 Quine’s (1953 [1980a]) initial explanation of the appearance of the analytic invoked his metaphor of the web of belief, claiming that sentences are more or less revisable, depending upon how “peripheral” or “central” their position is in the web, the more peripheral ones being closer to experience. The appearance of sentences being “analytic” is simply due to their being, like the laws of logic and mathematics, comparatively central, and so are given up, if ever, only under extreme pressure from the peripheral forces of experience. But no sentence is absolutely immune from revision; all sentences are thereby empirical, and none is actually analytic.