The Problems of Pure Act

The Problems of Pure Act August 27, 2020

This is a guest post from Gunther Laird, whose superb new book The Unnecessary Science: A Critical Analysis of Natural Law Theory (UK), a devastating critique of Ed Feser, Thomas Aquinas and Natural Law Theory, is out now. Over to Laird:

The philosopher Edward Feser, in most of his published books and articles (such as The Last Superstition, Five Proofs for the Existence of God, and Scholastic Metaphysics, among many others) has done more than any contemporary writer to popularize and defend the Catholic religion. I have endeavored to contest his efforts directly in the new book I have recently published, The Unnecessary Science: A Critical Analysis of Natural Law Theory. Building off previous entries I have written or been involved in for both Tippling Philosopher and Bob Seidensticker’s Cross Examined blog, I will summarize one of the arguments (out of many) I make in my book. This one comes from Chapter 6, and it’s a much more direct attack on the foundations of Feser’s theology. While in most of the previous chapters I accept Feser’s premises to illustrate how they still don’t support his conclusions, this time I’ll be contesting the premises directly. Here I will directly challenge his version of Aristotle’s argument for an Unmoved Mover, or Unchanging Changer.

Let us bring together some arguments Feser has provided in both Five Proofs and The Last Superstition. According to Five Proofs, the argument for change, strangely enough, applies to un-changing things as well. Recall that any sort of change is just the actualization of potential; for instance, if a hot coffee cup becomes cold, we say the coffee’s potential for coldness has been actualized, and actualized by something else—a cold breeze, for instance. But the breeze itself must be actually cold before it can actualize something else’s potential for coldness, and must be made cold by an air conditioner. All well and good, but even things that are just staying the same can be said to be actualizing potentialities. Feser asks us to imagine a cup on a desk. There is nothing inherent in the cup that mandates it be, say, three feet above the ground. Rather, its potential to be above the ground is actualized by the desk. But the desk also has no potential to hold things up—rather, it must be supported by the floor on which it stands. The floor itself must be supported by the ground beneath it, which is part of the Earth. And while the Earth doesn’t need to be supported by anything, it is reliant on the laws of physics and atomic bonds that ensure it doesn’t simply disintegrate. So in that sense, the potential of the Earth itself to exist must be actualized by the attraction between atoms. As Feser says,

Atoms have the potential to be bonded in other ways, and yet they are not so bonded. It is their potential to be bonded in such a way that [the Earth remains stable] that is in fact being actualized. Again, why? Appealing to the structure of the atom won’t answer the question either, but merely pushes it back a stage. For why are the subatomic particles combined in just the specific way they are, here and now, rather than some other way? What is it that actualizes that potential rather than another?[1]

This line of thought becomes very curious when we compare it to what Feser wrote in The Last Superstition. There, he explained potentiality in this way:

it might be said…that a thing is “potentially” almost anything, so that Aristotle’s distinction is uninteresting. For example…we can ‘conceive’ of a ‘possible world’ where rubber balls…move by themselves…. But the potentialities Aristotle has in mind are the ones rooted in a thing’s nature as actually exists, not just any old thing it might ‘possibly do’ in some expanded abstract sense rooted in our powers of conception. Hence, in Aristotle’s sense of ‘potential,’ while a rubber ball could potentially be melted, it could not potentially follow someone around all by itself.[2]

If we give these two passages a few moment’s thought, we can see how the latter undermines the former, and by extension the first Thomistic thesis upon which the argument for God rests. Feser tells us that the atomic particles which constitute the Earth (to take but one example) represent the actualization of a potential because there are ways they could otherwise be, not only at some point in the past but here and now. Their arrangement could be different, or the measurements of the forces holding them together could be something else. Crucially, however, Feser simply asserts this—he provides no independent reason this is true in reality as opposed to inside our minds. How can we be certain the Nature of atoms or the fundamental forces of physics actually could be different than what they are? Perhaps the alternate configurations of the atoms or measurements of the fundamental forces that Feser is thinking of belong in the same category as a rubber ball bouncing to the moon or rolling around by itself: figments of our powers of imagination and conception rather than any actual potentiality rooted in the Nature of these entities themselves. If that is the case, then it is entirely possible that such entities—the collection of fundamental particles, the physical forces, and so on—would be the “purely actual actualizer” or “unchanged changer” Feser says we need.

Now, Feser says such things cannot be “purely actual” because they can be differentiated from one another: “Even the fundamental particles—fermions and bosons—though they are not composed of other particles, still have parts in the sense that they have distinctive attributes. Furthermore, they exhibit potentiality insofar as they come into being and pass away.”[3] In his second point, Feser is not quite correct—the law of conservation of matter would imply that the fundamental particles may change their relationships and arrangement, but not actually pass out of existence.[4] But even his first point is somewhat unconvincing, given the religion to which he himself is dedicated. Recall from Chapter 1 that all of God’s apparently manifold attributes—Goodness, Power, Intelligence, Will, and so on—are not separate parts of God, but merely different aspects of the same thing. It’s just sort of hard to understand due to our limited intelligence. Well, two can play at that game. Perhaps it is the case that the apparent differences between fermions and bosons are merely reflections of the same underlying reality, only appearing to be different things due to our lack of scientific knowledge. Would such a thing be impossible, because the particles are actually distinct? Not a problem for us. Recall the doctrine of mysterianism—that the three separate parts of the Christian Trinity are actually the same Being, despite at least one of those parts (Christ) walking around and changing in ways Pure Actuality shouldn’t be able to do. We can fall back on the same doctrine—even if their characteristics seem to be distinct, fermions and bosons are the same thing, or reflections of a single reality, and we just can’t figure out how yet.

Feser might then offer another rejoinder, this time taken from his book, Philosophy of Mind. According to him, there are two kinds of impossibility. The first kind of physical impossibility revolves around “the way the world works,” and could conceivably be possible under different circumstances. The example of a rubber ball bouncing to the moon would be an example of such an impossibility: Given the laws of physics, rubber balls can’t do that, be we can coherently conceive of different laws (gravity being half as strong as it actually is, say), under which rubber balls could bounce to the moon. On the other hand, “no matter how different the world might have been,” we cannot conceive of 2 and 2 equaling 5 or round squares. These are simply metaphysically impossible.[5] Feser might argue that since we can coherently conceive, without any apparent contradiction, of the basic laws of physics being different than they are, they could potentially be so, which means that what they actually are right now needs an explanation, which would be God. The problem here is that I can easily say that worlds with different laws of physics are actually inconceivable in the same sense, and it just isn’t immediately obvious.

For instance, Feser might say “had…the gravitational pull of the earth been different, [it might have been possible to bounce a rubber ball to the moon]…we can give a description of such a state of affairs in a way that involves no contradiction.”[6] But this is not true—there is a contradiction there, it’s just not immediately obvious. The Earth’s gravitational pull is a function of the gravitational force in general, and that affects everything. In a possible world where Earth’s gravity was weak enough to permit a ball to bounce to the moon, gravity would also be too weak to keep the moon in its orbit, and it would have floated away long ago. The same applies to every other counterexample Feser might think of. A world where human beings run two-minute miles or jump fifty feet in the air (the ideas he came up with in Philosophy of Mind) would be so radically different from ours that such beings wouldn’t really be human at all—fleamen, perhaps, but not Homo Sapiens.[7]

Feser might argue that we can imagine someone running a two-minute mile in a way we can’t even imagine a round square or something similar. However, that the impossibility of such a state of affairs isn’t immediately obvious doesn’t mean it isn’t there. For instance, ask someone to imagine a round square and they might think of a polygon with rounded corners. Feser would say they’re just thinking of a semi-rounded shape, not an actual round square. But the same applies to Feser’s example: If we think of someone leaping tall buildings in a single bound, we’re not actually imagining a different world, we’re actually thinking of a flea-human or a superhero like Superman rather than someone with the Essence of a human being doing such a thing. Thus, we return to the conclusion that the laws of physics are, in reality, precisely a sort of “purely actual” being. Whether they’re descriptions of the Essences of the fundamental particles or something else, it is impossible to coherently conceive of them being different once you really understand what they entail, which means those laws have no potential—they’re just pure, undiluted actuality, baby. And that means there just might be no reason to postulate the further existence of some kind of God.

Now, Feser would say there are all other sorts of problems, like that of Universals, which necessitate that Pure Act be a deity rather than a force of nature or fundamental particles. However, as I mentioned, this is just a single example of what you can expect to find in chapter 6 of The Unnecessary Science—I discuss these other problems in much greater depth in the text itself! All I wanted for this entry was to explain the problems with Feser’s arguments as they pertain to the Aristotelian concepts of “act” and “potency.” If you find this compelling—or perhaps even amusing—whether you agree with it or not, I hope you’ll consider giving the book itself a look.


[1] FP, 20-40.

[2] TLS, 54.

[3] FP, 199-200.

[4] Bruce Reichenbach, “Cosmological Argument”, The Stanford Encyclopedia of Philosophy (Fall 2019 Edition), Edward N. Zalta (ed.), forthcoming URL = (last accessed on July 5, 2020). One thing I should mention here is that, as this article points out, if one holds that matter as a whole is a sort of “necessary being,” then every arrangement of that matter becomes necessary, which is unintuitive if not self-contradictory. A possible solution “would be to invoke an indeterministic presentation of quantum phenomena, which would allow contingency of individual phenomena but not of the overall probabilistic structure.”

[5] Edward Feser, Philosophy of Mind (Oneworld Publications, 2005), 23-25.

[6] Ibid.

[7] Ibid., 23.


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