Quine, Willard Van Orman

"The problem of universals cannot be solved by reference to abstract objects."

"Language is learned through stimulus and response, not through the apprehension of eternal truths."

"Every science is ultimately a way of organizing experience."

"The law of excluded middle presupposes a particular metaphysical outlook."

"Reference and meaning are not determinate facts about the world."

"What cannot be tested cannot be meaningfully asserted."

"Science and common sense differ in degree, not in kind."

"The mind is not a mirror of nature but a tool for organizing experience."

"Identity conditions determine what objects are."

"The supposed objects of philosophy are not entities but features of our language."

"All knowledge is provisional and subject to revision."

"Empirical content is what a statement shares with its alternatives."

"We project structure onto the world; the world does not force a unique structure upon us."

"The starting point of scientific knowledge is observation guided by theory."

"Logic is revisable in principle, though in practice we revise it rarely."

"The notion of synonymy cannot be sustained in a rigorous theory of meaning."

"Ontological commitments are made when we quantify over objects in our theory."

"Science progresses by simplification and unification of concepts."

"The truth of a statement is relative to a system of concepts."

"Real essences are not the concern of science; nominal essences suffice."

"Mathematics is not the study of abstract objects but of abstract structures we construct."

"Conceptual relativity means different schemes can describe the same world differently."

"The question 'What is there?' can only be answered relative to a language."

"Sensation is the starting point; theory builds upon sensation."

"Simplicity and elegance are virtues of theories because they aid understanding."

"The meaning of a word is not an intrinsic property but a relational one."

"Our theories about the world rest on a foundation of pragmatic choices, not absolute necessity."

"Science seeks the most economical description of experience."

"What one person calls a fact another might call an interpretation."

"Knowledge is not a collection of true statements but a systematic whole."