Abstract
D. M. Armstrong, Michael Tooley, and Fred Dretske have recently proposed a new realist account of laws of nature, according to which laws of nature are objective relations between universals. After criticizing this account, I develop an alternative realist account, according to which (1) the nomic structure of a world is a relation between initial world-histories and world-histories, and (2) a law of nature is a fact that holds solely in virtue of nomic structure (and not, for example, in virtue of past history).