Sean Morris’s new collection of papers on Carnap and Quine has now come out with CUP, and looks very interesting. I hope to comment on several different papers in it, if there is time, over the next couple of months. Right now I will comment on the first paper, by Sander Verhaegh, which meticulously documents the initial encounter between Carnap and Quine in Vienna and (mainly) Prague in 1932 and 1933. Verhaegh establishes without any doubt that I had got the timing of this initial encounter a bit wrong; I had thought, for some reason, that Quine’s recollection of eagerly reading the Syntax as it emerged from Ina’s typewriter referred to 1932, and thus to the first draft of the Syntax. This mistake was significant because Carnap arrived at his principle of tolerance after completing the first draft, sometime in late 1932 — the first appearance of this principle in print, it is generally agreed, was in the paper “Über Protokollsätze” published in Erkenntnis in late 1932 (Benson gives the date of 30 December 1932), a response to Neurath’s paper on the same subject. Verhaegh establishes that what Quine witnessed emerging from Ina’s typewriter wasn’t the first draft at all, it was the second draft (close but not identical to the final book).

This matters because I had occasionally invoked this inaccurate understanding of the chronology (in this blog and elsewhere) to explain how Quine could have missed the principle of tolerance. In his Harvard lectures on Carnap (published in Rick Creath’s Dear Carnap, Dear Van, 1990), the principle of tolerance is absent. Nor does it come up in any of Carnap’s notes on discussions with Quine, or in their correspondence during this period.

It is certainly possible that while Carnap had adopted the viewpoint of the principle of tolerance in late 1932 (saying things that sound to us as if he’d fully internalized it), he hadn’t yet thought of it self-consciously as anything so grand as a “principle,” hadn’t enunciated it — even to himself — as a distinct new perspective that needed a name. This may have come later, perhaps even after Quine’s visit to Prague. Verhaegh takes this view.

Sometime in 1933, most likely after his meetings with Quine, Carnap reformulated this insight as the Principle of Tolerance — the view that there are no morals in logic, and that “everyone is at liberty to build up his own logic, i.e. his own form of language, as he wishes”. . . (p. 24)

In other words (though he doesn’t say this explicitly), Verhaegh thinks that §17 of the Syntax (the section containing the famous enunciation of the principle of tolerance that’s always quoted), in its published form, must have been written and inserted after March of 1933. This is entirely possible, and there is no internal evidence one way or the other that I’m aware of. It would certainly explain how Quine could have missed the principle of tolerance, and also that it never came up in their pre-war conversations or correspondence. And perhaps it even goes some way toward explaining how Quine could have thought of himself as Carnap’s “disciple” at the time, in all apparent sincerity, despite such a fundamental disagreement.

It is entirely plausible that Carnap might initially have thought of the newly pluralistic attitude expressed in “Über Protokollsätze” as a natural extension of the incipient tolerance (and rejection of ontology) already evident in the Aufbau and other texts, and that drawing more explicit attention to it as a principle only came to seem necessary after his first attempts to get across to people (including Quine) what he was actually doing in the Syntax.

But of course that story will only do for the immediate context of 1933-4, extending perhaps to the Harvard lectures, or perhaps even through “Truth by Convention” (though that is stretching it). In the longer term, the fundamental disagreement was bound to emerge, and the commentators who talk about Quine “rejecting” the principle of tolerance have a good point. In fact, Verhaegh speculates that while Carnap solved some of Quine’s most urgent philosophical worries in 1933-4, Quine also came to this encounter with two strong underlying philosophical prejudices that differed from Carnap’s and distorted Quine’s understanding of Carnap from the beginning: behaviorism and phenomenalism. Regarding the first, Verhaegh cites Carnap’s note on a conversation with Quine in Prague:

He said after reading my MS ‘Syntax’: 1. Is there a principled distinction between the logical laws and the empirical statements? He thinks not. Perhaps though it is only expedient, I seek a distinction, but it appears he is right: gradual difference: they are the sentences that we want to hang on to. (31 March 1933, ASP/RC 102-60-12, cited by Verhaegh on p. 27)

Verhaegh acknowledges that Carnap’s note may indicate, as commentators have thought, that Quine was skeptical about the (or an) analytic-synthetic distinction right from the start, but points out that Quine went on trying to draw it somehow for the next fifteen years or so before he gave up. So:

What is more important, I think, is that the note shows that Quine interpreted Carnap’s theory through the lens of his own behavioristic epistemology, classifying the truths of logic and mathematics as analytic because it is a psychological fact that we will not give them up in the light of adverse experience. (pp. 27-8; appended here is an interesting footnote suggesting that Quine may have mistaken Carnap’s professed “physicalism” for behaviorism)

What Carnap’s note tells me is that even just two years after having escaped from what Steve Awodey and I called “Wittgenstein’s prison,” Carnap was open enough to suggestions that ran completely counter to the basic doctrines of the Tractatus that he was willing to take them seriously. For a moment, at least; there is no further evidence, even from the immediate context, that Carnap was tempted any further in this direction. He was too solidly anchored in what he (and the rest of the Vienna Circle) had learned and re-learned from Wittgenstein in the early 1920s: that logical and mathematical truth was an artifact of representation.

And what Quine’s behavioristic assimilation of Carnap tells me is that Quine, in contrast to Carnap, had never absorbed that Tractarian lesson. This is the fundamental difference. From his undergraduate days, Quine had been a Millian empiricist/behaviorist about all knowledge, including logic and mathematics, and he fit everything subsequent, even Kant, Russell, and then Carnap, into that corset.

I would also point out another element in Quine’s pre-Carnapian philosophical corset that distorted his reception of Carnap, in addition to the two (behaviorism and phenomenalism) discussed by Verhaegh: his relentless focus on ontology. As Gary Kemp and Andrew Lugg point out, the question of what really ultimately exists was on Quine’s mind throughout his early career; they quote him saying: “In my youth I thought of the question of existence, or what there is, as perhaps the most basic question of philosophy and science. In the fullness of time the scales fell from my eyes.” (They generously include Word and Object as still belonging to Quine’s “youth” — certainly the ontological fixation extended at least to the notorious nominalism of the 1940s.) Here it is harder to explain than in the case of behaviorism or phenomenalism (both of which Carnap had endorsed in some form, after all) how Quine could regard himself as Carnap’s “disciple” despite having read (if he had indeed got that far) the final section of the Aufbau, let alone Scheinprobleme. The complete and utter rejection of ontology in any form could not be more explicit in those texts!  

In any case, Verhaegh goes on to point out that the result of Quine’s somewhat distorted reception of Carnap was his inability to discern the fundamental importance of the principle of tolerance in Carnap’s new beginning after 1932:

What Quine failed to see, however, is that the Syntax program had replaced Carnap’s rational reconstruction program. Again, the problem seems to be that Quine misinterpreted the radical nature of Carnap’s principle of tolerance. Whereas Carnap believed that the question of what protocol language to adopt is a question of linguistic decision. . ., Quine seems to have mistakenly presupposed that Carnap revised some of the details of his view about the nature of protocol sentences without abandoning the Aufbau program itself. Indeed, in the remainder of his letter to Cooley [of 4 April 1933, from which Verhaegh has quoted earlier], Quine wrongly suggests that Carnap “would allow the Konstitution system to remain, but without claiming epistemological significance for the particular choice of primitive idea” and he apologizes that he “cannot explain exactly how the syntactic point of view” connects to the “epistemology and the relativity of Protokollsätze,” as the connection is “not treated in his coming book.” Quine, in sum, seems to have been unaware of the fact that Carnap had abandoned rational reconstruction for the logic of science. . .” (p. 29)

But for that, at least, Quine can certainly be forgiven. Carnap himself was never very clear or very explicit about his meta-philosophical stances. As late as the preface to the reissue of the Aufbau in 1961, he says (or seems to be saying) that “explication” is just a new term for “rational reconstruction.” (Which is superficially plausible, but in the new context of the principle of tolerance rational reconstruction had to become something quite different.) And it is likely that he was even less clear during this transitional period of the early to mid-30s, when everything was in flux and he was changing his positions from week to week. Everyone brings their previous prejudices to their reading and their assimilation of new ideas, and Carnap was a sufficiently ambiguous object of assimilation during this period that Quine can be excused for missing a thing or two.