Willard Van Orman Quine

"Contradiction cannot be tolerated in any scientific system."

"Meaning varies with context in bewildering ways."

"The problem of specifying the subject matter of thought remains one of the fundamental issues of philosophy."

"What makes sense in one linguistic community might be nonsense in another."

"The apparent objectivity of scientific discourse masks its conventional foundations."

"Epistemology is not immune from the problems it investigates."

"The criterion of meaningful discourse cannot itself be meaningful discourse."

"Natural language is vague; formal languages are precise."

"The categories we use to parse reality are not dictated by reality itself."

"What we call knowledge is really just a system of mutually supporting beliefs."

"The analytic-synthetic distinction cannot be sharply drawn."

"Every sentence in our language derives its meaning from its place in the whole fabric of language."

"To be is to be the value of a variable."

"The individual mind is a myth. What is real is the social practice of language."

"Grammar is not a mirror of reality."

"The boundary between science and non-science is blurred."

"Our conceptual schemes are like glasses through which we see the world, yet we are always wearing them."

"Identity is not a relation that makes sense except within a specific conceptual framework."

"The truth conditions of a statement depend upon our entire system of beliefs."

"Abstract objects exist because we need them for our theories."

"Language change is constant; linguistic purism is a losing battle."

"Synonymy is a matter of degree, not an absolute matter."

"The world does not come with coordinates; we impose them."

"Logic is not a constraint on reality; it is a constraint on coherent discourse."

"We cannot step outside language to compare our words with things in themselves."

"The notion of 'true for me but not for you' is incoherent."

"Mathematics is not about abstract entities but about manipulating symbols."

"Our beliefs about the physical world are underdetermined by experience."

"The empiricist's attempt to ground knowledge in sensation fails because sensation itself requires interpretation."

"Metaphysical questions often turn on how we should use words."