4.1 What Is Achieved in Perceiving

If it is correct that Aristotle’s first general account in An. 2.5 lays out the programme of his inquiry into perception and its first principles, as I have argued thus far, then this has two implications. By capturing, on the most general level, what kind of phenomenon perception is, the chapter effectively circumscribes what a successful account of its first principles would have to provide. But while offering an indispensable orientation about the goal of the inquiry, it falls short of reaching that goal in several respects (underlined in Sections 1.1 and 3.7). In An. 2.5, Aristotle tells us, in the most general terms, what perception is, but without saying anything specifically about the involvement of the perceptive body, or about the way in which the perceptive soul should be understood to account for the phenomenon of perception. Indeed, An. 2.5 on its own may easily give rise to doubt about whether perception, as it has been characterized here, is possible at all; and many of Aristotle’s predecessors and contemporaries would surely have been sceptical.Footnote ¹ The aim of the remaining four chapters is to address these looming questions by exploring how the programme laid out in An. 2.5 is carried out in An. 2.6–3.2.

Before introducing the wider context of Aristotle’s inquiry into perception in An. 2.7–12 and the key factors that are supposed to make perception, as understood by Aristotle, possible (in Sections 4.4 and 4.5), and before raising the questions concerning the respective roles played in perception by the perceptive organs and the perceptive soul (in Sections 4.6 and 4.7), it will be worth pausing to reflect on how much exactly Aristotle thinks is achieved in perception. I have argued that his first general account of perception in An. 2.5 as a complete passive activity is already aimed at contrasting continued perceiving from having a mere after-image (or acquiring a blind spot), and at capturing, on the most general level, the specific object-directedness characteristic of perception. It is essential for the activity of perceiving X that the perceiver (already) has a likeness of X in herself, while (still) being affected by X; and this is possible only because the likeness of X in the perceiver does not become a quality of the perceiver herself – rather, it seems to be present in her exactly as a quality possessed by X that is an object in the external world. This account, as we shall presently see in more detail, encapsulates a specific kind of direct realism according to which perceivers have an unmediated access to external objects whose qualities they receive and which they cognize, in principle, as they truly are on their own.

This characterization contains two main points that call for explication and defence. (1) I maintain that Aristotle’s account of perception as a complete passive activity aims at capturing the way in which perceivers access the external bearers of modal-specific qualities – without presupposing anything like an additional synthetic act and/or assuming that the bearers are perceived only coincidentally.Footnote ² (2) I maintain that perceivers have, in principle, access to the very qualities that the outside objects bear independently of whether they are being perceived or not.Footnote ³ This contrasts with the view that, according to Aristotle, outside objects possess, on their own, the modal-specific qualities (like colours) merely on the level of a first fulfilment – that is, they only possess powers for producing these qualities upon encountering a perceiver. In addition to these two points, I shall seek to show later (in Section 4.6) that (3) the directness of Aristotle’s realism cannot be accounted for in terms of any static representation.

The first two points (developed in Sections 4.2 and 4.3, respectively) raise questions that are beyond the scope of the present inquiry. I limit myself to what is crucial for the subsequent discussion, while remaining as non-committal as possible on what is not.

4.2 Perceiving the Bearers of Perceptual Qualities

In An. 2.5, Aristotle characterizes perceptual objects as ‘particulars’ existing out in the external world: ‘the agents [of perceiving] are external, I mean the visible and the audible’ (417b20–1); ‘the perceptual objects are among particulars and external things’ (417b27–8).Footnote ⁴ It is natural to take Aristotle here to be identifying perceptual objects with the bearers of perceptually relevant qualities, as he clearly does in his final summary (in An. 3.8) of the work he has accomplished in An. 2.5–3.7, where his example of an αἰσθητόν whose form is received in perception is ‘a stone’ (431b29–432a1).Footnote ⁵ However, perhaps the expressions in An. 2.5 can also be read as referring to the qualities themselves.Footnote ⁶

That may be suggested by Aristotle’s claim in An. 2.6 that only ‘the exclusive objects (τὰ ἴδια) are perceptible in the primary sense (κυρίως)’ (418a24–5). These were distinguished from the ‘common’ and the ‘coincidental’ objects and described as nothing other than the qualities defining each sense modality: ‘I call exclusive (ἴδιον) [to each sense] that which cannot be perceived by any other sense and which does not allow for deception, as, for instance, sight is of colours, hearing of sounds, and taste of flavours’ (418a11–13).Footnote ⁷ Interpreters often infer from here that, according to An. 2.6, the bearers of perceptual qualities are not only not perceptible ‘in the primary sense’ but are not even perceptible ‘in their own right’ (καθ’ αὑτό); they can at most be perceived ‘coincidentally’.Footnote ⁸ However, there are good reasons to think that this cannot be Aristotle’s view.Footnote ⁹ Indeed, closer attention reveals that not even An. 2.6 excludes the bearers of perceptual qualities from being perceptible in their own right.

When spelling out the above-quoted claim that the exclusive objects do not allow for error, Aristotle says the following about the individual senses:

It is admittedly not entirely clear how the expression ‘about colour’ (ὅτι χρῶμα) should be construed.Footnote ¹¹ Still, the way in which Aristotle continues suggests that more than perceiving the qualities themselves is involved here. In order to commit perceptual error concerning where a coloured thing is located or what kind of thing it is, the perceiver already needs, arguably, to have perceptual access not just to the colour in question, but also to its bearer; otherwise, it is unclear how she could – more or less correctly – perceive its identity or its position, rather than merely the identity or position of the colour.

The quoted passage is admittedly non-conclusive. However, the assumption that we perceive the bearers in their own right comes out more clearly in Aristotle’s characterization of coincidental objects, such as the son of Diares, a few lines later:

‘The white’ (τὸ λευκόν) here is unlikely to mean the white colour. It is something of which ‘the son of Diares’ can be predicated, and a colour is hardly a viable candidate for such predication. ‘The white’ seems rather to refer to the white thing out there in the world, of which I can meaningfully ask, ‘Oh, isn’t that the son of Diares?’Footnote ¹² And that white thing is said to be perceived without qualification – that is, apparently, in its own right. This suggests that even in An. 2.6 Aristotle is unwilling to endorse the view that qualities themselves are perceived independently of their bearers and that perceiving the latter presupposes an additional step, such as an act of synthesis.Footnote ¹³

It must be admitted that, throughout his discussion of individual sense modalities in An. 2.7–11, Aristotle repeatedly speaks of perceiving modal-specific qualities themselves.Footnote ¹⁴ This, however, need not mean that he takes these qualities to be perceived independently of their bearers. Indeed, the negative answer is suggested by the fact that Aristotle also freely speaks of perceiving the bearers of modal-specific qualities in a way that seems not to be just coincidental.Footnote ¹⁵ One such passage comes at the very outset of An. 2.7:

This must come as a surprise for those who read An. 2.6 as expressing Aristotle’s commitment to the view that bearers of modal-specific qualities are perceptible only coincidentally. Aristotle clearly states here that besides colour itself, its bearer is also visible – and visible in its own right.Footnote ¹⁶ This is so, apparently, because it belongs to colour’s visibility to make visible something else – namely, its bearer. I take Aristotle to be articulating the idea, presupposed throughout his treatment of perception, that what a modal-specific quality does to the perceiver receiving it essentially involves making her perceive the external bearer of it.

At the beginning of An. 2.8, building on the distinction between the perceptual object in capacity and the perceptual object in activity introduced at An. 2.5, 417a13–14,Footnote ¹⁷ Aristotle seems to have a similar idea in mind, although the case of sound turns out to be somewhat trickier:

What ‘can sound’ is the bearer of a sounding quality, such as a bell. When it sounds, it produces a sound that, via the medium, comes to be present in the perceiver. From this, it is admittedly not yet clear that the bell itself belongs to what we hear in its own right. However, that this is the case is strongly suggested by how Aristotle further develops the model – and extends it to other sense modalities – at An. 3.2, 425b25–426a27, where he draws on his general analysis of agency from Phys. 3.3.Footnote ¹⁹ The claim here is that the sound in activity or ‘the sounding’ of that which has a sound coincides, in the perceiver, with her hearing. Sounding is the acting of the external object on the perceiver, whereas hearing is the perceiver’s being affected by that object via the medium (425b26–8):Footnote ²⁰

Aristotle’s identification of the agent with the bearer of the sounding quality suggests that the bearer is, indeed, what the perceiver hears in its own right and no less primarily than she hears the sound itself.Footnote ²¹ The perceiver hears it owing to the sound of this bearer coming to be present – as its sounding or its sound in activity – in the perceiver and coinciding with her activity of hearing. This model dovetails with the idea that the quality received by the perceiver in perceiving remains a quality of the external agent and that perception consists in receiving forms that remain forms of the external objects.Footnote ²²

This analysis leaves many questions concerning Aristotle’s account of αἰσθητά open.Footnote ²³ What matters for our purposes here, however, is only that the perception of the bearers of modal-specific qualities is an essential part of what perception achieves at the most rudimentary level of being a complete passive activity. If that is correct, then this finding reveals a facet that puts additional pressure on Aristotle to explain how perception so defined is possible at all.

4.3 Uncompromised Realism

Further light can be shed on what is at stake here by briefly reflecting on the kind of perceptual realism that Aristotle embraces. I limit myself to pre-empting one possible misunderstanding of the account developed in An. 3.2.Footnote ²⁴ This account implies, as we have seen, that the activity of the external perceptual object and the activity of the perceiver always exist and cease to exist together. Yet – as Aristotle insists against the Protagorean approach of the ‘ancient physiologists’ – this is not to say that the existence (or the nature) of these perceptual objects depends on the existence of perceivers; rather, what depends on perceivers is only whether the perceptual objects are actively perceived or not.Footnote ²⁵ In other words, what exists in the perceiver is merely the external object’s activity of being perceived under the given qualitative aspect that (numerically) coincides with the perceiver’s passive activity of perceiving it.Footnote ²⁶

Aristotle’s point against Protagorean relativism here, however, has often been understood differently. It has been read as if Aristotle was himself effectively accepting a kind of ‘moderate Protagoreanism’ that conflicts with, or at least essentially tempers, the realism about perceptual qualities that he seems emphatically to endorse elsewhere. The idea is, roughly, that according to Aristotle what the external objects acting on perceivers possess on their own – in the absence of perceivers – are not full-blown colours, sounds, or flavours, as perceivers experience them, but only the powers to cause perception of these qualities when a perceiver comes into the appropriate relation with them.Footnote ²⁷ That is, they merely have these qualities in capacity and come to have them in fulfilment only for as long as they are actively being perceived.Footnote ²⁸ If this were Aristotle’s point, we would expect him to discuss what constitutes the power of perceptual objects to cause perception. On account of which actual characteristics of the perceptual object is it capable of causing the perceiver to perceive these qualities? What is it that the perceiver is assimilated to when perceiving, for instance, a colour? What Aristotle actually says, however, shows how far he is from any interest in tempering his realism in An. 3.2. What causes the passive activity of perceiving (together with the productive activity of being perceived), he maintains, is nothing other than the colour or the flavour of an external object.Footnote ²⁹ There is not even the slightest hint in this passage at the idea that what a rose is endowed with on its own could be anything short of the full-blown red colour as experienced by perceivers.Footnote ³⁰

What leads interpreters to read An. 3.2, 425b25–426a27 as Aristotle’s adoption of a kind of (moderate) relativism, I take it, is the tacit assumption that Aristotle is using the notion of ἐνέργεια here as equivalent to ἐντελέχεια: as if perceptual objects were in fulfilment (or ‘in actuality’) coloured or flavoured only when they are actively seen or smelled; and as if, when not perceived, they were themselves coloured or flavoured only in capacity. But this reading runs roughshod over a key distinction that Aristotle has already drawn in An. 2.5Footnote ³¹ and it, effectively, abandons a basic tenet of Aristotle’s first general account of perception. What we learnt in An. 2.5 is that perceptual objects are perceptual in capacity (i.e. ‘perceptible’) only as already being what they are in fulfilment, for only as having colours or flavours in fulfilment, independently of whether they are perceived or not, are they capable of acting on perceivers, assimilating them to themselves, and so making themselves actively perceived.Footnote ³² The distinction between perceptual objects in capacity and in activity that Aristotle is spelling out at An. 3.2, 425b25–426a27 was introduced in An. 2.5 clearly as concerning objects that already are what they are in fulfilment, independently of whether they are perceived or not. If these objects did not possess colours or flavours in fulfilment they would precisely lack the power of making themselves perceived – just as nothing can heat anything else if it is itself not already hot.Footnote ³³ The entire discussion of An. 3.2, 425b25–426a27 concerns the activity (ἐνέργεια) of perceptual objects (ἐντελέχεια is never mentioned); and what some interpreters thought was being qualified here, namely the claim that this activity already presupposes fulfilment on the side of perceptual objects, is, rather, duly presupposed throughout.

If this is correct, it further underscores the significance of the task of showing just how perception in this demanding sense can be realized in concreto.Footnote ³⁴

4.4 Perception and Mediation

In An. 2.5–6, Aristotle remained silent regarding two key factors essentially involved in perception and, thus far, I have done so as well. The first of these factors is introduced immediately after the sentence from the beginning of An. 2.7 quoted above, and it would be no exaggeration to describe it as the main topic of An. 2.7–11 as a whole: mediation. One reason why the media are important is obvious given Aristotle’s rejection of any actio per distans: clearly, perceivers smell and hear and see objects that are distant (and sometimes very distant); so it is obvious that there must be something in between the perceptual object and the perceiver mediating the agency of the former on the latter. However, there appears to be a deeper reason why Aristotle takes media to be indispensable, which leads him to extend the notion of mediation to the contact senses. Hence Aristotle’s prima facie surprising claim that the perceptive organ of tasting is not the tongue, and the perceptive organ of touching is not the skin or the flesh; rather, in both cases, it is something deeper within – namely, the heart.Footnote ³⁵ Unfortunately, none of the passages where Aristotle argues that media are indispensable quite spells out what this deeper reason is. It seems that media play an essential part in realizing perception as a presence of a quality of its external bearer in a perceiver affected by it or as a reception of forms without the matter, but we are left to speculate about what exactly their role consists in here.

The task is difficult partly because, towards the end of An. 2.7–11, Aristotle introduces the second key factor in the realization of perception whose relation to mediation is far from obvious: the discriminative mean. The thought is, roughly, that discrimination (κρίνειν) is an essential ingredient or essential characteristic of perception that is performed by – or on account of – the mean (μεσότης) between the two extremes defining each sense modality. It is no clearer than in the case of the media what exactly this mean is or what role it plays.

Be that as it may, there is a remarkable symmetry within the structure of An. 2.7–11. An. 2.7, on the one hand, introduces the notion of a medium, whose existence (albeit not its role) is obvious in the case of sight (and the remaining two distal senses of hearing and smell), and it announces the need to extend this notion to the contact senses. The final section of An. 2.11, on the other hand, introduces the notion of a discriminative mean, primarily for touch (in whose case, apparently, it is most obvious), and extends this notion immediately to the remaining four sense modalities. When Aristotle, in An. 2.12, again picks up the task of saying, in the most general terms, what perception is, the main progress that he takes himself to have made since An. 2.5 seems to consist exactly in introducing these two key factors.

However, the precise roles of each are something that we shall need to explore, beginning with the notion of mediation. It is telling that An. 2.12 closes with a puzzle about the way in which the media are affected, suggesting that Aristotle himself found the question of what exactly the media do in perception to be a difficult one. We shall come to that difficulty presently; but let us start from a more general worry that arises immediately on turning from An. 2.5 to An. 2.7.

The concept of preservative πάσχειν (as reconstructed in Chapters 1–3) naturally raises the following doubt: how could X be already assimilated to Y while still being affected by Y? The notion of the transparent medium introduced in An. 2.7 might seem to contain an answer. Colours are characterized as being that which can move what is transparent in fulfilment (418a31–b1) and the transparent is characterized as that which is not visible in its own right but, rather, owing to the colour of something else (418b4–6). It is itself colourless and, as such, is capable of receiving the colours of other things (418b26–7). Indeed, it can somehow receive the colour of the coloured object that acts on it (419a13–15, 27–8) without acquiring any colour of its own; and so it can be further affected by the same, or indeed any other, colour. So, in his account of the transparent media, Aristotle might seem to be giving us a concrete example of preservative πάσχειν.

However, what at first appears to be a helpful illustration turns out to be more of a problem. Aristotle speaks here about non-living bodies that are external to perceivers,Footnote ³⁶ and it would mark a flagrant failure if his general account of perceiving were to apply to mere mediation. The danger, in other words, is that the media are asked to do too much, so that it is not obvious why they themselves fall short of perceiving.Footnote ³⁷ In fact, the same kind of worry may be provoked by Aristotle’s treatment in An. 2.8 of ‘sounds in activity’ as present in the medium: we have seen that, in An. 3.2, ‘sounds in activity’ are said to coincide with the activity of hearing (as, indeed, one would expect from An. 2.5, 417a9–14); so it could seem from An. 2.8 that the auditory medium itself must hear.Footnote ³⁸

This kind of worry may seem too absurd to be taken seriously, but it is a worry very similar to the one that Theophrastus, as we have seen, raises for Empedocles and that is echoed in An. 1.5.Footnote ³⁹ Nobody wants to say, of course, that a glass of water sees the coloured objects around it,Footnote ⁴⁰ but Aristotle and Theophrastus seem to have found a useful test here for putative accounts of perception: if an account implies something like this, it is clearly not sound. Now, there is a reason to be concerned about whether Aristotle’s own account perhaps has such an unintended implication; and we will see that the worry he raises at the end of An. 2.12 can be read as articulating exactly this kind of concern.Footnote ⁴¹

However, let me first emphasize one thing that will become important later (in Section 4.7). It may seem that there is a straightforward solution to the canvassed worry: the glass of water does not perceive because, clearly, it does not have a perceptive soul. It is important to realize, though, that no such solution is available to Aristotle, as it is, in effect, circular. First of all, if such a solution were available, it would also be available to someone like Empedocles and there would be no point in raising this kind of objection against other thinkers’ accounts. The reason why it is not available is intimately connected to the very nature of Aristotle’s endeavour in the De Anima: the basic parts or capacities of the soul are meant to be defined as the first principles of the respective phenomena of life; and Aristotle is very explicit in An. 2.4 about the fact that one cannot define such a capacity without first defining the respective activity.Footnote ⁴² Hence, if the putative definition of perceiving turns out to imply that the media themselves perceive, there will remain no room for denying that they themselves possess perceptive souls. That said, it is obvious that the presence of the soul is, indeed, what makes the difference. The point is that we must first understand the difference itself, as a precondition of understanding how the soul (being the kind of entity it is) can make this difference.

It is usually tacitly assumed that Aristotle’s account of perception successfully passes this test. However, on closer scrutiny, it turns out that there are (and have been since antiquity) very different intuitions about what kind of solution his position really offers. In a first approximation, we can see the main differences articulated in three different understandings of how Aristotle is addressing the final puzzle of An. 2.12.

Aristotle’s initial question is ‘whether something incapable of smelling can be affected by an odour’ and similarly for the other (distal) senses (424b3–5). If, for instance, odour is understood as being what is smellable, then it would seem that being affected by odour is nothing other than smelling (424b5–9). However, this equation is obviously fallacious at least in the case of tangible qualities, such as heat: these clearly act on non-living things as well as on perceivers (434b12–13). Accordingly, we should not be deterred from allowing this to happen in the case of distal senses, too. And it is not difficult to deduce why this is the case: Aristotle’s account of perception has ascribed a very important role to mediation, and even if it did not, it is clear that seeing, hearing, and smelling involve some kind of being affected by colours, sounds, and odours that is not yet a case of perceiving – namely, the kind of being affected undergone by the media. Aristotle urgently needs to distinguish this kind of being affected from the kind that defines perception, especially since the former conspicuously resembles the latter.

In the final lines of An. 2.12, Aristotle provides at least a few hints towards his intended resolution of this worry:

As it stands, Aristotle’s answer is ambiguous. When he says that smelling is something ‘besides being affected in a way’, he could have any of the following three positions in mind:

• [Composition] smelling is somehow composed of ‘being affected in a way’ plus something else as two distinct elements;

• [Isolation] smelling is something else altogether than ‘being affected in a way’;

• [Specification] ‘being affected in a way’ is on its own an insufficient characterization, and if we are to define perceiving, such as smelling, then we need to specify what kind of ‘being affected’ it is.

Composition would suggest itself as perhaps the most intuitive reading were we to accept the καί at 424b17 (although, textually, this is a dubitable choice; see Footnote n. 44). If this reading is correct, it would imply that, according to Aristotle, something can perceive only when it is affected, but perceiving is not just a kind of being affected. Rather, for perception to take place, something else in addition to πάσχειν must be combined with it.Footnote ⁴⁵ Isolation may, on the other hand, seem attractive to the spiritualist.Footnote ⁴⁶ However, this reading admits of being developed in different ways that are less friendly to spiritualism, because saying that smelling is something quite different from being affected – namely perceiving – does not imply that it involves no ordinary affections.Footnote ⁴⁷

Be that as it may, these are not the only possible readings of the last two quoted sentences. With or without καί, these sentences can also be read in line with Specification.Footnote ⁴⁸ What does ‘smelling’ mean besides ‘being affected in a way’? Well, ‘smelling’ (also) means ‘perceiving’, and this is not the way in which media are affected. On this view, a distinction must be drawn between these two kinds of being affected that can seem so similar. Support for this third reading may be found in the first quoted sentence: the non-living things that can be affected by odours, sounds (and presumably colours) – that is, effectively, the media – are affected in a way that bears the mark of their indeterminacy and instability. Presumably, it is exactly in these two respects that the preservative πάσχειν – capturing the essence of perceiving – differs.

I believe that Specification is, indeed, the preferable reading. However, I do not think that the question can be decided on the basis of the present passage alone. Rather, in preferring one of the readings over the others, general considerations about the kind of explanatory account Aristotle intends to develop for perception begin to come into play, and these will have to be evaluated in a wider context. I shall take up this task in Section 4.7.

4.5 The Operation of the Media

Regardless of this larger question, the quoted passage provides valuable clues concerning Aristotle’s understanding of the operation of the media. Besides the mention of indeterminacy and instability, Aristotle also says that, when the air has been affected, then instead of perceiving, it ‘easily becomes perceptible’. This latter description, apparently, concerns the case of odours (i.e. the case when the air has come to ‘have an odour’). It seems that what Aristotle is describing here is, effectively, a failure of mediation: once the air acquires an odour of its own, it ceases to be capable of mediating this – or any other – smell; rather it itself becomes an object of smelling.Footnote ⁴⁹ Aristotle does not say whether some analogue of this failure can also occur in the case of sounds or colours.

Be that as it may, the characteristics of indeterminacy and instability were clearly introduced as being more general: they were explicitly said to concern sounds too, and there is no obvious reason for not taking the point as concerning colours, as well. Presumably, these two characteristics determine what happens in the case of a successful mediation. Themistius understood them as implying a contrast between the essentially flowing and evanescent nature of the media’s affections, on the one hand, and the persisting assimilation of the perceiver (even if just for a few seconds) on the other hand.Footnote ⁵⁰ As far as I can tell, this is a reasonable interpretation, although it raises questions about the persisting quality acquired in perceptual assimilation – questions that will need to be addressed later.Footnote ⁵¹ Setting them aside for now, however, the passage seems to capture a – or maybe the – characteristic feature of how the media are affected by perceptual objects: when affected, the medium immediately sends the impulse further. Before the relevant quality of the object could come to be present in the medium as a quality of the medium itself, the medium imposes this quality on something else – most often another portion of the medium, which does exactly the same, and so on.Footnote ⁵² In other words, when functioning well, the media are – more or less perfect – qualitative conductors. I shall say more about the degree of their perfection in Section 4.6.

The qualitative conductivity of the media helps us to see how they are capable of being further and further affected by the same or any other quality of a given range, or other ranges, in which they are conductive.Footnote ⁵³ However, it also helps us to see how this kind of being affected differs from the preservative πάσχειν capturing the nature of perception and, thus, why this conductivity of the media cannot amount to perceptivity. It is, strictly speaking, never true about the media, if they are functioning well, that they have been affected by, and assimilated to, the perceptual objects acting on them – that is, that they are like these objects. The quality of the perceptual object acting on a medium is never present in the latter; rather it is always being transmitted through it – as long as the medium is functioning well.Footnote ⁵⁴ Furthermore, we know from the case of odours what happens when the media cease to function well: the quality of the perceptual object comes to be present in the medium, but not as a quality of the perceptual object acting on it; rather, the quality comes to be present in it as a quality of the medium itself, and that is not a case of perceiving on the medium’s part, but simply a failure to mediate.

This being said, one can press the question of what exactly is happening within the medium when it is functioning as a qualitative conductor. A potential answer is that the qualities are encoded in it, either in the sense that their defining ratios are embodied in a different pair of contraries,Footnote ⁵⁵ or in the sense that they are ‘encoded in the movement of the medium’ rather as, according to Aristotle, the human form is encoded in the movements of the sperm.Footnote ⁵⁶ The latter, however, is in danger of explaining obsurum per obscurius. It seems hardly acceptable to think that a colour or an odour is encoded by a literal locomotion of the air; and if ‘movement’ is given a more relaxed interpretation, it is far from clear how the second option differs from the first one. However, assuming that the quality is encoded in a different pair of qualitative contraries seems, from a theoretical point of view, to be entirely idle: it contributes in no way to explaining the qualitative conductivity characteristic of the media.Footnote ⁵⁷ It thus seems wiser to simply take this conductivity to be a primitive feature of the media that cannot be explained (away) by encoding or anything else.Footnote ⁵⁸

This is not to deny that some encoding may be involved in certain kinds of mediation. Aristotle may well have empirical reasons for thinking that it is. Among the distal senses, hearing seems to be the most obvious candidate for such an encoding. The varying speeds of the wave motions, which according to Aristotle mediate sounds, are naturally understood as effectively encoding them. Here, the qualitative conductivity seems to be, effectively, analysed in terms of ‘vibrations’ (i.e. apparently, forwards and backwards spatial movements).Footnote ⁵⁹ However, if the proposed reading of the final lines of An. 2.12 is on the right track, then this cannot be a universal principle: there seems to be no encoding in the case of smell, because otherwise the quality acquired by the air when mediation goes wrong would have to be something other than odour, contrary to the fact and to what Aristotle says. By analogy, there seems to be no reason to assume any encoding for colours, and the same holds for the hot and cold. The only other sense for which the assumption that an encoding of some sort takes place seems attractive, if not necessary, is taste – at least as long as we take for granted Aristotle’s teaching (from An. 2.7 and 11) about the heart being the proper organ of touch and taste: what happens on the tongue appears to be a transformation of the affection that is further mediated by the flesh in an encoded form. But even this is no more than an educated guess, and we cannot be sure that Aristotle consistently adopted that idea.Footnote ⁶⁰ The point is that he could only have empirical reasons for assuming an encoding for some specific kinds of mediation but not others, while having theoretical reasons to prevent this move as far as possible,Footnote ⁶¹ particularly because his general account of mediation seems at any rate committed to something like the idea of qualitative conductors.

So much for the operation of the media. Let me now restate the main question that our discussion of the closing lines of An. 2.12 led up to in the preceding section: if Aristotle’s suggestion is, indeed, that the media, when functioning well, are qualitative conductors, how exactly should we understand the way in which the quality of the perceptual object remains in the perceiver throughout the duration of her perceiving that object? This question seems to be at the heart of the recent controversy surrounding Aristotle’s account of perception. But, in fact, the debate has mostly concentrated on just one aspect of this more general question, namely on how the body of the perceiver is involved. Is the organ literally assimilated to the perceptual object? Or does it embody the ratio defining the relevant quality in a different pair of contraries? Or does it, rather, undergo no material (or physiological) alteration whatsoever? In Section 4.6, I sketch out what light can be shed on this question by the proposed interpretation of Aristotle’s first general account. In Section 4.7, I then formulate an even more pressing, and more fundamental, question about the way in which qualities of perceptual objects are present in perceivers. This other question focuses, in turn, on the role of the soul in perception: on how exactly the soul makes the difference, according to Aristotle. This will become the central question of the following chapters.Footnote ⁶²

4.6 Beyond Spiritualism and Materialism

Let me begin with a brief reflection on the difficulties raised by the closing lines of An. 2.12 for the spiritualist account of mediation.Footnote ⁶³ According to this account, ‘the medium takes on the quality of the sense-object only insofar as the quality appears to a perceiver’; it is only changed phenomenally.Footnote ⁶⁴ This idea is entirely different from the concept of qualitative conductors; indeed, it seems that the spiritualist needs to presuppose that media are some very special kind of qualitative conductors in addition to this idea.Footnote ⁶⁵ Moreover, if what is transmitted through the medium is merely a phenomenal change, then it is hard to see what a failure to mediate this change could mean other than coming to perceive the perceptual object acting on the medium. So, on the spiritualist account, no such failure is possible. But what is then Aristotle talking about at An. 2.12, 424b16 and 18? The spiritualist answer is striking: it is something entirely different from, and indifferent to, mediation. A piece of fried bacon acts on the surrounding air simultaneously in two disconnected ways: it changes the air phenomenally insofar as I perceive the smell, and it changes the air literally insofar as the air, for a while, acquires an odour of its own.Footnote ⁶⁶ Besides violating lex parsimoniae, this interpretation makes Aristotle, strikingly, deny that there is any intrinsic relation between the phenomenal strength of the perceived odour and the likeliness that the air will come to possess that odour itself. This is a disquieting outcome.Footnote ⁶⁷ However, it is neither the only nor the main reason to reject spiritualism.Footnote ⁶⁸

If, against spiritualism, we accept the idea that, for Aristotle, there is an intrinsic connection between the mediating role of the air and the case of it coming to possess an odour of its own (as a failure to mediate), we can ask whether this is not intended to serve as a model example of a much more general, but usually not observable, phenomenon. Perhaps Aristotle envisioned smaller or larger vibration-like oscillations occurring throughout the train of the perceptual affections. I see no principled reason why he should exclude the possibility that what ostensibly sometimes happens in the case of strong odours for a time observable by the senses happens regularly (or at any rate fairly often) in the case of all sorts of perceptual qualities in the external media and/or in the body of the perceivers, but only for much shorter periods, like a fraction of a second – perhaps as the maximum/minimum of a quasi-sinusoidal (qualitative) process – so that the event is not observable by the senses and has no effect on the quality of one’s perception. The amplitude and the period of these oscillations would simply manifest the relative imperfection of the media as qualitative conductors, meaning that, at a micro-level, not noticeable by the senses, the media regularly do acquire the mediated qualities as qualities of their own – but only for a tiny fraction of a second and non-statically (they never cease acquiring/losing these qualities), which makes the oscillations harmless with respect to the media’s operation. Clearly, there would be great differences between various external media (and bodily parts like the flesh) concerning the nature of these oscillations. It could well turn out that the only perfect conductor is a perfectly transparent medium.Footnote ⁶⁹ But none of this would change anything about the overall picture of the media’s operation as qualitative conductors. It would, rather, make their operation less mysterious and would underline what is in any case suggested by Aristotle’s mention of the air becoming odorous, as well as by his description of the processes of smelling and tasting – namely, that this working is a thoroughly material and perceiver-independent process, distinguished from other processes primarily by the exceptional throughput (i.e. the remarkable conductivity of the substratum). This is what might make it seem that no material process is taking place, although this impression turns out to be mistaken even in the case in which the conductivity appears to be perfect.

All of this has a direct bearing on the notorious question of what happens in the perceiver’s body when the affection, transmitted by the medium, arrives at her organs. Do they take on the quality in the literal sense of becoming, for instance, red or fragrant? Or do they come to embody the ratio defining that quality in a different pair of contraries? Or is all that happens simply a case of perceiving that cannot be analysed any further? I want to argue that, if the interpretation of Aristotle’s first general account of perception offered in Chapters 1–3 is on the right track, then none of these answers can be quite right. While spiritualists unjustly deny the material nature of the processes that lead to perception, the critics of spiritualism tend to reify the likeness resulting from these processes in a successful perception.

Victor Caston’s paper ‘The Spirit and the Letter’ has rightly been considered to contain the most authoritative summary of the so-called spiritualist-literalist debate, together with providing an attractive alternative. I wish to argue that although this paper does an excellent job in showing that ‘spiritualism’ and ‘literalism’ are far from monolithic positions, and that, moreover, they are far from jointly exhaustive of the interpretative options, it tacitly excludes one promising set of options. Caston shows convincingly that Burnyeat’s disjunction between spiritualism and literalism is all too narrow. However, in doing so, he confronts us with another disjunction. Either we accept the so-called Broad Church Reading (‘If a subject S comes to perceive a perceptual quality F at time t, then S undergoes some physiological change in the relevant organ at t such that it becomes like F’),Footnote ⁷⁰ or we are condemned not just to High Church Spiritualism, which denies that ‘natural changes are a necessary condition for perception’,Footnote ⁷¹ but directly to Burnyeat’s New Age Spiritualism, which denies that material or physiological changes can be involved in perception at all (‘S does not undergo any physiological change in the relevant organ at t, or indeed any real alteration, but only “quasi-alteration”’).Footnote ⁷² That is, on Caston’s view, either we accept that at the time of perceiving F the organ is materially like F, or we are condemned to denying that any material or physiological process is involved whatsoever.Footnote ⁷³

Clearly this disjunction would constitute a genuine tertium non datur only if one’s allowing for a material (physiological) change or process involved in perception meant, eo ipso, accepting the idea that at the time of perceiving F, the relevant organ is like F in a material (physiological) sense. To be sure, Caston’s paper is persuasive in showing that being materially F does not necessarily mean being literally F: it can also mean embodying the same ratio (say, the ratio defining red colour), in a different pair of contraries (say, the pair of being viscous and being runny), that is, being literally G, and only in that sense being like F – receiving F-ness in a transduced form.Footnote ⁷⁴ But do we really need to commit Aristotle to a material likeness, in order to avoid the pitfalls of spiritualism? If the proposed analysis of mediation in terms of qualitative conductors is on the right track, it suggests that this is not necessary: the transparent air through which I see a red rose is being continuously affected and changed (κινεῖται) by its red colour without ever coming to be red in the sense of acquiring the red colour as a persisting quality of its own.Footnote ⁷⁵

Furthermore, not only is it the case that material likeness is not implied, but, rather, its possibility seems to be excluded; for if the air came to be red at t, it would cease to properly function at t as the medium of vision. And what holds about the medium will hold mutatis mutandis about the organ of vision: if it came to be materially red at t, it, too, would cease to be capable of being materially affected by red at t, and so it would cease to be capable of perceiving red at t. For if the organ were materially red at t, this would mean losing the perceptual contact with the object that was acting on the perceiver in causing this likeness, but that could no longer act on her. What is happening at t would at most be a case of having a phantasma of the object in question (or having an acquired blind-spot for it), but not a genuine case of perceiving it.

The ‘analogical reading’ proposed by Caston, as ingenious as it is, changes nothing about this predicament. If the material effect of the transparent medium on the organ consists in changing it towards G (say, the ratio defining red colour embodied in the pair of being viscous and being runny) then, once the organ has come to be G at t, it will no longer be capable of being affected and changed towards G by the medium at t, and so it will no longer be capable of perceiving red at t: the perceptual contact will be lost.

Another way of making this point would be to say that Caston’s objection against Canonical LiteralismFootnote ⁷⁶ can, in fact, also be turned against the position that he himself recommends. The objection is that Canonical Literalism presupposes an actual replica of the perceptual object existing at the time of perceiving in the perceiver,Footnote ⁷⁷ but that Aristotle rejects this kind of replica in his polemic against the traditional LKL position. I think this is perfectly correct. However, if the analysis of Aristotle’s involvement with LKL provided in Chapter 2 is on the right track, it follows that the reason for rejecting the traditional version of LKL applies equally well to the view advocated by Caston exactly because, like literalism, it commits Aristotle to the claim that at the time of perceiving F the organ is materially like F, the only difference being that the likeness is spelled out in terms of G embodying the same ratio as F.Footnote ⁷⁸ The problem is that if we assume that, for a perceptual object F, assimilating the perceiver to itself means making it G, then once the perceiver’s sensory organ already is G it cannot be further affected by the perceptual object F in the specified way and continued perception becomes impossible, or at least indistinguishable from having a phantasma.

This line of argumentFootnote ⁷⁹ is likely to be resisted by readers who approach Aristotle with the assumption that perceiving F must involve some kind of standing material representation of F in the perceiver.Footnote ⁸⁰ If this assumption were correct, then my argument would simply be asking for the impossible. However, this assumption is exactly what I intend to call in question. If the reconstruction of Aristotle’s first general account of perception provided in Chapters 1–3 is correct, then it strongly suggests that Aristotle’s account does not allow for any standing material representations, for these would mark exactly the end of perceiving.

Let me emphasize that, if the kind of argument sketched in the preceding paragraphs against the materialist assumption characteristic not only of literalism but of the Broad Church Reading as a whole is cogent, then it certainly does not support spiritualism. Against spiritualism, I have agreed that the media and the perceptive organs are, according to Aristotle, materially affected and changed by the perceptual object; and I have emphasized that these affections may even have the form of imperceptible oscillations and that they fairly often result in the media or the organs being materially like the perceptual objects for a certain period of time. I have only insisted that this material likeness cannot be what mediation and, a fortiori, perception are grounded in; rather, such a likeness is a mark of imperfection and, if it is not to turn mediation and perception into a failure, it must not last for more than a fraction of a second.

Moreover, the argument made above seems to apply, mutatis mutandis, to spiritualism no less than it applies to materialism. If the media and the organs of perception are only affected and altered ‘phenomenally’ or ‘spiritually’, one can raise the very same concern about this phenomenal affection. If the organ, upon being phenomenally affected by F, comes to be phenomenally F at t, then, apparently, it cannot continue being phenomenally affected by F at t, and so it cannot be perceiving F at t, because the perceptual contact with F has thereby been lost.

In any case, my present aim is not to insist that I have here produced a knock-down argument against the three reputable positions in the scholarly literature (i.e. literalism, spiritualism, and the analogical reading). Rather, I contend, more modestly, that these three positions do not exhaust the logical space of possibilities and that there is an attractive alternative directly suggested by the reading of An. 2.5 developed in Chapters 1–3, which is intelligible and sustainable independently of the complexities of Aristotle’s first general account of perception.Footnote ⁸¹

The thought can be summarized as follows. There is a grain of truth in spiritualism that has not been sufficiently appreciated by its opponents: (a) the way in which a perceiver is like the perceptual object she is perceiving cannot be captured in terms of a material or physiological likeness (whether literal or analogical). Indeed, (b) there is an important sense in which Aristotle’s account excludes any such likeness, for the perceiver can be perceptually assimilated to the perceptual object only if she continues being affected by it (otherwise the likeness could at most constitute a phantasma or a blind spot), and this presupposes that the perceiver remains in the relevant respect unlike her perceptual object. The problem of spiritualism, as developed by Burnyeat and Johansen, is its radicality in denying not only material likeness but also any material (physiological) affection and change. What all three positions have in common, I submit, is an all-too-static conception of the likeness in question. We need an account explaining how something along the lines of ‘phenomenal likeness’ comes to be present in the perceiver, dynamically, as a result of material (physiological) affections instead of these resulting in a material (physiological) likeness. Such an account would allow us to understand how the perceiver can be like the object she is perceiving in the requisite way and can at the same time continue being affected by it owing to her preserved unlikeness. This is possible exactly because the relevant organ remains materially unlike the perceptual object, as the material affections are turned in it into a phenomenal likeness – a dynamic presence of the perceptual object’s quality.

The key question, then, is how exactly this can happen. This concern contains the query about how the operation of the media is supposed to help in producing phenomenal likeness – that is, why it could not be produced if perceptual objects were directly acting on perceptive organs.Footnote ⁸² However, the core of the question is what exactly happens in the perceptive organ and what allows the material (physiological) affections to be turned into a phenomenal likeness in it.Footnote ⁸³

4.7 Discrimination and the Role of the Perceptive Soul

This last question is, in fact, just a special instance of a more general issue faced by any interpretation of Aristotle’s causal account of perception: how do the changes or affections transmitted from perceptual objects by the media to perceivers – whatever they are – cause or occasion the activity of perceiving these objects? This is, effectively, the same question that we have already encountered at the end of An. 2.12, where Aristotle asked what smelling is ‘besides being affected in a way’ and replied that ‘while smelling is [[also]] perceiving, the air, instead, when it has been affected, easily becomes perceptible’ (424b16–18). As noted in Section 4.4, two prominent ways of understanding this reply, and of construing Aristotle’s account as a whole, are based, respectively, on Isolation – treating the smelling (and perceiving in general) as being an additional element over and above being affected by perceptual objects – and on Composition, treating perception as being composed of being affected plus an additional element. The shared idea between both these interpretations is that Aristotle’s account of being affected by, and assimilated to, perceptual objects takes us, at most, to a necessary condition or one ingredient of perceiving. Very often, this necessary condition or ingredient is then understood as a certain kind of material/physiological likeness present in the perceptive organ (whether conceived literally or analogically).Footnote ⁸⁴ This approach is then open to the objection raised in the preceding section against the ‘materialist’ interpretations of Aristotle’s account. However, Isolation and Composition can also be fleshed out in a way that is immune to that objection: ‘being affected’ can be understood as being thoroughly mediative, meaning that no body involved in perceiving – the media and the organs alike – ever comes to be like the perceptual object; rather, the sole role of the body in perceiving is to mediate the agency of perceptual objects.Footnote ⁸⁵

The alternative to Isolation and Composition, as we have seen, is to understand Aristotle as insisting that smelling (and perceiving in general) is a different kind of being affected from the one undergone by the media (Specification). Prima facie support for this alternative is the frequency with which Aristotle maintains in the De Anima that perceiving is a kind of being affected – a claim that is extended to thinking in An. 3.4.Footnote ⁸⁶ The approach to the role of the perceptive organs canvassed in the preceding section can be understood as a first step towards developing this reading of Aristotle’s reply: the kind of being affected undergone by perceivers differs from the one undergone by media in that it does result in a likeness – namely, a phenomenal likeness: a dynamic presence of a quality of the external perceptual object in the perceiver.Footnote ⁸⁷

In order to make progress in clarifying and evaluating these options, I submit, we must get to grips with another major characterization of perception encountered in the De Anima – namely, as a case of κρίνειν. It has been convincingly argued by Theodor Ebert that κρίνειν must not be translated as ‘judging’, and that it rather has to do with discriminating/discerning, singling out, or telling things apart.Footnote ⁸⁸ We shall soon need to determine the meaning of perceptual discrimination more precisely (in Sections 6.1–6.3, and 6.6) and to analyse the passage (An. 2.11, 423b31–424a10) where Aristotle introduces the key notion of the discriminative mean (in Sections 6.4 and 6.5). For now, however, it will be sufficient to recall one of Ebert’s insights, namely that, unlike ‘judging’, κρίνειν is for Aristotle a success verb.Footnote ⁸⁹ It is a key characteristic of what is achieved in perception, capturing its veridical nature (cf. An. 2.6, 418a14–16): in perceiving, animals reliably discern things or tell those that are F from those that are non-F, at least with respect to their modal-specific qualities.

One issue that will need to be explored is how this characterization of perception relates to the one that dominated Aristotle’s first general account – that is, the claim that perception is a kind of being affected by a perceptual object. One way of approaching this question is along the lines of Isolation or Composition as against Specification: it may seem that Aristotle’s characterization of perception as a case of discrimination captures exactly the other element over and above ‘being affected’.Footnote ⁹⁰ Some such approach has often been adopted by scholars since at least Alexander of Aphrodisias – despite the fact that the underlying assumption (particularly if understood in terms of Isolation) is in a prima facie tension with Aristotle’s repeated claim that perceiving is a kind of being affected and although it leads, as we shall see (in Section 5.3), to other considerable difficulties.

In any case, this is certainly not the only way of understanding Aristotle’s talk of κρίνειν. It can be (and has occasionally been) taken, instead, as a way of contrasting the kind of being affected experienced by perceivers with the kind of being affected undergone by the media (and indeed by all imperceptive beings), along the lines of Specification.Footnote ⁹¹ On this reading, that which can perceive is, unlike the media, affected by perceptual objects in a ‘discriminative’ way so that its being affected by them is a case of discriminating them.Footnote ⁹² This would be just an alternative way of spelling out the same difference as has already been described above in terms of, on the one hand, being affected without determinacy and stability (i.e. merely as qualitative conductors) and, on the other hand, being affected in a way that results in a continuing ‘phenomenal’ likeness – that is, a dynamic but continuous presence of a quality of the external perceptual object in the perceiver. The key passage for evaluating the merits of these interpretative options is, arguably, the final part of An. 2.11 (discussed in Sections 6.4 and 6.5), where Aristotle’s account of the discriminative mean is introduced in a direct connection to his claim that perceiving is a kind of being affected by and assimilated to perceptual objects (423b31–424a2).

If we leave aside for a while the question of whether discrimination is better treated as an additional element over and above being affected or as the distinguishing feature of how perceivers are affected by perceptual objects, one thing is clear: under this description, perceiving is already characterized unambiguously as belonging to living beings endowed with a perceptive soul.Footnote ⁹³ In other words, when perception is described as a case of discrimination, there is no danger anymore of unwillingly ascribing perception to non-living things, such as the media. However, an explanatory account of perception will also have to say how perception qua discrimination is possible, and that means spelling out (at least on the most general level to start) how it fits into the assimilation model of perception, as outlined in An. 2.5. Without this, one would risk falling back into the Anaxagorean difficulty as described at An. 1.2, 405b19–23.Footnote ⁹⁴ In other words, discrimination is a useful label for what Aristotle thinks is achieved in perception; the question is now what exactly discrimination consists in and how it is achieved – that is, just how it comes to be that perceivers discriminate perceptual objects, rather than merely being turned into similar perceptual objects by them or becoming qualitative conductors of their agency. This question is intimately connected, if not identical, to the question of what difference the perceptive soul makes, and how.

This question which will be central for the following three chapters is different from, albeit not unrelated to, the notorious question about the role of the perceptive organs in perception. Answers to the latter question usually presuppose some basic assumptions concerning the status and the role of the perceptive soul, and the other way round: the understanding of the perceptive soul and its role that we arrive at is likely to determine the way in which we take the perceptive organs to be involved. Most notoriously, perhaps, Myles Burnyeat has insisted – against what he saw as a noxious fashion of assimilating Aristotle’s conception of soul to modern functionalism – that ‘to be truly Aristotelian, we would have to stop believing that the emergence of life or mind requires explanation’.Footnote ⁹⁵ What he meant is that the only thing Aristotle can say about why, for instance, perceptive beings are perceptive is exactly that they are perceptive – that is, endowed with a perceptive soul – period.Footnote ⁹⁶ This position leaves as little room for spelling out the role of the perceptive soul as it does for spelling out the role of the perceptive organs. The opponents of spiritualism have mostly concentrated on defending the claim that Aristotle is willing to say more about what happens in the perceptive organs than the spiritualists allow for (i.e. that these organs are what perceivers perceive by).Footnote ⁹⁷ But comparably little attention has been paid to the perceptive soul.Footnote ⁹⁸ As if, after spelling out the kind of material/physiological changes in the perceptive organs, the only thing Aristotle could add was: ‘and these constitute perception because the organs are endowed with a perceptive soul’. That, however, leaves the relation of perceptual awareness to body and bodily processes no less mysterious than on the spiritualist interpretation – as long as no account of how exactly the former should ‘supervene’ on the latter is available.Footnote ⁹⁹

These results are surprising, given that what we are studying is Aristotle’s treatise On the Soul, for which a key task is exactly determining as far as possible the way in which the soul is the principle of life and its characteristic activities, including perceiving. The question cannot be simply discarded by pointing to Aristotle’s famous – allegedly ‘Rylean’ – doctrine that it is not the soul itself that perceives, but the animal endowed with a soul.Footnote ¹⁰⁰ Just as this doctrine does not forbid us from asking about the nature of the changes occurring in the ensouled body, so it does not forbid us from asking about the nature of the soul’s involvement, either; what it forbids, arguably, is only understanding this involvement in terms of the soul itself perceiving, and so being moved by perceptual objects. In fact, as we shall see, this famous passage only highlights the need for spelling out the soul’s involvement in a non-circular and informative way: to understand perception, we must understand what difference it makes for the ‘changes’ or ‘motions’ transmitted through the body to extend ‘up until the soul’ (without, apparently, becoming changes or motions of the soul itself), as this is exactly what constitutes the difference between perception and mere mediation. Aristotle cannot succeed in defining the perceptive soul, as the first principle of perception, without spelling out, at least in the most general terms, both this difference and the way in which the soul accounts for it. Nor, however, is this an easy task.Footnote ¹⁰¹

One can, again, compare Aristotle’s treatment of nutrition.Footnote ¹⁰² While it would surely be absurd to say that the nutritive soul, as the first principle of nutrition, is itself nourished or that it nourishes itself, Aristotle finds nothing absurd in ascribing to the nutritive soul a fairly precise role in nutrition: it is that which nourishes (τὸ τρέφον) the body by the nutriment.Footnote ¹⁰³ Aristotle’s comparison with carpentry (416b2–3) signals that the nutritive soul is an agent of a very special kind; it is one of ‘the agents that do not have the form in matter’, and so are impassive.Footnote ¹⁰⁴ This gives us an informative account of how the nutritive soul is supposed to play the role of the first principle of nutrition (although the details are not entirely easy to tease out).Footnote ¹⁰⁵

Now, what corresponds to this account in the case of perception? The question here is significantly more difficult, and one reason for this is the following.Footnote ¹⁰⁶ Aristotle seems to define perceiving as a kind of being affected by and assimilated to perceptual objects; but in An. 1.3–4 he determinately opposed the assumption, adopted by virtually all of his predecessors, according to which the soul is responsible for animal locomotion – and apparently also cognition – on account of it itself undergoing the relevant kind of changes (either moving itself or being moved by perceptual objects). It is not difficult to see how Aristotle’s account of nutrition is consistent with this denial – he can draw on his account of unmoved movers and impassive agents already developed elsewhere. But how can he make his account of perception as a kind of being affected by and assimilated to perceptual objects similarly consistent? That is far from obvious. Indeed, this question leads to a dilemma that, arguably, lies at the heart of Aristotle’s inquiry, or is at any rate closer to it than the notorious question about the role of the body. This worry asks: how can the perceptive soul be the first principle of perceiving as a kind of being affected by, and assimilated to, perceptual objects, while itself remaining unmoved?Footnote ¹⁰⁷

This question will be explored in the following chapter, and it will provide the framework for the subsequent inquiry into Aristotle’s account of perceptual discrimination and reception of forms without the matter in Chapters 6 and 7.