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.

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.

Quine grew up in Akron, Ohio, where he lived with his parents and older brother Robert Cloyd.

His father was a manufacturing entrepreneur (founder of the Akron Equipment Company, which produced tire molds) and his mother was a schoolteacher and housewife.

[9] It was in Prague that Quine developed a passion for philosophy, thanks to Carnap, whom he defined as his "true and only maître à penser".

During the war, Quine lectured on logic in Brazil, in Portuguese, and served in the United States Navy in a military intelligence role, deciphering messages from German submarines, and reaching the rank of lieutenant commander.

For the academic year 1964–1965, Quine was a fellow on the faculty in the Center for Advanced Studies at Wesleyan University.

Only after World War II did he, by virtue of seminal papers on ontology, epistemology and language, emerge as a major philosopher.

Quine roundly rejected the notion that there should be a "first philosophy", a theoretical standpoint somehow prior to natural science and capable of justifying it.

Techniques he did not teach and discuss include analytic tableaux, recursive functions, and model theory.

While his contributions to logic include elegant expositions and a number of technical results, it is in set theory that Quine was most innovative.

He flirted with Nelson Goodman's nominalism for a while[27] but backed away when he failed to find a nominalist grounding of mathematics.

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: abstraction and inclusion.

[28] He also, in his famous essay On What There is, coined the term "Plato's beard" to refer to the problem of empty names: Suppose now that two philosophers, McX and I, differ over ontology.

This tangled doctrine might be nicknamed Plato's beard: historically it has proved tough, frequently dulling the edge of Occam’s razor.

[30] 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.

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.

In the 1930s and 40s, discussions with Rudolf Carnap, Nelson Goodman and Alfred Tarski, among others, led Quine to doubt the tenability of the distinction between "analytic" statements[32]—those true simply by the meanings of their words, such as "No bachelor is married"— and "synthetic" statements, those true or false by virtue of facts about the world, such as "There is a cat on the mat.

[34] But Quine believes, with all due respect to his "great friend"[35] Skinner, that the ultimate reason is to be found in neurology and not in behavior.

[36] Colleague Hilary Putnam called Quine's indeterminacy of translation thesis "the most fascinating and the most discussed philosophical argument since Kant's Transcendental Deduction of the Categories".

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.

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 ….

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 also points out that free logic additionally can handle the problem of the empty set for statements like

[42] Quine proposed that the best way to determine this is by translating the theory in question into first-order predicate logic.

Of special interest in this translation are the logical constants known as existential quantifiers ('∃'), whose meaning corresponds to expressions like "there exists..." or "for some...".

[42] Various followers of Quine's method chose to apply it to different fields, for example to "everyday conceptions expressed in natural language".

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.

[35] Quine's proposal is controversial among contemporary philosophers and has several critics, with Jaegwon Kim the most prominent among them.