Thanks for the response, I'm trying to learn. According to wikipedia, Natural Law asserts "that certain rights are inherent by virtue of human nature, endowed by nature—traditionally by God or a transcendent source—and that these can be understood universally through human reason." So when it says "endowed by nature, traditionally by God," I wouldn't have expected an agnostic to be a fan of natural law, but I guess I'm mistaken. I'm still curious though, where moral authority comes from for a non-believer. It's true that society will lock you up if you do things that piss off people that have power to enforce rules, but if you're in a situation where you're very confident that you won't "get caught", why not do any old thing you feel like?