through our senses… and accumulates and becomes digested’. This is a weaker theory than the tabula rasa theory which emphasises the perfect emptiness of the mind at birth. Popper is opposed to both these theories which are built on a passive theory of mind and an inductivist theory of learning. Popper also believed that such theories had a devastating influence upon behaviourists. See Popper, op. cit. note 28, 61. It is interesting to note that Popper's understanding of an active problem solving theory of mind anticipated the current trends in neuroscience associated with the work of Paul Bach-y-Rita et al., on neurological plasticity (‘Vision substitution by tactile image projection’. Nature, 221 (5184) 1969, 963–964). Also see Michael Merzenich, ‘Cortical plasticity contributing to childhood development’, in J. L. McClelland and R. S. Siegler, (eds.) ‘Mechanisms of cognitive development: Behavioral and neural perspectives’ (Mahwah, NJ: Lawrence Erlbaum Associates, 2001).

⁶⁵ For a discussion on the importance of problems in gaining ‘real understanding’, see Popper, op. cit. note 28, 180–183.

⁶⁶ According to Blair Campbell, we do not encounter ‘carefully reasoned arguments regarding the political significance of thinking and of history’ in Popper's thought. I explain this feature later in this study as resulting from Popper's scepticism and ‘negativism’. See Campbell, Blair ‘Helvetius and the Roots of the “Closed” Society’, The American Political Science Review, 68. 1. (1974), 153–168CrossRefGoogle Scholar.

⁶⁷ Popper, op. cit. note 5, 233.

⁶⁸ ‘Man muß sich in diesem Zusammenhang daran erinnern, daß die Aufklärung mit Voltaires Briefen aus London über die Engländer anfing: mit dem Versuch, das intellektuelle Klima Englands, jene Trockenheit, die so merkwürdig mit seinem physischen Klima kontrastiert, auf dem Kontinent einzuführen’. Popper, Karl, Auf der Suche nach einer besseren Welt: Vorträge und Aufsätze aus dreißig Jahren, (München: Piper Verlag GmbH, 2004 [1984]), 233Google Scholar.

⁶⁹ Miller, op. cit. note 12, 50.