Chris Wüthrich over at Taking Up Spacetime has an interesting post about laws and initial conditions, and an old objection by Sklar (1984). The post started me thinking about an interesting distinction among laws. In short, there seem to be two fundamentally different kinds of them.
Type 1. Laws that determine possible systems. A physical system is specified by a distribution of potential energy in space and time.
Type 2. Laws that determine the behavior of a given system.

