Nominalism, Platonism, Reductionism

Nominalism and Platonism are inverses--according to the former, Individuals are real, and Universals are not, and the reverse, according to the latter.  Schopenhauer also inverts Nominalism, but while for Platonists the Universals are Ideas, for Schopenhauer there is one Universal--the Will to Live, e. g. the reproductive drive.  Regardless, he does not resolve the problem that he shares with Platonists--explaining any divergence from the Universal, i. e. appearances, individuals, illusions, etc., even if 'irreal'.  In his case, the divergence is the Principle of Individuation, which, qua Principle, is real, and, hence, can be ascribed only to the Universal, from which it follows that the produced Individuals are real.  But, even if he were to retract Principle status from Individuation, thereby reducing it to mere illusion, the possibility of illusoriness still requires a ground.  So, what the conflicting inverses share is unsuccessful Reductionism, leaving both Universal and Individual intact.