ウィラード・ヴァン・オーマン・クワイン
This naturalization, then, may steer the foundations of knowledge in the direction of a survival mechanism that evolved due to certain environmental factors—a series of fortuitous genetic mutations that thrived and continued to evolve into what we consider knowledge today—and this seems to relegate us to little more than physical systems reacting to our environment. Some would disagree with this cynical look at naturalism and say that knowledge, with all its burdens, is a liberating phenomenon that gives us the reigns to our own lives and a consciousness to human fate. By bearing this phenomenon, we have an obligation to explore, perpetuate, and adapt it, using any means that hint at an epistemological cohesive whole.
Quine always maintained that mathematics required set theory and that set theory was quite distinct from logic. He flirted with Nelson Goodman's nominalism for a while, but backed away when he failed to find a nominalist grounding of mathematics.
New Foundations features a simple and economical criterion for set admissibility, which allows many "large" sets not allowed in the standard ZFC set theory. The (relative) consistency of New Foundations is an open question. A modification of NF, NFU, due to R. B. Jensen and admitting urelements (entities that can be members of sets but that lack elements), turns out to be consistent relative to Peano arithmetic, thus vindicating Quine's intuition.