Any Experts on Thomism? Re: Monotheism

Good evening, folks; I’m new to the forums and was wondering whether any participants here are experts or quasi-experts on Thomistic philosophy. I’m currently reading Dr. Edward Feser’s The Last Superstition: A Refutation of the New Atheism, and I’m trying to wrap my mind around the section (“Getting Medieval”) that explains and defends (three of) Aquinas’s cosmological arguments from God’s existence.

For some reason, it isn’t all connecting.

Let’s just start with the first one: the Unmoved Mover.

I understand that by “movement” Aquinas simply means “change,” and I get that all change needs to have its source in an unchanged changer, but here’s what I don’t get: a) why there can’t be more than one unchanged changer, whose collective changes result in the cosmos as we know it; and b) why this changer(s) must not only be unchanged, but unchangeable (i.e., immutable).


Occam’s Razor slices away unnecessary changers! Why postulate more than one?

If the ultimate changer were changed and changeable the origin of change would remain unexplained.

Those are extraordinarily weak arguments. For starters, you’re misappropriating Occam’s razor. The finding that change requires changers does not tell us anything about how many changers effect the change. Just assuming there’s only one changer is not a valid application of the razor, that’s just being arbitrary. If anything the Razor would require agnosticism.

Second, it’s not clear to me why an infinite regress of change is so irrational. Physicists tell us there are all sorts of physical laws that can account things constantly being in motion without the need of a first pusher. Why do we assume there needs to be an explanation for why these things are? Why isn’t “It just is” a valid response?

I fail the “expert or quasi-expert” criteria, but I think I can help. In Dr. Feser’s book Aquinas: A Beginner’s Guide, he explains both of these questions:

  1. Why can there only be one “First Mover”?
    (from page 30 of the above mentioned book)
    Aquinas teaches that the essence of the first cause is existence. “That is to say, something whose essence is its existence would depend on nothing else (e.g. matter) for its existence, since it would just be existence or being. But there could only possibly be one such thing, for there would be no way in principle to distinguish more than one. We could not coherently appeal to some unique form one such thing has to distinguish it from others of its kind, ‘because then it would not be simply an act of existing, but an act of existing plus this certain form’; nor could we associate it with some particular parcel of matter, ‘because then it would not be subsistent existence, but material existence,’ that is, dependent on matter for its being (DEE 4)”
    (Italics original. Feser explains more of Aquinas’s arguments for this. Ibid. pg. 121)

  2. Why must God be immutable?
    According to Dr. Feser (pg. 122), God is Pure Act. As such He cannot change, since change is the reduction of potency to act. On pg. 75, Feser says: “To account for the reduction of potency to act in the case of the operations of the hand, the muscles, and so on, we are led ultimately to appeal to the reduction of potency to act vis-a-vis the existence or being of ever deeper and more general features of reality; for ‘it is evident that anything whatever operates so far as it is a being’ (QDA 19). But the only wap to stop this regress and arrive at a first member of the series is with something whose very existence, and not merely its operations or activities, need not be actualized by anything else. This would just be something which, since it simply exists without being made to exist by anything, or is actual without being actualized, is pure act, with no admixture of potentiality whatsoever.” (italics original)

God bless you,
Andrew W

If this were true, then they would have to differ from one another in some way. This necessarily means that one god would have something that the other god does not, meaning that at least one god does not possess perfection. Thus, there can only be one God.

If you are viewing God as merely the “unmoved mover,” then perhaps you don’t require perfection as an attribute of God. Even so, Aquinas has an answer for this as well. He states that we perceive a causal unity in the universe. The universe conforms to certain uniform laws, and multiple different uncaused causes are inconsistent with the order we observe. Therefore, there is only one God.

b) why this changer(s) must not only be unchanged, but unchangeable (i.e., immutable).

Because nothing is the cause of its own change, at least not ultimately. And you would have to posit some kind of potentiality in God, perhaps even his ability to exist as an uncaused cause.

That being stated, I do think the Tonyrey has a point. It’s difficult to conceive of a good argument for multiple unmoved movers, when one is all that is required. If there is evidence for it, then that’s another matter.

The question you’re raising was raised by David Hume in his book Dialogues Concerning Natural Religion. He pointed out that most of the very greatest, extensive achievements of humankind were created by countless individuals; thus, it would make no sense to say, “who created New York?” or “who created Rome” and have the presumption of a single author. Some of the greatest of human achievements are the result of collaboration between thousands.

I believe he also questioned the necessity of omnipotence; all that would be required, one of the interlocutors argued (in the Dialogue), is a creator that was more powerful than its creation.

No doubt the Thomists will give reasons why God is one and why God is omnipotent, so I suppose the task then will be to focus on whether they have sufficiently demonstrated their premises and definitions.

You might try " Aquinas " by the same author. Also, Elements of Christian Philosophy by Etienne Gilson is very good. You might find one or both of these in a good library, certainly in a good Catholic College library. Then there is nothing like Thomas himself, especially the Summa Theologica.

You will notice that whatever is changed must have a potency to change and it obviously cannot change itself. It can only be changed by something in act with respect to the new actuality to which our object has a potency. That is it must have the power to change our object.

Now if this moving act has itself been brought into act ( the power it has to move our object ), something must have moved it from potency to act. But we cannot go on forever in this fashion, otherwise there will be no first mover and thus our object will not be able to be changed. In other words we must arrive at a First Unmoved Mover. Now we only have to find one instance of the necessity of such an Unmoved Mover and we have arrived at the universal cause of all reality, God.

Let me explain. Let’s say for example that the object of change above is going to be changed from a potential human being to an actual human being. In that case our Unmoved Mover would have to have the power to create life. He further must have this power in an uncaused ( unmoved ) manner, nothing else could have caused him to have it. He is in perfect act in regard to the power to create life in our human egg.

Now since he has one power perfectly and without cause, he must possess every power possible to imagine without cause and perfectly.To suggest that this Unmoved Mover did not have absolute uncaused power to create and move every aspect of whatever could be created and moved is to suggest that there exists an infinite number ( or nearly so ) of such beings, which is clearly contrary to reason, for how would their infinite number of acts ever be co-ordinated to create and maintain and order the universe? War in the heavens? Nothing would ever have gotten done.

No, we have to postulate that our Unmoved Mover is absolutely unique in every power imaginable or possible. And since he is pure act in one respect, he must be pure act in respect to all his possible powers. And since to be pure act means to have no potential, he must be a spiritual being and not a material being. Futher all his powers must be united in one being as ONE ACT. Otherwise he would be divided in himself. If that were not so, there would be an infinite number of such beings which is contrary to reason.

The conclusion is that he is one being, ONE PURE ACT, in which ACT all possible powers reside. And since he is a Spirit and PURE ACT, he cannot be a part of the universe. A being of PURE ACT cannot be a part of the universe of beings composed of potentiality and act.

And this is why it would logically be possible to have an infinity of accidental causes ( father begetting son, grandfater begetting father on to infinity.). But there could not be an infinity of instrumental causes. This father begets this son, a living human being, because our Unmoved Mover has breathed life into the human embryo which becomes this particular son.

In the same manner our Unmoved Mover has breathed life into every embryo as far back as we want to go. He operates vertically, right now in every change, not horizontally backwards or forwards.

It should be clear by this time that there is nothing that ever happened in the universe that has not been caused by him, as the Unmoved Mover, for there is no ultimate power other than his. And this is why Thomas called him God. For if the Christian God exists, the two must be one in the same.

Now brace yourself, we have some dedicated atheists on this forum and one dedicated at least one who absolutely hates metaphysics and especially Thomas Aquinas and most especially Edward Feser. So the fur is about to fly, so to speak.


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