In “Two Dogmas of Empiricism,” published in the journal The Philosophical Review (1951), Quine began with the accepted view that analytic statements are true based only on the meaning of the words they contain. There is nothing in the world that can affect the truth of an analytic statement. Synthetic statements are factual claims about the world. Quine then showed how it is impossible to define analyticity without a prior notion of sameness of meaning that itself presupposes analyticity. What this means is that unless you already know what “analytic” means you will not understand any definition of it, or that “analytic” cannot be defined without circularity.

If we do not know what analyticity is, there is a strong implication that for all practical purposes all of our beliefs are in some sense synthetic and subject to revision based on experience. The second dogma of empiricism that Quine attacked in the same article was the prevailing view that statements in a theory all face reality one by one. Quine claimed that all of the statements face reality together. Here, Quine meant that a whole theory or account of the world gets confirmed at once, rather than parts of the theory being confirmed separately.