Material Causality and Indefinite Dyad

Because it is nearly apocryphal, e. g. Aristotle alludes to it explicitly only once, the so-called Indefinite Dyad, allegedly of Platonism, has not been systematically developed.  But, there is sufficient evidence that it closely approximates the concept of Material Cause that has been defined here.  For, it is conceived to be the source of indeterminate Multiplicity, and of the substratum of Formal Causality.  Hence, where recognized, it has been subordinated to the principle of Unity, and, accordingly, denigrated as the source of Evil insofar as it functions independently of that superior principle.  So, one reason why Material Causality has been generally ignored is not because it has little Philosophical significance, but because of an implicit valuation based on the Parmenideanism that continues to influence Philosophy.