Moral facts are grounded in the reactions or attitudes of the moral action (See Action Contents). They are mind-dependent. Fundamental Moral Principles therefore, must be mind independent, and have nothing to do with what the mind thinks or believes. They must be like the laws of physics which have nothing essential to do with what we like or dislike.
Mind Dependence Example
Facts about pleasure are facts about the experiences of minds. Facts about virtue are facts about the character traits of minds. The idea of being popular depends on being liked by other minds. To remain mind-independent, you must not reduce the principle to facts about the mind at all.
Certain Theories are Also Mind Dependent
The rules of English are not concerned with the reaction of its users. But, the reactions of the users is what allows English to change. The dissatisfaction of previous grammar norms allowed Anglo-Saxon English to change to how it is now.