A great deal of Anglo-Saxon epistemology is marked by the controversy between foundationalists and anti-foundationalists. The key question is as to how propositions, or beliefs in propositions, are to be justified. Is our body of knowledge sustained by basic beliefs, as foundationalists claim? Or are there no basic beliefs, and is there only mutual support between the elements of the structure, as the anti-foundationalists maintain? The matter is made especially difficult by the fact that no-one knows what precisely epistemic justification is. Foundationalists appear to see justification in terms of transmission: when a proposition justifies another proposition a property is transferred from the one to the other lock, stock and barrel. Anti-foundationalists on the other hand think in terms of emergence: epistemic justification is brought about gradually within a network of propositions as a whole. While transmission can at least be elucidated by a comparison with deductive reasoning, emergence is more difficult to explicate. That is one of the reasons why anti-foundationalist positions are so hard to develop. In this article I show how epistemic justification can emerge in a network of propositions that support one another. I do this by means of a debate that at first sight seems not to have anything to do with the matter, namely the disagreement between the American logician and epistemologist Clarence Irving Lewis and the German-American philosopher of science Hans Reichenbach. This will enable us to establish the phenomenon of fading foundations, which will then yield a mechanism for the emergence of justification.