Saturday, May 18, 2013

Another look at the metaphysical argument for God's existence

1. Changing things exist. (Premise)

2. Changing things exhibit potentiality and actuality. (Premise)

3. No potentiality can actualize itself. (Premise)

4. Either some pure actuality exists, or else there is an infinite regress of potentialities being actualized. (Implied by 1 - 3)

5. There cannot be an infinite regress of potentialities being actualized. (Premise)

6. Therefore, some pure actuality exists. (From 4 and 5)

The divine attributes of pure actuality may be inferred easily.  First, pure actuality must be immutable and therefore eternal and indestructible, since only entities that exhibit potentiality can change (ceasing to exist would constitute a change).  Secondly, pure actuality must be unique (one), for if there were more than one pure actuality, then there would be distinctions between them.  However, to be distinct from actuality is to be non-actuality, in which case the latter does not exist anyway.

Other entities are distinct from pure actuality not by actuality, but by their varying levels of potentiality.  Pure actuality must also be omnipresent, since there is no place that can exist apart from actuality.  Finally, pure actuality must also be very powerful (if not omnipotent) in order to causally sustain all potentialities and their actualizations.  We have, then, an argument for a purely actual, immutable, eternal, indestructible, omnipresent, unique and very powerful entity.  If this isn't God, it's certainly very God-like.

Now, is the argument sound?

In defense of (1), we observe that changing things exist.  An acorn changes into an oak tree, for example.  This leads us to premise (2).  The acorn is merely an acorn in actuality (what a thing is), but is an oak tree or something else in potentiality (what a thing could be).

What about premise (3)?  Let's stick with the acorn analogy.  The acorn cannot actualize its own potentiality to become an oak tree.  Rather, it requires water, sunlight and soil, among other things, to sustain its change.  If at any point these actualities are removed, then the acorn's actualization to become an oak tree will cease.

(4) is implied by (1) through (3), so the only remaining key premise is (5).  Can there be an infinite regress of potentialities being actualized?  The beauty of this argument is that it leaves the finitude versus the infinitude of the universe's past as an open question.  Even if the universe's past were infinite, it would still be composed of finite intervals of time.  Now, at each finite interval, it is impossible to start counting and reach infinity.  This is because there will always and indefinitely be another number to count before arriving at infinity.

What this means is that the regress of potentialities being actualized at any finite time cannot be infinite. At each finite interval, the regress of sustaining actualizations begins anew, and since it is impossible to form an actual infinite by successive addition whenever one begins counting, it follows that the regress must be finite, in confirmation of (5).

Therefore, we are more than justified in believing in God or, at the very least, something very much like God.


  1. Doug

    You know my stance on this, so i am not goung to repeat it. You also know that I do not fancy an infinite regress.
    What i do not understand, however is why we would have to start counting at each interval. If the universe were past eternal, then if we start counting backwards now we will never reach infinity. But that's not an argument against an infinite temporal regress, so why would the fact that there are finite intrevals mean that we 'start counting'?

  2. This argument seems sound, but there's one problem I have with it: it seems to assume that libertarian free will does not exist from the outset.

    If no potentiality can actualize itself, then doesn't that mean that we can't act by ourselves? Doesn't it mean that everything we do, think, or feel is caused by something else, leaving us with no control over ourselves?

  3. Walter, at each finite interval, things begin to be sustained again. If you start taking things away, then potentialities will cease to be actualized. That's why it's important to interpret this argument vertically, as opposed to horizontally, if you prefer.

    1. I really do not see how at each finite interval, things begin to be sustained again. To be honest, I don't even see why things even begin to be sustained at all.
      Let's take an analogy. Let's suppose that the erath retst on top of a turtle, which rests onanaother turtle etc, 'turtles all the way down'. This seems vertical enough. Now supposed we take a random turtle X and another random turtle Y. No matter which X or y we choose, the number of turtles between X and Y will always be finite, yet every member of the infinite set of turtles and the Earth is 'sustained' by the previous turtle.
      Although this seems highly counter-intuitive, I cannot see any logical proof against this kind of infinite regress.
      But maybe I am looking at it the wrong way.

    2. If you don't see why things need to be sustained at all, that's where the problem lies. If you take away the water, etc., from an acorn, it will cease to become an oak tree. I give this example all the time because it illustrates the need of a sustaining cause of change.

  4. Hi ingx24,

    I don't think the argument rules out free will. Freedom of the will is a property of a person: an entity with consciousness and sentience. While it's true that the entity in question has its potentiality actualized by another, e.g. the laws of nature, it's only the person who is actualizing whatever potentiality he or she chooses.

  5. Doug,

    I'm not sure I understand what you're saying. How can a person "actualize whatever potentiality he or she chooses" if his or her potentiality is actualized by something else?

  6. Think of it this way. A stone is moved by a stick, and the stick is held by a hand. The hand is moved by a person who wills it. The person is moved by their own freedom, which is what is actualized.

  7. That's an interesting way of looking at the justification of premise (5). I hadn't heard that before, and I'm not quite sure I understand it.

    What I took to doing when explaining it (in trying to avoid an explanation of essentially and accidentally ordered series), is to just explain that a receiver necessitates a giver:

    Receiver <----- Giver

    If you remove the giver, then there is nothing being received:


    But if you go to infinity on the "receiving" line...

    Receiver <-----------------------------

    ...then you have in effect done the same thing: removed the giver.

    Therefore, as long as there is a receiver, then there is, by necessity, a giver.

    This seems to avoid confusion and the endless ridiculous objections to essentially ordered series.

  8. ingx24, I'm not an expert on free will. It seems to me, though, that a person's potentiality can be actualized with part of that potentiality being the freedom to choose. You might check out J.P. Moreland's conversational piece:

  9. Martin, I agree with your assessment. Thomas actually provides three distinct arguments against an infinite regress in the Summa Contra Gentiles.

    Just wanted to chime in one last time before my leave of absence. :)

  10. ingx24,

    >Doesn't it mean that everything we do, think, or feel is caused by something else, leaving us with no control over ourselves?

    This is addressed by Aquinas in the Summa. Basically, the very existence of our free wills is actualized by something else, and then we can exercise our free wills. I.e., the prime mover causes you to even have a body and hence free will in the first place. If it didn't, then there would not be any such thing as your free will to even be making any choices.