Reflections on Book Lambda

It turns out that Aristotle’s way of arguing for a first cause in book Lambda of the Metaphysics depends almost entirely on his unusual thesis of the priority of actuality or being-at-work or fulfillment over potentiality. His justification of the priority of actuality there also seems unexpectedly Kant-like, which means that so does his argument for a first cause.

We don’t positively know that actuality is prior, or that there is a first cause. Rather, Aristotle makes the indirect argument that a priority of actuality is a necessary condition for the kind of intelligibility that we need to have in order to be able to explain things at all. The pure actuality he attributes to the first cause is part of his affirmation that the priority of actuality is not an optional feature of his account.

I have been very impressed by Robert Pippin’s account of how Hegel’s rediscovery of the Aristotelian priority of actuality affects ethics and the theory of agency. Gwenaëlle Aubry increased my sensitivity to the normative, end-like character of Aristotelian actuality itself, and to his repeated associations of the first cause with the good and the beautiful. I’ve always read Aristotle’s first cause in terms of that-for-the-sake-of-which — as a sort of ultimate end — so this was a welcome perspective. This much seems to tightly cohere, and all to be nicely confirmed by the somewhat more disciplined reading of the Metaphysics I’ve just finished.

But I’ve been neglecting another strand from the Physics, which defines motion in terms of actuality and potentiality, and which ultimately traces every motion to the realization of an end, and to the actualization of a potential. Given my own interest in the idea of interpretation in an ethical spirit as first philosophy, this suggestion that material motion as such is in some minimal way ends-governed — even when no living plant or animal is involved — is something I find very appealing, albeit in need of clarification.

On the other hand, the arguments about a first motion and a first moved thing associated with the sphere of the fixed stars presuppose the non-relative status of a geocentric point of view in astronomy, and I don’t see any way to sustain that. The first cause of all things can no longer be conceived as having a special, more direct relation to the motion of the stars as viewed from earth, such as Aristotle suggests.

But we can still say that the pursuit and partial realization of the good and the beautiful are in a way involved in motions in general. This can be defined in a way that depends only on observable patterns of how various kinds of material things tend to seek completion in one way rather than another in different situations.

The good and the beautiful will be a “prime mover” only in this more diffuse sense, not as also having a special relation to the motion of the fixed stars. But we can still have entelechy from top to bottom, and we can still be moved by the beauty of the stars.

Pure Entelechy

Book Lambda (XII) of the Metaphysics sketches Aristotle’s brilliant and beautiful solution to the problems that have been under investigation in this work. The text of book Lambda itself, however, seems more like a series of fragments than the kind of tight, continuous development that characterizes the so-called “central books” Zeta (VII), Eta (VIII), and Theta (IX), or the books of Aristotle’s Physics.

He now clearly affirms that there is a first cause of all things — not only of their being what they are, but also of their motion. As a result, book Lambda presents a mix of philosophical theology and Aristotelian physics.

Aristotle has a very distinctive notion of what the first cause is. I would call this pure entelechy. I’m not aware that he literally uses that phrase, but he definitely says that the first cause is pure energeia (actuality, being-at-work, or fulfillment), and he very strongly identifies energeia with entelecheia (a new Greek word coined by Aristotle, meaning literally “in [it] end having”, or “being-at-work-staying-itself” in Sachs’ translation), for which I am using the English “entelechy”.

Entelechy is the theme that unifies Aristotle’s account of motion with the inquiry about why things are what they are. Motion is a kind of incomplete entelechy. The first cause, both of motion and of things being what they are — which he identifies with the good, that-for-the-sake-of-which, thought thinking itself, and what I would call a kind of pure delight — is a complete and pure entelechy. The concept of entelechy thus binds Aristotle’s physics together with his theology.

Apart from considerations related to the first cause, Aristotle normally distinguishes that-for-the-sake-of-which from the potentiality that is an internal source of motion in things. But he also says that every motion is for the sake of that toward which the potentiality inclines. And the first cause of all motion affects things purely as that-for-the-sake-of-which.

The kind of motion that best exemplifies entelechy is circular motion. Circularity is also a kind of figurative image or metaphor for entelechy. Continuous motion in a circle is in a sense always complete in the sense of unchangingly accomplishing its goal, and yet it is always ongoing. But not even the first motion is itself unconditionally complete as an entelechy, since it is still moving. Only the first cause is that.

For Aristotle, there is one thing that is directly moved by the first cause, and that is the sphere of the fixed stars, which also demarcates the most comprehensive whole of things that occupy space. Other motions are indirect consequences of this, which follow only in a conditional way.

The first cause is not just pure entelechy in the generic sense of a logical universal. It is a particular independent thing that turns out to be the unique exemplar of its kind.

In virtue of its unique relation to all other things, it plays the role of what Hegel would later call a concrete universal. Further, the unique character of that relation of “firstness” makes it an unconditioned concrete universal. This is the kind of unconditioned thing that Kant says reason is always reaching for, but that cannot be strictly known. It is also the kind of unconditioned thing that Hegel treats as the ultimate ground of intelligibility and value.

He begins by recalling that the path of the inquiry has approached “all things” by focusing on those sources and causes that make concrete independent things be what they are. Independent things turn out to be those that have some entelechy of their own, which exhibits greater self-determination than the minimal kind that applies to all motions. These include plants, animals, and the stars.

“Our study concerns thinghood, for it is the sources and causes of independent things that are being sought” (ch. 1, Sachs tr., p. 231).

“[E]verything changes from something that has being in potency to something that has being at-work” (ch. 2, p. 232).

All change for Aristotle is from something being potentially something to its being that same something in actuality or being-at-work or fulfillment. This is narrower than common English usage. In Physics book VII he says that “states, whether of the body or of the soul, are not alterations” (Collected Works, Barnes ed., vol. 1, p. 412).

“Now if something has being in potency, still this is not a potency to be any random thing, but a different thing comes to be from a different potency” (ibid).

Although one thing may have many potentialities, each of which may or may not be realized, each of these is a specific potentiality to be actual or at-work or fulfilled in some definite way.

“The kinds of thinghood are three, since the material is a this by coming forth into appearance (for whatever has being by way of contact, and not by having grown together, is material and underlies something else), while the nature of a thing is a this and an active condition into which it comes; and then the third kind is the particular thing that consists of these, such as Socrates or Callias” (ch. 3, p. 233).

He reminds us that when we speak of particular things, to avoid confusion we need to attend to whether we mean their matter, their form, or the composite consisting of both.

“Now things that cause motion are causes as being previously present, but things that are causes in the sense of rational patterns are simultaneous with what they produce” (p. 234).

Causes that are not of motion as such, but rather simply of being in a certain way, like form and that-for-the-sake-of-which, are not like more direct causes of motion in their mode of operation with respect to time. Their operation as causes does not involve a distinct externality related to a before and after, but rather unfolds immanently in their effects.

“Now there is a sense in which the causes and sources of different things are different, but there is a sense in which, if one speaks universally by way of analogy, they are the same for all things…. [B]ut the elements are different in different things, and the first cause that sets them in motion is also different in different things…. [B]ut still, over and above these, is the cause which, as the first of all things, sets all things in motion” (ch. 4, p. 234-236).

For Aristotle, everything has both a particular cause or causes, and a dependency on the first cause of all. The first cause of all operates through particular causes. This is the first time he has unambiguously implied that there is a first cause of all things. (In the middle above, when he speaks of “the first cause that sets them in motion”, this is not the first cause of all, but the first more specific cause of the motion in question.)

“Now since some things are separate while others are not separate, the former are independent things. And it is on account of this that all things have the same causes, because without independent things, attributes and motions are not possible. So then these causes will be, presumably, soul and body, or intellect, desire, and body. And in yet another way the sources of things are the same by analogy, namely being-at-work and potency, though these are both different and present in different ways in different things” (ch. 5, p. 236).

Once again, he recalls both the strategy of deriving the saying of being in the other categories from the saying of what independent things are, and the analogy by which the meanings of actuality and potentiality were illustrated. Again he emphasizes actuality and potentiality as sources of all things.

In passing, he seems to suggest thinking about human being in more specific terms of intellect and desire, rather than an undifferentiated soul. In the Nicomachean Ethics, he specifies that choice is grounded in a fusion of intellect and desire.

“Further, it is necessary to see that some things are possible to state universally, but others not. Now the primary sources of all things are a this that is first at work and something else which is in potency. So these are not the universal causes, since the source of particular things is particular; for a human being is the source of a human being universally, but no one is this universal, but rather Peleus is the source of Achilles and your father of you, and this particular B is the source of this particular BA, but B in general is the source of BA simply. And then, if the causes and elements of independent things are the sources of all things (but different ones of different ones), then as was said, of things not in the same class (colors and sounds, or independent things and quantity) they are different except by analogy; of things that are in the same kind they are also different, but not in kind, but because they are different for particular things, your material and form and mover from mine, though they are the same in their universal statement” (p. 237).

Again he emphasizes that particulars have particular causes. The kind of universality and operation that will be attributed to the first cause of all will be of a sort that respects this. He also again emphasizes that the primary sources of all things are particular actualities and potentialities.

“So as for seeking out what are the sources or elements of independent things and of relations and the of-what-sorts of things, and whether they are the same or different, it is clear that, since they are meant in more than one way, they do belong to everything, but when they have been distinguished they are not the same but different, except in one sense. And the causes of all things are the same in this sense — by analogy — because they are material, form, deprivation, and a mover, and the causes of independent things are the causes of all things in this sense — because when they are taken away everything is taken away; and further, the primary thing that is completely at work is the cause of all things. But the causes are different in this sense — they are as many as the primary contraries, described neither generically nor ambiguously, and as there are kinds of material as well. So what the sources are of perceptible things, and how many there are, and in what way they are the same and in what way different, have been said” (pp. 237-238).

At long last, we come to the argument that there really is a first cause of all things. Again he emphasizes that everything also has particular sources and causes.

“Now since there are three kinds of thinghood, two of them natural and one motionless, about the latter one must explain that it is necessary for there to be some everlasting motionless independent thing” (ch. 6, p. 238).

“For independent things are primary among beings, and if they were all destructible, everything would be destructible; but it is impossible for motion either to come into being or to be destroyed (since it always is), and impossible too for time” (ibid).

For Aristotle there is no first motion, or first moment in time. Instead, there must be an everlasting cause of motion.

“For if there were no time, there could be no before and after; and motion is continuous in just the way that time is; since time is either the same as or some attribute of motion” (ibid).

He points out that to speak of anything “before” there was any time is incoherent, since before and after presuppose time.

“But there is no continuous motion other than in place, and among these, other than in a circle” (ibid).

Only motion in a circle could continue forever. Space is vast, but Aristotle does not believe in infinite distances, so for him there could not be motion continuing forever in a straight line.

He seems to imply that the most fundamental motion of all — that of the fixed stars — provides a uniform measure for time. In modern terms, this is the earth’s rotation on its axis, as observed from a point on the earth. In the absence of evidence refuting what we see to be the case, he assumes that the stars forever rotate around the earth, and that the apparent motion of what is apparently the outermost sphere of the fixed stars is therefore a primary motion that spatially surrounds all things. If we take earth as the point of reference for whatever relativistic motions we see in the sky, this fits all the observational facts.

“But surely if there is something capable of moving and producing things, but not at work in any way, there will not be motion; for what has a potency admits of not being at work” (ibid).

Here he returns to the Physics sense of potentiality and actuality, and to the priority of the actual. Every potentiality is a source of motion that requires something external that is already an actuality of the same sort, in order for the potentiality to be actualized. The child requires a parent, the artifact a Platonic model.

“Therefore, there is no benefit even if we adopt everlasting independent things, as do those who bring in the forms, unless there is in them some source capable of producing change; moreover, even this is not enough, not even if there is another independent thing besides the forms, since if it is not going to be at work, there will not be motion” (ibid).

A pure form or logical universal that is not “actual” cannot explain motion. Once again, motion as the actualization of a potential depends on a pre-existing actuality.

“What’s more, it is not enough even if it will be at work, if the thinghood of it is potency, for there would not be everlasting motion, since what has being in potency admits of not being” (ibid).

Further, any first cause of motion must be everlasting, continuous, and unchanging in its action. That is to say, it must itself be purely actual, with no admixture of potentiality. It would not be sufficient to explain everlasting, continuous motion if the first cause just happened to be actual for some period of time.

“Therefore it is necessary that there be a source of such a kind that the thinghood of it is being-at-work. On top of that, it is necessary that these independent things be without material, for they must be everlasting, if indeed anything else is everlasting. Therefore they are being-at-work” (ibid).

As he just suggested, any first cause of all must therefore be a pure actuality with no potentiality. What Aristotle calls matter is kind of potentiality, so the first cause must have no matter either.

“For how will things have been set in motion, if there were not some responsible thing at work? For material itself, at any rate, will not set itself in motion” (p. 239).

“And this is why some people, such as Leucippus and Plato, bring in an everlasting activity, for they say there is always motion. But why there is this motion, and what it is, they do not say, nor the cause of its being in a certain way or some other way. For nothing moves at random, but always something must be present to it, just as now something moves in a certain way by nature, but in some other way by force or by action of intelligence or something else” (ibid).

It is not enough to simply posit motion. This does not explain anything.

“And then, what sort of motion is primary? For this makes so much difference one can hardly conceive it. But surely it is not possible for Plato to say what he sometimes thinks the source of motion is, which sets itself in motion; for the soul is derivative, and on the same level as the heavens, as he says” (ibid).

The thought here seems to be that if there is a first cause of motion, there must be a primary sort of motion that it primarily causes. For Aristotle, this is the movement of the fixed stars.

“Anaxagoras testifies that being-at-work takes precedence (since intellect is a being-at-work), as does Empedocles with love and strife, and so do those who say there is always motion, such as Leucippus; therefore there was not chaos or night for an infinite time, but the same things have always been so, either in a cycle or in some other way, if being-at-work takes precedence over potency. So if the same thing is always so in a cycle, it is necessary for something to persist always at work in the same way” (pp. 239-240).

If all things did not come from something that is an actuality or being-at-work or fulfillment, then they could only come from what the poets called “chaos and night”. But if all things came from chaos and night, there would be no hope of understanding anything. Aristotle suggests that several of his predecessors ought to have recognized the priority of actuality, as an implicit presupposition of what they did say.

“But since it is possible for it to be this way, and if it is not this way things will come from night and from ‘all things together’ and from not-being, these questions could be resolved; and there is a certain ceaseless motion that is always moving, and it is in a circle (and this is evident not only to reason but in fact), so that the first heaven will be everlasting” (ch. 7, p. 240).

He does not claim to positively know that actuality is necessarily prior to potentiality. He claims that the account is plausible, and that any alternative must lead back to sheer chaos, which would make it impossible for anything to be truly intelligible at all.

“Accordingly, there is also something that moves it. And since what is in motion and causes motion is intermediate, there is also something that causes motion without being in motion, which is everlasting, an independent thing, and a being-at-work” (ibid).

Behind each independent celestial motion, there must be some actual everlasting independent thing. Behind these, there must be something that is completely unmoved, and that is a pure actuality or being-at-work or fulfillment.

“But what is desired and what is thought cause motion in that way: not being in motion, they cause motion” (ibid).

For Aristotle, desire and thought are unmoved movers.

“But the primary instances of these are the same things, for what is yearned for is what seems beautiful, while what is wished for primarily is what is beautiful; but we desire something because of the way it seems, rather than its seeming so because we desire it, for the act of thinking is the beginning” (pp. 240-241).

Desire and thought both aim at what is good or beautiful. The way things seem — and consequently, the act of thinking or judging — drives wishing and willing, not vice versa. Further below, he will again emphasize the active rather than merely receptive role of thought.

“But the power of thinking is set in motion by the action of the thing thought, and what is thought in its own right belongs to an array of affirmative objects of which thinghood is primary, and of this the primary kind is that which is simple and at work” (p. 241).

Thinking itself is driven by the actuality of what it thinks. This does not negate his emphasis on thinking as act.

“But what is one and what is simple are not the same, for oneness indicates a measure, but what is simple is itself a certain way” (ibid).

The simplicity he attributes to the first cause is a stronger criterion than being one.

“But surely the beautiful and what is chosen in virtue of itself are also in that same array, and what is primary is always best, or analogous to it” (ibid).

First things are good and beautiful, and the first thing of all can be identified with the good and the beautiful.

“And that-for-the-sake-of-which is possible among motionless things, as the [following] distinction makes evident; for that-for-the-sake-of-which is either for something or belonging to something, of which the former is and the latter is not present among motionless things” (ibid).

Here he explicitly says that that-for-the-sake-of-which has a broader scope than any source of motion. Alone among the four kinds of causes, it provides ultimate reasons why things are what they are. Form may be identified with what things are, but that-for-the-sake of which is the cause of form and the reason why it is what it is.

“And it causes motion in the manner of something loved, and by means of what is moved moves other things” (ibid).

The highest kind of cause, that-for-the-sake-of-which, involves no force or compulsion or unconditional necessity. Other things are moved because they love it or are attracted by it, but they could not be so moved if they did not have their own sources of motion. They are not moved by some active power emanating from the first cause.

“But since there is something that causes motion while being itself motionless, this does not admit of being otherwise than it is in any respect at all” (ibid).

“For among changes, the primary one is change of place, and of this the primary kind is a circle, but this is what this mover causes” (ibid).

“Therefore [the first cause] is something that has being necessarily…. On such a source, therefore, the cosmos and nature depend” (pp. 241-242).

“And the course of its life is of such a kind as the best we have for a short time. This is so because it is always the same way (which for us is impossible), and because its being-at-work is also pleasure (which is what makes being awake, perceiving, and thinking the most pleasant things, while hopes and memories are pleasant on account of these)” (p. 242).

If we speak in terms of pleasure here, it would be of the highest possible sort. I think “pure delight” captures the meaning more clearly.

“And the thinking that is just thinking by itself is a thinking of what is best just as itself, and especially so with what is so most of all” (ibid).”

“But by partaking in what it thinks, the intellect thinks itself, for it becomes what it thinks by touching and contemplating it, so that the intellect and what it thinks are the same thing” (ibid).

And this, I say, is pure delight.

“For what is receptive of the intelligible and of thinghood is the intellect, and it is at work when it has them; therefore it is the being-at-work rather than the receptivity the intellect has that seems godlike, and its contemplation is pleasantest and best” (ibid, emphasis added).

He is saying that it is by virtue of the more perfect entelechy of intellect, which goes beyond the limited entelechy associated with motion — rather than intellect’s incidental touching or contemplation of something else — that intellect seems godlike. Here again he emphasizes the primarily active rather than receptive character of thought.

“So if the divine being is in this good condition that we are sometimes in, that is to be wondered at; and if it is in it to a greater degree than we are, that is to be wondered at still more. And that is the way it is” (ibid).

For Aristotle, the divine is not incommensurable with the human. Albeit in a very partial manner, we also partake of it, and the more so the more that we are moved by our highest values.

“But life belongs to it too, for the being-at-work of intellect is life, and that being is being-at-work, and its being-at-work is in itself the best life and is everlasting. And we say it is a god who everlastingly lives the best life, so that life and continuous and everlasting duration belong to a god; for this being is god” (ibid).

“That, then, there is an independent thing that is everlasting, motionless, and separate from perceptible things, is clear from what has been said. And it has also been demonstrated that this independent thing can have no magnitude, but is without parts and indivisible (for it causes motion for an infinite time, while no finite thing has an infinite power, and since every magnitude must be either finite or infinite, it cannot have magnitude, either finite, for the reason given, or infinite, because there is no infinite magnitude at all). But surely it has also been demonstrated that it cannot be affected or altered” (p. 243).

Sachs says in a note that the reference to a demonstration that the first cause is not involved with magnitude effectively incorporates the entire argument of the Physics by reference. Book VIII of the Physics has a far more thorough argument that there must be a first unmoved mover corresponding to the primary observable motion of the circling of the fixed stars, but that account does not address the what-it-is of things.

“But since… we see in addition to the motion of the whole heaven, other everlasting motions which belong to the planets…, it is necessary that each of these motions also be caused by something that is itself motionless and an everlasting independent thing. For the nature of the stars is for each to be an everlasting independent thing, while the mover is everlasting and takes precedence over the thing moved, and what takes precedence over an independent thing must be an independent thing” (ch. 8, p. 244).

The terrestrial independent things are mainly plants and animals. These have the richest entelechies among terrestrial perceptible things.

Aristotle also acknowledges each star participating in the motion of the heaven as an entelechy of its own. At least in a way, it is superior to ours, in that to all appearances it lasts forever.

The stars he calls planets are those that stand out by having observable independent motions of their own, different from the primary motion that they share with all the stars that are called “fixed” by contrast.

“[B]ut the number of motions is already something one must examine from that kind of mathematical knowledge that is the nearest kin to philosophy, namely from astronomy. For this kind makes its study about perceptible, everlasting thinghood, while the others, such as those concerned with numbers and with geometry, are not about thinghood at all” (ibid).

“[A]s for how many [independent motions] there happen to be, we now state what some of the mathematicians say, for the sake of a conception of it, … and as for what remains, it is necessary to inquire into some things ourselves, while listening to what other inquirers say about others. If something should seem to those who busy themselves with these matters to be contrary to what has just now been said, it is necessary to welcome both accounts, but trust the more precise one” (pp. 244-245).

“[F]or let the number that is necessary be left for more relentless people to say” (p. 246).

Apparently he made an arithmetic error counting the motions (“either 55 or 47”, where the 47 should have been 48, according the details I have not reproduced), then made a joke of it. I don’t believe Aristotle is very attached to specific enumerations of any sort. It is the principles upon which distinctions are based that matter.

“There has been handed down from people of ancient and earliest times a heritage, in the form of myth, to those of later times, that these original beings are gods, and that the divine embraces the whole of nature. The rest of it was presently introduced in mythical guise for the persuasion of the masses and into laws for use and benefit” (p. 247).

The divine embraces the whole of nature. We still name the planets by the Roman names for the Greek gods that were associated with them in antiquity.

Next he seems to respond to, or perhaps anticipate, doubts about what he said earlier about intellect.

“Now concerning the intellect there are certain impasses, for it seems to be the most divine of things that are manifest to us, but the way it is if it is to be of that sort contains some things that are hard to digest. For if it thinks nothing, what would be solemn about that? Rather, it would be just like someone sleeping. But if it does think, but something else has power over it, then, since it is not thinking but potency that is the thinghood of it, it could not be the best independent thing, for it is on account of its act of thinking that its place of honor belongs to it. And still, whether the thinghood of it is a power of thinking or an activity of thinking, what does it think?” (ch. 9, p. 247).

“For [what intellect thinks] is either itself or something else, and if it is something else, either always the same one or different ones. And then does it make any difference, or none, whether its thinking is of what is beautiful or of some random thing? Isn’t it even absurd for its thinking to be about some things? Surely it is obvious that it thinks the most divine and honorable things, and does not change, since its change would be for the worse, and such a thing would already be a motion” (p. 248).

Intellect will prefer the beautiful and the good over any random thing. Physics book VII much better explains why certain things that we are used to calling “changes” are not considered changes in his way of speaking.

“First, then, if it is not an activity of thinking but a potency, … it is clear that something else would be more honorable than the intellect, namely what it thinks…. Therefore what it thinks is itself, if it is the most excellent thing, and its thinking is a thinking of thinking” (ibid).

For a third time, he insists that intellect is primarily active, rather than receptive. Its main concern seems to be with whatever is most good and beautiful and honorable. It is a thinking of thinking — true higher-order thinking, rather than a first-order “thinking” of something external.

“But [the human soul’s] knowledge and perception and opinion and step-by-step thinking seem always to be about something else, and about themselves only as something secondary” (ibid).

The above seems to be in implicit contrast with the active thinking about which he was speaking just before. In this way, intellect in its own right is unlike the human soul.

“What’s more, if the thinking and the being thought are different, then in virtue of which of them does what is good belong to it? For to be an act of thinking and to be something thought are not the same” (ibid).

They are the same and yet not the same. Of course, this is in different respects. This is the model for many similar formulations in Hegel.

“Or is it rather that in some cases the knowledge is the thing it is concerned with, so that in the case of the kinds of knowing that make something, the thinghood without material and what it is for something to be, or in the case of the contemplative kinds of knowing, the articulation, is both the thing the knowledge is concerned with and the activity of thinking it? So since what is thought and what is thinking are not different with as many things as have no material, they will be the same, and the act of thinking will be one with what is thought” (ibid).

Here he suggests that we may after all be able to see instances of this identity by reflecting on our experiences of productive and contemplative knowing. Insofar as we actually know anything, we partially escape the inherent limitations of the human soul.

“But there is still an impasse left as to whether what is thought is composite, for then thinking would be changing among the parts of the whole. Or is it the case that everything that has no material is indivisible?” (pp. 248-249).

Implicitly, he seems to favor the latter alternative. Then twice more he speaks of intellect’s predilection for what is good and best.

“So the condition the human intellect, or that of any composite being, is in at some period of time (for it does not have hold of what is good at this or that time, but in some whole stretch of time it has hold of what is best, since that is something other than itself), is the condition the thinking that thinks itself is in over the whole of time” (p. 249).

Again, for Aristotle we have a little bit of the divine within us insofar as we have intellect, so there is no radical incommensurability between the divine and the human.

“One must also consider in which of two ways the nature of the whole contains what is good and best, whether as something separate, itself by itself, or as the order of the whole of things. Or is it present in both ways…?” (ch.10, p. 249).

Book Lambda’s final chapter ends with a quote from a speech by Odysseus in Homer’s Iliad. The whole chapter is oriented toward this literary image. At this point in the Iliad, the Greeks had been in complete disarray, a confused mass, but Odysseus’ words restore their morale and disciplined unity. (Notably, Odysseus was not the high king or commander-in-chief, though he was a leader. It was what he said that mattered.) Aristotle wants us to see this as a metaphorical answer to the question just posed. What is good and best must indeed be present in both ways — both as from the first cause, and as distributed and embodied throughout the whole — but he wants to emphasize that the “for the sake of which” of the first cause plays a real leading role, even though it does not govern by force.

“But beings do not present the aspect of being badly governed” (pp. 251-252).

As we have seen, this does not mean that all the facts of the world are as they ought to be. It does mean that life and the world are essentially good.

Toward a First Cause

Book Kappa (XI) of Aristotle’s Metaphysics briefly reviews material from books Beta (III), Gamma (IV), and Epsilon (VI) about the aims of the ultimate inquiry into first things that is still to be pursued. It also incorporates a brief review of his discussions in Physics books II, III, and V about what motion and change are. Both parts of the presentation here add more explicit hints that we will be looking for something that is both separate and unmoved. These hints are the book’s main interest.

Perhaps surprisingly given its review of content from the Physics, Metaphysics Kappa makes no reference to the detailed argument in Physics book VIII that there is a first unmoved mover of all things, or to the related background about unmoved things in Physics book VII. The beginning of Physics book VIII refers back to “our course on physics”, which is ambiguous, but could imply that it was written later, and possibly after Metaphysics Kappa, which would explain why book VIII’s argument about the first mover is not mentioned here.

“But neither ought one to set down the kind of knowledge being sought as concerning the causes spoken of in the writings about nature, since it is not about that for the sake of which (for this sort of cause is the good, and this belongs among actions and things that are in motion, and it moves things first — for that is the sort of thing an end is — but a thing that first moves them is not present among immovable things). And in general, there is an impasse whether the knowledge now being sought is about perceptible independent things at all, or not, but about other things. For if it is about others, it would be about either the forms or the mathematical things, but it is apparent that there are no forms…. But neither is the knowledge being sought about mathematical things, nor is it a knowledge of perceptible independent things, since they are destructible” (ch. 1, Sachs tr., pp. 205-206).

This passage is interesting in a couple of ways. The knowledge being sought in the inquiry to be conducted is now more definitely said to be not about perceptible independent things, not about mathematical things, and not about Platonic forms.

He also points out that what he calls physics is concerned primarily with what he calls sources of motion and change. It does not address questions about the good or that-for-the-sake-of which, except in an incidental way. But in Parts of Animals book I, he clearly says that in the overall scheme of things, the good and that-for-the-sake-of-which are more primary than sources of motion. The implication here in Metaphysics Kappa is that the inquiry being prepared for will address them in their own right.

“Also, ought one to set down anything besides the particular thing or not, and is the knowledge being sought about particulars?” (ch. 2, p. 207).

For Aristotle, no universal is an independent thing. The knowledge being sought does seem to be about particulars.

“And there is besides an impasse, that all knowledge is of universals and of the suchness of things, but thinghood does not belong to universal” (p. 208).

Knowledge, however, is concerned with universals. This was the major impasse remaining at the end of book Zeta (VII).

“Now since the knowledge that belongs to the philosopher concerns being as being universally and not in relation to a part, … if it is meant in accordance with something common, it would be subject to one knowledge. It seems to be meant in the way that has been spoken of, in just the way that medical and healthy are meant” (ch. 3, p. 209).

He refers back to the discussion of how the saying of being in the other categories points back to the saying of substance-essence-thinghood.

“Since all being is meant in accordance with something that is one and common, even though it is meant in a number of ways, … such things are capable of being subject to one knowledge” (p. 211).

This enables us to say that there is after all one knowledge that can be said to be of being as such. It will address the proper saying of substance-essence-thinghood directly, and the proper saying of being in the other categories in a derivative way.

“And since the mathematician uses common notions in a particular way, it would also belong to the primary sort of philosophy to study the things that govern these” (ch. 4, p. 211).

He seems to assert in passing that first philosophy includes what we would call the foundations of mathematics. Elsewhere he mentions that the first principles of mathematics are similarly supposed to be applicable to all things. But mathematics does not address what things in general are in their own right.

“And it is the same way also with the knowledge about nature as with mathematics, for physics studies the attributes and sources of beings insofar as they are in motion and not insofar as they are, (but we have said that the primary sort of knowledge is about these things to the extent that the things underlying them are beings, but not insofar as they are anything else). For this reason one must set down both this sort of knowledge and the mathematical sort as parts of wisdom” (pp. 211-212).

Neither mathematics nor what Aristotle calls physics addresses substance-essence-thinghood, or what things are in their own right. It is left to first philosophy to do this, as well as to inquire into the ultimate principles that underlie mathematics and physics.

Just as in book Gamma (IV), Aristotle’s claim that there is after all a knowledge that applies to all being as such, and that the philosopher is the one who has it, is immediately followed by a somewhat lengthy expression of outrage against those who claim a right to contradict themselves, or deny that there is any such thing as contradiction. Just as in book Gamma, the concerns he expresses are about dialogue, the understanding of meaning, and the possibility of sound reasoning.

This makes perfect sense when we recall that Aristotle has consistently treated being in a transitive way, as always being this or being that; and as intimately involved with saying, especially the saying of what things properly are in their own right. He has at the same time treated saying as meaningful saying, intimately involved with reasoning. So we should not be surprised when it turns out that the knowledge that applies to all being as such has to do with fundamental principles and presuppositions of reasoning and the understanding of meaning.

“Now those who are going to participate in a discussion with each other must in some way understand what they say…. It is necessary then for each of the words to be intelligible and to mean something, and not many things but only one, but if it does mean more than one thing, it is necessary to make clear to which of these one is applying the word. So the one who says ‘this is and is not’ denies that which he says, and so he denies that the word means what it means, which is impossible” (ch. 5, p. 212).

Then he again expresses outrage at what he takes to be Protagoras’ claim that truth is entirely subjective. If this were the case, there would be no being as Aristotle understands it. Being “in its own right” is discursively communicable intelligibility.

“Something closely resembling these things being discussed is what was said by Protagoras, for he said that a human being is the measure of all things, meaning nothing else than that what seems so to each person is solidly so” (ch. 6, p. 213).

“And since it is necessary for each sort of knowledge to know in some way what something is, … one must not let it go unnoticed in what way the one who studies nature needs to define it and how he needs to get hold of the articulation of the thinghood of things” (ch. 7, p. 217).

The inquiry to be pursued here is implicitly presupposed by physical inquiries. To the extent that one of these two, taken in itself, governs the other, taken in itself, the inquiry to be pursued here is more primary than physics (or mathematics).

“Now the study of nature is about things having a source of motion within themselves, while mathematics is contemplative and concerns something that remains the same, but is not separate. Therefore, about the sort of being that is separate and motionless, there is another sort of knowledge that is different from both of these, if there is any such independent thing — I mean something separate and motionless — which is just what we shall try to show. And if there is any such nature among beings, that would be where the divine also is, and this would be the primary and most governing source of things. It is clear, then, that there are three classes of contemplative knowledge: physics, mathematics, and theology” (ibid).

What he calls nature is a source of motion within something “as itself” (all other sources of motion he calls potentialities).

Now he explicitly mentions that he intends to show that there is a kind of being that is both separate and motionless, as he understands these two terms. He says that if there is such a thing, it will be “where the divine is”, and it will be “the primary and most governing source of things”. First philosophy will therefore be alternately characterized as theology.

He returns to the impasse about knowledge in first philosophy. “One might be at an impasse whether the knowledge of being as being ought to be set down as universal or not” (p. 218). Knowledge is supposed to be concerned with universals, but we are seeking an independent thing, and no logical universal is an independent thing.

In the earlier suggestion of a solution to this impasse, he re-interpreted the many ways in which being is said for the different categories, re-describing them as multiple derivative meanings pointing to one primary meaning. This seemed to eliminate the need to refer to a universal that abstracts over the ways being is said for the different categories.

Now he complements this by introducing a new way of speaking universally, which does not depend on abstraction. Instead, universality can be achieved by referring to a concrete thing or things that is or are concretely the cause or causes of all things, and that therefore is or are prior to all the rest.

“So if natural independent things are primary among beings, then also physics would be the primary sort of knowledge; but if there is another nature and independent thing that is separate and motionless, it is necessary that the knowledge of it be other than and prior to physics, and universal by being prior” (ibid).

Everything that Aristotle calls independent, he also calls separate. Also equivalent to these is calling something a this. As noted earlier, the challenge is to find something that is independent and separate and a this, but that is also unmoved in his sense. The impasse about universality will be conclusively resolved by finding something that is universal not in the sense of being abstract, but rather, as he says, universal in the sense of being “prior” to all other things, because it is a cause for all of them.

“And that, of what is so incidentally, there are not causes and sources of the same sort as there are of what is so in its own right, is clear, for then everything would be by necessity” (ch. 8, p. 219).

As he said in book Zeta (VII), the contingency of incidental being must have contingent, incidental causes. Now he relates this more specifically to a consideration of that-for-the-sake-of-which.

“That which is for the sake of something is present in things that happen by nature or as a result of thinking, but it is fortune when any of these happen incidentally, for just as being is in one way in its own right and in another way incidental, so also with cause. And fortune is an incidental cause in the things that are by choice, among those that happen for the sake of something, for which reason fortune and thinking concern the same things, since there is no choice apart from thinking…. And since nothing incidental takes precedence over things in their own right, neither then do incidental causes, so if fortune or chance is a cause of the heavens, intelligence and nature have a prior responsibility” (pp. 219-220).

There is such a thing as fortune or things happening by chance, but “intelligence and nature have a prior responsibility”, just as what things are in their own right takes precedence over things that are the case incidentally.

“Something is in one way only as at-work, in another way as in potency, and in another way both in potency and at-work, and again in one way as a being, in another as a so-much, in other ways in the rest of the categories; and there is no motion apart from things, since something changes always according to the categories of being, and there is nothing common to these which is not within a single category” (ch. 9, p. 220).

Every change is understood by Aristotle as a change with respect to one of the categories. What is common to these is not an abstraction, but the single concrete sense for one category (substance-essence-thinghood), from which the senses for the other categories are derived.

Here he mentions being in the sense of potentiality and actuality, before he mentions being in the senses of the categories. Next, he summarizes the Physics‘ account of motion. “Motion” is the (incomplete) actualization of a potentiality, where actuality or being-at-work or fulfillment would be its complete actualization.

“So the being-at-work-staying-itself [entelechy, identified by Aristotle with actuality or being-at-work or fulfillment] of what is in potency, whenever it is at-work as a being-at-work-staying-itself, not as itself but as movable, is motion” (p. 221).

“And the reason for motion’s seeming to be indefinite is that it is not possible to place it as a potency or as a being-at-work of beings, for neither is what is capable of being so-much necessarily in motion, nor what is actively so-much; and motion seems to be a certain sort of being-at-work, but incomplete, and the reason is that the potency of which it is the [complete] being-at-work is itself incomplete. And for this reason it is hard to grasp what it is, for it is necessary to place it either as a deprivation or as a potency or as an unqualified being-at-work, but none of these seems admissible; so what remains is what has been said, both that it is a being-at-work and that it is the sort of being-at-work that has been described, which is difficult to bring into focus but capable of being” (p. 222).

Motion is an incomplete actuality or being-at-work or fulfillment. This is a rather subtle thought, the grasping of which requires that we first understand that-for-the-sake-of-which, actuality, and potentiality. (Motion in the modern sense, on the other hand, has no teleological significance. It is entirely reducible to measurable quantities. It it not that one of these is “right” and the other “wrong” — they are two different concepts, grounded in different kinds of explanation.)

“And it is clear that motion is in the movable thing, for it is the being-at-work-staying-itself of this by the action of the thing capable of causing motion. And the being-at-work of the thing capable of causing motion is not different, since it is necessary that it be the being-at-work-staying-itself of both; for a thing is capable of causing motion by its potency and is in motion by being-at-work, but it is capable of being-at-work upon the thing moved, so that the being-at-work of both alike is one, just as the interval from one to two and from two to one is the same, and the uphill and downhill road, though the being of them is not one, and similarly also in the case of the thing causing motion and the thing moved” (ibid).

Motion for Aristotle is always said to be in the thing moved, not in the mover. The potentialities of mover and moved with respect to any motion are said to be one.

“Now it is not possible for the infinite to be something separate…. Also, how could the infinite admit of being something in its own right, if number and magnitude, of which the infinite is an attribute, do not?…. And it is clear that it is not possible for there to be an infinite actively…. [T]hat there is no infinite among perceptible things is clear…. [N]or could there be a number that is separate and infinite, since a number or that which has a number is countable…. In general it is impossible for there to be an infinite body and a place for bodies” (ch. 10, pp. 222-224).

As he argues in greater detail in the Physics, there is no “separate” or “actual” infinite.

“[T]here is something that is moved primarily on account of itself, and this is what is moved in its own right. And this is the same way also with the thing that causes motion, for it does so either incidentally, or on account of a part, or in its own right” (ch. 11, p. 225).

There is something that is a mover in its own right.

“But the forms and the attributes…, such as knowledge and heat, are motionless; it is not heat that is a motion but the process of heating. Change that is not incidental is not present in all things but in contraries and what is between the and in contradictories, and belief in this comes from considering examples” (ibid).

For Aristotle, it is only composite things (i.e., those he understands as formed from material) that are subject to motion and change. In his sense, for instance, a composite thing may undergo a process of becoming warmer, and that would be a kind of motion of the thing. But heat itself is not a composite thing. (That heat itself does not move would be true even under the modern interpretation of it as the amount of molecular motion within a material.)

“A thing that changes does so either from one underlying thing to another, or from what is not a subject to what is not another subject, or from what is not a subject to that subject (and by ‘subject’ I mean what is declared affirmatively), so that there must be three kinds of change, since that from what is not one subject to what is not another subject is not a change, for they are neither contraries nor is there a contradiction, because there is no opposition between them” (ibid).

“And since every motion is a change, and the kinds of change mentioned are three, but those that result from coming-into-being or destruction are not motions, and these are the changes between contradictories, it is necessary that change from one subject to another be the only sort of change that is motion” (p. 226).

A “subject” here is just some thing that underlies something else that has the character of an attribute. I would infer that the change from one subject to another that is spoken of here is a reference to the way that something that is potentially X becomes actually X by the action of something else that is already actually X, as the parent of a child and the Platonic “model” of an artifact were said to be.

“So if the ways of attributing being are divided into thinghood, quality, place, acting or being acted upon, relation, and quantity, there are necessarily three kinds of motion, with respect to the of-what-sort, the how-much, and the place. There is no motion with respect to thinghood, because nothing is contrary to an independent thing, nor of relation …, nor is there a motion of acting and being acted upon, nor of moving and being moved, because there is not a motion of a motion or a coming into being of coming into being, or generally a change of a change…. For every motion is a change from one thing to another, and this is also with coming into being and destruction, except that these are changes into one sort of opposites, while motion is a change into another sort” (ch. 12, pp. 226-227).

The modern concept of acceleration is not a “change of a change”, but a change in a rate of change. Surprisingly, he does not seem to mention change with respect to place, or locomotion, here.

“Also, it would go to infinity if there were to be a change of a change and a coming into being of coming into being…. And since of infinite things there is no first one, there would not be a first becoming, and therefore no next one either, and then nothing would either come into being or be moved or change” (pp. 227-228).

Here as elsewhere, Aristotle is anxious to avoid any form of infinite regress. Showing that there is a separate, unmoved, everlasting thing that moves others is what will enable him to do that. That will be the main task of book Lambda (XII).

Potentiality and Actuality

Here I will treat what Aristotle says about potentiality and actuality in Metaphysics book Theta (IX). On this closer reading, I was initially disappointed that he did not say more about how potentiality and actuality provide the detailed basis for the “internal” teleology that is at the core of his thinking. But on further reflection, perhaps this is another case of what I have elsewhere appreciated as a kind of careful minimalism.

“[L]et us make distinctions also about potency [aka potentiality] and complete being-at-work [aka actuality], and first about potency in the sense in which it is meant most properly, although it is not the sense that is most useful for what we now want. For potency and being-at-work apply to more than just things spoken of in reference to motion. But when we have discussed them in this sense, we will make clear their other senses in the distinctions that concern being-at-work” (ch. 1, Sachs tr., p. 167).

This most elementary sense of what I prefer to guardedly call potentiality was originally developed in the Physics, in connection with the theory of what he broadly calls “motion”. Here, he will ultimately extend it to cases that do not involve motion in this sense. I tend to think of the latter cases as primary.

“[A]s many [senses of potency] as point to the same form are all certain kinds of sources… of change in some other thing or in the same thing as other. For one kind is a power of being acted upon, which is a source in the acted-upon thing itself of passive change by the action of something else or of itself as other; another is an active condition of being unaffected for the worse…. And these potencies are in turn spoken of as only acting or being acted upon, or as acting and being acted upon” (pp. 167-168).

This is a thin, elementary definition, like that of substance in the Categories, with no mention of potentiality’s important role in Aristotle’s teleology. Until recently, working mostly from memory, I had not been thinking about what he calls “sources” (something strictly broader than “causes”) at all, or about this Physics sense of potentiality that is specifically a “source” of motion.

In the Physics, motion is in fact defined in terms of elementary versions of potentiality and actuality. Aristotle says “thus the fulfillment [actuality, being-at-work] of what is potentially, as such, is motion — e.g., the fulfillment of what is alterable, as alterable, is alteration; of what is increasable and its opposite, decreasable… increase and decrease; of what can come to be and pass away, coming to be and passing away; of what can be carried along, locomotion” (book III ch. 1, Collected Works, Barnes ed., vol. 1, p. 343).

I rather like the Collected Works translators’ choice of “fulfillment” as an English alternative to “actuality” or “being-at-work”. Grounded more in what Aristotle says about energeia than in the etymology of the new Greek word he coined for it, it does nicely capture the teleological role of actuality. Translation is often not a simple affair.

The Physics definition of motion, though, is a tricky thought: the actuality of something that as such is a potentiality. This illustrates that there can be a kind of layering with respect to these terms.

“And it is clear that there is a sense in which the potency of acting and being acted upon is one (since something is potential both by means of its own potency to be acted upon and by something else’s potency to be acted upon by it), but there is a sense in which they are different” (p. 168).

The way in which these potentialities of acting and being acted upon are said to be “one” is structurally similar to what he says in On the Soul and Metaphysics book Lambda about thought and the thing thought being one. It seems like Aristotle might consider that to be one case of this.

“[A]ll the arts and productive kinds of knowledge are potencies” (ch. 2, p. 169).

This sort of case is very important to remember when considering the meanings of “potentiality” or “source of motion”. When he is speaking the most carefully, Aristotle says the art of building is the primary “source of motion” for the building of a house.

“And all potencies that include reason are capable of contrary effects, but with the irrational ones, one potency is for one effect, as something hot has a potency only for heating, while the medical art is capable of causing disease or health” (ibid).

He treats this thesis about rational potentialities producing “contrary” effects as important. The sense seems to be that because the actualization of rational potentialities involves practical judgment about what is appropriate in a given situation, the judgment can go wrong, leading to the production of the “opposite” of the intended effect. Heat and similar things can’t “go wrong” in this way,

“And it is clear that, with the potency of doing something well, the potency of merely doing or suffering it follows along, while the former does not always follow along with the latter, since the one doing something well necessarily also does it, but the one merely doing it does not necessarily also do it well” (ibid).

This is a nice incidental mention of the normative dimension involved in all practical doing, though the technical point is about what cases include what other cases.

“There are some people, such as the Megarians, who say that something is potential only when it is active, but when it is not active it is not potential…. The absurd consequences of this opinion are not difficult to see…. [T]hese assertions abolish both motion and becoming. For what is standing will always be standing and what is sitting always sitting, since it will not stand up if it is sitting” (ch. 3, p. 170).

The Megarian logicians claimed that potentiality has no reality of its own — that everything that is, is actual. This position results in paradoxes similar to those following from the claims of Parmenides about non-being and being.

“What is capable is that which would be in no way incapable if it so happened that the being-at-work of which it is said to have the potency were present” (p. 171).

This is another specification I had lost track of working mainly from memory. I’m not sure how it would apply to his example of arts and productive knowledge, which comes closest to the extensions of Aristotelian potentiality that I have suggested (to characterize recent notions of both the “space of reasons” and “structure” as belonging to potentiality).

“And the phrase being-at-work, which is designed to converge in meaning with being-at-work-staying-complete [entelechy], comes to apply to other things from belonging especially to motions” (ibid).

This seems to be an application of Aristotle’s frequent distinction between how things are “for us” and how they are “in themselves”. The appeal to motion as a basis for understanding being-at-work or actuality is an appeal to common experience. But further below, he will contrast motion with being-at-work in a fuller sense.

He goes on to make a number of logical distinctions.

“[I]t cannot be true to say that such-and-such is possible, but will not be the case” (ibid).

(When we say something will not be the case, we are also implicitly saying there is no possibility that it will be the case. Therefore, it cannot be possible, and the statement contradicts itself.)

Potentiality is a more specific notion than possibility, but it seems that whatever is potential must also be possible, and therefore the generalization about possibility applies to all cases of potentiality.

“For the false and the impossible are not the same thing; for that you are now standing is false, but not impossible” (ch. 4, p. 172).

Similarly, generalizations about impossibility also apply to the more specific notion of potentiality.

“[I]t is also clear that, if it is necessary for B to be the case when A is, it is also necessary for B to be capable of being the case when A is capable of being the case” (ibid).

If there is a relation of necessity between actual things, then logically there must be a corresponding relation of necessity between the corresponding potential things. Possibility and necessity are the two most basic modalities in modern modal logic.

“Of all potencies, since some are innate, such as the senses, while others come by habit, such as that of flute playing, and others by learning, such as the arts, some, those that are by habit and reasoning need to have previous activity, while others that are not of that kind, and apply to being acted upon, do not need it” (ch. 5, p. 172).

For Aristotle, a sense like vision is to be understood first of all as a potentiality for the complete act of actually seeing. All other details — of optics, of physiology, of the operations of imagination, of what modern people might call the consciousness of seeing — that are conditions of the complete act, are subordinate to the complete act itself as a realized end. This is a good example of how Aristotle uses teleology to organize and coordinate other sorts of explanation.

The distinction between by “habit” (hexis, or acquired disposition) and by learning does not seem to be strict. Further below, he mentions practicing in order to play the harp as a form of learning, rather than habit. I think he is speaking casually both times. One might even say that all habits are learned; at the very least, they are acquired. (This broader term related to “second nature” seems to have been particularly important for al-Farabi, who uses it in his classic neoplatonizing elaboration of the Aristotelian theory of intellect.)

“[With irrational potencies] it is necessary, whenever a thing that is active and a thing that is passive in the sense that they are potential come near each other, that the one act and the other be acted upon” (pp. 172-173).

This formulation is surprising. I don’t understand why the qualification he applies immediately below for the case of rational potentialities (“not in every situation but when things are in certain conditions”) would not also apply to irrational potentialities. The distinction between the “rational” and “irrational” cases is based on presence or absence of a dimension of desire or choice, which seems not to affect the relevance of situations and conditions.

“[B]ut with [rational potencies] this is not necessary…. It is necessary, therefore, that there be something else that is governing; by this I mean desire or choice. For whatever something chiefly desires is what it will do whenever what it is capable of is present and it approaches its passive object…. not in every situation but when things are in certain conditions” (p. 173).

“Since what concerns the kind of potency that corresponds to motion has been discussed, let us make distinctions about being-at-work, to mark out both what it is and what sort of thing it is. For that which is potential will also be clear at the same time to those who make distinctions, since we speak of the potential not only as that which is of such a nature as to move some other thing or be moved by something else, … but also in another way, and it is because we are inquiring after that other meaning that we went through this one” (ch. 6, p. 173).

He explicitly says he will not define actuality or being-at-work, but instead suggests that we infer a pattern from a series of examples. Actually, it turns out that the more abstract pattern he is thinking of includes two distinct variants.

“The other way these things are present is in activity. And what we mean to say is clear by looking directly at particular examples, nor is it necessary to look for a definition of everything, but one can see at a glance, by means of analogy, that which is as the one building is to the one who can build, and the awake to the asleep, and the one seeing to the one whose eyes are shut but who has sight, and what has been formed out of material to the material, and what is perfected to what is incomplete…. But not all things that are said to be in activity are alike, except by analogy…. For some of them are related in the manner of a motion to a potency, others in the manner of thinghood to a material” (pp. 173-174).

At the end, he is now saying that motion and substance-essence-thinghood are the two alternate kinds of actuality or being-at-work. Motion is the “imperfect” kind that is still in process of realization, and substance-essence-thinghood is the “perfect” or “complete” kind that is an entelechy.

“And since, of the actions that do have limits, none of them is itself an end, but it is among things that approach an end, (such as losing weight, for the thing that is losing weight, when it is doing so, is in motion that way, although that for the sake of which the motion takes place is not present), this is not an action, or at any rate not a complete one; but that in which the end is present is an action. For instance, one sees and is at the same time in a state of having seen, understands and is at the same time in a state of having understood, or thinks contemplatively and is at the same time in a state of having thought contemplatively, but one does not learn while one is at the same time in a state of having learned, or get well while in a state of having gotten well. One does live well at the same time one is in a state of having lived well, and one is happy at the same time one is in a state of having been happy” (p. 174).

“And it is appropriate to call the one sort of action motion, and the other being-at-work. For every motion is incomplete: losing weight, learning, walking, house-building…; but one has seen and is at the same time seeing the same thing, and is contemplating and has contemplated the same thing. And I call this sort of action a being-at-work, and that sort a motion. So that which is by way of being-at-work, both what it is and of what sort, let it be evident to us from these examples” (pp. 174-175).

Motion and being-at-work are both said to be forms of “action”. Anything broad enough to comprehend both of these will not fit common connotations of the English word “action”, so we need to recognize that it is being used in a special sense closer to “activity”, which seems better suited to something that includes both.

“Now when each thing is in potency and when not must be distinguished, since it is not the case at just any time whatever…. Then it would be just as not everything can be healed, by either medical skill or chance, but there is something that is potential, and this is what is healthy in potency” (ch. 7, p. 175).

The reference to time does not seem to be essential. What seems decisive for these distinctions are the possibly blocking circumstances or “conditions” mentioned earlier.

“And since the various ways in which something is said to take precedence have been distinguished, it is clear that being-at-work takes precedence over potency. And I mean that it takes precedence not only over potency as defined, … but over every source of motion or rest in general. For nature too is in the same general class as potency, since it is a source of motion, though not in something else but in a thing itself as itself” (ch. 8, p. 177).

This is the first of several iterations on the precedence of actuality or being-at-work over potentiality. The way that he respectively defines potentiality and nature as sources of motion, they are strict logical complements of one another, so he is implying that all sources of motion are either natures or potentialities.

“And this is why it seems to be impossible to be a house-builder if one has not built any houses, or a harpist if one has not played the harp at all; for the one learning to play the harp learns to play the harp by playing the harp, and similarly with others who learn things…. But since something of what comes into being has always already come into being, and in general something of what is in motion has always already been moved…, presumably the one who is learning must also already have something of knowledge” (p. 178).

Aristotle’s account of the precedence of actuality over potentiality might be the origin of the “always already” theme. This is also the root of many interesting things that Hegel says about Wirklichkeit (commonly translated as “actuality”, with Aristotle in mind).

“But surely [being-at-work] takes precedence in thinghood too, first because things that are later in coming into being take precedence in form and in thinghood (as a man does over a boy, or a human being over the germinal fluid, since the one already has the form, and the other does not), and also because everything that comes into being goes up to a source and an end (since that for the sake of which something is is a source, and coming to be is for the sake of an end), but the being-at-work is an end, and it is for the enjoyment of this that the potency is taken on. For it is not in order to have the power of sight that animals see, but they have sight in order to see, and similarly too, people have the house-building power in order that they may build houses, and the contemplative power in order that they may contemplate; but they do not contemplate in order that they may have the contemplative power, unless they are practicing, and these people are not contemplating other than in a qualified sense, or else they would have no need to be practicing contemplating” (ibid).

Here he implicitly mentions the teleological aspect, referring to ends and that-for-the-sake-of-which.

Sachs aptly comments, “How does nature display that a squirrel has reached the completion for the sake of which it exists? In the spectacle of the squirrel at work being a squirrel…. Aristotle is arguing that the very thinghood of a thing is not what may be hidden inside of it, but a definite way of being unceasingly at-work, that makes it a thing at all and the kind of thing it is” (p. 179n).

(I would say “is what it is” instead of “exists” in the part about the squirrel.) The other part, that thinghood is not hidden inside things, but rather manifest in their ways of being at work, makes me think of what Hegel says about essence.

“[T]he putting to use of some things is ultimate (as seeing is in the case of sight…), but from some things something comes into being….[O]f those things from which there is something else apart from the putting-to-use that comes into being, the being-at-work is in the thing that is made…; but of those things which have no other work besides their being-at-work, the being-at-work of them is present in themselves (as seeing is in the one seeing and contemplation in the one contemplating, and life is in the soul, and hence happiness too, since it is a certain sort of life). And so it is clear that thinghood and form are being-at-work” (p. 179).

The last sentence is a principal new conclusion of book Theta: substance-essence-thinghood and form are both said to be cases of actuality or being-at-work.

Since actuality or being-at-work has already been identified with entelechy, this means that both independent things and (some) forms are now also being said to be entelechies. In the case of independent things, this is not surprising, given everything that was said about them in book Zeta. In the case of forms, I suspect he means that those forms that are souls are entelechies.

“But being-at-work takes precedence in an even more governing way; for everlasting things take precedence in thinghood over destructible ones, and nothing that is in potency is everlasting…. Therefore nothing that is simply indestructible is simply in potency (though nothing prevents it from being potentially in some particular respect, such as of a certain sort or at a certain place), and so all of them are at work. And none of the things that are by necessity is in potency (and yet these are primary, since if they were not, nothing would be), nor is motion, if there is any everlasting one; … and this is why the sun and moon and the whole heaven are always at work” (p. 180).

Aristotle generously calls everything “everlasting” that is apparently so, and for which he has no evidence to the contrary.

“And things that undergo change, such as earth and fire, mimic the indestructible things, since they too are always at work, for they have motion in virtue of themselves and in themselves” (p. 181).

What Aristotle calls matter is not itself alive, but nonetheless he says it has intrinsic motion. Motion, as we saw above, is defined in implicitly teleological terms in the Physics, using both potentiality and actuality. This is how the behavior of inanimate matter for Aristotle ends up having teleological characteristics.

“And that being-at-work is a better and more honorable thing than a potency for something worth choosing, is clear from these considerations. For whatever is spoken of as being potential is itself capable of opposite effects…. And in the case of bad things, it is necessary that the completion and being-at-work be worse than the potency…. Therefore it is clear that there is nothing bad apart from particular things, since the bad is by nature secondary to potency. Therefore among things that are from the beginning and are everlasting, there is nothing bad, erring, or corruptible” (ch. 9, pp. 181-182).

Things that don’t measure up to what they are supposed to be are “bad” examples of the kind of things that they are. I am surprised that he speaks of any “completion and being-at-work” of bad things at all.

“And geometrical constructions are discovered by means of activity, since it is by dividing up the figures that people discover them…. And so it is clear that the things that are in the figures in potency are discovered by being drawn into activity, … and for this reason it is only those who make a construction who know it” (p. 182).

Aristotle seems to anticipate the attitude of mathematical constructivism.

“[B]ut the most governing sense [of being and not being] is the true or the false…. For it is necessary to examine in what way we mean this. For you are not pale because we think truly that you are pale, but rather it is because you are pale that we who say so speak the truth” (ch. 10, p. 183).

I was a bit surprised when he earlier ruled out further discussion of being in the sense of the true and false attributed to the “is” or “is not” used to form propositions. But here, he goes on to speak of a different notion of truth, which seems to be more like metaphorically “grasping” an essence.

“But now for things that are not compound, what is being or not being, and the true and the false? For the thing is not a compound, so that it would be when it is combined and not be if it is separated, like the white on a block of wood or the incommensurability of the diagonal; and the true and false will not still be present in a way similar to those things. Rather, just as the true is not the same thing for these things, so too being is not the same for them, but the true or false is this: touching and affirming something uncompounded is the true (for affirming is not the same thing as asserting a predication), while not touching is being ignorant (for it is not possible to be deceived about what it is, except incidentally). And it is similar with independent things that are not compound, since it is not possible to be deceived about them; and they are all at work, not in potency, for otherwise they would be coming into being and passing away, but the very thing that is does not come to be or pass away, since it would have to come from something. So it is not possible to be deceived about anything the very being of which is being-at-work, but one either grasps it or does not grasp it in contemplative thinking; about them, inquiring after what they are is asking whether they are of certain kinds or not” (p. 184).

What is meant to be included under “independent things that are not compound” and “anything the very being of which is being-at-work” — about both of which it is said to be impossible to be deceived — has yet to be specified.

The “grasping” and “touching” metaphors here need not be taken as literally implying a kind of immediate experiencing. The next book will be explore at length the ways in which things are one, and thus form wholes. I think the implicit emphasis here is on a grasping of things as integral wholes. When we think of an essence as an integral whole, either we get it or we don’t, just as he says here. How we are able to do this is another question, not addressed here, but I think that for rational animals, the immediacy of grasping an essence can only be what Hegel would call a “mediated” immediacy.

“The true is the contemplative knowing of these things, and there is no falsity, nor deception, only ignorance, and not the same sort of thing as blindness; for blindness would be as if someone were not to have the contemplative power at all” (ibid).


I think “entelechy” — or what Kant called internal teleology — is probably the most important guiding concept of Aristotle’s Metaphysics (rather than the “Being” championed by many). There is a great deal to unpack from this single word. Here is a start.

The primary examples of entelechy are living beings. Aristotle also suggests that pure thought (nous) is an entelechy. I think the same could be said of ethos, or ethical culture.

Sachs’ invaluable glossary explains the Greek entelecheia as “A fusion of the idea of completeness with that of continuity or persistence. Aristotle invents the word by combining enteles (complete, full-grown) with echein (= hexis, to be a certain way by the continuing effort of holding on in that condition), while at the same time punning on endelecheia (persistence) by inserting telos (completion [what I have been calling “end”]). This is a three-ring circus of a word, at the heart of everything in Aristotle’s thinking, including the definition of motion. Its power to carry meaning depends on the working together of all the things Aristotle has packed into it. Some commentators explain it as meaning being-at-an-end, which misses the point entirely” (p. li).

He points out the etymological connection of echein (literally, “to have”) with hexis, or “Any condition that a thing has by its own effort of holding on in a certain way. Examples are knowledge and all virtues or excellences, including those of the body such as health” (p. xlix).

I previously suggested a very literal rendering of entelechy as something like “in [it] end having”, with the implication that it more directly means being subject to internal teleology. As Sachs says, this is very different from just being at an end. The latter would imply a completely static condition not subject to further development.

Entelechy is Aristotle’s more sophisticated, “higher order” notion of an active preservation of stability within change, which in the argument of the Metaphysics accompanies the eventual replacement of the initial definition of ousia (“substance”, which Sachs renders as “thinghood”) from the Categories as a kind of substrate or logical “subject” in which properties inhere. What he replaced that notion of substrate with was a series of more refined notions of ousia as form, “what it was to have been” a thing, and what I am still calling potentiality and actuality.

Whether we speak of active preservation of stability within change or simply of persistence (implicitly in contrast with its absence), time is involved. Reference to change makes that indisputable. Persistence is a bit more of a gray area, since in popular terms lasting forever is associated with eternity, but strictly speaking, “eternal” means outside of time (which is why the scholastics invented the different word “sempiternal” for things said to persist forever in time).

Sachs’ translation for what I will continue to simply anglicize as “entelechy” is “being-at-work-staying-itself”. This is closely related to energeia (“actuality”), which Sachs renders as being-at-work. I think it is important that there is nothing literally corresponding to “being” in the Greek for either of these, and want to avoid importing connotations of Avicennist, Thomist, Scotist, or Heideggerian views of the special status of being into Aristotle.

I also think “staying itself” tends to suggest a purely static notion of the identity of a “self” that is foreign to Aristotle. Sachs might respond that “at-work-staying” negates the connotation that “itself” is static, but I don’t think this necessarily follows. It might take significant effort to remain exactly the same, but this is not what Aristotle is getting at. To be substantially the same is not to be exactly the same.

Entelechy is intimately connected with actuality (energeia) and potentiality (dynamis). As Sachs points out, “actuality” in common contemporary usage has connotations of being a simple matter of fact that are at odds with the teleological, value-oriented significance of energeia in Aristotle.

“The primary sense of the word [entelecheia] belongs to activities that are not motions; examples of these are seeing, knowing, and happiness, each understood as an ongoing state that is complete at every instant, but the human being that can experience them is similarly a being-at-work, constituted by metabolism. Since the end and completion of any genuine being is its being-at-work, the meaning of the word [energeia] converges [with that of entelecheia]” (p. li).

If we take “being” purely as a transitive verb (as it is indeed properly meant here), my objection above to connotations of its use as a noun could be overcome. But in English, “being” remains ambiguous, and it is not there in the Greek.

Further, though it has the good connotation of something being in process, “at work” also introduces all the ambiguities of agency and efficient causation, in which overly strong modern notions tend to get inappropriately substituted for Aristotle’s carefully refined “weak” concepts. Aristotle very deliberately develops weak concepts for these because — unlike most of the scholastics and the moderns — he thinks of all agency and causing of motion as subordinate to value-oriented entelechy and teleology.

Sachs’ glossary explains dynamis (“potentiality”, which he calls “potency”) as “The innate tendency of anything to be at work in ways characteristic of the kind of thing it is…. A potency in its proper sense will always emerge into activity, when the proper conditions are present and nothing prevents it” (p. lvii).

He notes that it has a secondary sense of mere logical possibility, but says Aristotle never uses it that way.

I fully agree that potentiality in Aristotle never means mere logical possibility. Kant’s notion of “real” as distinct from logical possibility comes closer, but it still lacks any teleological dimension. I think Paul Ricoeur’s “capability” comes closer than Sachs’ “potency”, because it it seems more suggestive of a relation to an end.

However, I am very sympathetic to Gwenaëlle Aubry’s argument that Aristotelian dynamis should not be understood in terms of any kind of Platonic or scholastic power. “Power” once again suggests all the ambiguities of efficient causality. I think such a reading is incompatible with the primacy of final causality over efficient causality in Aristotle. (Historically, of course, the divergence of scholastic “power” from Aristotelian dynamis was accompanied by assertions of a very non-Aristotelian primacy of efficient causality.) To my ear, “potency” has the same effect. (See also Potentiality and Ends.)

Sachs had said that entelechy is also at the heart of Aristotle’s definition of motion. (Motion with respect to place is only one kind of motion for Aristotle; he also speaks of changes with respect to substance, quality, and quantity as “motions”. He also says there are activities that are not motions.)

Properly speaking, motion (kinesis) for Aristotle is only “in” the thing that is moved. That is how it becomes reasonable to speak of unmoved movers. A moved mover is indeed moved, but not insofar as it is itself a mover, only in some other way. He says there is no “motion” in being-at-work or actuality as such, but there is activity.

In book III chapter 1 of the Physics, Aristotle says that “the fulfillment [energeia] of what is potentially, as such, is motion — e.g. the fulfillment of what is alterable, as alterable, is alteration; … of what can come to be and pass away, coming to be and passing away; of what can be carried along, locomotion” (Collected Works, Barnes ed., vol. I, p. 343).

Sachs expresses this by saying that as long as “potency is at-work-staying-itself as a potency, there is motion” (p. lv). Otherwise said, motion is the entelechy and “actuality” of a potentiality as potentiality. As I’ve noted before, Aristotle doesn’t just divide things into actual and potential, as if they were mutually exclusive, but at times uses these notions in a layered way.

A mover (kinoun) is “Whatever causes motion in something else. The phrase ‘efficient cause’ is nowhere in Aristotle’s writings, and is highly misleading; it implies that the cause of every motion is a push or a pull…. That there should be incidental, intermediate links by which motions are passed along when things bump explains nothing. That motion should originate in something motionless is only puzzling if one assumes that what is motionless must be inert; the motionless sources of motion to which Aristotle refers are fully at-work, and in their activity there is no motion because their being-at-work is complete at every instant” (pp. lv-lvi).

It is worth noting that Aristotle has a relatively relaxed notion of completeness or perfection. We tend to define perfection in a kind of unconditional terms that are alien to him. For Aristotle in general, complete actualization or perfection is always “after a kind”, and it is supposed to be achievable. But also, it is only unmoved movers (and not organic beings) whose being-at-work is being said to be complete at every instant.

When he says “the phrase ‘efficient cause’ is nowhere in Aristotle’s writings”, he means that “efficient” is another Latin-derived term that diverges from the Greek. Aristotle in book II chapter 3 of the Physics speaks of “the primary source of the change or rest” (Collected Works, Barnes ed., vol. I, p. 332), but again we have to be careful to avoid importing assumptions about what this means.

As I’ve pointed out several times before, the primary source of the change in building a house according to Aristotle is the art of building, not the carpenter or the hammer or the hammer’s blow, and everything in this whole series is a means to an end. The end of building a house, which guides the form of the whole series, is something like protection from the elements. Neither the end nor the source of motion is itself an entelechy. But the house-building example is a case of external teleology. Correspondingly, it requires an external source of motion.

Internal teleology and the entelechy that implements it are more subtle; entelechy is an in itself “unmoving” and “unchanging” activity. The things subject to motion and change in the proper sense are only indirectly moved by it (by means of some source of motion).

We might say that Kantian transcendental subjectivity and Hegelian spirit are also entelechies.

Recently I suggested that what makes Hegel’s “subjective logic” to be “subjective” is its focus on the activity of interpretation and judgment, which in fact always aims to be “objective” in the sense of reaching toward deeper truth, and has nothing at all to do with what we call “merely subjective”. This is a sense of “subjective” appropriate to what Kant calls transcendental as opposed to empirical subjectivity. This higher kind of subjectivity, characteristic of what Hegel calls “self-consciousness” and of the activity of Kantian reflective judgment, would be very well characterized as an entelechy.

I strongly suspect that what Hegel metaphorically calls “logical motion” would be expressed by Aristotle in terms of the end-governed “unmoving activity” of entelechy. (See also Reflection, Apperception, Narrative Identity.)

Aristotle on Perception

Real and meaningful analytic distinctions in experience such as activity and passivity need not be grounded in ontological dualities.

It is common to hear Aristotle summarized as asserting a monolithic passivity in processes of perception. This is a considerable simplification. What is true is that in the absence of something perceptible that does not depend on us for its being, Aristotle would say we have a case not of perception but of something else. This does not mean there are not many active dimensions to typical sense perception as well.

One of Aristotle’s deepest principles involves a recognition of profoundly mixed conditions as being more typical of real life than monolithic or homogeneous ones. Plato treats “mixture” as a first-class topic at the heart of what Aristotle would call first philosophy, and not as a mere derivative from “pure” concepts.

Later authors have often tended to downplay Plato and Aristotle’s emphasis on mixed cases in experience as normal, and instead to privilege pure “black and white” distinctions. I think we should if anything privilege the mixed cases, and demand evidence when confronted with claims that any real-world cases involve “pure” black-and-white distinctions.

Aristotle’s account of perception in book 2 of On the Soul relies mainly on descriptions expressed in terms of actuality, potentiality, and actualization. While it is true that actuality has a character that is mostly active and potentiality has a character that is mostly not active, it is once again an oversimplification to simply equate actuality with activity and potentiality with passivity.

Aristotle’s description of perception is deliberately abstract, which reduces the need to speculatively fill in missing details. Perhaps the most salient overall aspect of this account is that it involves a multi-leveled layering of actuality and potentiality and of active and passive aspects that may be only analytically distinct. He focuses very generally on the various requirements of the kinds of form involved, and works hard to avoid causal explanations not clearly grounded in evidence.

It is very characteristic that Aristotle treats perception and whatever is perceptible in a single context. For instance, his discussion of light occurs here. He has no theory of the transmission of light, which was only experimentally demonstrated in early modern times. In the absence of evidence to the contrary, he sees light as instantaneously diffused through a medium, and reasons that the medium must therefore play a necessary role in perception. For him, light is “the being-at-work of the transparent as transparent” (On the Soul book 2 ch. 7, Sachs trans., p. 101). “By transparent I mean what is visible but not visible in its own right, to put it simply, but on account of the color of something else…. Light is a sort of color of the transparent, whenever it is at-work-staying-transparent by the action of fire or something of that kind…. What, then, the transparent is, has been said, and what light is, that it is not fire or any body at all, nor anything that flows out of any body…, but the co-presence of fire or any such thing in the transparent” (ibid). “Rather, the color sets a transparent thing, such as air, in motion, and by this, if it is continuous, the sense organ is moved” (p. 103).

It is important to recognize that this is a thoughtful interpretation of ordinary experience, with minimal assumptions. We would say, e.g., that light is transmitted at the speed of light rather than instantaneously diffused, but this can only be justified by complex empirical evidence. We associate colors with particular wavelengths of light, and we think of light as consisting of material waves (or alternatively, particles of a particular kind) that cannot be directly observed, but all this depends on complex evidence and test equipment. By contrast, Aristotle aims mainly to do justice to our ordinary experience of seeing things — a dog, a rose, a landscape, and so on. He seems to think of the air in the presence of light as metaphorically “charged” with sensible forms, such that there is a continuous translation of visible configurations of color through the air along each perspectival line of sight.

He somewhat paradoxically speaks of a “transmission” of “forms without the matter” in perception, and of the soul-as-active-form-of-the-body “receiving” them. The soul, as an entelecheia (in Sachs’ translation “being-at-work-staying-itself”, or more literally “in [itself] end having”) of an organic body, is active at root. Perception is then at top level supposed to be the being-at-work of a receptivity of the primarily active soul. Since the “transmission” of color through the air is said to be without matter, it must be more like a translation of color between the medium and the eye.

Some contemporary writers have claimed that Aristotle’s account of perception is of historic interest only, sheerly on the ground that it focuses on potentiality and actuality rather than physical causes. But as usual, Aristotle is far more interested in interpreting experience in meaningful ways, with as few assumptions as possible.

I think it is better to have a very abstract description that remains descriptive of experience, rather than imaginatively positing physical or physiological explanations. That is to say, it is better to be only abstractly descriptive but faithful to ordinary experience like Aristotle, than it is to have a more physically grounded explanation like the Stoics, at the cost of depending on additional assumptions of fact that turned out to be wrong in light of more detailed empirical investigations.

The Stoic theory — following the general Stoic precept that everything that has being must be some kind of body — seems to involve a kind of subtly material forms of objects invisibly but literally flying through the air as distinct wholes, ancestral to the medieval “sensible species”. This is a logically consistent physical and physiological account, which however makes numerous speculative leaps of the sort Aristotle aimed to minimize.

The mathematicians Euclid and Ptolemy geometrically analysed properties of light rays, but believed light rays were actively emitted by the eye, rather than received by it.

The “father of modern optics” and early contributor to scientific method, Iraqi polymath Ibn al-Haytham (ca. 965-1040 CE), known to Latin readers as Alhazen, was the first to explain that vision occurs when light reflected from objects passes to the eye, and to assert that the brain plays a major (active) role in the process of identifying objects. His work was taken up by Roger Bacon, Robert Grosseteste, Leonardo da Vinci, Galileo, Huygens, Descartes, and Kepler, among others.

The reception of light in and of itself is passive, but ordinary seeing has a large cognitive and interpretive dimension, whether considered at the level of events in the brain or at the level of an interpretation of meaningful content. Reception of light rays is passive, but even the most minimal identification of objects cannot be entirely passive.

The visible forms of patches of color that are diffused through the transparent medium in Aristotle — just like the reflected light in the modern account — are indeed passively received, but that no more makes the entire process of vision necessarily passive in Aristotle than it does in the modern account.

“But about all sense perception in general, it is necessary to grasp that the sense is receptive of the forms of perceptible things without the material, as wax is receptive of the design of a ring without the iron or gold…; and similarly the sense of each thing is acted upon by the thing that has color or flavor or sound, but not in virtue of that by which each of those things is the kind of thing it is, but in virtue of that by which it has a certain attribute, and according to a ratio” (book 2 ch. 12, p. 118).

Joe Sachs comments in a note that “Some of the difficulty can be avoided if one keeps in mind that, by form, Aristotle does not mean shape or appearance. In the Platonic dialogues, it is always emphasized that the eidos is not the mere look of a thing…. That to which one must look, according to Aristotle, is the being-at-work of the thing. It is, then, no part of the analogy Aristotle intends with the wax impression, that the eyeball, say, becomes shaped and colored like an olive when it looks at one. What it takes on must be some sort of active condition” (p. 118n, emphasis added).

This last point about the active condition, I think, is the import of Aristotle’s phrase in the above quote, “not in virtue of that by which each of those things is the kind of thing it is, but in virtue of that by which it has a certain attribute, and according to a ratio”. We do not directly perceive the kinds of things we perceive, but rather “that by which [things have] a certain attribute, and according to a ratio”. I take this to be a suggestion of what should or should not count as a “perception”.

There is a puzzle here about how “that by which” a thing has an attribute would count as perceptible. I would argue that if this kind of abstraction does count as perceptible in some way, that would be another indication that perception is not entirely passive. Aristotelian “perception” would then be quite rich, including many things I have been calling products of the Kantian synthesis of imagination. But it would still stop short of, say, directly apprehending a complex gestalt or whole “image” as an immediately intelligible unit.

Worries about “passivity”, it seems to me, ought to be directed mainly at the kind of claims of direct apprehension of complex images as meaningful wholes that Aristotle explicitly rules out in this passage.

“But ‘being acted upon’ is not unambiguous either…. For the one who has knowledge comes to be contemplating, and this is either not a process of being altered (since it is a passing over into being oneself, namely into being-at-work-staying-oneself), or is a different class of alteration” (p. 98).

“Being-at-work perceiving is described in the same way as contemplating, but differs in that the things that produce the being-at-work of perceiving are external, the visible and audible things, and similarly with the rest of the senses. The reason is that active perception is of particulars, while knowledge is of universals, which are in some way in the soul itself. Hence thinking is up to oneself, whenever one wishes, but perceiving is not up to oneself, since it is necessary that the thing perceived be present. And similarly too, even the kinds of knowing that deal with perceptible things are not up to oneself, and for the same reason, that the perceptible things are among particular, external things” (book 2 ch. 5, pp. 98-99, emphasis added).

I note first of all the explicit reference to “active perception”. Second, it makes perfect sense that “the kinds of knowing that deal with perceptible things are not up to oneself” — that in some way sensible things are what they are, independent of us, in a way that abstractions and universals are not. Aristotle even seems to think there is an at least abstractly identifiable level at which the particular senses cannot be deceived.

“[T]he means by which we live and perceive is meant two ways, as is the means by which we know (by which is meant in one sense knowledge but in another the soul, since by means of each of these we say we know something)” (book 2 ch. 2, p. 87).

“And neither is thinking the same as perceiving, for in thinking there is what is right and what is not right, … for sense perception when directed at its proper objects is always truthful, and is present in all animals, but it is possible to think things through falsely, and this is present in no animal in which there is not also speech” (book 3 ch. 3, pp. 133-134).

Here he explicitly bounds the analogy between perception and thought. We have already seen that perception for Aristotle is not entirely passive, so thinking, as something that is more up to us, must be less passive than that.

“And it is certainly not the reasoning part, or intellect in the way that word is used, that causes motion, for the contemplative intellect does not contemplate anything that has to do with action…. And even when the intellect enjoins and the reasoning part declares that something is to be fled or pursued one does not necessarily move, but acts instead in accordance with desire, as does one without self-restraint…. But neither is it desire that governs this sort of motion, since self-restrained people, even when they desire and yearn for something, do not necessarily do those things for which they have the desire, but follow the intellect” (book 3 ch. 9, pp. 152-153).

Later he specifies that the motion mentioned here is motion with respect to place, i.e., bodily movement, not anything directly associated with perception or thought. Comparatively speaking, the earlier “motion” of air in the presence of light was said in a different, more figurative way. We should not assume that the way activity and passivity apply in the one context is the same as in the other.

He continues, “But it is obvious that these two things [together do] cause motion, desire and/or intellect, since many people follow their imaginings contrary to what they know, and in other animals there is no intellectual or reasoning activity, except imagination. Therefore both of these are such as to cause motion with respect to place, intellect and desire, but this is intellect that reasons for the sake of something and is concerned with action, which differs from the contemplative intellect by its end…. So it is reasonable that there seem to be two things causing the motion, desire and practical thinking, since the thing desired causes motion, and on account of this, thinking causes motion, because it is the desired thing that starts it. So it is one thing that causes motion, the potency of desire” (book 3 ch. 10, pp. 153-154, emphasis added).

What Aristotle initially mentions as “obvious” is refined and corrected later in the chapter. This sort of thing is very common in Aristotle. In book 2 chapter 2, he says that “what is clear and more knowable by reason arises out of what is unclear but more obvious” (p. 84).

“[B]ut the potency of desire is not present without imagination, while all imagination is either rational or sensory” (p. 156).

The imagination is identified in Aristotle’s On Memory and Recollection as the root of all perception. Here he suggests that it also depends on the particular senses. Both could easily be true if the sense in which imagination is the “root” of perception is teleological, rather than causal in the modern sense.

“For imagination is different both from perceiving [by the particular senses] and from thinking things through, and does not come about without perception, and without it there is no conceiving that something is the case” (book 3 ch. 3, p. 134).

Aristotle is saying that while conceiving that something is the case depends on imagination and imagination ultimately depends on the particular senses, we never directly perceive that something is the case. That something is the case is a practical judgment about particulars, rather than a perception. “Thinking things through” (dianoia) is discussed separately from pure thought or intellect (nous), and is a rational activity of the soul grounded mainly in imagination. To really “occur” in a human, pure thought depends on the activity of thinking things through as its vehicle.

“[F]alsehood is always in an act of putting things together…. What makes each thing be one is intellect” (book 3 ch. 6, p. 144). “[B]ut thinking what something is, in the sense of what it keeps on being in order to be at all, is true, and is not one thing attached to another” (p. 145).

Here he seems to be emphasizing that the idea of what something truly is, in the sense of being-at-work-staying-itself, is not adequately expressible in terms of a simple combination of pre-existing parts or independently defined features. Also, no expression of a “what” by itself forms an assertion that could then be either true or false. A “what” by itself has more of the character of a definition that could be either accepted by hypothesis or considered hypothetically.

If the thought of a being-at-work-staying-itself is simply “true”, it seems to me it must be true in some sense other than correspondence — perhaps a being-true-to-itself through coherence. This use of “true” is also different from the way it is defined in On Interpretation, where truth and falsity are said to apply if and only if we say something about something, which means a “what” taken in isolation would be neither true nor false. Only what is said about the what could be true in that sense, but then it could also be false, depending on what is said. So “true” is being said in a different, special way here.

“Knowledge, in its being-at-work, is the same as the thing it knows, and while knowledge in potency comes first in time in any one knower, in the whole of things it does not take precedence even in time, for all things that come into being have their being from something that is at-work-staying-itself. And… the perceiving thing is not [merely] acted upon nor is it altered. Hence this is a different kind of event from a motion” (book 3 ch. 7, pp. 145-146, brackets in original, emphasis added).

Here he emphasizes a distinction between motion in the primary sense of ordinary bodily motion on the one hand, and the actualization of a potential on the other, identifying perception with the latter.

Aristotle on Explanation

Book 1 chapter 1 of Parts of Animals provides an overview of Aristotle’s perspective on explanation in general. It is a nice synthetic text that brings together many of Aristotle’s core concerns, and shows his vision of how natural science ought to fit in with broader philosophy.

He begins by distinguishing between mere acquaintance with an area of study and being educated in it. “For an educated [person] should be able to form a fair judgment as to the goodness or badness of an exposition” (Complete Works, Barnes ed., vol. 1, p. 994). This seems to apply to any subject whatsoever.

Next he raises the more specific question of method. “It is plain then that, in the science which inquires into nature, there must be certain canons, by reference to which a hearer shall be able to criticize the method of a professed exposition, quite independently of the question whether the statements made be true or false” (ibid).

Continuing to emphasize the critical thinking that is the mark of an educated person, he makes it explicit that some of the most important questions about a subject are what I would call second-order questions, having to do with how we ought to approach the matter at hand. The educated person will give due emphasis to these, rather than naively rushing to deliver judgments on questions of fact.

“Ought we, for example (to give an illustration of what I mean) to begin by discussing each separate substance — man, lion, ox, and the like — taking each kind in hand independently of the rest, or ought we rather to lay down the attributes which they have in common in virtue of some common element of their nature? For genera that are quite distinct present many identical phenomena, sleep, for instance, respiration, growth, decay, death, and other similar affections and conditions…. Now it is plain that if we deal with each species independently of the rest, we shall frequently be obliged to repeat ourselves over and over again; for horse and dog and man present every one of the phenomena just enumerated” (ibid).

The educated person looks for explanations, not just facts or correspondences. The specific “dogginess” of a dog, for example, does not explain its sleeping, breathing, and so on. Instead these activities, which it shares with many other animals, are explained by natures common to all of them.

Further, the kind of method Aristotle commends to us is not a matter of following recipes by rote. Instead, it is a thinking approach that involves persistently following the thread of explanations wherever it leads.

“So also there is a like uncertainty as to another point now to be mentioned. Ought the student of nature follow the plan adopted by the mathematicians in their astronomical demonstrations, and after considering the phenomena presented by animals, and their several parts, proceed subsequently to treat of the causes and the reason why; or ought he to follow some other method? Furthermore, the causes concerned in natural generation are, as we see, more than one. There is the cause for the sake of which, and the cause whence the beginning of motion comes. Now we must decide which of these two causes comes first, which second. Plainly, however, that cause is the first which we call that for the sake of which. For this is the account of the thing, and the account forms the starting-point, alike in the works of art and in works of nature. For the doctor and the builder define health or house, either by the intellect or by perception, and then proceed to give the accounts and the causes of each of the things they do and of why they should do it thus” (p. 995).

He raises the question of which kind of cause comes first, because he wants to suggest a different answer from that of the pre-Socratic “physicists” who attempted to explain everything by properties of different kinds of matter. Elsewhere he says that Plato and the atomist Democritus (whose writings are lost) did better than others at following the thread of explanation, but he considers the elaborated account of ends or “that for the sake of which” to be one of his own most important contributions.

Notably he only mentions two kinds of cause here, rather than the classic four. Similarly, there are passages in other texts where he lists a different number of categories than the canonical ten from the Categories. Later authors often viewed things like causes and categories in a reified, univocal way, as susceptible to exact enumeration. But for Aristotle, these are abstractions from a concrete reality that comes first, to be wielded in a context-sensitive way, so the canonical enumerations are not absolute.

Aristotle’s understanding of the “beginning of motion” is different from that promoted by early modern physics. Conventionally in the reading of Aristotle, the “beginning of motion” is associated with the efficient cause, and these two terms are understood in a somewhat circular way, which is really informed by some broadly intuitive sense of what a “beginning” of motion is. Early modern writers assumed that this “beginning” must be some kind of immediate impulse or force. Aquinas associated it with God’s act of creation and with the free acts of created beings. For Aristotle himself it is neither of these.

My best reading of efficient cause is that it is the means by which an end is realized. In many cases the end is realized not by just one means but by a hierarchy of means (e.g., art of building, carpenter, carpenter’s hammer, hammer’s blow). Aristotle and the scholastics emphasized the top of such hierarchies (e.g., the art of building for Aristotle; God or some metaphysical principle for the scholastics), whereas the early moderns emphasized the bottom (e.g., the hammer’s blow), akin to the proximate cause of concern to liability lawyers. For Aristotle, the art of building and not the hammer’s blow is the true “beginning” of the motion of house construction, because it provides the guiding thread of explanation for the whole process of building the house. But even the art of building is still just a means that gets its meaning from the reasons why we would want to build a house in the first place.

He continues, “Now in the works of nature the good and that for the sake of which is still more dominant than in works of art, nor is necessity a factor with the same significance in them all; though almost all writers try to refer their accounts to this, failing to distinguish the several ways in which necessity is spoken of. For there is absolute necessity, manifested in eternal phenomena; and there is hypothetical necessity, manifested in everything that is generated as in everything that is produced by art, be it a house or what it may. For if a house or other such final object is to be realized, it is necessary that first this and then that shall be produced and set in motion, and so on in continuous succession, until the end is reached, for the sake of which each prior thing is produced and exists. So also is it with the productions of nature. The mode of necessity, however, and the mode of demonstration are different in natural science from what they are in the theoretical sciences [e.g., mathematics]…. For in the latter the starting-point is that which is; in the former that which is to be. For since health, or a man, is of such and such a character, it is necessary for this or that to exist or be produced; it is not the case that, since this or that exists or has been produced, that of necessity exists or will exist. Nor is it possible to trace back the necessity of demonstrations of this sort to a starting-point, of which you can say that, since this exists, that exists [as one might do in mathematics]” (ibid).

In Aristotle’s usage, “nature” applies to terrestrial things that are observably subject to generation and corruption. He earlier referred to astronomical phenomena like the apparent motions of the stars and planets as “eternal” because on a human scale of time, these are not observably subject to generation and corruption. For Aristotle, absolute necessity could only apply to things that are absolutely unchanging. We may have a different perspective on astronomy, but that does not affect the logical distinction Aristotle is making. His key point here is that things subject to generation are not subject to absolute necessity. Leibniz took this a step further and argued that hypothetical necessity is the only kind there is. Kant, in arguing that hypothetical and disjunctive judgment (“if A then B” and “not both A and B“) are more fundamental than categorical judgment (“A is B“), made a related move.

Hypothetical necessity has a particular form that is worth noting. As Aristotle points out in the quote above, under hypothetical necessity “it is not the case that, since this or that exists or has been produced, that of necessity exists or will exist”. To give a positive example, hypothetical necessity says that to continue living, we must eat. But it does not in any way dictate a particular series of motions that is the only way this can be accomplished, let alone the whole series of eating-related actions throughout one’s life. Neither does it dictate that we will eat in any particular instance.

How we meet a particular need is up to us. The reality of this flexibility built into nature is all we need to explain freedom of action. Humans can also affirmatively embrace commitments and act on them; that too is up to us. Freedom is not an arbitrary or supernatural power; it simply consists in the fact that nature is flexible, and many things are up to us.

Aristotle contrasts the way a thing is naturally generated with the way it is. “The best course appears to be that we follow the method already mentioned — begin with the phenomena presented by each group of animals, and, when this is done, proceed afterwards to state the causes of those phenomena — in the case of generation too. For in house building too, these things come about because the form of the house is such and such, rather than its being the case that the house is such and such because it comes about thus…. Art indeed consists in the account of the product without its matter. So too with chance products; for they are produced in the same way as products of art” (pp. 995-996).

“The fittest mode, then, of treatment is to say, a man has such and such parts, because the essence of man is such and such, and because they are necessarily conditions of his existence, or, if we cannot quite say this then the next thing to it, namely, that it is either quite impossible for a man to exist without them, or, at any rate, that it is good that they should be there. And this follows: because man is such and such the process of his development is necessarily such as it is; and therefore this part is formed first, that next; and after a like fashion should we explain the generation of all other works of nature” (p. 996).

This way of reasoning backwards from an essence to its prerequisites is complemented by the fact that for Aristotle (and Plato) essences themselves are a prime subject of investigation, and not something assumed. “Begin with the phenomena”, he says.

Many 20th century philosophers have objected to presumptuous talk about the “essence of man”, and to any explanation in terms of essence. But these objections presuppose that the essence is something assumed, rather than being an object of investigation as it clearly was for Plato and Aristotle. Here also it is needful to distinguish between what we might call the distinguishing essence of humanity used to pick out humans — e.g., “rational/talking animal” — and what Leibniz later called the complete essence of each individual. Clearly also, the parts of the human body do not follow directly from “rational/talking animal”, but from many other attributes “presented in the phenomena”. It turns out that humans share these attributes with other animals, and they can therefore be conceptualized as attributes of common genera to which we and those other animals belong.

Because essences themselves are a prime subject of investigation and are ultimately inferred from phenomena, the kind of teleological reasoning Aristotle recommends always has a contingent character, which is how it naturally accounts for what the moderns call freedom. This contingency is built into in the “hypothetical” character of hypothetical necessity.

“Does, then, configuration and color constitute the essence of the various animals and their several parts? For if so, what Democritus says will be correct…. And yet a dead body has exactly the same configuration as a living one; but for all that it is not a man. So also no hand of bronze or wood or constituted in any but the appropriate way can possibly be a hand in more than name. For like a physician in a painting, or like a flute in a sculpture, it will be unable to perform its function” (p. 997).

Aristotle was the historic pioneer of “functional” explanation. Here he insists that the essences of living beings and their parts must be understood in terms of their characteristic activities. This development for the sake of biology parallels the deeper development of the meaning of “substance” in the Metaphysics as “what it was to be” a thing, and as actuality and potentiality.

“If now the form of the living being is the soul, or part of the soul, or something that without the soul cannot exist; as would seem to be the case, seeing at any rate that when the soul departs, what is left is no longer an animal, and that none of the parts remain what they were before, excepting in mere configuration, like the animals that in the fable are turned into stone; if, I say, this is so, then it will come within the province of the natural scientist to inform himself concerning the soul, and to treat of it, either in its entirety, or, at any rate, of that part of it which constitutes the essential character of an animal; and it will be his duty to say what a soul or this part of a soul is” (ibid).

Here it is important that we consider soul in the “phenomena first” way that Aristotle develops it.

“What has been said suggests the question, whether it is the whole soul or only some part of it, the consideration of which comes within the province of natural science. Now if it be of the whole soul that this should treat, then there is no place for any philosophy beside it…. But perhaps it is not the whole soul, nor all of its parts collectively, that constitutes the source of motion; but there may be one part, identical with that in plants, which is the source of growth, another, namely the sensory part, which is the source of change of quality, while still another, and this is not the intellectual part, is the source of locomotion. For other animals than man have the power of locomotion, but in none but him is there intellect. Thus it is plain that it is not of the whole soul that we have to treat. For it is not the whole soul that constitutes the animal nature, but only some part or parts of it” (p. 998).

Aristotle’s opposition to treating the soul as a single lump reflects his overall functional, activity-oriented, and phenomena-first approach.

“Again, whenever there is plainly some final end, to which a motion tends should nothing stand in its way, we always say that the one is for the sake of the other; and from this it is evident that there must be something of the kind, corresponding to what we call nature” (ibid).

Overall teleology always has to do with tendencies, not absolute determinations. He begins to wrap up this introduction by giving another example of the hypothetical necessity whose concept he pioneered.

“For if a piece of wood is to be split with an axe, the axe must of necessity be hard; and, if hard, must of necessity be made of bronze or iron. Now in exactly the same way the body, since it is an instrument — for both the body as a whole and its several parts individually are for the sake of something — if it is to do its work, must of necessity be of such and such a character, and made of such and such materials.”

“It is plain then that there are two modes of causation, and that both of these must, so far as possible, be taken into account, or at any rate an attempt must be made to include them both; and that those who fail in this tell us in reality nothing about nature” (p. 999).

Again, the two modes here are “that for the sake of which” and the phenomena associated with generation. Considering either of these in isolation yields an incomplete understanding, as we see respectively in bad scholasticism and bad empiricism.

“The reason why our predecessors failed to hit on this method of treatment was, that they were not in possession of the notion of essence, nor of any definition of substance. The first who came near it was Democritus, and he was far from adopting it as a necessary method in natural science, but was merely brought to it by constraint of facts. In the time of Socrates a nearer approach was made to the method. But at this period men gave up inquiring into nature, and philosophers diverted their attention to political science and to the virtues that benefit mankind” (ibid).

Socrates and Plato initially pioneered the notion of “that for the sake of which”, but in turning away from the phenomena of generation and becoming, they gave it a somewhat one-sided character.

The subtle way in which Aristotle wields the concept of essence avoids treating it as an absolute, or as something strictly univocal. In any given context, there is a clear relative distinction between essence and accident, but the distinction is not the same across all contexts. Hypothetical necessity provides the mechanism by which what is “accident” at one level of analysis can be incorporated into “essence” at another level. (See also Hermeneutic Biology?; Aristotelian Causes; Secondary Causes; Aristotle’s Critique of Dichotomy; Classification.)

Russell on Causality

Bertrand Russell (1872-1970) was one of the founders of analytic philosophy. His contributions to mathematical logic, philosophy of mathematics, and philosophy of language were highly influential, and he wrote on a host of other topics as well. In a famous 1912 essay “On the Notion of Cause”, he addressed the common prejudice that I have been referring to vaguely as “causality in the modern sense”, and argued that modern science does not in fact rely on it. I support this conclusion.

According to Russell, “the word ’cause’ is so inextricably bound up with misleading associations as to make its complete extrusion from the philosophical vocabulary desirable” (Mysticism and Logic, p.180). “In spite of these difficulties, it must, of course, be admitted that many fairly dependable regularities of sequence occur in daily life” (p. 187).

The idea of the supposed “law of causality” is that the same causes always produce the same effects. Russell points out that the alleged necessity with which one “event” is said to follow another depends on an abstracted notion of repeatable “events”, but every concrete event implicitly involves such a vast amount of individualizing detail as to be essentially unrepeatable.

“What I deny is that science assumes the existence of invariable uniformities of sequence of this kind, or that it aims at discovering them. All such uniformities, as we saw, depend upon a certain vagueness in the definition of the ‘events’…. In short, every advance in a science takes us farther away from the crude uniformities which are first observed” (p. 188, emphasis added).

Behind such presumptions of uniformity lies the prejudice that a cause somehow compels a particular effect. “What I want to make clear at present is that compulsion is a very complex notion, involving thwarted desire. So long as a person does what he wishes to do, there is no compulsion, however much his wishes may be calculable by the help of earlier events. And where desire does not come in, there can be no question of compulsion. Hence it is, in general, misleading to regard the cause as compelling the effect” (p. 190, emphasis added). “A volition ‘operates’ when what it wills takes place; but nothing can operate except a volition. The belief that causes ‘operate’ results from assimilating them, consciously or unconsciously, to volitions” (p. 191).

“[A]ny causal sequence which we may have observed may at any moment be falsified without a falsification of any laws of the kind that the more advanced sciences aim at establishing” (p. 194). “The uniformity of nature does not assert the trivial principle, ‘same cause, same effect’, but the principle of the permanence of laws” (p. 196). “In all science we have to distinguish two sorts of laws: first, those that are empirically verifiable but probably only approximate; secondly, those that are not verifiable, but may be exact” (p. 197).

“We cannot say that every law which has held hitherto must hold in the future, because past facts which obey one law will also obey others, hitherto indistinguishable but diverging in future. Hence there must, at every moment, be laws hitherto unbroken that are now broken for the first time. What science does, in fact, is to select the simplest formula that will fit the facts. But this, quite obviously, is merely a methodological precept, not a law of Nature” (p. 204, emphasis in original).

“We found first that the law of causality, as usually stated by philosophers, is false, and is not employed in science. We then considered the nature of scientific laws, and found that, instead of stating that one event A is always followed by another event B, they stated functional relations between certain events at certain times, which we called determinants, and other events at earlier or later times or at the same time…. We found that a system with one set of determinants may very likely have other sets of a quite different kind, that, for example, a mechanically determined system may also be teleologically or volitionally determined” (pp. 207-208, emphasis added).

I have suggested that scientific laws expressed in terms of equations are a specific kind of what Aristotle called formal “causes” (or better, formal “reasons why”). They are the kind that is expressible in mathematics. But natural or physical causes are still commonly conceived as efficient causes in the sense that this term acquired in late scholasticism, and it is this prejudice that Russell was addressing here.

The diverse compilation Aristotle’s early editors called Metaphysics (“after the Physics“) includes a summary of the four causes discussed in the Physics. Unlike other parts of the Metaphysics that, for example, discuss the term commonly translated as “substance” in far greater depth than in the Categories, the summary of efficient cause in the Metaphysics is less sophisticated than the discussion in the Physics. Thomistic and late scholastic notions of efficient cause seem to be based on the more simplistic account given in the Metaphysics, where the efficient cause is treated as more narrowly concerned with motion.

The Physics says very explicitly that the art of building, not the carpenter or the carpenter’s action, is most properly the “efficient cause” of the building of a house. The building of a house is implicitly considered as an end, not as a concrete motion. The art of building is the primary means by which this end can be successfully accomplished. This suggests to me that just as the “material cause” in Aristotle is hylomorphically paired with the “formal cause”, the “efficient cause” is related to the “final cause” as means are related to ends. Efficient cause as the means by which an end is realized is quite a bit different than, and more general than, the efficient cause as cause of motion that is the basis of the Thomistic and late scholastic concepts, as well as of the “modern” prejudice addressed by Russell.

Separate Substances?

One of the more difficult or troublesome aspects of the Aristotelian tradition for me is the notion of “separate substances”. Certainly this was greatly expanded by later writers, but it appears to have a basis in the texts we attribute to Aristotle.

A separate substance would seem to be something that at least does not participate in earthly matter, but in Aristotle there is some ambiguity whether separate substances are supposed to be completely free of matter, or just free of earthly matter. In Aristotle’s thought this makes a difference, because he regarded celestial matter as being fundamentally of a different kind than the earthly matter that is subject to generation and corruption. Conditioned as we are by theories of modern science, this may seem quaint to us, but it is a reasonable inference if we focus on ordinary human experience. In a similar way, Aristotle refers to the movements of the stars as “eternal”, on the practical ground that humans looking up from Earth do not observe them to change.

There is a more general point regarding eternity. Aristotle seems most often to use this term in the pragmatic way mentioned above. He calls things eternal if they are constant within human experience. This is quite different from the stricter sense of eternity, as meaning outside of time altogether. Plato’s geometrical objects and Augustine’s God, I think, are supposed to be outside of time altogether. Both the Aristotelian and the strict notion of eternity are different from the more popular religious sense of eternity as lasting forever. Medieval theologians coined a special word for the latter: “sempiternity”.

The separate intellect or intellects that Averroes talks about do not seem to me to be eternal in the strict sense of outside of time. At one point, Averroes says for example that while he assumes humans will always exist, if per contra humans became extinct, there would no longer be a material intellect. Aristotle had said that the potential intellect is nothing at all until it begins to think, and Averroes seems to say that humans provide the occasions for it to think. Having a dependency on temporal beings seems to me to be incompatible with eternity in the strict sense.

An even subtler question is how to regard the situation in which something strictly eternal is said to act as a final cause that is said to move something earthly. As noted in the last post, Aristotle regarded motion as something existing only in the thing moved. He distinguished “moved movers” from “unmoved movers”, but moved movers are moved by something other than themselves. For Aristotle, everything that is moved is moved by something else; there are no absolute by-their-bootstraps “self-movers”, although most or possibly all beings have some degree of activity of their own. So a moved mover is called that only insofar as it is moved by something else.

The preeminent movers in Aristotle are ends — not mechanical impulses, not generators of something from nothing, not “agents” of any sort at all. Ends have a kind of virtual existence or subsistence that could in principle be independent of any embodiment. They move us in the way that values move us. Aristotle suggests that even earthly matter is moved by ends in some rudimentary way — not that it has consciousness of its own, but that its being exhibits something analogous to preferences to being in one state rather than another. This is just what it is to “have a nature”. All Aristotelian natures have some involvement with ends in this way.