When we conceptualize reality, we divide a unit. After this, our question is whether it is things or classes that are real, both of which thus are wrong, because they are in reality a single unit. The fundamental question is thus instead whether it is our division of the unit or the unit that is real. And, the answer to this question is, of course, the unit (if any of them).
The answer to our question (after conceptualization) is thus that neither things nor classes are real. The difference between assuming that one of them is real is that the former (ie, assuming that things are real, or nominalism) is ambiguous, whereas the latter (ie, assuming that classes are real, or realism) is paradoxically contradictory – both per definition, ie, due to conceptualization itself. It means that only nominalism can be consistent.
This leaves realism as a dead end. In spite of this, realism still lives and thrives. The realistic approach “cladistics” dominates biological systematics and the realistic approach “particle physics” was recently awarded the Nobel Prize for finding a “thing” (ie, “Higgs particle”) which actually is the paradox of the approach itself. If this “Higgs particle” indeed would be real, then the unit we discuss would thus not be real, but instead leaving our conceptualization hanging free in nothing as an mere illusion. Luckily, this possibility has already been falsified by the empirical finding that time is relative to speed in space, which thus also actually falsified the empirical finding of “Higgs particle” before it was claimed. Claiming a falsified approach gives rise to absurd statements. Fact is thus simply that realism, like cladistics and particle physics, was falsified before cladistics and particle physics emerged. The problem is just that realism is very difficult to kill.