Proof from motion

Onward, out of the mire of metaphysics and on to firm ground!

The First Way—the proof from motion—is one of Thomas's five arguments for the existence of God. It goes something like as follows:

1. Motion—i.e., change—is caused by something that already exists.
2. Nothing can be both moved and mover at the same time.
3. There can be no infinite regression of movers.
4. Thus, for any given motion, there must exist a first mover—an unmoved mover—and that is taken to be God.

After describing the First Way, Feser raises the common objections and explains why the objections fail. For example:

Objection: The first mover could be anything; this proof doesn't say anything about God.
Answer: The First Way doesn't intend to prove the existence of God. Rather, it shows that if God exists then God should have, among other properties, the property of being a first mover. Other parts of the Summa Theologiae ascribe the divine attributes to the first mover.

Objection: But what moves God?
Answer: Irrelevant, the proof doesn't claim God moves. God is pure act and thus, possessing no potency, doesn't move.

Objection: Why can't a series of causes—i.e., motions—regress to infinity?
Answer: Because they can't.

OK, Feser answered the third objection a little more rigorously than my three-word summary, but I found his answer lacking nevertheless. As for the first two objections, these are the kinds of ideas that drew my to learning about Thomism in the first place—that many of the common criticisms against classical monotheism are based on misconceptions of the underlying philosophy.

An infinite series of movers

Though he didn't convince me that there can exist neither an infinite series of movers nor a circular series of movers, Feser did answer a few of my questions I posed last week: specifically, that causes really do happen simultaneously with their effects and that the distinction between essence and accident is well defined.

Indeed, the difference between accidental causes and essential causes is that a series of accidental causes occur non-simultaneously whereas a series of essential causes happens simultaneously. This definition of essential causes differs from a casual, man-in-the-street view of causes, where we perceive things in the past to cause effects in the present or more recent past and things in the present to cause effects in the future. Essential causes all happen now. For example, imagine a moving hand that moves a stick that moves a rock that moves a leaf. The motion of the hand is an essential cause for the motion of the stick, rock, and leaf, and all move together simultaneously.

Such a simultaneous series of causes can't regress to infinity. Why? I don't know, and this is one aspect of the explanation I found lacking. Another aspect I found lacking is whether any two causes in a series can ever happen simultaneously. Taking the view of modern physics' general relativity, where no information can travel faster than light, it seems safest to presume that there exists no series of essential causes greater than one. Just as we may define a three-sided polygon who angles sum to 270 degrees in Euclidean space, we're playing with a definition of a thing that doesn't exist. We know from experiment that the hand and the leaf really don't move simultaneously.

What the First Way doesn't say

The big idea I gleaned from Feser's explanation of the First Way is that the First Way isn't a proof for God's existence, though it's commonly marketed that way. Rather, the First Way is a conditional statement that goes something like as follows:

If motion is only caused by something that exists and if nothing can be both mover and moved at the same time and there can be no infinite regression of movers then motion is ultimately caused by something that itself doesn't move.

This seems valid to me. Interesting, though, what the First Way doesn't say. It doesn't say:

There can be only one first mover in the universe.

Nowhere do I see it argued or implied that all series of essential causes are themselves linked together to the same first mover. For example, two different hands and leaves moving about may have two distinct first movers. This is a point Greer made in his polytheism book: that with the exception of the Ontological Argument, all the arguments for the existence of one god work just as well as arguments for many gods. Thomas himself rejected the Ontological Argument, so I'm eager to see how he ascribes the divine attributes of a singular, infinite God to the being postulated by his Five Ways.