Full Idea
The Mill-Ramsey-Lewis theory takes laws to be axioms (or theorems) of the best possible systematizations of the world's total history, where such a history is a history of events or facts.
Gist of Idea
Laws are the best axiomatization of the total history of world events or facts
Source
report of David Lewis (Psychophysical and theoretical identifications [1972]) by Stephen Mumford - Laws in Nature 1.3
Book Reference
Mumford,Stephen: 'Laws in Nature' [Routledge 2006], p.9