Full Idea
As there are an infinity of possible worlds, there are also an infinity of laws, some proper to one, another to another, and each possible individual of any world contains in its own notion the laws of its world.
Gist of Idea
Each of the infinite possible worlds has its own laws, and the individuals contain those laws
Source
Gottfried Leibniz (On Sufficient Reason [1686], p.95)
Book Reference
Leibniz,Gottfried: 'Leibniz Selections', ed/tr. Wiener,Philip P. [Scribners 1951], p.95
A Reaction
Hence Leibniz is not really a scientific essentialist, in that he doesn't think the laws arise out of the nature of the matter consituting the world. I wonder if the primitive matter of bodies which attaches to the monads is the same in each world?