Per Hume's is-ought problem, most people consider ethical questions to be independent of empirical facts.
The physicalist/materialist world-view is based on the idea that only thing that exists are physical facts about the world.
If someone were to establish beyond any reasonable doubt that ethical principles such as "Killing is bad","Discrimination based on gender, race or orientation is bad","Stealing is bad" are universally true, does this amount to dualism?
That these propositions are objectively true (independently of any subject) would make them true facts about the world, but they would be independent of any physical facts as well. Wouldn't this amount to a form of dualism or platonism? Is this what Kant meant by "metaphysics of morals"?
Or is it the case instead that these ethical propositions would acquire a status similar to the laws of mathematics and logic? Or maybe the same stauts as the laws of science and physics?