  There is reason to doubt that the compresence of opposites or the mere complexity of particulars is responsible for their deficiency (but see Fine 1993, esp. Ch. 4).  According to Aristotle, change is critical, especially in so far as it precludes definability and thus knowledge. Given that knowledge requires essence, and essence excludes change (in the case of the essential properties), Aristotle would have us deny that essence is predicable of particulars for the Plato of the middle period. Particulars will be epistemologically deficient in that there can be no knowledge of them, unless we abandon the thesis that knowledge is of essence. And particulars will be metaphysically deficient, at least to the extent that possessing an essence is a better state than lacking one. But more can be said about the peculiar contingent manner in which particulars have their properties and why it is that one cannot look to the particular beauties to obtain knowledge of, e.g., Beauty.