In the previous essay, we left Spinoza in search of an idea upon which he could found his philosophical system. As he set out on his way, he looked back to Aristotle in order to orient his thinking.
This is curious, because uppermost in the program of the scientific revolution of the 17th century, which Spinoza approved of and to which he contributed, is the repudiation of Aristotle (384–322 bce). His theory of nature and of the universe, which I will try briefly to describe later in this essay, was judged to be profoundly mistaken and it was generally repudiated.
But although Aristotle’s reputation as the “master of those who know” had become tarnished, it was not entirely effaced, and in many respects it is not possible even today to progress in philosophy without checking out what Aristotle thought. It’s somewhat like trying to reinvent the wheel.
Spinoza knew this. He studied Aristotle and borrowed from him, but used what he borrowed in new and original ways.
One of Aristotle’s enduring contributions to philosophy was a technical vocabulary. Most of our current philosophical terms derive from him. One in particular stands out among the rest. The Greek word, “ousia,” in Latin, “substantia,” in English, “substance,” denoted for him the primary object of thought and of reality, and the subject of the most universal science, which we have become accustomed to label “metaphysics” — a term Aristotle never used, although it has come down to us as the title of one of his most important works.
In ancient Greek common usage, ousia signified a person’s property or wealth; in current English, “substance” means much the same: we speak of persons of substance, meaning, the very rich; however “a person of substance” can also mean someone with moral gravity, or wisdom; “substance” is also used to signify what is at the heart of things, for example, when someone reports strange happenings, we may dismiss the message as having no substance, that is, no truth or no reality.
Aristotle used the term to signify the very being of a thing that persists through change; whether it moves from one place to another, increases or diminishes in size, acquires or discards certain qualities, it is still the same ousia, that is, the same thing.
We think and talk about things primarily, and only secondarily about how big they are, where they are, or what’s beside them; that latter, he called accidents. Substance and accident is like subject and predicate. You and I are substances, so is the tree outside my window, the fly on my windowpane, the pebble in my shoe, the flower in my buttonhole, the button on my coat, and all those “better things for better living through chemistry,” and about all these things much can be predicated. Subject and predicate must not be confused, any more than a thing and its accidents.
Aristotle liked to say that a substance is something about which things are said, but which cannot be said or predicated of anything.
Imagine a bluebird. Much can be said about it; it flies over rainbows or the white cliffs of Dover; it is blue, of medium size, eats almost everything, and if female, she builds her nest and incubates her eggs. It is true that “is a bluebird” is a common predicate, but this is said of all bluebirds and does not refer to any one in particular; whereas a particular bluebird cannot be said about anything, it just is. Aristotle was so sure that particular things are the primary elements of reality that he declared that if there were no substances, no particular things, there would be nothing at all.
In Book XII of his Metaphysics, Aristotle set out to describe a science that at the time had no name, a science of substances. He supposed there are three sorts of substances. Two are sensible and material, the third is immaterial and invisible; all three are parts of the world.
Of the two kinds of sensible substance, one consists of perishable things, like plants and animals, the other consists things that never change, that neither increase nor diminish, although they are in perpetual motion. The third substance is unique; it is eternal and unmoved; yet it is the ultimate source of all motion and change.
Using these three classes of substance, Aristotle fashioned a world system, which he supposed represents the very one in which we exist. It is perfectly spherical in shape, finite in size, without temporal beginning or end, and there is nothing beyond it. It is unique.
Aristotle believed that this world system contains varieties of matter: earth, water, air and fire, and perhaps a fifth, ether, each with its own chemistry and disposition. Each material element always seeks its proper place. Earth, which is grossest, locates itself at the center of world, and from it there spring all perishable sensible things: animal, vegetable and mineral.
The earth, a great dense sphere, is surrounded by a series of concentric spheres, 27 to be exact, to which are affixed the heavenly bodies. The sun, moon, and the fixed stars are incorruptible, they are fiery or ethereal; each has its sphere, which moves without beginning or end in regular concentric circular paths, and by this motion, they provide things on earth with light and warmth and moisture in regular seasons. This is a very simplified description of Aristotle’s cosmology, which, by the way, he appropriated from Eudoxus of Cnidus (408–355 bce), a mathematician, astronomer, and sometime student of Plato.
Now the question arises, what is the principle of cosmic motion and where is it to be found? It cannot reside in perishable things, for then the world would not be eternal. Nor can it be found in the celestial spheres, for although they move eternally, they must have a reason for moving.
Aristotle’s answer is that this ever-present cause of existence must be eternal and unmoved, an unmoved mover, for, as I’ve said, perishable things cannot be the sustaining cause of the world, and eternal things that move must have a reason for moving. The ultimate cause of existence is an intelligence, whose sole object is a simple idea of the purest most enticing value, which is itself—like Plato’s Idea of the Good it is operative throughout the physical universe, but it is not identical with any material part of it.
Aristotle supposed that every eternal sensible being, that is, all of the celestial bodies that move in regular order above us, are not only made of the purest stuff, incorruptible matter, but are also intelligent. Their intellects directly perceive the Unmoved Mover, and just as dancers inspired by a vision of beauty move in perfect harmony and with consummate grace, as though to imitate this perfect intelligible object. They, in imitation of its eternal sameness, move in perfect circular paths — for Aristotle, following Plato, regarded circular motion as the moving image of eternity.
Such is the universe imagined by Aristotle. It is an object of austere beauty, a thing without beginning or end, self-moving, intelligent, requiring no explanation from anything beyond itself.