Archive for June, 2008

CT 5: The Eternity of God

Wednesday, June 25th, 2008

Chapter 5 is remarkably brief:

The further conclusion is evident that God is eternal. For everything that begins to be or that ceases to be, is affected in this way through motion or change. But we have just shown that God is absolutely immobile. Consequently He is eternal.

There’s a footnote in Aquinas’ Shorter Summa that suggests that perhaps this chapter was left in the finished work inadvertantly, as Chapters 6 and 7 treat of the subject in considerably more detail. Nevertheless, I like this one, because I can understand it. Generation and corruption, coming to be and ceasing to be, are kinds of change. Consequently, the first mover, being unchanging (CT4), never comes to be or ceases to be. And something that never comes to be nor ceases to be must either never exist or always exist. But the first mover must exist (CT3). Thus, the first mover, God, must always exist, that is, must be eternal.

CT 4: The Immobility of God

Tuesday, June 24th, 2008

Having shown that God exists, Thomas goes on to show that God is immobile, that is, that God is unchanging:

We clearly infer from this that God, who moves all things, must Himself be immovable. If He, being the first mover, were Himself moved, He would have to be moved either by Himself or by another. He cannot be moved by another, for then there would have to be some mover prior to Him, which is against the very idea of a first mover.

Recall that Thomas showed in chapter 3 that there must be a first mover, and that he equated this first mover with God. So if God is moved, that is, if He changes, He Himself must be the cause of the change. So far, so good.

If He is moved by Himself, this can be conceived in two ways: either that He is mover and moved according to the same respect, or that He is a mover according to one aspect of Him and is moved according to another aspect. The first of these alternatives is ruled out. For everything that is moved is, to that extent, in potency, and whatever moves is in act. Therefore if God is both mover and moved according to the same respect, He has to be in potency and in act according to the same respect, which is impossible.

When a thing changes, some potential of that thing is becoming actualized. The ball is here, but potentially it is there; if I move it there, then it is no longer potentially there, it is actually there. My eldest son is a boy, but potentially he is a man; in time (God willing) he will be one in actuality. This is true, according to Aristotle, of all change. So Thomas is saying that God is moving Himself “in the same respect” then He is both “in act” as the mover and “in potency” as the thing moved, and is therefore in act and in potency “in the same respect”, which is impossible.

I confess that I do not entirely understand what Thomas means by “in the same respect”. In the next bit, he speaks of God as having two parts, one part moving (i.e., causing the change) and the other moving (i.e., changing). So it’s possible that by “in the same respect” he means that the same part of God is both moving and moved. Also, while I can see why the thing moved is in potency, I can’t see why the mover is in act.

The second alternative is likewise out of the question. If one part were moving and another were moved, there would be no first mover Himself as such, but only by reason of that part of Him which moves. But what is per se is prior to that which is not per se. Hence there cannot be a first mover at all, if this perfection is attributed to a being by reason of a part of that being. Accordingly the first mover must be altogether immovable.

OK, this I can see. If God has two parts, one causing change and one being changed, then God isn’t really the first mover at all; rather, that part of God which is causing the change is the real first mover. I’m still puzzing over the line “…what is per se is prior to that which is not per se.”

Now, I’ve read somewhat further than this, and discovered that the translator has used the terms per se and per accidens to refer to a being’s essential and accidental features respectively. Something is essential if it cannot be changed, and accidental if it can be. Thus, a dog is a dog; its dogginess is an essential feature. If you changed it, you’d no longer have a dog. But the length of the dog’s coat is accidental. You can trim it, or the dog can shed it, and still have a dog, indeed, you still have the same dog. And I think that phrase I used, “if it cannot be changed,” is beginning to get at the heart of the matter. As God is the first mover, the fact that God is a mover, is a cause of change, is clearly per se, clearly essential. The notion that God is being moved by Himself is not essential, and so we can’t insist on it.

This indicates to me that God need not be moved; I’m not sure Thomas has shown that God can not be moved. But then, what we’ve got here in the Compendium aren’t full-fledged proofs, but rather brief sketches of arguments.

Among things that are moved and that also move, the following may also be considered. All motion is observed to proceed from something immobile, that is, from something that is not moved according to the particular species of motion in question, Thus we see that alterations and generations and corruptions occurring in lower bodies are reduced, as to their first mover, to a heavenly body that is not moved according to this species of motion, since it is incapable of being generated, and is incorruptible and unalterable. Therefore the first principle of all motion must be absolutely immobile.

This is a second sketch of an argument. I don’t know whether the principle Thomas cites, that “All motion is observed to proceed from something…that is not moved according to the particular species of motion in question,” is really valid apart from the Aristotelian notion of the heavenly bodies and their effects. It certainly seems unlikely, so I’ll not worry at this argument further. Clearly I should write something about alterations, generations, and corruptions, though, and that means I should write something about forms. Oh, joy!


Monday, June 23rd, 2008

When I hear the word “substance,” I think of an arbitrary quantity of some particular kind of relatively homogeneous but not necessarily identifiable stuff, as in “The murder weapon was coated with an unpleasant cheese-like substance.” When philosophers use the word “substance” it means, more or less, an individual thing, something that has its own identity. I’m a substance; you’re a substance; your dog is a substance; the chair you’re sitting on is a substance, and so is the computer you’re reading this on.

Or so I gather. It’s not clear to me whether one substance can be a part of some other substance. My wife and children and I are each substances; but is our family a substance? I have the notion that it isn’t.

In Summa of the Summa, Peter Kreeft defines a substance as “a being that exists in itself rather than in another.” So since my brain exists as part of me rather than in itself, I would guess that my brain isn’t a substance. Unless, of course, it was removed from my head and preserved in a jar. In that case, I would cease to be a substance, having lost my substantial form. But that’s another topic.

Update: Actually, on second thought, perhaps my brain is a substance either way. Kreeft contrasts substance with accidents, which I’ll have to define later; but I gather that the color “green”, for example, is not a substance because it doesn’t exist in itself. Substances can be green; but you can’t pick up a green at the store. You can pick up an orange at the store; so an orange is a substance that happens to be colored orange, which color is not a substance.

Incidentally, the Summa of the Summa is also available from Amazon.

Summa of the Summa

(I don’t get any kickbacks if you order the book by clicking on the link, by the way.)

Update: I found a resource on-line, the Stanford Encyclopedia of Philosophy, which has more on the notion of “substance”. It turns out that there are primary substances and secondary substances. My brain is a primary substance; “the human brain” is a secondary substance, the kind to which my brain belongs.

CT 3, The Existence of God

Sunday, June 22nd, 2008

The first two chapters of the Compendium Theologiae introduce the work and describe its structure. The meat begins in chapter 3. Thomas begins,

Regarding the unity of the divine essence, we must first believe that God exists. This is a truth clearly known by reason. We observe that all things that move are moved by other things, the lower by the higher.

The verb to move in this context means to change. We’re not solely talking about motion from place to place, but about all kinds of change.

The elements are moved by heavenly bodies; and among the elements themselves, the stronger moves the weaker; and even among the heavenly bodies, the lower are set in motion by the higher.

Thomas’ work was a synthesis of Christian revelation with Aristotelian cosmology, which is where this comes from. By elements, I gather he means the four elements of earth, air, fire, and water; and in his day the heavenly bodies, e.g., the Sun, the Moon, the Planets and the Stars, were thought to be different in kind than our own earth. However, as this is given more as an example than as part of the argument I think we’re OK to move on.

This process cannot be traced back into infinity. For everything that is moved by another is a sort of instrument of the first mover.

An instrument, then, is essentially a tool: something I move—that is, something I use—in order to move something else. What he’s saying here is that if A moves B, and B consequently moves C, then B is, in a sense, A’s instrument.

Therefore, if a first mover is lacking, all things that move will be instruments. But if the series of movers and things moved is infinite, there can be no first mover. In such a case, these infinitely many movers and things moved will all be instruments. But even the unlearned perceive how ridiculous it is to suppose that instruments are moved, unless they are set in motion by some principal agent. This would be like fancying that, when a chest or a bed is being built, the saw or the hatchet performs its functions without the carpenter.

Don’t confuse this with the argument from design that the presence of a watch implies a watchmaker. This is simply saying that we mustn’t ascribe to B the effects ultimately caused by A.

Accordingly there must be a first mover that is above all the the rest; and this being we call God.

And if we follow the change of causes all the way back, one of two things happens: either we follow it infinitely (which Thomas would not admit) or we arrive at some mover G which moves other things but is not an instrument of any third thing. And G we call God.

So as Thomas points out, we can actually prove God’s existence using pure reason. But we still haven’t proven that G has all of the other attributes we believe God to have. This is just the first step.

Update: I should point out that Thomas gives five distinct arguments for God’s existence in the Summa Theologiae, and I gather he goes into even greater detail in the Summa Contra Gentiles.  The Compendium is Thomas’ version of Theology for Dummies.

What’s All This, Then?

Sunday, June 22nd, 2008

I figure things out by talking and writing about them. Recently I’ve embarked on an investigation of the works of St. Thomas Aquinas, and frankly there’s a lot to figure out. In this blog I’m going to post my thoughts, as well as excerpts from the works in question, and we’ll see how it goes. Fair disclosure: I am not a philosopher, nor a theologian; with luck and the grace of God, I hope to uncover a little of the essence of what Thomas has to say, but I expect the accidents to be major. Please feel to chip if there’s aught in which you can remedy my ignorance!

I’ve looked into Peter Kreeft’s Summa of the Summa, a one-volume abridgement with copious footnotes of the Summa Theologiae; I’ve gotten something out of it, but I really don’t have quite enough background. Consequently, the work I’m going to focus on first is his Compendium of Theology, which has also been published as the Light of Faith, and more recently as Aquinas’ Shorter Summa. (The complete text is also available on-line.) It’s written to be simpler and more straightforward, and from my cursory browsing also contains a few more examples. My hope is that through wresting with it, I’ll gain some of the background I need to begin to contemplate the possibility of maybe starting to tackle the real Summas.

If you’d like a printed copy, you can get it at Amazon: