Via Wikipedia-Quine’s position denying the analytic/synthetic distinction is summarized as follows:

It is obvious that truth in general depends on both language and extralinguistic fact. … Thus one is tempted to suppose in general that the truth of a statement is somehow analyzable into a linguistic component and a factual component. Given this supposition, it next seems reasonable that in some statements the factual component should be null; and these are the analytic statements. But, for all its a priori reasonableness, a boundary between analytic and synthetic statements simply has not been drawn. That there is such a distinction to be drawn at all is an unempirical dogma of empiricists, a metaphysical article of faith.^[13]

— Willard v. O. Quine, “Two Dogmas of Empiricism”, p. 64

As a pretty strong materialist, Quine rejects a priori synthetic statements as necessary, as well as mind/body duality problems, regarding the ‘why?’ questions as fundamentally unanswerable.  At least such questions are not for philosophy to posit nor answer, anyways.

There simply doesn’t exist a category of knowledge we humans possess that doesn’t have its origins in our experience.

For Quine, it seems, philosophy is more abstract and general than the sciences (asking questions about questions, clarifying), but it it can’t hope, as Kant hoped, to be placed onto the same ground as the sciences.

Yet, as a Youtube commenter points out: Aren’t there still abstract entities beyond our material existences on Quine’s view (not souls, not God, not ideal forms), but rather just numbers and number sets naturally existing, and perhaps waiting to be discovered?

A link posing a re-purposed Quinian idealism:

ABSTRACT. Quine’s web of belief is influenced by, and encompasses, the entire scope of reality. It is established with a minimalist vocabulary, and is an efficient and integral vehicle toward his metaphysical [a]nd unambiguous ontological commitment, which leads to a somewhat bleak but rigorous membership in the world. Physical objects exhaust the domain of substance, and man becomes a mere four dimensional physical object. All states of mind are psychologized, or reduced to their impact on behaviour. Effectively, idealist criticisms have not simply been taken note of, but idealism has been hijacked, and the result is a new kind of empiricism and an original view of the world.