Steps Toward a Constructive Nominalism
Article written by Quine and Nelson Goodman, published in 1947 in the Journal of Symbolic Logic.
Two Dogmas of Empiricism
Noted 1951 paper in which Quine attacks the analytic/synthetic distinction. Full text with hyperlinked footnotes, from the Sellars Project at the University of Chicago.
Verification Theory and Reductionism
A 1951 article by Quine in defense of the empiricist foundation of mathematics.