Lets keep things simple again. If there were objective morals do you think they would be a "physical" thing or something "Non material".
Obviously, it would be super helpful if it were physical. A strong pulse of magnetic field when something wicked happens. That would be objective, certainly, but that doesn't seem likely.
More likely it would have to be some
quality of an act. To be real/objective, it would have to be unambiguous without the need for any human umpire to call balls and strikes, or to
perceive this quality.
Think of the equivocal word 'sound'. One can think of it as compressions and rarefactions in air (or other medium). Or as 'a thing one hears'.
If a tree falls in a forest yadda yadda... certainly it makes a sound in the first sense, but not the second.
The first sense of sound is objective. And we know (I hope) that that tree does make a sound when it falls. As a matter of objective fact.
Sound as a physical phenomenon is a fact. An objective category. We can even apply
qualities to sound like loudness that can be objectively measured, even if no human is there to hear it. We can apply other qualities to sound, like "Country & Western". This is not a natural category. Not an objective category. Indeed, 'musical genre' is
a human invention. And clearly there will be grey areas, where people will have honest disagreements on genre.
We cannot measure genre of a sound if there is no human there to hear it. [At best, we could train an AI
on human judgments, but I submit that we're not creating a machine that analyzes sound, but one that analyzes human judgments. And it would still be subject to grey areas and 'mistakes'.]
It seems to me that morality is a human invention like genre. And thus there is no fact of the matter. We can determine loudness objectively, but not genre. Nor can we determine morality objectively. Or at least, the many requests for
how to do this objective determination have been largely left unanswered. And I can't think of anything either. So much so that I think it is a fool's errand.
It might seem attractive to move
entirely to the world of ideas, since my example still rests on the physical phenomenon of sound. But really things become worse. This way lies o_mily and the syllogisms. But we've already seen there is disagreement about the axioms and premises. These are matters of
choice, not objective facts. What is the sum of the interior angles of a triangle? Depends on your axioms. And there's no objective fact of the matter. So sure, you can work in some particular moral system resting on particular axioms, and you can grind out logical conclusions. But there is nothing objective about the choice of axioms that produced that system. And other equally internally consistent systems of morality will come to different conclusions.