Willard Van Orman Quine ( ; known to his friends as "Van"; June 25, 1908 – December 25, 2000) was an American philosopher and logician in the analytic tradition, recognized as "one of the most influential philosophers of the twentieth century". He was the Edgar Pierce Chair of Philosophy at Harvard University from 1956 to 1978.
Quine was a teacher of logic and set theory. He was famous for his position that first-order logic is the only kind worthy of the name, and developed his own system of mathematics and set theory, known as New Foundations. In the philosophy of mathematics, he and his Harvard colleague Hilary Putnam developed the Quine–Putnam indispensability argument, an argument for the reality of mathematical entities.Colyvan, Mark, "Indispensability Arguments in the Philosophy of Mathematics", The Stanford Encyclopedia of Philosophy (Fall 2004 Edition), Edward N. Zalta (ed.). He was the main proponent of the view that philosophy is not conceptual analysis, but continuous with science; it is the abstract branch of the empirical sciences. This led to his famous quip that "philosophy of science is philosophy enough". He led a "systematic attempt to understand science from within the resources of science itself" and developed an influential naturalized epistemology that tried to provide "an improved scientific explanation of how we have developed elaborate scientific theories on the basis of meager sensory input". He also advocated holism in science, known as the Duhem–Quine thesis.
His major writings include the papers "On What There Is" (1948), which elucidated Bertrand Russell's theory of descriptions and contains Quine's famous dictum of ontological commitment, "To be is to be the value of a variable", and "Two Dogmas of Empiricism" (1951), which attacked the traditional analytic-synthetic distinction and reductionism, undermining the then-popular logical positivism, advocating instead a form of semantic holism and ontological relativity. They also include the books The Web of Belief (1970), which advocates a kind of coherentism, and Word and Object (1960), which further developed these positions and introduced Quine's famous indeterminacy of translation thesis, advocating a behaviorist theory of meaning.
Quine was politically conservative, but the bulk of his writing was in technical areas of philosophy removed from direct political issues. The Wall Street Journal, obituary for W. V. Quine – January 4, 2001 He did, however, write in defense of several conservative positions: for example, he wrote in defense of moral censorship; Quiddities: An Intermittently Philosophical Dictionary, entry for Tolerance (pp. 206–208). while, in his autobiography, he made some criticisms of American postwar academics."Paradoxes of Plenty" in Theories and Things, p. 197. The Time of My Life: An Autobiography, pp. 352–353.
Quine's student Dagfinn Føllesdal noted that Quine suffered from memory loss towards his final years. The deterioration of his short-term memory was so severe that he struggled to continue following arguments. Quine also had considerable difficulty in his project to make the desired revisions to Word and Object. Before passing away, Quine noted to Morton White: "I do not remember what my illness is called, Althusser or Alzheimer, but since I cannot remember it, it must be Alzheimer." He died from the illness on Christmas Day in 2000.
Like the majority of analytic philosophers, who were mostly interested in systematic thinking, Quine evinced little interest in the Western canon: only once did he teach a course in the history of philosophy, on David Hume, in 1946.
Quine wrote three undergraduate texts on formal logic:
Mathematical Logic is based on Quine's graduate teaching during the 1930s and 1940s. It shows that much of what Principia Mathematica took more than 1000 pages to say can be said in 250 pages. The proofs are concise, even cryptic. The last chapter, on Gödel's incompleteness theorem and Tarski's indefinability theorem, along with the article Quine (1946), became a launching point for Raymond Smullyan's later lucid exposition of these and related results.
Quine's work in logic gradually became dated in some respects. Techniques he did not teach and discuss include , recursive functions, and model theory. His treatment of metalogic left something to be desired. For example, Mathematical Logic does not include any proofs of soundness and completeness. Early in his career, the notation of his writings on logic was often idiosyncratic. His later writings nearly always employed the now-dated notation of Principia Mathematica. Set against all this are the simplicity of his preferred method (as exposited in his Methods of Logic) for determining the satisfiability of quantified formulas, the richness of his philosophical and linguistic insights, and the fine prose in which he expressed them.
Most of Quine's original work in formal logic from 1960 onwards was on variants of his predicate functor logic, one of several ways that have been proposed for doing logic without quantifiers. For a comprehensive treatment of predicate functor logic and its history, see Quine (1976). For an introduction, see ch. 45 of his Methods of Logic.
Quine was very warm to the possibility that formal logic would eventually be applied outside of philosophy and mathematics. He wrote several papers on the sort of Boolean algebra employed in electrical engineering, and with Edward J. McCluskey, devised the Quine–McCluskey algorithm of reducing to a minimum covering sum of .
Over the course of his career, Quine proposed three axiomatic set theories.
All three set theories admit a universal class, but since they are free of any hierarchy of types, they have no need for a distinct universal class at each type level.
Quine's set theory and its background logic were driven by a desire to minimize posits; each innovation is pushed as far as it can be pushed before further innovations are introduced. For Quine, there is but one connective, the Sheffer stroke, and one quantifier, the universal quantifier. All polyadic predicates can be reduced to one dyadic predicate, interpretable as set membership. His rules of proof were limited to modus ponens and substitution. He preferred conjunction to either disjunction or the conditional, because conjunction has the least semantic ambiguity. He was delighted to discover early in his career that all of first order logic and set theory could be grounded in a mere two primitive notions: set abstraction and inclusion. For an elegant introduction to the parsimony of Quine's approach to logic, see his "New Foundations for Mathematical Logic", ch. 5 in his From a Logical Point of View.
In his famous essay "On What There Is", he connected each of the three main metaphysical ontological positions—realism/conceptualism/nominalism—with one of three dominant schools in the modern philosophy of mathematics: logicism, intuitionism, and formalism respectively. In the same work, he coined the term "Plato's beard" to refer to the problem of :
Suppose now that two philosophers, McX and I, differ over ontology. Suppose McX maintains there is something which I maintain there is not. McX can, quite consistently with his own point of view, describe our difference of opinion by saying that I refuse to recognize certain entities ... When I try to formulate our difference of opinion, on the other hand, I seem to be in a predicament. I cannot admit that there are some things which McX countenances and I do not, for in admitting that there are such things I should be contradicting my own rejection of them ... This is the old Platonic riddle of nonbeing. Nonbeing must in some sense be, otherwise what is it that there is not? This tangled doctrine might be nicknamed Plato's beard; historically it has proved tough, frequently dulling the edge of Occam’s razor.
Quine was unsympathetic, however, to the claim that saying 'X does not exist' is a tacit acceptance of X's existence and, thus, a contradiction. Appealing to Bertrand Russell and his theory of "singular descriptions", Quine explains how Russell was able to make sense of "complex descriptive names" ('the present King of France', 'the author of Waverly, etc.) by thinking about them as merely "fragments of the whole sentences". For example, 'The author of Waverly was a poet' becomes 'some thing is such that it is the author of Waverly and was a poet, and nothing else is such that it is the author of Waverly'.
Using this sort of analysis with the word 'Pegasus' (that which Quine is wanting to assert does not exist), he turns Pegasus into a description. Turning the word 'Pegasus' into a description is to turn 'Pegasus' into a predicate, to use a term of First-order logic: i.e. a property. As such, when we say 'Pegasus', we are really saying 'the thing that is Pegasus' or 'the thing that Pegasizes'. This introduces, to use another term from logic, bound variables (ex: 'everything', 'something,' etc.) As Quine explains, bound variables, "far from purporting to be names specifically...do not purport to be names at all: they refer to entities generally, with a kind of studied ambiguity peculiar to themselves."
Putting it another way, to say 'I hate everything' is a very different statement than saying 'I hate Bertrand Russell', because the words 'Bertrand Russell' are a proper name that refer to a very specific person. Whereas the word 'everything' is a placeholder. It does not refer to a specific entity or entities. Quine is able, therefore, to make a meaningful claim about Pegasus' nonexistence for the simple reason that the placeholder (a thing) happens to be empty. It just so happens that the world does not contain a thing that is such that it is winged and it is a horse.
Like other analytic philosophers before him, Quine accepted the definition of "analytic" as "true in virtue of meaning alone." Unlike them, however, he concluded that ultimately the definition was circular. In other words, Quine accepted that analytic statements are those that are true by definition, then argued that the notion of truth by definition was unsatisfactory.
Quine's chief objection to analyticity is with the notion of cognitive synonymy (sameness of meaning). He argues that analytical sentences are typically divided into two kinds; sentences that are clearly logically true (e.g. "no unmarried man is married") and the more dubious ones; sentences like "no bachelor is married." Previously it was thought that if you can prove that there is synonymity between "unmarried man" and "bachelor," you have proved that both sentences are logically true and therefore self evident. Quine however gives several arguments for why this is not possible, for instance that "bachelor" in some contexts means a Bachelor of Arts, not an unmarried man.
The gavagai thought experiment tells about a linguist, who tries to find out, what the expression gavagai means, when uttered by a speaker of a yet unknown, native language upon seeing a rabbit. At first glance, it seems that gavagai simply translates with rabbit. Now, Quine points out that the background language and its referring devices might fool the linguist here, because he is misled in a sense that he always makes direct comparisons between the foreign language and his own. However, when shouting gavagai, and pointing at a rabbit, the natives could as well refer to something like undetached rabbit-parts, or rabbit-tropes and it would not make any observable difference. The behavioural data the linguist could collect from the native speaker would be the same in every case, or to reword it, several translation hypotheses could be built on the same sensoric stimuli.
Quine concluded his "Two Dogmas of Empiricism" as follows:
As an empiricist I continue to think of the conceptual scheme of science as a tool, ultimately, for predicting future experience in the light of past experience. Physical objects are conceptually imported into the situation as convenient intermediaries not by definition in terms of experience, but simply as irreducible posits comparable, epistemologically, to the gods of Homer …. For my part I do, qua lay physicist, believe in physical objects and not in Homer's gods; and I consider it a scientific error to believe otherwise. But in point of epistemological footing, the physical objects and the gods differ only in degree and not in kind. Both sorts of entities enter our conceptions only as cultural posits.
Quine's ontological relativism (evident in the passage above) led him to agree with Pierre Duhem that for any collection of empirical evidence, there would always be many theories able to account for it, known as the Duhem–Quine thesis. However, Duhem's holism is much more restricted and limited than Quine's. For Duhem, underdetermination applies only to physics or possibly to natural science, while for Quine it applies to all of human knowledge. Thus, while it is possible to verify or falsifiability whole theories, it is not possible to verify or falsify individual statements. Almost any particular statement can be saved, given sufficiently radical modifications of the containing theory. For Quine, scientific thought forms a Coherentism web in which any part could be altered in the light of empirical evidence, and in which no empirical evidence could force the revision of a given part.
A curious thing about the ontological problem is its simplicity. It can be put into three Anglo-Saxon monosyllables: 'What is there?' It can be answered, moreover, in a word—'Everything'—and everyone will accept this answer as true.W. V. O. Quine, "On What There Is", The Review of Metaphysics 2(5), 1948.
More directly, the controversy goes:
How can we talk about Pegasus? To what does the word 'Pegasus' refer? If our answer is, 'Something', then we seem to believe in mystical entities; if our answer is, 'nothing', then we seem to talk about nothing and what sense can be made of this? Certainly when we said that Pegasus was a mythological winged horse we make sense, and moreover we speak the truth! If we speak the truth, this must be truth about something. So we cannot be speaking of nothing.
Quine resists the temptation to say that non-referring terms are meaningless for reasons made clear above. Instead he tells us that we must first determine whether our terms refer or not before we know the proper way to understand them. However, Czesław Lejewski criticizes this belief for reducing the matter to empirical discovery when it seems we should have a formal distinction between referring and non-referring terms or elements of our domain. Lejewski writes further:
This state of affairs does not seem to be very satisfactory. The idea that some of our rules of inference should depend on empirical information, which may not be forthcoming, is so foreign to the character of logical inquiry that a thorough re-examination of the two inferences existential may prove worth our while.
Lejewski then goes on to offer a description of free logic, which he claims accommodates an answer to the problem.
Lejewski also points out that free logic additionally can handle the problem of the empty set for statements like . Quine had considered the problem of the empty set unrealistic, which left Lejewski unsatisfied.Czeslaw Lejewski, "Logic and Existence". British Journal for the Philosophy of Science, Vol. 5 (1954–1955), pp. 104–119.
The form of the argument is as follows.
The justification for the first premise is the most controversial. Both Putnam and Quine invoke naturalism to justify the exclusion of all non-scientific entities, and hence to defend the "only" part of "all and only". The assertion that "all" entities postulated in scientific theories, including numbers, should be accepted as real is justified by confirmation holism. Since theories are not confirmed in a piecemeal fashion, but as a whole, there is no justification for excluding any of the entities referred to in well-confirmed theories. This puts the nominalism who wishes to exclude the existence of sets and non-Euclidean geometry, but to include the existence of and other undetectable entities of physics, for example, in a difficult position.
Epistemology, or something like it, simply falls into place as a chapter of psychology and hence of natural science. It studies a natural phenomenon, viz., a physical human subject. This human subject is accorded a certain experimentally controlled input—certain patterns of irradiation in assorted frequencies, for instance—and in the fullness of time the subject delivers as output a description of the three-dimensional external world and its history. The relation between the meager input and the torrential output is a relation that we are prompted to study for somewhat the same reasons that always prompted epistemology: namely, in order to see how evidence relates to theory, and in what ways one's theory of nature transcends any available evidence... But a conspicuous difference between old epistemology and the epistemological enterprise in this new psychological setting is that we can now make free use of empirical psychology.
As previously reported, in other occasions Quine used the term "neurology" instead of "empirical psychology".
Quine's proposal is controversial among contemporary philosophers and has several critics, with Jaegwon Kim the most prominent among them. "Naturalized Epistemology". Stanford Encyclopedia of Philosophy. Plato.stanford.edu. July 5, 2001. Accessed March 8, 2010.
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