moral 'knowledge ' is not possible.

 How is moral knowledge possible? This question is central in moral epistemology and marks a cluster of problems

No moral facts exist to be known, since moral disagreements exemplify merely clashes in moral sensibility rather than differences about matters of fact

Moral knowledge exists, but moral facts are relative to the social group in which moral sensibility is formed with the result that no moral truths are known to hold universally

Moral judgments are intrinsically motivating. Judgments about matters of fact, on the other hand, are never motivating just in themselves. Since to constitute moral knowledge a moral judgment must be made about some moral fact, moral knowledge is not possible.

 Moral knowledge is about moral reality. How is that reality constituted? Three general possibilities present themselves. (a) Moral reality might be theological in nature, pertaining to (say) the will of God. (b) It might be a non-natural realm that is neither theological nor natural, but sui generis.