1. (Only sacred value) You must not kill other that are of a different opinion. (Basically the golden rule: you don't want to be killed for your knowledge, others would call that a belief, and so don't kill others for it.) Show them the facts, teach them the errors in their thinking and they clearly will come to your side, if you are so right.
2. Don't have sacred values: nothing has value just for being a best practice. Question everthing. (It turns out, if you question things, you often find that it came into existance for a good reason. But that it might now be a suboptimal solution.)
Premise number one is not even called a sacred value, since they/we think of it as a logical (axiomatic?) prerequisite to having a discussion culture without fearing reprisal. Heck, even claiming baby-eating can be good (for some alien societies), to share a lesswrong short story that absolutely feels absurdist.