The Harmony of Plato and Aristotle

A strange line from a review by Lloyd Gerson of a recent book by George Karamanolis raises fundamental questions about how any supposed "harmony" between Plato and Aristotle may be conceived:

Aristotle's metaphysics was not thought by Plotinus to be "considerably different" from Plato's, except in the way, for example, that Newtonian mechanics may be supposed to be "considerably different" from quantum mechanics. The latter encompasses the former; it does not negate it. It is this conception of harmony that Plotinus bequeathed to the later Platonic tradition

I wonder if Gerson didn't mean special relativity, rather than quantum mechanics. If anything, because of the use of the correspondence principle, quantum mechanics is, in a sense, a part of classical mechanics. (The correspondence principle is the requirement, in effect, that values for quantum mechanical states must be selected so that its results are consistent with classical mechanics.)

But then consider, in quantum mechanics: wave-particle duality; non-determinism; superposition; indeterminacy; non-locality. All of these are at odds with classical mechanics. So if Plato and Aristotle are as different as that, what exactly is the "harmony" between them?

Gerson seems to be suggesting that Aristotelian philosophy may be restricted to simply one part of a larger whole, which then Platonism deals with. This is on its face implausible, since both Plato and Aristotle aim to give an account of everything.

But does another line in the review reveal more exactly what Gerson means?

It is also to Porphyry that we owe the strategy, taken up enthusiastically by Simplicius among others, of arguing that the apparent differences between Aristotle and Plato are often owing to a difference in "explanatory direction," that is, as to whether an effect or a cause of a subject phenomenon is being adduced (pp.266-70). That is to say, the difference is only apparent because the problems that were being treated were different. This strategy is applied to questions in ethics, psychology, physics, and metaphysics. Actually, Plotinus takes a similar approach, for example, when he argues that Aristotle's categories are inadequate for understanding the intelligible world, the implication being that they are perfectly suitable for the sensible world (my emphasis).

Thus: Aristotle talks about the lower two segments of the Divided Line, Plato talks about the entire Line. We relegate Aristotle to the sensible world, Plato to the vast reaches of the non-sensible world.

Presumably it's possible to use Aristotle and Plato in this way, that is, to make them come into harmony, by suitable adjustments and changes in their philosophies (in the manner of some neo-Platonists), or by appropriating ideas from Aristotle and Plato and weaving these into a distinct and ostensibly coherent whole (as in the manner of Thomas Aquinas). This would be harmony as the possibility of constructing some suitable harmonization. But it seems misleading to refer to refer to this as "the harmony" (or "agreement") that exists between them.