If you switch to the physical perspective, then the notion of a Universal Argument seems noticeably unphysical. If there’s a physical system that at time T, after being exposed to argument E, does X, then there ought to be another physical system that at time T, after being exposed to environment E, does Y. Any thought has to be implemented somewhere, in a physical system; any belief, any conclusion, any decision, any motor output. For every lawful causal system that zigs at a set of points, you should be able to specify another causal system that lawfully zags at the same points.
Someone who asserts they existence of a universally compelling argument only means that it is compelling to rational minds...it’s a somewhat restricted sense of “universal” .
If you “switch to the physical perspective” in that sense, then you are no longer talking exclusively about minds, let alone rational minds, so no relevant conclusion can be drawn.
Moral realism could be still false for other reasons , of course.
Someone who asserts they existence of a universally compelling argument only means that it is compelling to rational minds...it’s a somewhat restricted sense of “universal” .
If you “switch to the physical perspective” in that sense, then you are no longer talking exclusively about minds, let alone rational minds, so no relevant conclusion can be drawn.
Moral realism could be still false for other reasons , of course.