The Question That Quine Refused To Answer
In 1998, at The World Philosophy Congress in Boston, W.V.O. Quine, the leading Analytic philosopher of the second half of the 20th century, was asked by a New York Times reporter: “what have we learned from philosophy in the twentieth century?”
Quine replied: “I should have thought up an answer to that one. I’m going to have to pass.”
Later he was given a second chance, but said: “I really have nothing to add.”[i]
Now, since Quine is generally, and with good reason, taken to be the source of the barbed witticism, “there are two kinds of philosophers: those who are interested in the history of philosophy, and those who are interested in philosophy,” I think that we can safely assume that by “philosophy in the twentieth century,” Quine understood Analytic philosophy in the 20th century.
Granting this, I’ve often wondered why Quine refused to answer that question?
Finally, however, I think that I have an adequate explanation: it all has to do with logical psychologism, scientism, and the history of post-classical Analytic philosophy.
Logical psychologism says that logic is explanatorily reducible to empirical or scientific psychology.[ii]
Scientism says that the formal sciences (especially logic and mathematics) and the natural sciences (especially physics, but also chemistry, biology, and the cognitive sciences) are the paradigms of knowledge, reasoning, and rationality, as regards their content and their methodology alike.[iii]
And by post-classical Analytic philosophy, I mean the second seventy year phase of the 140 year tradition of Analytic of philosophy, that runs from 1950 to 6am this morning; correspondingly, the first seventy years of that tradition (i.e., 1880 to 1950) is what I call classical Analytic philosophy.[iv]
Now back to logical psychologism.
From Pierre Arnauld and Jean Nicole’s Art of Thinking (1662), through Immanuel Kant’s Jäsche Logic (1800), J. S. Mill’s System of Logic (1843), and George Boole’s Investigation of the Laws of Thought (1854), right up to the appearance of Gottlob Frege’s revolutionary Begriffsschrift (1879), logic and psychology seemed to be, if not precisely the same subject, then at least theoretically married to one another.
But the much-celebrated attack on “the sin of logical psychologism” at the end of the nineteenth century brought about a nasty divorce.
According to the leaders of the attack—Frege, and especially Edmund Husserl in his 1900 book Prolegomena to Pure Logic[v]—this parting of the ways was a simple matter of irreconcilable differences: the principles or laws of logic are absolutely necessary, whereas the laws of empirical or scientific psychology are only contingent generalizations; logic is true, whereas empirical or scientific psychology deals only with human belief; laws of logic are necessarily true, whereas, at best, laws of empirical or scientific psychology are only contingently true; logic is a fully formal or “topic-neutral” science, whereas empirical or scientific psychology focuses only on the species-specific or individual contents of mental states; logical knowledge is a priori or independent of all sense experience, whereas empirical-scientific psychological knowledge is a posteriori or dependent on experience; and so on.
Thereafter “pure logic,” pursued in armchairs by philosophers and other pure logicians, and by philosophically-minded or logically-minded mathematicians, went one way, and “experimental psychology,” pursued in laboratories by men in white coats, went diametrically another.
To make things worse, as Elliott Sober aptly observes, “while the psychologists were leaving, the philosophers were slamming the door behind them.”[vi]
Indeed, logical psychologism is a particularly strong version of the denial that pure logic is an independent and absolutely foundational science.
Logical psychologism was a widely held view in the second half of the 19th century, that grew out of the neo-Kantian and neo-Hegelian traditions alike, and it’s also closely associated with the origins of empirical psychology as an autonomous discipline.[vii]
Husserl’s arguments against logical psychologism in chapters 1-8 of Prologemena to Pure Logic, often referred to simply as Husserl’s “refutation” of logical psychologism, constitute one of the most famous and broadly influential critical set-pieces in 20th century philosophy, comparable in these respects to Quine’s famous attack on the analytic-synthetic distinction in “Two Dogmas of Empiricism,”[viii] first published in 1951, almost exactly fifty years after the Prolegomena, which brought about the end of classical Analytic philosophy.[ix]
Indeed, the original working title of another one of Quine’s famous and closely-related essays from the same period, “Epistemology Naturalized,”[x] was “Epistemology Naturalized: Or, the Case for Psychologism.”[xi]
So, by the 1950s, following Quine’s lead, psychologism was making a serious comeback in post-classical Analytic philosophy.
But here’s where it gets complicated.
In the fifth section of “Two Dogmas of Empiricism,” Quine somewhat abruptly switches from his attack on the analytic/synthetic distinction, to an attack on what he calls “reductionism: the belief that each meaningful statement is equivalent to some logical construct upon terms which refer to immediate experience.”[xii]
The rejection of reductionism enables Quine to move from the semantic atomism of the verificationists to a semantic holism (of beliefs), which in turn sets up his new form of radical empiricism in the sixth and last section, aptly dubbed “empiricism without the dogmas.”[xiii]
In this section, he argues that what traditional philosophers had regarded as necessary a priori truths and beliefs—especially logical truths and beliefs, and mathematical truths and beliefs—differ from contingent a posteriori truths and beliefs only by their high degree of centrality or indispensability in our overall scientific conceptual scheme (our web of beliefs), not by any fundamental semantic or epistemological difference in kind
So, according to Quine, in some loose and unsystematic sense, talk about the a priori will always be with us; but, at bottom, that way of talking is ultimately holistic, altogether continuous with the natural sciences, and above all revisable.
It is this thesis of universal revisability, or fallibilism, that expresses the pragmatic dimension of Quine’s view.
Now, it has been occasionally noticed that there exists a peculiar anomaly or gap in this dimension of Quine’s view.
For Quine must presuppose and use the canonical notation of elementary logic,[xiv] and especially monadic logic[xv] (i.e., a restricted version of elementary logic that includes sentential logic and the logic of quantification into one-place predicates—hence, the monadic truths of elementary logic include all the truth-functional tautologies, and all the logical truths involving one-place predicates and one-place quantifiers only) in order to establish his holistic, behavioristic, fallibilistic, or pragmatic naturalism,[xvi] yet it’s not at all obvious just how his holism, behaviorism, fallibilism, and pragmatic naturalism apply to elementary logic or monadic logic.
Indeed, the very same argument Quine used to such tremendous effect against the conventionalist theory of logical truth in his breakthrough 1935 essay, “Truth by Convention,”[xvii] seems to apply directly to his own positive doctrine.
Just as unreduced, preconventionalized logic is required in order to give the reductive conventionalist definition of a logical truth,[xviii] so it appears that an unreduced, prenaturalized, logic is required in order to naturalize logic.
One way of seeing this point vividly is to raise three questions: (i) what sense could be made of holism itself without logic?, (ii) what sense could be made of the revisability of beliefs or propositions without logic?, and (iii) what sense could be made of the natural sciences without logic?
The doctrine of holism, after all, claims that every belief or proposition is related to every other by consistency or entailment; but consistency and entailment are notions straight out of logic.
So too the very idea of the revisability of a belief or proposition is that its denial is logically consistent, hence it’s able to be rationally discarded by the believer under suitable conditions.
And, finally, by Quine’s own admission, the natural sciences themselves are partially defined by their shared possession of a common or universal logic:
All sciences interlock to some extent; they share a common logic and generally some common part of mathematics, even when nothing else.[xix]
So the very idea of a pragmatically naturalized logic presupposes a common or universal logic—more precisely, what, in his 1970 book Philosophy of Logic, Quine calls “orthodox logic” or “sheer logic,” by which, he must mean either elementary logic or monadic logic:
If sheer logic is not conclusive, then what is? What higher tribunal could abrogate the logic of truth-functions or of quantification?[xx]
This leads to a more direct question: can orthodox or sheer logic really be at bottom empirical, as Quine insists?
A closer look at the texts suggest that Quine was in fact a moving target on this crucial issue; for he said at least two very different things about the revisability of logic.
In “Two Dogmas,” and in chapter 7 of Philosophy of Logic, Quine says explicitly that even the most basic logical truths are subject to possible revision.[xxi]
But then in chapter 6 of Philosophy of Logic, he says this of any “deviant logician” who tries to reject the principle of non-contradiction, aka PNC:[xxii]
Here, evidently, is the deviant logician’s predicament: when he tries to deny the doctrine he only changes the subject.[xxiii]
That is, a deviant logician’s attempted revision of the PNC is self-undermining; he can’t continue to be a logician in the strict sense and seriously deny the PNC.
For the denial of the PNC would imply that the deviant logician has changed the very meanings of the logical constants he’s using.
Or, to put the same idea more positively: to be a logician is to presuppose the absolute unrevisability of some principles of orthodox or sheer logic, including the PNC.
In my opinion, Quine’s “deny the doctrine, change the meaning” argument about the absolute unrevisability of the most basic parts of logic is directly on target.
But it has some implications that Quine could not happily accept.
In 1983, Hilary Putnam gave us a nudge in the direction of fully grasping this point, in “Analyticity and Apriority: Beyond Wittgenstein and Quine.”[xxiv]
Here, Putnam aptly observed that sceptical attacks on the very possibility of a priori truths in classical logic or simple arithmetic are, at bottom, direct challenges to our self-defining conception of human rationality.[xxv]
But I think that the logico-philosophical situation is even worse than that.
The pragmatic naturalist Quinean sceptic claims to be able to conceive the revisability of all truths, including all the laws of orthodox or sheer logic.
Nevertheless, conceivability presupposes the PNC, and also Quine’s “orthodox” or “sheer logic” more specifically, assuming that this is either elementary logic or monadic logic.
So the pragmatic naturalist Quinean sceptic is challenging our self-defining conception of human rationality by covertly using an element of that conception—elementary logic, or at least monadic logic—as a critical weapon.
But, by Quine’s own account, elementary logic, or at least monadic logic, is absolutely unrevisable.
So this is to fall into the most extreme form of pragmatic contradiction—self-stultification or cognitive suicide: you are using your own sceptical weapon on yourself.
As Kant puts it in “The Vienna Logic”:
Proceeding sceptically nullifies all our effort, and it is an antilogical principle . . . For if I bring cognition to the point where it nullifies itself, then it is as if we were to regard all human cognitions as nothing.[xxvi]
If I’m right, then this was the unhappy, paradoxical, and ultimately self-defeating predicament of post-classical Analytic philosophy by 1970—the year Quine published his Philosophy of Logic.
So, by 1970, the most that Quine could do as a philosopher, was to fall on his own logical sword, and gesture mutely toward the natural sciences.
In a substantive philosophical sense, therefore—as opposed to a merely social-institutional sense—the Analytic tradition has been living on borrowed time and running on empty, for seventy years: from 1951, when Quine published “Two Dogmas of Empiricism,” through 1970, when he fell on his logical sword in Philosophy of Logic, to 6am this morning.
Otherwise and more generally put, post-classical Analytic philosophers belonging to the seventy year pragmatic naturalist scientistic tradition since Quine published “Two Dogmas of Empiricism,” have set for themselves the cognitively suicidal aim of replacing Analytic philosophy with natural science.[xxvii]
As we saw, Analytic philosophy began 140 years ago with the expulsion of psychologists and other natural scientists from philosophy departments, and the philosophers slamming the door behind them.
But nowadays, 140 years later, in a complete and utterly ironic reversal, post-classical Analytic philosophers in the post-Quinean pragmatic naturalist scientistic tradition are banging on the doors of psychology departments, and other natural science departments, begging to be allowed in, so that they can wear white coats, and commit cognitive harakiri by replacing Analytic philosophy with natural science.
And that’s why, in 1998, two years before he died, Quine, the leading Analytic philosopher of the second half of the 20th century, had precisely nothing to say about what we can learn from Analytic philosophy in the 20th century, and thus refused to answer the interviewer’s question.
Or as I’d prefer to put it nowadays, in 2021: goodbye Analytic philosophy, and good riddance.[xxviii]
[i] S. Boxer, “Think Tank; At the End of a Century of Philosophizing, the Answer is Don’t Ask,” New York Times (15 August 1998), available online at URL = <https://www.nytimes.com/1998/08/15/arts/think-tank-at-the-end-of-a-century-of-philosophizing-the-answer-is-don-t-ask.html>.
[ii] See, e.g., M. Kusch, Psychologism (London: Routledge, 1995); R. Hanna, Rationality and Logic (Cambridge MA: MIT Press, 2006), ch. 1; R. Hanna, “Husserl’s Arguments against Logical Psychologism: Prolegomena §§ 17-61,” in V. Mayer (ed.), Husserls Logische Untersuchungen (Munich: Akademie Verlag, 2008), pp. 27-42; and R. Hanna, “Transcendental Normativity and the Avatars of Psychologism,” in A. Stati (ed.), Husserl’s Ideas I: New Commentaries and Interpretations (Berlin: De Gruyter, 2015), pp. 51-67.
[iii] On the crucial distinction between science and scientism, see also S. Haack, Science and its Discontents (Rounded Globe, 2017), available online at URL = <https://roundedglobe.com/books/038f7053-e376-4fc3-87c5-096de820966d/Scientism%20and%20its%20Discontents/>.
[iv] See R. Hanna, The Fate of Analysis: Analytic Philosophy From Frege to The Ash-Heap of History, and Toward a Radical Kantian Philosophy of The Future (New York: Mad Duck Coalition, 2021).
[v] E. Husserl, Prolegomena to Pure Logic, in E. Husserl, Logical Investigations, trans. J. N. Findlay (2 vols., London: Routledge & Kegan Paul, 1970), vol. 1, pp. 51–247; see also Hanna, “Husserl’s Arguments against Logical Psychologism: Prolegomena §§ 17-61.”
[vi] E. Sober, “Psychologism,” Journal for the Theory of Social Behavior 8 (1978): 165–192, at p. 165.
[vii] See, e.g., Kusch, Psychologism.
[viii] W.V.O. “Two Dogmas of Empiricism,” in W.V.O. Quine, From a Logical Point of View (2nd edn., New York: Harper & Row, 1961), pp. 20-46.
[ix] See Hanna, The Fate of Analysis, esp. ch. XVI.
[x] W.V.O. Quine, “Epistemology Naturalized,” in W.V.O. Quine, Ontological Relativity (New York: Columbia Univ. Press, 1969), pp. 69-90.
[xi] Kusch, Psychologism, p. 11.
[xii] Quine, “Two Dogmas of Empiricism,” p. 20.
[xiii] Quine, “Two Dogmas of Empiricism,” p. 42.
[xiv] See, e.g., W.V.O. Quine, Methods of Logic (4th edn., Cambridge MA: Harvard Univ. Press, 1982); and B. Mates, Elementary Logic (2nd edn., New York: Oxford Univ. Press, 1972).
[xv] See, e.g., G. Boolos and R. Jeffrey, Computability and Logic (3rd edn., Cambridge: Cambridge Univ. Press, 1989), ch. 25.
[xvi] See, e.g., W.V.O. Quine, Word and Object. Cambridge MA: MIT Press, 1960), pp. 157-161.
[xvii] W.V.O. Quine, “Truth by Convention,” in W.V.O. Quine, The Ways of Paradox (2nd edn., Cambridge, MA: MIT Press, 1976), pp. 77-106.
[xviii] Quine, “Truth by Convention,” p. 104.
[xix] Quine, as quoted in R. Fogelin, “Quine’s Limited Naturalism,” Journal of Philosophy 94 (1997): 543–63, at pp. 550-551.
[xx] W.V.O. Quine, Philosophy of Logic (2nd edn., Cambridge MA: Harvard Univ. Press, 1986), p. 81.
[xxi] Quine, “Two Dogmas of Empiricism,” p. 43; and Quine, Philosophy of Logic, p. 100.
[xxii] In fact, there’s an important distinction to be drawn between (i) the strong or maximal principle of non-contradiction, which says that it’s not the case that any sentence (proposition, statement, belief, judgment, etc.) is both true and false, and (ii) the weak or minimal principle of non-contradiction, which says that it’s not the case that every sentence (proposition, statement, belief, judgment, etc.) is both true and false. The weak or minimal principle of non-contradiction leaves open the possibility that some sentences are both true and false—e.g., paradoxical sentences like the Gödel sentence and the Liar sentence—even though such “truth-value gluts” are not allowed to occur unrestrictedly, which is an apocalyptic logical condition called explosion. See, e.g., H. Putnam, “There is at Least One A Priori Truth,” in H. Putnam, Realism and Reason: Philosophical Papers, Vol. 3 (Cambridge: Cambridge Univ. Press, 1983), pp. 98-114; and Hanna, Rationality and Logic, ch. 2. Deviant logics that permit some truth-value gluts, but rule out explosion, and thus obey the weak or minimal principle of non-contradiction, are called “paraconsistent.” See, e.g., G. Priest, In Contradiction. Dordrecht: Martinus Nijhoff, 1987); and G. Priest, “What Is So Bad About Contradictions?” Journal of Philosophy 95 (1998): 410-426. In Philosophy of Logic, Quine presumably has the strong or maximal principle of non-contradiction in mind; but he also seems not to have recognized the possibility of, or at least seems not to have countenanced the legitimacy of, either the weak or minimal principle of non-contradiction or paraconsistent logic.
[xxiii] Quine, Philosophy of Logic, p. 81.
[xxiv] H. Putnam, “Analyticity and Apriority: Beyond Wittgenstein and Quine,” in Putnam, Realism and Reason: Philosophical Papers, Vol. 3, pp. 115–38.
[xxv] Ibid., pp. 110-111.
[xxvi] I. Kant, “The Vienna Logic,” in I. Kant, Immanuel Kant: Lectures on Logic, trans. J. M. Young (Cambridge: Cambridge Univ. Press, 1992), pp.249–377, at p. 332 (Ak 24: 884).
[xxvii] See also N. Mabaquiao, “The Death of Philosophy Through the Naturalization of the Mind,” (Unpublished MS, 2021), available online at URL = <https://www.academia.edu/21801066/The_Death_of_Philosophy_Through_the_Naturalization_of_the_Mind>.
[xxviii] See Hanna, The Fate of Analysis, esp. chs. XVIII and XIX. The Fate of Analysis is affordably available in hardcover, softcover, and epub, at URL = <https://themadduckcoalition.org/product/the-fate-of-analysis/>.
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