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 GwenaĆ«lle 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.