Ethics
The Ethics of metaculture is based on Utilitarianism, but with some evidence-based solutions to the various problems of utilitarianism that have been raised by critics.
The reason for Utilitarianism is that it is the only ethical system that is potentially subject to scientific inquiry, as long as good can be quantified objectively. Since evolution has correlated what is good for humans with what gives us happiness, if we can measure the happiness of a population we can tell if what we are doing is good, at least relative to other societies we've been able to study.
What Are The Rules?
Saying that people should practice utilitarian ethics is easy. Doing the necessary research to determine the best course of action personally as well as in politics and economics is hard. Fortunately there have been many brilliant people throughout history who have worked on this and we can summarize their research into something easy and practical that can be applied in your daily life.
Do unto others as you would have them do unto you.
If you are looking for much more specific recommendations that can help your life choices, see Evidence-Based Best Practices.
If you have recently been quantum leaped into the body of a black person, the following musical provides great advice on the rules for this very specific situation.