“Logical Positivism”— “Logical Empiricism”: What’s in a Name? Thomas Uebel University of Manchester Do the terms “logical positivism” and “logical empiricism” mark a philo- sophically real and signiªcant distinction? There is, of course, no doubt that the ªrst term designates the group of philosophers known as the Vi- enna Circle, headed by Moritz Schlick and including Rudolf Carnap, Her- bert Feigl, Philipp Frank, Hans Hahn, Otto Neurath, Friedrich Wais- mann and others. What is debatable, however, is whether the name “logical positivism” correctly distinguishes their doctrines from related ones called “logical empiricism” that emerged from the Berlin Society for Scientiªc Philosophy around Hans Reichenbach which included Walter Dubislav, Kurt Grelling, Kurt Lewin and a young Carl Gustav Hempel.1 The person who called the co-referentiality of the two terms into ques- tion was Reichenbach himself. He did so in two publications of the second half of the 1930s—in an article in Journal of Philosophy (1936) and in his Experience and Prediction (1938)—in order to alert readers to important dif- ferences between his own philosophy and that of the Vienna Circle.2 Reichenbach’s distinction was taken up by his former student Wesley Salmon.3 Not only did Salmon restate it, but he also asserted, categorically and very much in Reichenbach’s spirit, that “our chief inheritance from logical positivism” is “logical empiricism” ([1985] 2005, p. 7). The story of this inheritance is the story of “twentieth-century scientiªc philoso- phy”: 1. In their “Introduction” to the Cambridge Companion to Logical Empiricism Richardson and Uebel solve the matter by decree, declaring both terms to be “synonymous” (2007, p. 1 fn.). 2. Reichenbach’s way of drawing the distinction and its context will be discussed in de- tail in sect. 6 below. 3. This distinction also appears to be basic to Nicolas Rescher’s account of the “Berlin School of Logical Empiricism” (2006). Perspectives on Science 2013, vol. 21, no. 1 ©2013 by The Massachusetts Institute of Technology 58 Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/POSC_a_00086 by guest on 23 September 2021 Perspectives on Science 59 This movement grew chieºy out of the logical positivism of the Vi- enna Circle (with which Carnap was mainly associated) and the log- ical empiricism of the Berlin Group (with which Hans Reichenbach was connected). By midcentury virtually every important ªgure in the movement had relinquished some of the more extreme views of early logical positivism, abandoned the designation of ‘logical posi- tivist’, and adopted ‘logical empiricism’ as the name of their move- ment. After that, logical positivism no longer existed. ([1994] 2005, p. 19) Who then “killed” logical positivism—on this story?4 In print Salmon him- self went no further than to state that Reichenbach regarded his 1938 book as “his refutation of logical positivism” ([1994] 2005, p. 21; cf. [1985] 2005, p. 7) but he also gave no sign of dissent.5 There is, to be sure, this difference between the historical constructions of Reichenbach and Salmon: given his longer-term perspective Salmon allowed Carnap to be- come a logical empiricist, whereas Reichenbach was unable to report such redemption. Yet Reichenbach, as logical empiricism personiªed, remained central on his sketch of the development of analytic philosophy of science. Now there are, of course, many ways of telling a story of development and it is not my business here to deny the importance of Reichenbach ei- ther as a philosopher in his own right or as a moving force of twentieth- century scientiªc philosophy.6 What I do want to call into question, how- ever, is the reliability of this Reichenbachian account as far as the Vienna Circle is concerned. There are different ways in which this can be done. One can point out that the development of Vienna Circle philosophers away from what Reichenbach designated as the doctrines and preoccupa- tions of logical positivism was to a very large extent an internal matter prompted by internal opposition.7 One can point out that Carnap’s thought in particular underwent a development far beyond the embrace of 4. Readers will no doubt recall Popper’s self-incrimination (1974) or the frequent claims made on behalf of Quine’s “Two Dogmas” (1951) or Kuhn’s Structure (1962). Need- less to say, each such claim requires separate treatment. 5. There are, however, clear indications that Salmon made Reichenbach’s story his own: see his unqualiªed use of locutions like “the Vienna Circle of logical positivism” (1977, pp. 6 and 10), his Reichenbachian claim that phenomenalism was a “doctrine to which a number of early positivists had been committed” (1977, p. 47, without drawing any dis- tinction between logical positivism and its positivist predecessors) and footnote 2 of his ([1990] 2005, p. 244) where these points reoccur. (See also his 2005, pp. 3–4.) 6. Nor, I hasten to add, is it to deny the importance of Wesley Salmon himself or that of the Department of Philosophy which Rescher portrays as the for now terminal point of the Berlin School of Logical Empiricism. 7. For a detailed reconstruction of the Vienna Circle’s so-called protocol-sentence de- bate, see Uebel (2007). Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/POSC_a_00086 by guest on 23 September 2021 60 “Logical Positivism”—“Logical Empiricism” the probabilistic realism that Reichenbach championed and so effected a radical reorientation of the ofªce even of scientiªc philosophy.8 On either of these arguments the Vienna Circle regains the doctrinal multidimen- sionality that the Reichenbachian account denies it. Here I shall pursue my objective differently, however, by engaging di- rectly with the history of the appellations which encapsulate Salmon’s Reichenbachian account.9 I shall review the use that leading members and early onlookers of the movement(s) made of the terms in question (and closely related ones), both in terms of self- and third person-ascriptions, to see whether the usage championed by Reichenbach reºects a distinction recognized by the philosophers involved themselves. It might be won- dered whether this is a proper deployment of scholarly effort. Aren’t names but “smoke and mirrors”—or “Schall und Rauch” as a Goethe had Faust replying to the “Gretchenfrage”?10 The quick answer is that even if they carry little signiªcance in and of themselves, nevertheless names so described are indexical signs and we may inquire what ªre their smoke bears witness to. We may do so especially in the case of a philosophical movement whose name is contested. The politics of naming, as it were, may indicate fractions and divisions that subsequent developments of the movement tend to obscure. So even if on grounds of doctrines held it can be shown that the Reichenbachian distinction is over-sharp and mislead- ing it might be held that the distinction does after all reveal important so- cial distinctions and that its use can be defended on their account. Whether this holds true is what is investigated below. 1. Anticipations of “Logical Empiricism,” “Logical Positivism” and “Neopositivism” Before turning to the inception proper of the term “logical positivism”, it must be noted that one individual anticipated more or less all three of the appellations in question—without himself being a protagonist of the movement at the time.11 Eino Kaila, a Finnish philosopher and psy- chologist, coined the phrase “logical empiricism” already in his 1926 monograph on probability theory (see von Wright 1979, p. xxvii) and in 8. For reconstructions of Carnap’s explicationist conception, see, e.g., Carus (2007) or Creath (2009). 9. A still further third appellation, “neopositivism,” must also be taken note of, but since it has a similarly controversial denotation as “logical positivism” it does not require extensive discussion on its own. 10. Goethe, Faust, Act 1, Scene 3. The Gretchenfrage to Faust was: “Und wie hälst Du es mit der Religion?” (And what is your attitude to religion?) 11. Von Wright (1979), Niiniluoto (1992) and Manninen (2009) note that at the time Kaila distanced himself from all extant forms of “positivism” as he understood it. Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/POSC_a_00086 by guest on 23 September 2021 Perspectives on Science 61 1930 published the ªrst in-depth, monograph-length critical study of Carnap’s Aufbau under the title “Logistic Neopositivism” (Der logistische Neupositivismus). Kaila, who had been in correspondence with Reichenbach since 1923 and quoted Schlick’s attribution to Einstein of the “principle of observ- ability” as the “supreme principle of all empirical philosophy” (see Manninen 2010, pp. 49–50), employed the phrase “logical empiricism” in order to describe the view that knowledge of reality was constituted by a system of probability statements that are viewed as a logical function of statements about the given. What connected the latter to the higher reaches of empirical knowledge was a probability logic. Kaila thus op- posed a “reductionist version of positivism” (von Wright 1979, p. xxviii). It has been suggested that Kaila coined the phrase “logical empiricism” with the then very recent psychologism disputes in mind, for he con- trasted its concern with “logical reasons” explicitly with a “psychologistic empiricism” (1926, p. 35, orig. emphasis) that attempted a causal expla- nation (see Manninen 2009, p. 50). By contrast (and probably unknown to Kaila), John Dewey had once called “orthodox logical empiricism” a view that he opposed, namely that “there can be ‘givens,’ sensations, percepts, etc., prior to and independent of thought or ideas, and that thought may be had by some kind of com- pounding or separating of the givens”, as opposed to what he believed, namely that “sensation or perception...issointernally fractionized or perplexed as to...require an idea, a meaning.” (1907, p.