While it is possible to account for everything in reality at any one (synchronic) time, it is not feasible. As a thought experiment, it is worthwhile.

Since mass-energy in reality is finite and constant all particulars can be accounted for with a kind of synchronic snapshot. Let us say that some particulars while everything else unaccounted for are lumped into a category of “other”. In this way we still have a complete inventory of reality. This is important because it takes into consideration the context for which a particular belongs. Logic ignores context, that is, logic de-contextualizes the particulars.

But that is the nature of universals. To generalize is to remove context, to think of the concept without particulars. As such, universals are useful mental “objects” but literally useless as physical objects.

The mistake often is to forget that mental “objects” only “exists” as long as conceptualizing physical objects exist. And for this reason we should keep an inventory of particulars before we keep an inventory of universals.