Laws or morals? It's broadly accepted that certain behaviours aren't right, like killing and causing others harm and this doesn't have to be written as law to be accepted. It's still a concept that we decide on, though, and some still find ways to justify themselves doing it or situations where it's okay to do it (eg. war).

Or do you mean the laws of physics, as in what goes up, must come down? Those really don't have to be written to exist.