Summary: Metaphysics (page 2)

Thus Love is, for Parmenides, both the final cause and the driving cause — that is, the universal principle of all things. However, since the universe contains not only love and beauty but also hatred and ugliness, Empedocles proposes his system of Love and Strife.

Anaxagoras, for his part, posits Intelligence (noûs) as a universal principle. Yet Aristotle criticises him for invoking this notion merely as a fallback whenever he cannot find a direct cause for a phenomenon.

For Democritus, the principles are Being and Non-Being, or emptiness and fullness. Things are differentiated according to their shape (A and N), order (AN and NA), and position (N and Z).

The Pythagoreans, meanwhile, maintain that the principles of mathematics are also the principles of all beings ¹.

For example, a particular numerical configuration corresponds to justice; another corresponds to the soul or reason ².

Since harmony can be reduced to proportional numbers, they inferred that the same must hold for all things, and they conceived the world, taken as a whole, as harmony and number ³.

What Aristotle generally criticises the pre-Socratics for is that they had recourse to only two of the four causes. Most of them restricted themselves to the material cause; the most advanced among them went so far as the efficient cause.

Nonetheless, their great merit lies in having set in motion the search for the principle of things.

Aristotle then turns to Plato's doctrine of Ideas, seeking to trace the intellectual roots of this theory. For Aristotle, it arose from Plato's intellectual training: with the Pythagoreans, from whom he discovered the realm of the intelligible; with Cratylus, a disciple of Heraclitus, who showed him the ceaseless flux of the sensible world; and with Socrates, who directed his attention toward questions of morality and the search for definitions.

Plato's interest in definitions stems from their capacity to open onto the universal, and thus onto the intelligible world. Sensible things are not definable, caught as they are in a perpetual flux.

Plato calls these intelligible, universal, and therefore definable beings Ideas.

Here, Aristotle develops his famous critique of Plato's theory.

For Plato, a sensible being finds its identity through its participation in one Idea or another. It is by participating in the Idea of Man that Socrates is a man. However, Aristotle criticises the obscurity of this notion: Participation: Plato left it to whoever wanted to explain what was to be understood by this ⁴.

Elsewhere, he remarks that these are perfectly empty words and mere metaphors, better suited to poetry ⁵.

According to Plato, the Ideas are the first principles, for they are the causes of everything else. He thus draws on only the formal cause (the Idea) and the material cause. But the problem is that Platonic Ideas cannot serve as a moving cause: being immobile, they can account only for rest. Thus, Plato's doctrine is insufficient to account for the world as we perceive it — a world in motion.

Aristotle concludes that Plato did not uncover the cause of beings but merely invented additional ones:

As if someone, having to count a relatively small number of things and thinking he could not get to the bottom of them, were to multiply that number, imagining thereby that he could count them more easily ⁶.

Thus, the Idea appears in the Metaphysics as a superfluous duplication of the thing itself: Ideas are as numerous as things ⁷.

Moreover, we do not know which things possess Ideas: do Ideas exist for everything we can know? Are there Ideas of negations? Of relative terms — such as 'with', 'of'? Of accidents?

Aristotle raises, without resolving it, the problem traditionally known as the "third man": is there an Idea of the Idea? And then an Idea of the Idea of the Idea, and so on, ad infinitum.

Is the Idea within the thing, in which case there would be no distinct intelligible world, or is it external to the thing? In the latter case, things could not be grasped through the Ideas, since the Ideas are not present in them.

Either way, the notion of Idea proves useless.

How, moreover, can we conceive that the essence of a thing might exist outside the thing itself (in some intelligible reality), when the essence is precisely what is most intimately bound up with the thing?

Further critical arguments against the Platonic theory can be found in Book B.

¹ Book A, 5
² A, 5
³ ibid.
⁴ A, 6
⁵ A, 7
⁶ A,7
⁷ ibid.