We have surprisingly few legal duties, you know, at least in the United States, in an affirmative sense. Most of the law concerns itself with what not to do, rather than with what to do. For example, there is no legal obligation to help others or to report criminal activity (for most of us.) I would say that much of what we do is more a function of the social contract than it is of the law. When I teach a law class, I always like to give the example of the red light I stop at in the middle of the night in the middle of nowhere. I know I am not going to get caught and get a ticket if I go through that red light. What makes me stop? I think it's that social contract. Few societies have sufficient enforcement mechanisms to make everyone do what he or she is supposed to do, so it must be something beyond the law that makes us perform our various duties. Certainly, there are some who perform their duties solely because they are afraid of the legal consequences of not doing so, and they would not perform those duties absent the law. And, of course, there are those who will not do so, with or without the law. Having said all of that, we still need the law because it provides a clearer and more detailed road map for us, of various requirements, and it provides for consequences for the outliers amongst us who would otherwise not perform their duties.