How can a law that is over 200 years old still be relevant today?

That depends on the nature of the law involved 200 hundred years ago murder was against the law as was stealing etc and these laws are still relevant.

ANSWER: I was thinking the same thing just the other day. You know like gravity? Is it really relevant today? I mean, come on! How old is that law? What about murder, how the hell old is this law? Theft? Just another ancient law written by old guys who aren't nearly as sophisticated as you and I. And what about Murphy's law? It may not be as old as things like the Ten Commandments, or even gravity, but who cares? Does anyone know who the hell Murphy even is? If what can go wrong, right? It will go wrong because everything is wrong, right? Wrong, wrong, wrong! If everything is wrong, then how can it possibly go wrong, right? I say any law written before yesterday be repealed as irrelevant and useless. Does anybody know the statutory construction for repealing gravity?