, Volume 31, Issue 2, pp 209–220 | Cite as

Capacity and Potentiality: Aristotle’s Metaphysics Θ.6–7 from the Perspective of the De Anima



The notion of a capacity (dunamis) in the sense of a power to bring about or undergo change plays a key role in Aristotle’s theories about the natural world. However, in Metaphysics Θ Aristotle also extends ‘capacity’, and the corresponding concept of ‘activity’ (energeia), to cases where we want to say that something is in capacity, or in activity, such and such but not, or not directly, in virtue of being capable of initiating or undergoing change. This paper seeks to clarify and confirm a certain view of how Aristotle wishes us to see the relationship between the two uses of ‘capacity’ and ‘activity’. To that end, I consider also Aristotle’s employment of the terms in the De Anima, which sheds light on the key examples which direct the discussion in Metaph. Θ.


Capacity (dunamisActivity (energeiaFulfilment (entelekheiaChange Body-soul relationship Instrument Teleology 

The notion of a capacity (dunamis) in the sense of a power to bring about or undergo change plays a key role in Aristotle’s theories about the natural world. He sees such capacities for change as the principles which explain the behaviours of natural beings. However, Aristotle also, notoriously, seeks to extend the use of the term ‘capacity’ to cases which do not involve or do not directly involve change; cases where we want to say that something has the capacity to be such and such but not, or not directly, in virtue of being capable of initiating or undergoing change. It is this extension in the use of ‘capacity’ which has become enshrined in the wider notion of ‘potentiality’, with its correlative ‘actuality’. So Aristotle wants to talk, not just, of the capacity of a stove to heat up water, or the capacity of the eyes to see, and so of the stove as heating up the water in capacity or potentially or the eyes seeing in capacity or potentially, but also of the wood of this box as being the box potentially or the body of this dog being a dog potentially. That is to say, he wants to use the notion of capacity to describe the way the matter of a substance relates to the substance itself.

The Metaphysics Book Θ offers Aristotle’s most extensive analysis of the notion of a ‘capacity’ (dunamis). His discussion relies on a distinction between two uses of the term. First, there is a primary use of the term (kuriôs), whereby we speak of something as capable or having a capacity when it is capable of initiating or undergoing a change (Metaph. 1019a15–16). Aristotle defines such a capacity as a principle of change in another thing or in oneself qua other, or in the passive case, a principle of being changed by another thing or by oneself qua other (1046a9–18). He calls this a ‘capacity said in accordance with change’, and I shall accordingly refer to the ‘kinetic’ notion of capacity. The other notion of capacity underlies our talk of things being in capacity, in contrast to their being in activity. Aristotle does not directly define this notion but seeks to elucidate it by analogy with the kinetic notion. Aristotle thinks that this notion applies to the relationship between a substance and its matter. I shall refer to it as the modal notion, to reflect that it involves being in the two modes of capacity and activity, often captured by an adverbial form of dunamis and energeia, (dunamei, en dunamei, kata dunamin).

While the modal notion does not obviously involve change, Aristotle still suggests that it can somehow be understood in extension of the kinetic notion. That is why he first discusses the kinetic notion in chapters before turning to the other notion in Chap. 6.1 However, it is not clear just what is supposed to carry over from the discussion of the kinetic notion. He indicates that the way in which substance is the energeia of matter is different from the way in which change is the energeia of a capacity, yet is importantly analogous to the latter. The presumption seems to be that by focusing in the right way on the change-capacity relationship we can extrapolate the features which will help us understand the substance-matter case.2

Aristotle develops the analogy through five examples:
  1. 1.

    As what is building stands to what has the capacity to build so…

  2. 2.

    what is awake stands to what is asleep,

  3. 3.

    what is seeing to what has eye-sight but has shut its eyes,

  4. 4.

    what has been separated out of the matter to the matter,

  5. 5.

    what has been worked up from what has not been worked up.


It seems clear that some of these examples, most probably the first three, are examples of the activity of capacities for change, while the last two are activities of capacities in the way substance is related to matter. However, very little else seems clear. In particular, it is obscure just how the analogy is supposed to tie together the two relationships of activity to capacity. Of course, Aristotle’s refusal to offer a proper definition may be meant to warn us against offering a single account of what the different cases have in common. Analogy after all is used in order to express sameness or oneness in cases where there is no single shared kind by reference to which we may define the analogous terms.3 When we are dealing with terms of the most common kind, like activity and capacity or form and matter,4 analogy may take the place of definition, exactly because there are no more basic terms by which they could be defined. Yet it is not unreasonable to seek some description or story, short of a definition, by which the relationship can be communicated.

In this paper I want to attempt such a story of how Aristotle might think one can get from the kinetic to the modal notion of capacity. It is story in many ways familiar from recent scholarship on Metaphysics Θ. What I hope to accomplish in this paper is to clarify and confirm a certain view, already represented in current scholarship,5 of how Aristotle wishes us to see the relationship between the two uses of ‘capacity’. To this end, I shall make more use of Aristotle’s psychology than is customary, since the key examples which direct Aristotle’s discussion in Metaph. Θ are more fully explained in his work on the soul, the De Anima (DA). I think this approach is justified for two reasons. One is the brevity and difficulty of Metaph. Θ.6–7. The second is that the key examples that Aristotle uses in Θ.6 to communicate the broader notion of being in capacity and in activity, the relationship between sight and seeing, knowing and contemplating, and the relationship between the matter and the substance of human being are themselves analysed in the DA from the point of view of the distinction between capacity and activity. Indeed, in the DA itself we see through the case of living beings how the notion of being in capacity extends from the kinetic notion to the broader modal use. There is some reason to hope, then, that by looking at these fuller discussions we can get a better grip on Aristotle’s intentions in Θ.6–7.

By way of introduction, I want to make some remarks about the translation of the key terms dunamis and energeia. It is common practice to translate dunamis differently when the term is perceived to indicate the kinetic notion from where it is used modally. So dunamis is often translated as ‘capacity’ or ‘potentiality’, while en dunamei or dunamei is rendered as ‘in potentiality’ or ‘potentially’ but not ‘in capacity’. Similarly, for energeia we may be given ‘activity’ or ‘actuality’, but en energeiai or energeiai is translated as ‘in actuality’ or ‘actually’, but rarely ‘in activity’.

We might think that a clear marker of the difference is Aristotle’s use of the dative construction or similar adverbial constructions (e.g. en dunamei or kata dunamin) for the modal notion. But the account of the soul in DA II.1 shows that this is dubious. Aristotle starts by saying that matter is dunamis (nominative), and form fulfilment, entelekheia. It is clearly this notion of dunamis that is picked up on when he concludes that the soul is the form of a living body having life dunamei (412a20–21); otherwise the argument would involve a fallacy of equivocation. If, then, the modal notion of dunamis is marked by its contrast with entelekheia, its use is not confined to the dative construction. We may of course still maintain that where the dative construction occurs we are supposed to think specifically of the modal notion. However, there can be no presumption that the dative construction indicates just modality in contrast to the kinetic notion, if the nominative can be used to express both the kinetic and the modal notions.

I want to suggest that there is indeed a modal aspect to the term dunamis which particularly comes to the fore in the adverbial constructions, but also that this use is connected with the kinetic use in such a way that it would be wrong to say that such uses of dunamis were modal in contrast to kinetic. Here is the idea. When we say that someone is such and such dunamei or en dunamei, we mean that, in relation to being such and such, he is in the condition that his capacity makes him be in, and no more. Put differently, since having a capacity (dunamis) does not in itself make one exercise that capacity, saying that he is ‘in capacity’ (en dunamei) means that he is only, as the standard translation goes, ‘in potentiality’. Again this does not mean that somebody who has the capacity does not also exercise the capacity. But it does suggest that when we specifically say that he is in the state that his capacity bestows on him, no more, he is in potentiality. For a capacity as such puts you in the state of potentiality, no more, with respect to its exercise.

The reason why the capacity for change is not in itself sufficient for its own exercise is that other factors are required, such as one’s desire and the opportunity to exercise the capacity in the case of active capacities, or external agents or prompts in the case of passive capacities, as Aristotle shows in Metaph. Θ.5.6 If I have learnt carpentry, then I have acquired a capacity, which may or may not be realised. By having the capacity I am able to practice carpentry, but my having the capacity in itself does not ensure or require its actual practice. For the exercise requires also the desire and the opportunity to exercise it. Or if I have vision, a passive capacity, then I have the capacity to see and when there is a light and a coloured object in my line of vision, I will see, if nothing else interferes. But by having the capacity I am ipso facto in a state of potentiality with respect to the activity, nothing other than having the capacity is required to be in such a state. So it makes sense to say that the capacity as such puts me in a state of potentiality rather than actuality (energeia).

Compare Aristotle’s discussion in DA II.5 of the different uses of dunamis (417a21ff). He uses the example of the knowledge of grammar to distinguish three levels of dunamis and fulfilment (entelekheia). One level of knowing grammar potentially (kata dunamin) is the one that qualifies a human being who has not yet learnt grammar, but who as a human being is capable (dunatos) of being a grammarian. Another level of potentiality characterises the person who has acquired grammatical knowledge and is capable (dunatos) of exercising his knowledge whenever he wants to and whenever there are no external impediments (417b22–28). Aristotle thus uses the notion of being capable to elucidate the modal notion of potentiality, here the notion of ‘being a knower’ in potentiality. One might say that the different levels of potentiality are expressions of different levels of development of the same capacity: the more developed the capacity the higher the level of potentiality. All of this presupposes that we can elucidate the notion of potentiality in terms of that of a capacity.7

A parallel point can be made about ‘activity’ (energeia). When we use the term energeia as opposed to dunamis in the kinetic way, it is attractive to translate the term ‘activity’.8 The term indicates that the dunamis is working or is in action (en ergôi). So ‘seeing’, ‘running’, ‘fishing’ are the activities of the capacities to see, run and fish. ‘Actuality’, meanwhile, may be said to be the implied modality of such activities. ‘John is fishing’ understood as ‘John is now engaged in the activity of fishing’ normally indicates that he is actually fishing, and not, or not merely, potentially fishing. There is an interpretative question as to whether Aristotle thinks that ‘A is actually Φ-ing’ excludes ‘A is potentially Φ-ing’. If so, saying that ‘John is fishing’ would exclude that he is merely potentially fishing since he would not be potentially fishing at all. There is at least one case, namely, ‘God is contemplating’, where Aristotle would insist that that activity excludes the potentiality. But this is a rather special case in that God’s nature excludes any sort of potentiality. I think cases where we are tempted to think that the potentiality survives are in fact cases where we believe that the capacity survives. So in the case of knowledge we clearly think that the mathematician’s capacity for mathematical thought survives episodes of actual thinking. We may also think it is true to say that the mathematician who is actually thinking is also potentially thinking in the sense that he could go on thinking or be thinking again on another occasion. Indeed, we may think he comes out strengthened by the experience, and is more likely to engage in successful acts of mathematical thinking for it. But these claims about his potential to think rely on his retained, or strengthened, capacity to think. Indeed we can say that as long as the capacity is retained the possessor has the potential to engage in the activity. It seems safe to say, then, that the modal state of a capacity as such is potentiality, while that of activity as such is actuality. That is why Aristotle by using adverbial forms of capacity and actuality can indicate the modal statuses which tradition has come to know as ‘potentiality’ and ‘actuality’.

There are reasons, I have suggested, for reading Aristotle’s modal notion of potentiality as an aspect of his notion of capacity: to have the capacity to be or to do or to suffer something means to be potentially that thing or to be potentially doing or suffering it. The term ‘dunamis’ used in the contexts where we commonly translate it as ‘capacity’ does then have a modal implication. Its use implies the presence at least of a potentiality and without the further factors required for its actualisation, no more than a potentiality. Or, as I would put it, the default modality of a capacity is that of being potentially. Given this close connection, the translations of en dunamei, dunamei, kata dunamin as ‘in capacity’, ‘in the manner of a capacity’, and ‘with respect to capacity’ may be more authentic than the standard ‘in potentiality’, ‘potentially’, ‘with respect to potentiality’.9 However, I shall continue sometimes to use forms of ‘potential’ both because it is sometimes useful to have a term that highlights the modal status and because English lacks a suitable simple adverbial form of ‘capable’.10

When we now turn to Metaph. Θ.6 it will be helpful to bear in mind the modal aspect to Aristotle’s talk of ‘capacity’ and ‘activity’ because it helps see how he thinks we can move from the kinetic uses of capacity to a more generalised notion of being in capacity or potentiality. He indicates, as we saw, that the way substance is the energeia of matter is different from the way in which change is the energeia of a capacity, yet is importantly analogous to the latter. The presumption seems to be that by focusing in the right way on the change-capacity relationship we can understand what it is to be an activity in a way that carries over to the different case of the relationship between substance and matter.11 From this broader notion of energeia we can then, in Θ.7, also conceive of a way in which matter is in capacity what substance is in activity.

Aristotle, to recall, works the analogy through five examples:
  1. 1.

    As what is building stands to what has the capacity to build so…

  2. 2.

    what is awake stands to what is asleep,

  3. 3.

    what is seeing to what has eye-sight but has shut its eyes,

  4. 4.

    what has been separated out of the matter to the matter,

  5. 5.

    what has been worked up from what has not been worked up.12


The cases seem at first blush roughly to fall into two groups (1)–(3) as examples of how change stands to what is capable, and (4)–(5) as illustrations of the relationship of substance to matter.13 The cases represent, as we have been warned, different kinds of relationships, yet they have something in common. To see just what, it is helpful to attend to the ways in which Aristotle has chosen and described the examples so as to increase their similarity. Attending to these features is a key, I want to suggest, to understanding the analogy.

One such point is that while each of the five examples refers to the same thing in different states, none of them refers to the changing of that thing from one state to the other. In (4)–(5) the perfects which Aristotle uses to refer to the substance clearly indicate the finished product rather than something which is causing or undergoing some change. Similarly, (1)–(3) do not refer to the changing from one state to other: Aristotle is not describing, for example, the relationship of changing from having your eyes closed to actually seeing; rather, he is describing the relationship between something in the state of seeing and in the other state. This makes the description of (1)–(3) similar to that of (4)–(5) where the relationship between the finished product and the unworked matter is also diachronic. Neither kind of case is describing the activity as a process of transition between states but rather as a state where the transition has been accomplished.

This brings us to a second point of similarity: in (1)–(3) Aristotle chooses examples of change that do not essentially involve the subject’s becoming different but are rather fulfilments (entelekheiai) of what they already are. On Aristotle’s analysis in Phys. I, change involves the replacement of an attribute by its opposite’. Let’s call such changes ‘o’ (for ‘ordinary’) changes. However, in the cases we are considering in (1)–(3) the change is rather peculiar, as Aristotle shows in DA II.5, the text we looked at earlier. As we saw, he distinguishes three ways in which something can be said to be a knower: (1) by being capable of learning, (2) by having learnt and thereby being capable of using one’s knowledge, (3) by actively using one’s knowledge. Now when a human changes from (1) to (2) and from (2) to (3) the changes involved are different from o-changes in that the change does not lie in acquiring an opposite attribute. Where heating a cup of milk involves changing the milk from being cold to its opposite, hot, teaching somebody mathematics does not involve making him the opposite of what he was previously14: rather it is a fulfilment of a knowledge he already possessed in potentiality or capacity in virtue of being a human being (417a23–24). Aristotle also describes learning as a change to the thing’s natural state (epi tas hexeis kai tên phusin), rather than as a change to a privative disposition (417b12–16). Nor does the skilled mathematician’s exercise of his knowledge mean that he becomes the opposite of what he was: after all, he already had the knowledge that he is now displaying. Here Aristotle speaks of contemplation as ‘a transition to the thing itself to its fulfilment’ (417b6–7). One feature of such ‘changes as fulfilments’, ‘f-changes’ for short, is that the subject of the f-change does not lose the attribute that is fulfilled.

In view of the earlier point that the analogy talks about the relationship between two states before and after a transition from the one to the other rather than the relationship that is the transition from one to the other, one might insist that Aristotle’s point in Θ.6 cannot be drawn from what he says in DA II.5 about transitions between states. In reply, Aristotle in DA II.5 seems to talk about both the transition and the state of contemplating or perceiving or building as f-changes.15 In any case, the point that the transition does not involve becoming other relies on the point that the state that the transition aims at is not one of being other than before. From our perspective what matters is that all of the three changes mentioned, seeing, building, being awake, fulfil what the subject already was given certain capacities. For this point in turn helps us with the notion of a perfected substance as an energeia since we are led to the thought that for something to be in energeia need not lie in its manifesting a capacity to be different, but may involve more fully manifesting what it already is. We may think of an energeia in all of (1)–(5) as a fulfilment of what the subject already is in virtue of a certain capacity.16 Nor, conversely, does something which is in capacity have to be such that its fulfilment involves losing the capacity, or the feature that grounds that capacity, e.g. as being human grounds the capacity to learn.

One further point of significant similarity in the descriptions of and (4)–(5) is that Aristotle (1)–(3) refers to the relata not as the capacity and the activity but to what is capable (to dunaton) and what is active, so to what has eyes-sight versus what is seeing, for example. Aristotle also later (1048b8) sums up the relationship as one between dunamis and energeia. However, these are not mutually exclusive descriptions: one may think of the dunaton as capable in virtue of possessing the dunamis, and so say that its dunamis is active when the dunaton is active, or vice versa. For example, one might switch between saying that sight sees and a man sees in virtue of having sight.17 Nonetheless, it seems significant that the analogy takes the perspective of what has the capacity and what engages in its activity. This increases the similarity with what has been worked up and what has not been worked up, by fitting all the cases under the schema ‘what is F in activity versus what is F in capacity’. Moreover, this schema extends the teleological perspective on the development of the capacities to the possessors of the capacities: The development of the capacity is a development also of the subject insofar as it has that capacity. Compare again DA II.5: Aristotle there talked about three different kinds of knower (epistêmôn) according to the level of fulfilment of his capacity to know. Θ.6 appears to adopt a similar perspective on the subject of the capacity in a way that facilitates the analogy with the matter-substance case: just as the activity of seeing, say, is the fulfilment of the animal qua capable of seeing, so the substance is the fulfilment of the matter qua capable of being this substance.

DA II.5 gives us one further way of assimilating the two kinds of case. Aristotle spoke there of a human being as a knower in capacity in virtue of being the ‘genus and the matter’ (417a27). If we allow ourselves to talk in this way of a man qua human being as being the matter for the man who has learnt, and the learned man as fulfilling the capacity which this matter has in virtue of its nature, a man being essentially rational and such as to learn, then we seem within striking distance of a notion of how a substance might fulfil the potential of matter to be such a substance. The matter has a capacity to be whatever we take the substance to be, just as a human being as such has a capacity to be a knower. Certainly, this thought is not contained in the analogy in Θ.6, but DA II.5 gives us a way of seeing how the analogy could be developed in this direction; helpfully so in my view since DA II.5 shows how also the kinetic cases may be understood as a thing’s fulfilling what it already was in virtue of some capacity, a capacity which at some level may be derived from its matter. This seems a good vantage point from which to approach the substance-matter case.

Θ.6 has expanded our notion of energeia from the kinetic cases to the case of substances. It has done so by highlighting the similarity between the way in which a change fulfils a prior state of capacity and the way in which a perfected substance fulfils the capacity of the matter. What the analogy illustrates then is an overarching notion of energeia as fulfilment. Our look at the DA has been instrumental in bringing out this point because it helped us understand how the activities featured in the kinetic cases are to be conceived as fulfilments of capacities in a way that might also carry over to the substance-matter relationship.

Looking back on the earlier parts of Metaph. this alignment of energeia with entelekheia should not surprise us. In Metaph. Δ.7 Aristotle listed the different ways we talk about being, drawing the same distinction as in Θ.6 with the same examples, but using entelekheia for the activity side of the relationship.18 Fulfilment was the term contrasted with dunamis when Aristotle at beginning of Θ.1 said that we were to distinguish concerning capacity and fulfilment before he then rephrased the distinction in terms of capacity and activity.19 In Θ.4 he drew the connection between energeia and entelekheia in etymological terms: ‘the term “activity” (energeia), which is composed in relation to fulfilment (entelekheia), and deriving most of all from changes is applied to other cases. For it seems that activity most of all is change.’ The same thought seems to be developed in Θ.8, where Aristotle says that ‘the work (to ergon) is an end, and the activity (energeia) is the work,20 which is also why the name “activity” is said according to the work and points towards (sunteinei pros) the fulfilment.’ The full thought here seems to be that since works are amongst ends,21 and the activity is the work, the activity too is an end. This explains not just why energeia derives its name from ergon, but also the way in which energeia involves the thought of a fulfilment (1050a22–24). There is good evidence, then, that Aristotle takes the notion of fulfilment as implied in that of an energeia. Moreover, since he thinks that the ergon in a change is the most obvious case of a capacity’s being fulfilled he also thinks that the kinetic case can be used to illuminate more general cases of fulfilments of capacities, even where these do not specifically involve something’s being changed.

Now the argument of Θ.6 was meant to communicate a broader notion of activity applying both to changes and substances, such that we in turn could elucidate the notion of capacity involved in the substance case by reference to this broader notion. This capacity Aristotle ascribed to matter. The next step he pursues in Θ.7, therefore, is to consider how matter is to be understood as being substance in capacity. It is worth underlining how he approaches this question, namely in terms of when we say that some matter is in capacity F. One might think that this is a significantly different question from asking what it is for some matter to be in capacity F.22 However, if the argument so far has been correct the notion of energeia in terms of which the capacity of matter is now to be understood is that of fulfilment. We might say therefore that the notion of being in capacity will be a developmental notion: what it is to be in capacity F is to be at some point in the development towards being fully F. So insofar as it is clear what it is to be in F in fulfilment, we may appropriately ask at what point something is close enough to being F in fulfilment to count as being in capacity F. Here the answers turn out to be different for different kinds of thing: in the case of living beings we say that that the matter, say, the seed, is only potentially a human, once it has the ability under its own steam to become a human being, if nothing interferes, whereas in the case of artefacts we say that the matter is a house, say, in capacity, if there is nothing in it that prevents its being turned into a house. The different answers clearly reflect the way we see living beings, in capacity or in activity, as having the principle of change within themselves (the seed does not yet have this), while artefacts have the principle of change outside of them, and therefore need to be understood as having in capacity or in activity the ability to be changed by a craftsman from without.23

In both cases Aristotle adopts a diachronic perspective according to which the matter is seen as being in capacity before it is turned into a certain substance. The diachronic perspective is a particularly vivid one since we see the various levels of matter’s development rolled out before us in stages, as if in a movie. However, there is no need to think that what it is about matter that qualifies it as a substance in capacity is tied to this temporal process. Indeed, we might understand the temporal process as dependent on a non-temporal order: this is the way developing into a human plays out over time because these are the stages of manifesting a capacity that are closer and closer to being a human in fulfilment. However this may be, it is clear that the diachronic perspective is not Aristotle’s only take on matter in Θ.7. For he also offers a view on matter as substance in capacity which applies to the matter that already is part of a certain substance, the ‘concurrent’ matter. So he talks of the relationship that obtains between a box and the wood it is made of. One response to this kind of example is to see in extension of the diachronic model. So Michael Frede argued that what justifies saying that the matter of the box is the box in potentiality is the fact that it could be turned into, not this box, but another such box. On this account, being in capacity a box relies on the potentiality to become a box. However, there is a difficulty with this suggestion. As scholars have noted,24 there is a range of cases where the matter does not retain its capacity to be turned into another substance of the sort it is part of. So the matter of an animal cannot be turned into another such animal. This would require decomposition of the body to point where it would no longer be the matter of an animal. Nor can the ingredient of a cake be taken out of the cake to make another, or generally mixtures in which the ingredients by being mixed have lost those properties that made them suitable for entering the mixture in the first place. While the point could then apply to certain cases, like the box, it does not generalize.

Another suggestion made by Stephen Makin is that the concurrent matter qualifies as the substance in capacity insofar as it composes the substance. However, here the worry is the opposite one, that this answer will not generalise to the diachronic cases: the ingredients which went into the cake will have changed so much that we cannot say they compose the finished substance. One might reply that there are clearly some properties of the concurrent matter which are retained from before; however, it is not clear that these are the properties that constitute either the matter’s ability to be turned into this substance, nor the concurrent matter’s capacity to be part of this substance. So, for example, what makes the jelly suitable matter for a trifle seems not to be attributes gelatine leaves and water had before they were mixed. So we still have not found, it seems, a general basis for saying that the matter is the substance in capacity which applies both to the matter before and after the creation of the substance.

Let’s look a little more closely at Aristotle’s discussion of the wooden box. The box is made of wood, but we do not say that it is wood, but rather that it is wooden. Or to generalise we refer to the matter of completed compound substances as ‘that-en’ (ekeininon) rather than ‘that thing’ (tode). Now first, this gives us a way of distinguishing between the wood that is in capacity a box, but is not yet the matter of a completed box, and the wood that is in capacity a box, but is the matter of an actual box. The applicability of the adjectival form, wooden, golden, etc. rather than the substantival form, wood, gold, to the compound offers us as a way of distinguishing whether the matter is in capacity F in virtue of being part of the something actually F or as being in capacity F but not yet F.

Second, the reason why this verbal criterion works is that it reflects an ontological difference between the matter before and after it becomes part of the box. Before the wood becomes that of an actual box, the wood still exists in actuality as wood but only in capacity as a box. That is why it is right to use the substantival form ‘wood’ of it: it exists as a subject of predicates in its own right. However, when the wood becomes part of an actual box it is now part of another substance, the box. Moreover, as matter, it is not part of the box as what determines the box as such: that would be the shape and form of the box. The adjectival, rather than the substantival, expression, is therefore appropriate: it indicates that the matter does not exist in its own right as a subject of predicates but is said in relation to another thing, its form, which makes it the substance it is. So it is the box, the substance, that is wooden rather than the wood that is box-en or boxy.25 The adjectival form indicates the dependency of matter on something else which plays the role of substance.

Aristotle points out that this characterisation of matter as dependent on something else for being what it is assimilates ‘matter’ to ‘affections’ (pathê): ‘it is only right that “that-en” (ekeininon) is said both in accordance with the matter and the affections: for both are indeterminate’ (1049a36–b1). Like the affections matter is said in relation to a substance because it is only determined as such and such by being related to a certain substance. An affection such as ‘healthy’ only means something specific when attached to a certain kind of thing, a healthy drink differs from a healthy walk, for example. Similarly, the matter of something is indeterminate until determined as the matter of a certain substance, a determination for which the form is responsible.26

This way of thinking of matter as indeterminate in relation to a certain substance is of course compatible with thinking of it also as having certain specific properties that make it determinable by the substance. It is exactly the properties of wood as wood that make it suitable for being shaped in the manner of a box. This wood could also be turned into a chair or a cupboard, so in this way it is indeterminate in relation to what will make it into, specifically, a box. However, even in cases where the matter is only suitable for one outcome, we may insist that it as matter is indeterminate. It may be, for example, that asphalt is only useful for one thing, surfacing roads, but in terms of its material properties (weight, adhesiveness, colour, etc.) this is still indeterminate in relation to this specific substance. The key point seems to be that the matter should, in the context of viewing it as being in capacity, be viewed as indeterminate in the manner of a determinable, where being a determinable involves having certain positive attributes, which do not as such select for a certain form.

There is an obvious parallel between this view of matter as a determinable and the genus as a determinable by a specific difference. Aristotle assimilates the genus to matter and the species to form on the basis of the way the genus is differentiated by the species.27 In his account of change,28 Aristotle requires that the patient of a change should already prior to the change belong to the same genus as the agent, since only then can the latter make the patient specifically like itself. The parallels underscore the point that matter to be determinable by form already has to bear a certain basic similarity to the form.29

Now, returning to Θ.7, Aristotle imagines that there is a series of terms, such as earth, bronze, statue, in which earth stands to bronze as the matter to bronze, and bronze as the matter of statue. What underlines the ordering of the terms of the series is the former being determined in the manner of a substance by the latter, so the bronze counts as matter for the statue and so is a statue in capacity, if it is determined by statue as the substance it is, with the linguistic marker that the term for the matter occurs in the adjectival form ‘brazen-en’ qualifying the term for the substance. Given this ordering we say, then, that bronze is a statue in capacity, but earth is not, because bronze is determined by statue as the substance it is, while earth is not.

Now this distinction between what counts as matter synchronically clearly matches the earlier discussion of what counts as matter, and so being in capacity, diachronically. Just as we would say that the earth is not in capacity a statue—it is too far removed—but were happy to say that the bronze is potentially a statue, so we do not now want to say that the statue is earthen, but rather that it is brazen. The serial relationship recasts, then, our insights about when to talk of matter as being potentially X, in a way that applies both the diachronic case and the synchronic case.30

A further point which the series seems designed to capture is the teleological relationship between matter and substance: what is later in the series fulfils the capacity of the earlier. In the diachronic cases, it was clear that what was said to be in capacity a human being or a statue was said so because it was capable at a later time of being such in activity. When Aristotle talks of the box being later than the wood this seems similarly to capture the way the box fulfils the potential of the wood to be a box, but without this diachronic aspect.31 In this way, the earlier-later relationship in the series is a teleological relationship, which may or may also be a diachronic relationship. In the next chapter, Θ.8, Aristotle is explicit that the relationship between matter and substance is both definitional and teleological. The teleological relationship may also be a temporal one of coming into being for the sake of end, and in this case what is later in the process of becoming is prior in being and account as the end of the process. Similarly, in the case of the series it seems that we can say that what is prior in the series is for the sake of what is later: the wood understood as a capacity to be a box is for the sake of the box. The box is then prior to the wood as the end of the wood, and this priority relationship also obtains when we consider the wood as the concurrent matter of the box. The substance, then, specifically the substance as form, determines what the matter is as the end which fulfils what the matter is in capacity. We may add now to the earlier answer that that matter is in capacity substance in the sense that it is indeterminate but determinable by substantial form as an end.32

Does this understanding of matter demarcate those cases where we want to say that the matter is the substance in capacity from those where we do not? In the diachronic cases, it may at first seem too inclusive: would we not say after all that a seed also prior to conception is determined by the human form? It is after all uniquely a human seed. Aristotle acknowledges in DA II.1 that one might say that the human seed is a human body in capacity, but this is not the same as being a human being in capacity. The seed needs to be further changed before it is a human being in capacity. Or as one might say, a seed is potentially a potential human being by being a potential human body. We would not say that it is yet a human being in capacity since it does not yet have an inner principle of change, and is therefore not yet such that it can come to be a human being. Similarly, in the case of a house, one might say that the mud before it is baked into bricks are potentially a potential house, and only when it has been made into actual bricks a house in capacity. In these cases, the matter is too indeterminate to be determinable by the form in question: rather it needs to be more fully determined by another form (brick, embryo) before it is determinable by this form (house, human). What we need to be clear about then is that the matter qualifies as being the substance in capacity insofar as it is directly determinable by the form of this substance, say, man or house, rather than indirectly through being determinable by some other form, determination by which will in turn make it determinable by this form. ‘Being in capacity’ is not a transitive relationship. When we say that the human seed is uniquely human what this means is not that it is already in capacity a human being but that it has a capacity to be something which can become a human being, and that this, not the capacity to be a human being, is the capacity which determines it. This is true whether or not a human seed is uniquely human in the sense of being suited only to becoming a human being.

This worry was about whether the criterion let in too many potential beings. Conversely, however, one might worry whether the criterion allows for the concurrent matter to be merely in capacity a human being. The body of an adult human being is fully determined by the human form, so should we not say that the concurrent matter is actually a human being and not just potentially one? The problem is a general one that interpreters have long been aware of, and it is worth looking at how the interpretation I have developed might deal with it. We need to turn to the DA for explicit discussion of the form-matter relationship in living beings. The subject requires much fuller discussion than I can give it here.33 All I want to do here is to sketch, rather dogmatically, how the DA may be read as clarifying the implications of Θ.7.

In DA II.1 (412a3–b6) Aristotle accounts for the soul in outline. In quick succession, he presents three closely related accounts:
  1. 1.

    The soul is the form of a natural body potentially having life.

  2. 2.

    The soul is the first fulfilment of a natural body potentially having life.

  3. 3.

    The soul is the first fulfilment of a natural instrumental body.


Of these three (3) is presented as the concluding account, and we can see (1) and (2) as steps towards this formulation. One striking feature of Aristotle’s approach is that he seeks to identify the soul in relation to a certain kind of body. He takes substances first of all to be bodies, then, natural bodies, and amongst these living bodies. The fact that these are natural shows that they are compounds of form and matter, and the fact that these bodies have life suggests that the soul likewise is said of the body (rather than the other way around). But if soul is said of body, then it must be form rather than matter (since matter is body).

But why is the body in the definition only said to have life potentially (dunamei)? The claim may seem to follow immediately from Aristotle’s earlier assumption that ‘matter is potentiality (or ‘capacity’: dunamis) and form fulfilment’. And true enough, in the next sentence Aristotle says that substance is fulfilment and so that the soul is fulfilment of the body (412a21–22), that is, (2) above. So clearly Aristotle is thinking of this kind of body as being in capacity because he thinks that body is aligned with capacity and the soul, as form, with fulfilment. Yet a worry remains with this alignment. How can it be true to say that the body potentially has life? For surely the body of which the soul is the fulfilment has life not just potentially, but actually. If it didn’t have life actually it wouldn’t be a living body, but if it wasn’t a living body, then it would only be a body homonymously, in the way a drawing of an eye is an eye only homonymously (412b20–22). However, Aristotle underlines at 412b25–26, ‘it is not what has cast off the soul which is potentially such as to live, but what has [the soul].’34

Given that the soul is present as its fulfilment and this soul is predicated of the body, why do we say that such a body has life potentially, and no more? I think there are two kinds of answer to this question suggested in II.1, answers which ultimately come together in one. The first kind of answer starts from thinking about potentiality in relation to matter. Already at 412a7–9 Aristotle says of matter that it is ‘what is not in itself (kath’ hauto) something determinate (tode ti)’; rather it is in relation to form that something is said to be something determinate.35 As in Metaph. Θ.7, on my reading, we may think of the matter, then, as what is indeterminate but determinable by form. This would translate into thinking of the matter of a human being as what is in capacity a human being insofar as it is determinable by the form of human being. Clearly other kinds of matter, straw and cloth, say, are not such as to be determinable by the human form. The strategy of DA II.1 is to show how the soul as form determines a certain kind of body, a natural body that is itself such that it can be determined by soul. The description of the body as potentially alive points us then towards thinking of the body as the kind of thing that is apt for being determined by the soul.

This take on the body as potentiality goes particularly well with a passage at the end DA II.2 where Aristotle recapitulates the common account of the soul:

‘For “substance” is said in three ways, just as we said, of which one is form, the other matter, the third what is made out of both, and of these matter is potentiality, form fulfilment, since what is made out of both is ensouled, the body is not the fulfilment of the soul, but it is the fulfilment of a certain kind of body. And for this reason those suppose correctly who think that the soul neither is without body nor is some body. For it is not body but something of body, and for this reason it exists in a body, and in a body of a certain sort, and not in the way our predecessors fitted the soul into a body without specifying in which body and in what sort of body, even though it is clear that not any old thing will receive any other thing. But it happens also in this way according to reason: for the fulfilment of each thing comes by nature to be in what exists in potentiality and in the appropriate matter. It is clear from these considerations that there is some fulfilment and account of something that has the capacity to be such a thing.’ (414a14–28)

Aristotle here emphasises the way in which the body has to be of a certain kind for the soul to be present in it. The soul is the fulfilment of a body with a specific capacity. The matter has to be ‘appropriate’ (oikeia), a term which suggests a certain level of specificity, and contrasts with the lack of specification offered by the predecessors’ description of the body.36 It is attractive, therefore, to think of the potentiality of the body as being that of matter which is specifically geared to receiving a particular kind of form. The soul fulfils the body’s potential to be a certain kind of living being in the sense that it makes the body a fully determinate and specific living being, it makes it a tode ti, as the opening of DA II.1 had it. The body becomes a fully determinate thing, then, by being ensouled. In virtue of ensouled it has actual life, but in virtue simply of being matter it is not a determinate living thing and so only has potential for life. It is not in its resources as body, in other words, to have actual life, and for that reason the common account of the soul describes the body has having potential life.

However, alongside this aspect of Aristotle’s thinking about how the body potentially has life, there is another, which reflects more precisely the idea that the soul is the fulfilment (entelekheia) of the body’s potentiality. When Aristotle describes the soul as the fulfilment of the body’s potential he is therefore thinking of the relationship between soul and body in teleological terms: in having a soul, the body realises its potential to be a certain kind of living being. The distinction between first and second fulfilment is correspondingly to be read in terms of the degrees with which the soul realises the body’s potential: in the activity of contemplating, perceiving, taking nourishment, the body’s potential is more fully realised than in merely having the capacity to do these things, though in having the capacity the body’s potential is sufficiently realised for us to say that it has soul and that a living being of a certain kind exists.

This teleological relationship between body and soul may be understood temporally: as the embryo develops its capacity to be a human being it comes closer to the actuality which defines it. But it may also be understood synchronically: the body of the fully formed human is for the sake of the activities which define it as human. It is this sort of relationship which Aristotle seems to have in mind when he goes on to say in (3) that the body is instrumental.37 Instruments are made so as to be able to perform certain functions, so if we say that the body is an instrument and that the soul is the fulfilment of that instrument, it follows that the body is for the sake of the soul, that is, that the soul is the final cause of the body. The teleological conception of the body-soul relationship goes well with the thought that the soul determines the body as a certain kind of thing: for what makes instruments what they are is the function they are designed to serve. So we can say that the bodies of living being are determined by their ends.

However, why does Aristotle think that he can substitute the phrase ‘potentially having life’ in (2) with ‘instrumental’ in (3)?38 Perhaps the example of the plants gives us guidance. What the example brings out is that the parts of plants are instruments insofar as they serve a function: the leaf provides protection (skepasma) for the pericarp, the pericarp for the fruit, while the roots serve to ingest nutriment (412b1–3). So we may think that what triggers Aristotle’s move from ‘a body potentially having life’ to ‘an instrumental body’ is the thought that an instrument provides the potentiality for the exercise of a certain function. So if life is understood minimally, as at 412a14, in terms of being able to take nourishment and grow and decline, we may think that if plants have parts that serve as instruments in performing these functions, then it follows that the body in this and similar cases provides a potentiality for the life functions which the soul fulfils. In other words, Aristotle thinks that instruments are in potentially the functions they can be used to perform, so if the parts of the body are instruments of life functions, it follows that they also have the potentiality to participate in these functions.

We might think that our old problem now rears its head again: instruments convey more than a mere potentiality for a capacity, they provide the capacity itself. For what else is there to having the capacity to chop in the manner of an axe than just being composed of certain matter in this way? However, it is clearly possible to describe an axe in a number of ways that are irrelevant to its ability to chop wood. So I might say that it is coloured, weighs so and so much, smells of something, or makes a dull sound when dropped. These are accidental attributes of any axe from the point of view of its function as an axe. The point is that it is only by specifying its function that one gets a fix on which of its various material attributes are relevant to its capacity to be used in chopping. We may therefore say that while its various features give the axe the potential to be an axe, to be something that can be employed in chopping wood and such, it is only by specifying the function it serves, its final cause, that one can determine which of these features are relevant. Again, it seems proper therefore to think of the matter as determinable by the function, rather than itself determining the function. So it seems appropriate to say the matter as such provides the potentiality for the capacity that defines the soul rather than the capacity itself.

Consider the same point from the perspective of knowing what tool something is. TV programs (such as The Antiques Roadshow) will sometimes present odd instruments whose function we are invited to guess, before an expert tells us what they really are. A layman is clearly in a position to offer an extensive material description of the instrument before him, if we think in terms of the object’s weight, shape, size and so on. But none of these characteristics may reveal the function of the instrument. However, once we know the function we can see which characteristics are relevant and why and which are not. In Aristotelian terms it therefore seems appropriate to say that the material characteristics of the object do not themselves as such determine the function, rather they present a potentiality, while the function makes that potentiality determinate. One might say that the epistemic indeterminacy of the object from the point of view of its material attributes alone mirrors the ontological indeterminacy of its matter taken in separation from its form.

The final version of the common account (3) indicates that the relationship between the body and the soul is that of an instrument and its function. Now in the rest of DA II.1 (412b10–413a10) Aristotle tells us more about this relationship. He does so by developing an analogy between the body and tools such as axes:

As then cutting and seeing are a fulfilment so also is being awake, and as the ability to see and the capacity of the tool, so is the soul [a fulfilment]: and the body is what is in potentiality. But just as the eye is eye-jelly and the ability to see, so also in the other case are the soul and the body [together] the animal. (412b27–413a3)

The analogy spelt out reaffirms the teleological relationship: the soul defines the body—is the essence and logos of the body—in the manner of the proper function of a tool with the activity as the highest fulfilment. The implication then is that the definition of the soul is a teleological one: it presents the soul as both the formal and final cause of the body. And, as we saw, it is appropriate in this context to understand the body as a potentiality for the soul, in that it is only because of the soul that it becomes and is a determinate thing, the body of an animal, or a plant, or a human being.

The notion of the body’s being a tool is particularly suited to bringing out the teleological relationship between matter and substance. However, even without this development of the account of the soul, Aristotle’s account of the soul as the fulfilment of the body having life potentially seems a perspicacious illustration of the way in which we can think of concurrent matter as being the substance in capacity, that of being determinable by the substance’s form as an end. If my argument in this paper has been correct, it is this teleological conception of matter which we are meant to grasp in Θ.7, and which forms the natural complement to the teleological conception of activity as fulfilment that Aristotle adverted to in Θ.6. In Θ.8 he says that activity is prior in account to potentiality. By his own standards, then, he has proceeded correctly in articulating being in activity in Θ.6 before giving the matching teleological story about potentiality in Θ.7.


  1. 1.

    Since we have treated of the kind of capacity which is related to change, let us discuss activity -what, and what kind of thing, activity is. For in the course of our analysis it will also become clear, with regard to the capable, that we not only ascribe capacity to that whose nature it is to change something else, or to be changed by something else, either without qualification or in some particular way, but also use the word in another sense, which is the reason of the inquiry in the course of which we have discussed these previous senses also. Activity, then, is the existence of a thing not in the way which we express by 'in capacity'; we say that in capacity, for instance, a statue of Hermes is in the block of wood and the half-line is in the whole, because it might be separated out, and we call even the man who is not contemplating a man of science, if he is capable of contemplating; the thing that stands in contrast to each of these exists in activity. Our meaning can be seen in the particular cases by induction, and we must not seek a definition of everything but be content to grasp the analogy, that it is as that which is building is to that which is capable of building, and the waking to the sleeping, and that which is seeing to that which has its eyes shut but has sight, and that which has been shaped out of the matter to the matter, and that which has been wrought up to the unwrought. Let activity be defined by one member of this antithesis, and the capable by the other. But all things are not said in the same sense to exist actually, but only by analogy—as A is in B or to B, C is in D or to D; for some are as change to capacity, and the others as substance to some sort of matter (1048a25-b9 transl. after Ross).

  2. 2.

    And since ‘being’ is in one way divided into ‘what’, quality, and quantity, and is in another way distinguished in respect of potentiality and fulfillment, and of function, let us discuss potentiality and fulfillment. First let us explain potentiality in the strictest sense, which is, however, not the most useful for our present purpose. For potentiality and actuality extend further than the mere sphere of motion. But when we have spoken of this first kind, we shall in our discussions of actuality explain the other kinds of potentiality (1045b33–1046a4, transl. by Ross).

  3. 3.

    Cf. Metaph. Δ.6 1016b31–1017a2.

  4. 4.

    Cf. Metaph.Λ.4.

  5. 5.

    The publications I have relied on most in writing this paper are Frede (1994), Makin (2006), Beere (2009), Charles (2010). With at least two considerable exceptions, noted below, my reading is particularly close to that of Charles, from whose paper I have drawn much inspiration.

  6. 6.

    Cf. also DA III.10.

  7. 7.

    Cf. also Generation of Animals I.19 726b18–20 where it is indicated that semen’s being in potentiality (dunamei) a living being may be explained in terms of its having a dunamis, specifically that of the soul (b23).

  8. 8.

    See Beere (2009, 155–167) for an illuminating discussion of the problems of translating ‘energeia’.

  9. 9.

    The translation of the adverbial energeiai or kata energeian as actually or according to actuality is the correlative of the translation of dunamei as ‘potentially’. So if we choose to advert to capacity in our translation of dunamei we may wish to revise our translation of energeiai, correspondingly. In that case, it is natural to opt for the translation ‘in activity’. For the activity seems to manifest the capacity in the way Aristotle thinks a energeia manifests the dunamis. If we ask what a capacity is for it is natural to say that it is a capacity for a certain sort of activity. So sight is the capacity for the activity of seeing, the art of strategy the capacity for engaging the activity of warfare, and so on. However, as Beere (2009, p. 157) points out there are cases such the claim that the infinite is not in energeia where ‘activity’ is less apt.

  10. 10.

    ‘Capably’ tends to apply to actions and imply ‘skilfully’.

  11. 11.

    So I agree with Makin (2006, p. 132) when he says that ‘The important point is that Θ.6 is not a “horizontal” move, from a discussion of one relation (change-capacity) “sideways” to discussion of another (substance-matter). It is rather a “vertical” move, from discussion of the change-capacity relation “upwards” to a consideration of the more general schema: actual-potential being.’ This insight is due to Frede (1994, p. 184).

  12. 12.

    As Beere (2009, pp. 191–195) argues, it is the first case, which forms the basis of the analogy, but this stills allows us to see roughly two kinds of case involved (1)–(3) and (4)–(5).

  13. 13.

    Contrast Frede (1994, p. 185), who denies that seeing is a change or a mode of change. While there is a point, as I go on the argue, to (1)–(3) not being ordinary changes, denying that they are changes in any sense disconnects the analogy from the idea that we are supposed to get from the core notion of change as activity to the substance cases. Admittedly, is not clear how being awake as such might count as a change, though Aristotle may take it to imply that certain changes happen to the waking animal, such as perceiving or moving.

  14. 14.

    See Burnyeat (2002, pp. 61–67); Bowin (2011, pp. 147–148). For an alternative view, see Lorenz (2007, p. 183).

  15. 15.

    Cf. in particular 417b5–16. See Heinaman (2007), for a strong view of the importance of the distinction in this chapter.

  16. 16.

    See the helpful comments in Makin (2006, pp. 172–173).

  17. 17.

    Notwithstanding Aristotle’s preference for the latter expression at DA 408b13–15.

  18. 18.

    Metaph. 1017a35–b8: Again, ‘being’ and ‘that which is’, in these cases we have mentioned, sometimes mean being potentially, and sometimes being in fulfilment. For we say both of that which sees potentially and of that which sees in fulfilment, that it is seeing, and both of that which can use knowledge and of that which is using it, that it knows, and both of that to which rest is already present and of that which can rest, that it rests. And similarly in the case of substances we say the Hermes is in the stone, and the half of the line is in the line, and we say of that which is not yet ripe that it is corn. When a thing is potential and when it is not yet potential must be explained elsewhere’ (transl. after Ross).

  19. 19.

    Metaph. 1045b32–1046a2: And since ‘being’ is in one way divided into ‘what’, quality, and quantity, and is in another way distinguished in respect of potentiality and fulfillment, and of function, let us discuss potentiality and fulfillment. First let us explain potentiality in the strictest sense, which is, however, not the most useful for our present purpose. For potentiality and actuality extend further than the mere sphere of motion’. (transl. by Ross).

  20. 20.

    ‘Work’ is an appropriate translation of the Greek ergon also because it is ambiguous between the activity of working and its result.

  21. 21.

    One might in principle take to gar ergon telos to mean the activity is the work, and so as an identity claim, but Aristotle’s careful use of the article with the subject complement to make such a claim in the following proposition, hê de energeia to ergon, suggests that its omission here is deliberate and significant.

  22. 22.

    For a helpful account of the distinction, see Charles (2010, pp. 171–172). The answer I develop involves taking the temporal question as a way of posing the question about minimal conditions since the case of becoming is, for Aristotle, the most perspicacious way of showing that way in which being in capacity is teleological notion.

  23. 23.

    See Frede (1994, pp. 188–190).

  24. 24.

    Charles (2010, p. 172) for one.

  25. 25.

    See Beere (2009, chap. 11) for an illuminating account.

  26. 26.

    Cf. Metaph. Ζ.17 1041b6–8: ‘Why is this individual thing, or this body in this state, a man? Therefore what we seek is the cause, i.e. the form, by reason of which the matter is some definite thing; and this is the substance of the thing.’

  27. 27.

    Cf. Metaph. Η.6.

  28. 28.

    Cf. On Generation and Corruption I.7.

  29. 29.

    Putting aside outliers in the tradition of Plato’s receptacle, such as prime matter and passive nous.

  30. 30.

    This is one of the points on which my interpretation differs from that of Charles (2010, pp. 192–193), who explains the potentiality of synchronic matter primarily in terms of its retaining properties that made it suitable for becoming the substance.

  31. 31.

    1049a21–23: ‘something is always potentially (in the full sense of that word) the thing which comes after it in this series. E.g. a casket is not earthen nor earth, but wooden; for wood is potentially a casket and is the matter of a casket, …’ (transl. by Ross).

  32. 32.

    While my interpretation shares with that of Charles (2010) the emphasis on the teleological conception of matter, it differs in relating this to the indeterminacy of matter, of whose relevance Charles (2010, p. 183) is critical.

  33. 33.

    For a fuller account, I refer the reader to Chap. 1 of my book The Powers of Aristotle’s Soul (Oxford 2012).

  34. 34.

    Aquinas in his commentary on the De Anima (Foster and Humphries 1951, §222) suggests that if Aristotle had said that the body had actual life, then he would have implied that the body itself was a form-matter compound. However, Aristotle’s claim is put in terms of the body’s having life, not being life, and there seems to be no greater threat to the status of the body as matter by saying that the body has actual life than by saying that it has the form actually.

  35. 35.

    DA II.1 412a6–10: We say that substance is one the things that are, and we speak of one kind of substance as matter, which is not in itself (kath’ hauto) something determinate (tode ti), and another as shape and form, according to which it is said to be something determinate, and a third is what is composed out of these. For the matter is capacity, and the form fulfilment...

  36. 36.

    Cf. oikeios at 414b27.

  37. 37.

    Cf. GA II.6 742a27–33: ‘So we have three things: (1) the end, which we describe as being that for the sake of which; 2) the things which are for the sake of the end, namely, the activating and generative, qua such, is relative to what it produces and generates; (3) the things which are serviceable, which can be and are employed by the end’.

  38. 38.

    It is possible that (2) and (3) are meant to be no more than co-extensive and that ‘instrumental’ is not supposed to imply ‘potentially having life’ but simply offer an alternative, independent specification of the body which serves the job of specifying what kind of the thing ‘soul’ is. But if so, it is odd that Aristotle after stating (2) immediately adds the notion of instrumentality by saying ‘but such a body would be instrumental’, as if the notion of the body’s instrumentality somehow linked up with the notion of its having potential life.


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© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.Faculty of Philosophy, Brasenose CollegeUniversity of OxfordOxfordUK

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