On Aristotle’s Metaphysics 12 • Cathal Woods

Source: Ancient Philosophy Handouts by Cathal Woods

Readings: Metaphysics 12.6-10

Introduction

There are serious difficulties in the interpretation of Aristotle’s doctrine of an Unmoved Mover or prime changer, and this has led people to think that it belongs to a different stage of Aristotle’s development, and even that there are different stages within the doctrine itself.

An example of the latter is that Aristotle seems to hold that there is a single Unmoved Mover, but in 12.8 he numbers them at 55, these being the number of heavenly bodies according to Callipus.

It can also be though that the treatment of ousia in 7-8-9 is a further move away from Platonic beginnings, from the investigation into a single, universal, primary being, to a multitude of primary (changing) beings. “The world is alive with multiple beings.”

The Heavens

At the opening of book 12, Aristotle again surveys the debate – some people say that primary being is universal(s), others particular(s). Among sensible substances there are those that perish (plants, animals) and those that do not (planets). The particular substances have as explanations (or: causes) changeless, immaterial beings (forms, essences) which are (existentially) inseparable from their composites.

Although perishable substances undergo change of all four types, including generation and destruction, we can consider nature as a whole, and see that it is eternal and does not perish. (Indeed, Aristotle thinks that each species is eternal.) There is always matter, and there is always change, and the change happens in regular patterns, as dictated by the seasons.

It is empirically clear to Aristotle that not all beings are changing in the sense of generation and destruction. Aristotle looks at the heavens and admits that these arebeings too. So the understanding of being must not include matter (generation and destruction) but rather be fundamentally about activity (energeia, entelcheia.) The heavenly bodies are material entities, but theirs is a different type of matter, such that they undergo only locomotion and not the other forms of change.

Everlasting Motion

The heavenly bodies that explain the changes of the perishable things, as the seasons depend on the (annual) motions of the heavenly bodies.

The heavenly bodies are arranged in a series of spheres (around the earth) and each one moves the one inside it. Space, however, is finite, and so there is a final, outermost, sphere. At the opening of 12.6 Aristotle notes that since the planets are changeless, except for locomoting, and everlasting, the ousia of the stars must be changeless (including no locomotion) and everlasting.

Aristotle begins by arguing for the everlasting motion of the spheres, as follows: If all changing things were destructible, time would be destructible So, Not all changing things are destructible.

1. Time is uniform, and everlasting.
2. Only circular change (circular locomotion) is uniform (because space is finite).
3. So, There is everlasting circular change.

Not all changing things can be destructible, otherwise time would cease. The existence of time depends on the movement of the heavens, which is likewise everlasting; the measure of time depends on the uniformity of their motion, which motion must be circular, since space is finite. This conclusion is stated at the opening of 12.7. So: Aristotle argues for an unchanging, separate (in the senses of ontologically separate, and distinct) final/formal cause of motion (activity). As an intermediate step, he argues for the existence of everlasting motion.

Unmoved Mover as Cause

Aristotle immediately (1072a23) goes on to ask: What causes the spheres to move? We can say that one sphere moves another, so we are most interested in the outermost sphere. Note that the Unmoved Mover is a final and a formal cause, but not an efficient cause, at least, not in the typical sense, for, as we shall see in a moment, it does not interact with what is moved.

When Aristotle asks ‘what is this thing, motion?’, by this he does not mean “What is the efficient cause of motion?’ but rather ‘why is motion?’ ‘what purpose has it?’.

At this point we can note that we are talking about the final cause of the whole universe, and note a similarity to Plato’s form of the Good, and what makes the world both intelligent and intelligible.

• Q: Why think that this everlasting circular change has a change? Why not take it
  as basic? The circular change of the outermost sphere could have been different from
  what it is (even though it always moves in exactly the same way) and we need an
  explanation of why it changes in this way.
  • Answer: At 1072a24, Aristotle writes that since the outermost sphere is itself moving and moving other things, there must be something which only moves the outermost sphere, without itself moving. In short, Aristotle is denying a regress of movers. If we allow that the mover of the outermost sphere both moves and is in motion, then we can ask for the cause of its motion, and so on. Unlike the outermost sphere, this prime changer could not have been other than it is in any way at all.

Note: Aristotle is not asking about motion over time (a temporally first cause, which sets the sphere in motion), but is asking, rather, what is it that is the cause of the everlasting motion of the outermost sphere (and from there, of all change)? Similarly, the first cause does not interact with the outermost sphere. How does it cause the motion of the sphere?

Aristotle provides us (1072a27) with the thought that the object of desire moves other things without itself moving. This seems plausible as an account of how animals are caused to move, but if we want to apply this idea to the outermost sphere, we must think that the sphere thinks and desires. It is difficult to understand what sense to make of this, particularly when we note the difference between desiring the object of desire and desiring to be like the object of desire. It is the latter kind of effect that Aristotle thinks is the effect of the first cause – the spheres move in uniform circles, which is a more perfect (i.e. rational) motion than the motion of any other sensible object. What, then, is the nature of the first cause which causes, by being an object of desire, such motion?

Remember that the question is not about the activity of the unmoved mover, but about the energeia/entelecheia that is the unmoved mover.

The Nature of the Unmoved Mover

The unmoved mover also has a perfect activity, thinking, and it thinks uniformly and everlastingly of what is best: itself. Its thinking is the thinking of thinking. (1074b33) If we think of the thinking of the first cause along the lines of human intellection, we will want to distinguish thinker from thought, but this is not Aristotle’s intent. Rather, the first cause is intellection. Recall that for Aristotle, form is immaterial but intelligible and it is what the intellect (which is immaterial) understands when it understands. At the time of understanding, our intellect takes on the form that it understands – we are understanders understanding a form, or simply, there is understanding of the form. In understanding a form we (humans) also understand (think (about)) understanding. That is, we understand understanding. The first cause does this all the time, without having to think (of) anything else. That is, it is an understanding understanding understanding.

Moreover, the divine intellect does not change its nature, that is, its thought, since this would be a change for the worse. (1074b25)) This means that God’s nature is both an activity and changeless, which seems a contradiction.

In 12.10 Aristotle asks whether the good is the orderly arrangements of the parts of the universe, or something separate. He answers ‘both’, just as the general is separate and gives order to the rest.

Why are movers intelligible? Because they strive to be intelligent. What is (primary) being? In part, to be intelligible. Some things are more intelligible than others.