  Theories of decoherence come in two flavors---Platonic and Aristotelian.
Platonists grant ontological primacy to the concepts and mathematical symbols
by which we describe or comprehend the physical world. Aristotelians grant it
to the physical world. The significance one attaches to the phenomenon of
decoherence depends on the school to which one belongs. The debate about the
significance of quantum states has for the most part been carried on between
Platonists and Kantians, who advocate an epistemic interpretation, with
Aristotelians caught in the crossfire. For the latter, quantum states are
neither states of Nature nor states of knowledge. The real issue is not the
kind of reality that we should attribute to quantum states but the reality of
the spatial and temporal distinctions that we make. Once this is recognized,
the necessity of attributing ontological primacy to facts becomes obvious, the
Platonic stance becomes inconsistent, and the Kantian point of view becomes
unnecessarily restrictive and unilluminating.
