The universe was here before people existed. But it didn't operate according to mathematical laws, it just operated, period. Laws (unlike Plato's Forms), however, exist only in human brains; they represent our collective effort (never complete, never exact) to understand that operating of the universe. No human brains, no laws, mathematical or otherwise. It has been a long time since I read the _Anti-Duhring_, but as I understood it at the time, Engels held to this position: i.e., he held that the belief in the non-mental existence of laws led to idealism. The universe is extra-mental; laws are mental.
Carrol
^^^ CB: I think your recall of the principle from _Anti-Duhring_ is correct. The idea is that mathematical and scienific "laws" ( metaphorically analogizing to jurisprudence) are unchanging. The real world is changing in its essence. So, "laws" which pronounce unchanging patterns are abstractions from the concrete truth of the world. They are like single frames from a movie. Only ideas are unchanging, not reality. Things are only identical with themselves in ideas, mathematics, law, and other metaphysical systems.
^^^^^^
P.S. I don't know if this is relevant or not. The ratio of the circumference to the radius of a circle is _not_ equal to any value of pi that has ever been expressed. And in fact the mathematician's circle does not exist in extra-mental reality; it is only an ideal abstraction from the 'circles' we see in the world. Mathematics only approximates the real world; but the real world is not an approximation to itself. It merely is.