0. I’ll start this post, the sixth in a series dedicated to a sustained reading of and commentary upon Thomas Aquinas’s Commentary on the Metaphysics of Aristotle,* with a brief overview of the posts that have seen the light of day thus far in the series. I’ll then touch upon the Aristotelian theory of act and potency.
1. The posts that have seen the light of day thus far in the series fall into two categories. The first of the two categories includes two posts dealing with the arguments Aquinas presents in the very first paragraph of his “Prologue.” In the first of these two posts, I set out and offered a critique of the paragraph’s most explicitly stated argument, the conclusion of which is that one science must rule the other sciences. In the second, I did the same for the paragraph’s main argument, the conclusion of which is that wisdom is the science that rules the other sciences. The primary critique in both cases is that, though they both are valid arguments, Aquinas does not offer, at least in the prologue, all that we need to see to see whether they are in addition sound arguments.
The two posts are:
Aquinas’s Argument That One Science Must “Rule” the Others. A Critical Assessment
Aquinas’s Argument That Wisdom Is the Ruler of the Other Sciences. A Critical Assessment
The second of the two categories includes three posts reflecting in various ways upon the relationships, or possible relationships, between the neo-Aristotelianism motivating After Aristotle and the Aristotelianism, or, possibly, the Aristotelianisms, of Aristotle and Aquinas. One of the three is the post introducing the series,
Reading Aquinas’s Commentary on the Metaphysics of Aristotle. Introduction
The other two posts point to some of the fundamental ways in which this blog’s philosophical perspective is in agreement with the Aristotelianism of Aristotle and Aquinas, thus justifying the “Aristotelian” of the “neo-Aristotelian” of the tag, “Analyses and Essays from a Neo-Aristotelian Point of View,” at the top of this page. In the one,
The Principle of Metaphysical Realism
I point to the metaphysical realism that After Aristotle shares with the Aristotelianism(s) of Aristotle and Aquinas. In a subsequent postlette (which I, arbitrarily, it has to be said, decided not to include in the numbering of the posts of series),
Metaphysical Pluralism. An Appendix to “The Principle of Metaphysical Realism”
I went on to point to the metaphysical pluralism and, moreover, the philosophical dynamism that After Aristotle shares with the Aristotelianism(s) of Aristotle and Aquinas.
In the remaining of the posts pointing to ways in which this blog’s neo-Aristotelianism is in agreement with the Aristotelianism of Aristotle and Aquinas,
Aquinas on the First Principles 1
I spelled out the metaphysical principles of non-contradiction and excluded middle and underlined the need to distinguish between the two metaphysical principles and the logical principles of non-contradiction and excluded middle, to which latter the metaphysical principles are prior.
I have not yet fully worked out what I will do in the post to come and bearing the title, “Aquinas on the First Principles 2.”
2. The primary intention of the present post is that of drawing attention to a central thesis in the holding of which the philosophical perspective of After Aristotle stands in agreement with that or those of Aristotle and Aquinas. Then, in the next post in the series, I will draw attention to a central thesis in which it differs from it or them.
Both the one thesis and the other, however, receive expression in Comment 2 of Aquinas’s commentary. There, after having reported, in Comment 1, that Aristotle
says … that the desire to know belongs by nature to all men.
Aquinas goes on to say
Three reasons can be given for this. The first is that each thing naturally desires its own perfection. Hence matter is said to desire form as any imperfect thing desires its perfection. Therefore, since the intellect, by which man is what he is, considered in itself is all things potentially, and becomes them actually only through knowledge, because the intellect is none of those things that exist before it understands them, as is stated in Book III of The Soul [429a23]; so each man naturally desires knowledge just as matter desires form.
The philosophical theory making its entrance here, with which After Aristotle’s neo-Aristotelianism is in agreement with that or those of Aristotle and Aquinas, is the theory of actual being and potential being or, as it is often put, being in act and being in potency, or yet more simply, act and potency. The philosophical thesis evident here with which there is disagreement is the thesis of the identity of the intellect actually knowing with that which the intellect actually knows.
3. The theory of act and potency will be the object of extensive discussion as the present series of posts unfolds. In this post, therefore, I will content myself with just the setting forth of two theses that my neo-Aristotelianism upholds and offering some indication of their contemporary relevance. The one is that
Whatever is actually something is also potentially that something.
Anyone actually knowing what the twenty or so amino acids are is also potentially knowing what the twenty or so amino acids are.
The converse, however, is not true; that is, it is not true either that
Anyone potentially knowing what the twenty or so amino acids are is also actually knowing what the twenty or so amino acids are.
Whatever is potentially something is also actually that something.
Not all persons potentially knowing what the twenty or so amino acids are actually know what they are. That is, it rather is the case that
At least one person potentially knowing what the twenty or so amino acids are is not actually knowing what they are.
At least one thing that is potentially something is not actually that something.
The theory of act potency is, as I briefly indicated above, still with us in contemporary philosophy, albeit, in most cases, with major differences from any Aristotelian understanding. There is, to point to just one example, John-Paul Sartre’s Being and Nothingness.**
The duality of potency and act falls by the same stroke [as that of “being and appearance”]. The act is everything. Behind the act there is neither potency nor “hexis” nor virtue.
Sartre’s metaphysics is then, at least to the degree that it consistent, one in which everything that is must be pure act, for it does not provide for any distinction between act and potency. And, as you may be aware, though I am now getting way ahead of myself, for the Aristotelian metaphysics of Aristotle and Aquinas, the divine and the divine alone is pure act. Sartre may then be seen, at least from that point of view, as holding that all actual things are divinities. As, however, we advance in this series of posts, it will be clear that I, along with Aristotle and Aquinas, do not see it to be the case either that everything is pure act or that all actual things are divinities.
4. The theory of act potency is also, of course, still with us in contemporary Aristotelianism and Thomism. An important statement of the theory can be found in the famous “Twenty-Four Thomistic Theses.” The first of these two theses, as it is translated on the Catholic Biblical Apologetics website, “The 24 Thomistic Theses,”*** reads:
Potency and Act divide being in such a way that whatever is, is either pure act, or of necessity it is composed of potency and act as primary and intrinsic principles.
The second of the twenty-four Thomistic theses is
Since act is perfection, it is not limited except through a potency which itself is a capacity for perfection.
This, of course, is not simply a thesis, but an argument. Regimented just a bit, or so spelled out as to bring out its logic just a bit more expressly, the argument is:
Act is perfection.
Therefore, act is not limited except through a potency which itself is a capacity for perfection.
For now, I will content myself with the observation that at least one, and quite likely more than one, additional premise is needed if that conclusion is to be completely justified.
Until next time.
* Thomas Aquinas, Commentary on the Metaphysics of Aristotle. Translated and introduced by John P. Rowan (Revised edition; Notre Dame, Indiana: Dumb Ox Books, 1995 )
This edition of Aquinas’s text is serving as the text at hand in the present series of readings and comments. It is available online, at:
If you prefer to do your reading in hard copy, you may easily purchase a copy of the work through Amazon.com., by simply clicking on the following:
** John-Paul Sartre, Being and Nothingness, translated by Hazel Barnes (New York, Philosophical Library, 1956), p. 4.
*** One of the places online where a translation of the document can be found is:
Hello Richard, I’m getting a lot out of following you.
As to your thesis that whatever is actually something is potentially that something, this is probably going to be a matter of semantics, but does a problem for your formulation arise from Physics III.1, 200b26-28? Sc. “there is something that is only actual (ἐντελεχείᾳ), another that is in potentiality (δυνάμει) and actuality” in the categories of substance and all the others.
From what I’ve seen, Aristotle will at times use ‘dunamis’ to mean “power,” so a mover actually moving something is exercising power. But above, where he’s getting ready to discourse on actuality and potentiality re motion, it seems we need ‘potentiality’ as the sense of ‘dunamis.’
God, of course, or the First Mover, is not going to be potential anything, correct? The FM’s moving of something is never not actual.
And, David, I’mm getting a lot out of you following me.
I thought that the thesis that what is actually something is also potentially that something would raise eyebrows.
You may be right that it is a matter of semantics. That is, if or when someone identifies being something potentially with being something potentially and not actually, then that someone will not accept the thesis at hand, for from the conjunction of that thesis and that identification it would follow that whatever is actually something is not actually that something. But someone, like yours truly, who distinguishes between being something potentially and being something potentially and not actually, is not faced with that implication.
In, then, the case of a being that changes from something to something: before the change, the being is that something it will change to potentially and not actually; and after the change, it is that something it has changed to potentially and actually. The potency has been actualized and not destroyed (yes, that makes me think of nature and grace).
You understood that my thesis commits me to saying that even in the case of God, if such there be, God’s being actually whatever God is entails God’s also being that whatever potentially. But, in the case of the divine, it has to be understood that the divine potency is identical with the divine act. In fact, I was led to the thesis at hand by reflecting on the two theses of Aquinas, the one that essence stands to existence as the potential to the actual and the other that, in the divine, essence and existence are identical.
That “if such there be” above is inserted because I have had a devil of a time being able to affirm that the five ways of Aquinas or the five proofs of Feser are indeed proofs, proofs according to the scientific standards of Aristotle himself. But, on the other hand, I have something like an intuition, or perhaps just a hunch or a hope, that one or more of them are such proofs.
Hi Richard, can you elaborate on this of yours?
“The potency has been actualized and not destroyed”
What does Ari mean when he talks about things that are “in entelechy” only vs. other things that are so and also in potency?
Maybe I’ve been misconceiving potentiality and it’s really closer to power or potency. I usually think of the process of bringing something potential into a state of actuality as a process of completion or fulfillment, as in “entelechy.” “Destroyed” seems to be the wrong word to use for what happens to the potentiality. When a thing is configured so that it is fully F, there isn’t any work left to be done to convert it to the state of being F. Isn’t the potentiality swallowed up in victory, as it were?
David, what I meant by “the potency has been actualized and not destroyed” is that, when a being that has been something potentially becomes actually that something, i.e., when its potency has been actualized, that potency continues to be and to be a principle of that being; it has not been destroyed.
Or, when a being has become fully F and there is no longer any unactualized potency, but only actualized potency, the potency remains, just completely actualized.
I have not by any means thought through the relationship of the theory of act and potency to that of modern modal theory. But it seems to me that just as, according to the latter, whatever is actually the case is also possibly the case, so too, according to the former, whatever is actually the case is also potentially the case.
I am not ready to speak to exactly what Aristotle himself had in mind in that particular passage.
How do statements like the following fit the idea that whatever is actually something is potentially that thing? Sc. “For what is actually hot cannot simultaneously be potentially hot; but it is simultaneously potentially cold.” From ST 1a art. 3 (the First Way)
They cannot, if it is understood that whatever is actually something is not also potentially that something.
That I understand that whatever is actually something is also potentially that something, though not only potentially that something, puts, of course, the burden on me of restating the proposition you quote, as: “whatever is actually hot cannot simultaneously be only potentially hot; but it is simultaneously potentially cold.”
I understand my thesis to be, not even a friendly amendment to the Aristotelian theory of act and potency, but a friendly precision of it.
In my friendly revision, not amendment, of Aquinas’s statement, accomplished by simply inserting the word, “merely,” the statement comes to read, “For what is actually hot cannot simultaneously be merely potentially hot; but it is simultaneously potentially cold.”
In the sentence you quoted, Aquinas presents us with an instance of a principle, the statement of which principle can be found in the sentence immediately preceding the one quoted. It reads, “Now it is not possible that the same thing should be at once in actuality and potentiality in the same respect, but only in different respects.” In my friendly revision, not amendment,of the statement of this principle, I’d insert the word, “mere,” thus: “Now it is not possible that the same thing should be at once in actuality and mere potentiality in the same respect, but only in different respects.”
In line with Aquinas’ commentary on the Physics III.1, C280-285 or so, I’m wondering whether the following conception would explain how a thing that actualizes a potentiality no longer is in potency in that respect.
Say I move a bookend to the top shelf. The bookend has the potentiality to be moved, both per se – it will “seek” the center of the cosmos, i.e. go down, if impediments are removed – and per accidens – it can be picked up and carried, etc. Aristotle followed by Aquinas defines a motion as the actuality/fulfillment, entelechy, of what is potentially, as such (201a11-12). When the bookend is on the desk, it has pure potentiality of being moved to the top shelf. When it is in motion in my hand, then that potentiality of movement is actual; it’s actually in motion. But the motion only becomes completed when the end is reached. When it reaches the top shelf and is set down at rest, the bookend is in fulfillment with respect to that motion. Its potentiality for undergoing THAT motion is exhausted. You cannot undo an action that has been done.
The bookend has the potentiality for other motions, but no longer for THAT motion from desk to top shelf at time t in Murphy’s hand.
I think Ari and Aq are interested in act and potency as modes of being, not as qualifications of the truth value of a proposition. Your friendly precision seems to call attention to the latter as an important consideration.
I’m not sure whether I’ve got this right.
BTW I haven’t checked in the literature to see how this article was received, but what seems to be a helpful discussion of energeia and entelecheia in Aristotle, and of how Ari shifts toward more exclusive use of energeia, is George A. Blair, ‘The Meaning of “Energeia” and “Entelecheia” in Aristotle,’ International Philosophical Quarterly 7 (1967), 101-17.
Let me be honest with you here. I have a great deal of thinking and investigating before I have anything that even I would dare to think approaches being worthy of publication, even in a blog. I would, however, like to express one hunch, that it is because the bookend resting on the desktop is potentially on the top shelf of the bookshelf that it is potentially in motion, in the motion towards being actually on the top shelf of the bookshelf. Were I to express that humch, however, I would begin to sense the presence of Zeno in the room. So, at least for now, I won’t express it.
There’s also the problem that your friendly precision seems to undo what Aquinas needs for his Ways, if “whatever is actually something is potentially that thing” applies to a mode of being. The Unmoved Mover is supposed to be pure act; if it has some potentiality as well as actuality, it’s no good as an Unmoved Mover. If a part of it is wholly actual, so that it can do the work that the UM is supposed to do, then it won’t be potentially anything. I know I brought this up before. But I’m wondering whether your precision will undermine the First and probably others among the Ways.
On the other hand, if the UM can be without any potentiality and also can “be potentially” the UM, as in your precision, then I am quite confused.
On to absorb your latest about the supreme science.
My thought on this point has been that the unmoved mover or the divine being, if (I’ll insert again) such there is, must indeed be “purely actual.” This, however, means that there is nothing belonging to the divine being that is other, really other, than actuality or act. This in turn means, not just that there is no unactualized potentiality within the divine, but also that the potentiality or potency within the divine being is identical with the actuality or act within the divine being. Thus it is that (1) essence is to existence as potency is to act and (2) the divine essence and the divine existence are identical.
Hi Richard, thank you for answering my questions. So far I can’t commit to speaking of a fully actualized potentiality as though it is still potentiality, but I’ll leave this and wait for your next installment.
I’m not trying to have the last word on the point, but: a fully actualized potentiality is still a potentiality, albeit fully actualized.