The Prime Mover and the Nature of Immutability

An interesting objection to the Prime Mover argument is that its conclusion is self contradictory. The underlying question in this objection is how a being can cause movement without being moved itself. So the issue is that any being which causes all motion (change) would itself have to change in order to cause change, thus requiring another cause outside of itself. But this being is supposed to be the cause of all change, so how can something else be the cause of change in it?

This is a question I’ve heard several times in response to the Prime Mover argument, including once recently. Along with it came several corollary objections, which I’ll list below:

  1. How can an immutable being do anything at all, let alone create?
  2. Doing anything at all requires change. Pure action is change.
  3. Cause without time is, by definition, incoherent. Without change there cannot be cause-effect
  4. Without time you’d be stuck in an eternal state, unable to affect anything at all. Even thought and personality aren’t possible.

These are some pretty hefty claims about the nature and limitations of an immutable being, which, if accurate, do render the Prime Mover argument inert. The problem is in the understanding of what an immutable being actually is. And in order to understand what an unchanging being is, we have to first understand what change itself is.

In Aristotelian-Thomistic thought, change is understood as the actualization of potency; or, in technical terms, potency raised to act. The first full presentation of this conception of change is found in Aristotle’s Physics. I explained it briefly in my first Prime Mover post, and will be writing more fully on it in the future, but a quick examination of it will suffice here:

When something changes, it transitions from one mode of existing to another. A seed planted in the earth, for instance, will transition from the mode of existing as a seed, to eventually, given the proper conditions, the mode of existing as a tree. It first existed as a seed, now it exists as a tree. Each mode of existing is a distinct actuality of the substance. Actuality is just the fully present existence of a substance in a particular mode/manner. However, we also most posit the potency or potentiality which a substance has. The seed must have “the mode of existing as a tree” as an intrinsic potency; if it did not, it would always remain a seed and could never become a tree. But as a seed, when “being a seed” is its current state of actuality, “being a tree” is not its current state of actuality. Being a tree is just a potential state of actuality which it contains within itself as part of its nature. So change is the transition from one mode of existence/actuality to a separate mode of existence/actuality; and this is accomplished metaphysically by way of the potency for a certain mode of existence becoming actual, being actualized.

The Prime Mover argument argues from this reality of change to a source and cause of all change in a being which is Purely Actual, or Pure Act. Since change is only possible by way of potencies becoming actual, and since the Being of Pure Act by definition contains no potency within itself, then the Being of Pure Act cannot undergo change; it is immutable.

But the present objection contends that such a being is incoherent, or at least is self contradictory in relation to the argument. Specifically, the purported conflict is that such a being would not be able to do anything at all, including cause change in other beings or even “think”. But this, I would contend, is a misunderstanding of immutability. Immutability is not equivalent to stagnant inaction; as Pure Act, it is in fact the exact opposite of inaction. It is fully and wholly and purely active, in a way that no material being could ever be. Being immutable entails not having the capacity for being passively acted upon; it does not entail the inability to act in itself. The Scholastic tradition also holds God to be Pure Existence or Being Itself, which is identical to Pure Act, because existence just is act! To exist is to actively stand out from nothingness, which is why Aquinas refers to it as the act of existing. But the essence of God just is the act of existence; pure, Subsistent Being Itself.

Philosopher W. Norris Clarke, S.J. writes beautifully:

“It is through action, and only through action, that real beings manifest or “unveil” their being, their presence, to each other and to me. All the beings that make up the world of my experience thus reveal themselves as not just present, standing out of nothingness, but actively presenting themselves to others and vice versa by interacting with each other. Meditating on this leads us to the metaphysical conclusion that it is the very nature of real being, existential being, to pour over into action that is self-revealing and self-communicative. In a word, existential being is intrinsically dynamic, not static” [1].

So why think that such a Being of Pure Act would be unable to do or cause anything? The reason why this might seem to be the case is because, for the most part, beings in our experience really are only able to do or cause something by way of motion within themselves. But this is because all beings other than the Being of Pure Act, including all material beings, are, necessarily, not Pure Act; they are intrinsically composed of both act and potency. Such beings do not exist as fully actual; their existence is limited by their nature to one mode of being or actuality at a time. Everything that exists has an act of existing, and everything that exists is what it is by virtue of some limiting essence that defines the act of existing to some certain nature with specific properties, attributes, functions, abilities, etc., which are its intrinsic potencies. To move, change, act, etc. is just to transition from states of actuality by way of those potencies being actualized. And, as the Prime Mover argument explains, this process of transition between states of actuality must be accomplished, or caused, by some external thing already itself in a state of actuality conducive to that act of causation. This is because no potency, in principle of what it is, could actualize itself.

So actuality is a current state of existing, of a being presenting itself out of nothingness to reality in a certain mode, self-communicating its essence. Potency is all the possible states of actuality an essence intrinsically holds within it as its nature. And change is the process of potency coming into actuality, by way of some causal action performed by a being already in act.

Now consider this being performing the role of cause. For illustration, imagine a pot of room-temp water placed on a stove. The water exists currently as room-temp, but it has the potency to become boiling. This potency is actualized by the heat of the pot in which it rests. But the pot itself also had to change from its previous temperature to its much hotter one. And this change was actualized by the heat/energy from the stove. But the stove likewise changed in temperature, and so on. In each case, the agent acting as cause required movement for itself, in order to actively move something else. This is because, for material beings, action, in the sense of performing some function or operation, requires us to utilize our intrinsic potencies for those functions/operations, and thus requires actualization.

So in a sense, for beings which are composites of act and potency, it is indeed correct to maintain that “doing anything at all requires change”. It is entirely incorrect, however, to say that “pure action is change”. For remember that change itself is the transition between states of actuality, not the actuality in itself. Act is not change; it is real, present, actual existence that is what it is, as it is. So it wouldn’t make sense at all to say that a Being which is purely Act could be change; such a Being in principle is incapable of changing. But again, this does not mean that it is incapable of acting or causing or “doing”, it just means that it does not change in order to do so. Whatever action it performs is not some movement or process, it is a totality, a wholeness. Action for this Being does not involve the actualization of potency, for He is already fully actual in every sense.

To see this, the best analogy, which I have used before, is that of moons and sun. No moon has within itself the ability to give off light from itself. It only has the ability to to reflect light from another source. Now imagine that our sun was much farther away from the earth, and all we had is a moon. And now suppose that the moon we could see from earth didn’t actually reflect light from the sun, but from another moon. And that second moon only reflected light from a third moon, and so on and so on. Now we from earth would have no perception of a “sun”. Such a thing would be totally outside our realm of awareness and experience. But by understanding the nature of light and moons, we could deduce that something like a sun must exist, something which is the source of all light for these other moons which merely reflect its light, something which has light in itself. Now even though all the objects of our experience (the moons) require reflecting light in order to give it, we would still have to posit necessarily a being which does not need to reflect light in order to give it, a being which just “gives light” from itself as its very nature. Consider also that each successive moon in the series must be considerably larger and more powerful (in terms of capacity for reflecting light) than the one before it, in order to give off enough light for the lesser moon to still reflect some to the next moon. And so consider in turn how exponentially larger and more powerful this sun must be, whose light is so great and overwhelming that it is able to be reflected by so many moon in a series all the way to earth. In the same way, all our experience is of material objects which are composed of potency and which, in order to act, require their potencies to be actualized in the process of change. But the Prime Mover argument deduces from this that there must exist a being who is the source of all change and action, a being of Pure Act who “gives action” from Himself without needing to “reflect” it from another. In other words, a Being which can actively “move” others without needing to be moved Himself. This is only possible in a Being without any potencies. We may not be able to grasp how this is so, but we know from the argument that it necessarily must be.

A Being of Pure Act is full, unlimited actuality/existence. He cannot transition between different states of actuality, because He is all of actuality at once. Every “mode of being” that He possible can be He is simply and entirely and altogether at once. Action for him does not require an intrinsic change, because it is what He is fully and indivisibly.

But from this comes the issue of time and causation. To see this, I will quote the objection as it was delivered to me, in its own words:

“Picture this Prime Mover, in a state in which He hasn’t yet created the universe. At some point in reality, He decides to create something else other than Himself. He undergoes change by the mere act of creation: there’s Prime Mover without the universe, and then poof, there’s Prime Mover and the universe. Creating the universe is a potency He actualizes, thus a change.”

This analysis would be correct of any temporal being operating within time. But, as I’ve explained elsewhere, the Being of Pure Act must necessarily be timeless. For humans, deciding to act, and indeed all reasoning, involves a series of steps toward a conclusion of the will. For God this cannot be the case. He does not experience reality as a succession of moments, for He is outside of all moments, and is aware of all time as if it were instantaneously present to Him. We cannot apply any tensed or temporal terms/concepts/frameworks to God, for He entirely transcends them. For God there is no one moment and then another, for He is not within any moments at all. Thus it is false to say that “at some point He decides to create”, because this implies a series of successive “points” in time. There is no Prime Mover without the universe and then Prime Mover with the universe, because, again, that’s a temporal progression.

This is obviously very much in opposition to our normal way of thinking about things, because we are such completely tensed creatures who are so deeply imbedded within the framework of time, that to grasp such a reality is utterly beyond our wildest imaginations. For example, it is not rare to hear a question such as “what was God doing for all those eons of eternity before He created the universe?” But this question just doesn’t make sense, for time was created with the universe, so we cannot even posit a “before” time at all. God is certainly causally prior to the universe, but to apply any sort of temporality to Him is just meaningless. It is, as such, also incorrect to say that God has “always” been creating, because that again is a temporally imbued term. It is more correct to just say that God is, eternally and timelessly, and that part of God’s “is-ness” (if you will) involves creating a temporally finite creation, which flows from Him and is sustained in being by Him. There is no “act” of creating that is separate and distinct from God’s totality of Act. There is no Point A at which God “decides” to create, then Point B at which He does create, and then Point C “after” He has created. It is all one, and undivided, and non-successive to God.

Remember that change is the transition from one state of actuality to another, not the actuality itself. God is the entirety of His actuality altogether at once. There are no different “states” or “modes” or “points” to which He can transition, for He is all that He is and never anything else, for there is nothing else for Him to be. And part of this actuality of God involves His creating the universe.

This idea is radical and incomprehensible for us, so embedded in our finite, physical, temporal reality as we are. The objector next states:

“You claim this being is personal, and capable of thought. I cannot fathom a definition of thought or consciousness that doesn’t entail a stream of events, an actualizing state of potential happening in the mind of this agent.”

But that is certainly true, that we are completely incapable of fathoming this reality that is Reality Itself. And yet we know it must be so by understanding the very nature of our own reality.

As for being personal/capable of thought, there is nothing per se about intellect that requires it to entail a stream of events. The reason that is the case in us is because our intellect is based in a material brain limited by our physical senses. But for a purely simple, immaterial Intellect entirely outside physical and temporal reality, there is no stream of events, but rather a whole and instantaneous awareness of everything as it is. There is no need to reason to a conclusion, because all knowledge is already present. There is no need to perceive and experience reality as a stream of events, because all events are known directly and equally all at once.

To say that this is beyond understanding is an extremely exaggerated understatement. But being beyond understanding does not render something incoherent or unbelievable. We know this must be the case given our metaphysical understanding, and there is nothing self-contradictory within it, no matter how utterly beyond comprehension it might be. And so we must assent to it as the marvelous truth that it is.

Next is the claim that cause and effect relationships without time are, by definition, incoherent. This objection is only plausibly true on the modern conception of causation as distinct “events” separated in time. The Scholastic understanding, however, holds causation as being one simultaneous event between two distinct substances, not separated by time. In this case, cause and effect do not require being within time to operate. Of course, one might disagree with the Scholastics concerning this account, but that is a much larger topic which will have to be considered in another post.

The conclusion of the objection:

“Probably due to framing,  to me, change is merely a notion, an idea, not an actual physical process. To me, an object which actualizes its potency is exactly the same object, with a different arrangement of its constituent parts. I don’t need a source for change, only a causal explanation, when possible.”

I’m not sure exactly what is being said here. If one denies the reality of change, then of course the argument doesn’t work, as the argument is entirely based upon explaining change as a real feature of our world. But it doesn’t sound like this person is actually denying change, as they admit that an object can undergo a transition such that it has “a different arrangement of its constituent parts”, which just is a type of change. Aristotelian-Thomists distinguish between substantial and accidental change, the former being when there is a change of essential/substantial form in a subject, such as when a living organism dies; and the latter being just a change in properties/attributes of a substantial form, without the form itself changing, such as a child growing into an adult. As far as “source” as opposed to “causal explanation” of change, I’m not really sure what the difference is. By both I would just mean the agent in act that actualizes the potency of something.

This person is right, however, to identify that the real issue in the argument is the underlying, metaphysical framework. If the Aristotelian-Thomistic metaphysical principles are correct, then the existence of God follows directly and automatically. Unfortunately, a great many people do not accept the metaphysical framework, but I believe there are drastic implications for such a rejection which most would not be willing to maintain if properly understood. To me, the Aristotelian-Thomistic metaphysical system makes the most sense, and explains most fully, my experience of the world, which is why I am committed to these principles, and will be until some other framework of thought offers a better overall glimpse into the nature of reality.



[1]. Clarke, W. Norris. The One and the Many: A Contemporary Thomistic Metaphysics. Notre Dame: University of Notre Dame Press, 2001.

Cover image in the Public Domain in the United States, taken from Wikimedia Commons:


2 thoughts on “The Prime Mover and the Nature of Immutability

  1. […] Obviously, there are some major holes/weaknesses in their version of the argument which need to be worked out/developed more fully. But that’s just precisely what Aristotle and Aquinas did. In particular, as already noted, a key different would be between seeing the First Mover as “self moving” and the First Mover as immutable, causing motion but not undergoing any in itself (to consider how this is possible, see my article here). […]


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