The Soul’s Tool: Plato on the Usefulness of the Body

1 Perception: What It Is, and Its Advantages

Each episode of perception happens in two stages. For my purposes here, it is sufficient to say that in the first stage, an object external to us causes a disturbance to be conducted through our body (Ti. 43c1–3). In the second stage, the disturbance reaches the soul (43c4–d3). In the background of Plato’s account of perception is the view that each of the four so-called elements is made up of polyhedrons. Fire, for instance, is composed of tetrahedra. This informs how the body perceives things as hot or cold. The fire in something hot acts on our skin by cutting and dividing it, entering our body then (Ti. 61e–62a). We perceive sourness when the earth in what we eat is rough against our tongues; the less rough, the tangier the taste (65d). Colors are analyzed as flames that flow from objects (67c–d). Odors are more complicated: we cannot smell any of the elements. Plato thinks that our nostrils are too narrow for earth and water but are too wide to properly capture fire and air (66d). Instead, we perceive only the transitions between the elements.^[5] Bodies produce odors when they decay, become damp, melt, or evaporate. In general, when there is some transition between water and air, an odor is produced that can fit into our nostrils.

Plato does not talk about sense-data or sensory information being transmitted in these episodes. He talks instead of motions. For example, he speaks about more or less “penetrating” motions being produced by color-flames (68a–b). Sound is the percussion of air in the ear-canal, but hearing is the motion (κίνησις) that the percussion causes, which is transmitted from the head to the liver (67b–c).^[6] These motions seem to be transmitted through the blood. When Plato explains how the rational kind of soul is disturbed by perception, he says that the violent motions join with the “perpetually-moving stream” (τοῦ ῥέοντος ἐνδελεχῶς ὀχετοῦ) in our body to reach and then stir the soul (43c–d). It might be at first be surprising, then, that the gods seemed to have designed the blood-stream exactly for this purpose: the gods connected the whole body with the veins so that no part of us was kept in the dark about what we perceive (77d–e).^[7]

The motion that is conducted through the body reaches reason, whose circles have orbits that ideally are copies of the world-soul’s, and then throws them off-course (43d–44a). Perception exists as one cause of psychic disorders, alongside nutrition, bile, and phlegm. Yet, on the other hand, perception occupies a unique and perhaps unexpected status among these causes. For it seems that the gods deliberately created our bodies as capable of perception. This is not true of, say, nutrition: we need to nourish ourselves because the gods were incapable of furnishing us with a less needy body. In designing our bodies, the gods made certain concessions to necessity, but making us capable of perception does not seem to be one of them. For the gods deliberately designed our bodies with this in mind: consider that in the Timaeus, some perceptions are good for us. See the following passage:

The god invented sight and gave it to us in order that we might observe the revolutions of intelligence in the heavens and apply them to the revolutions of our own thought, since there is an affinity between them (Ti. 47b–c).

The same idea recurs throughout the dialogue: we must “correct the motions in our head that were corrupted at the time of our birth by learning the harmonies and revolutions of the cosmos” (90d). Perception is as useful for us as it is dangerous, but it is easy to miss this. Brisson (1997, 166), for instance, says “the contemplation of the universe and, above all, of the celestial movements is supposed to preserve the excellence of the soul. Otherwise, sensation may transform the soul into something bad.” He sets up a contrast between contemplation of the universe and sensation – but in such passages as 47b–c, the relevant kind of contemplation is an instance of sensation. It might at first be tempting to think that astronomy in the Timaeus is metaphorical for contemplation of the intelligible, especially following crucial passages in the Republic (e.g., 529) where Plato denigrates empirical astronomy and takes up something more philosophical.^[8] Yet, this line is not consistent with what he says about the invention of sight or with the reason we are reborn as land animals with heads close to the ground.

So, perception plays an important role in restoring our soul’s orbits back to their original condition, but it also was a culprit in ruining those orbits in the first place.^[9] The reason why perception is both dangerous and useful to the soul has to do with how reason responds to the perception-motion. Let us consider the case of sight. There is a visual stream that is the coalescence of the fire from our body and the fire from an external object and that is transmitted through our eyes; this perception-motion transmission is then conducted through the blood and reaches the soul.^[10] The damage to our soul is done when the motion strikes the circles of the same and different that are spinning around inside our heads. There is nothing useful about that: it is a purely destructive event. What comes next might help us, though. If what we have observed are the heavenly bodies, then awareness of their motions will help us imitate them in our own lives (47b–c; 90d).

There is a sense in which this claim is what we would expect Plato to say. The Timaeus also says that we care for our body by making it like the cosmic receptacle: we must always keep it moving to keep it in good shape (88c–d). Assimilation to the structure of the cosmos is a central idea in the Timaeus. The world-soul is a model for our own souls, so it makes even more sense in this case for the latter to imitate the former. When scholars note the importance of observing specifically the heavenly bodies, they are indisputably getting at an essential part of the dialogue’s ethics. However, when they say that observing the celestial bodies is the only way for perception to be useful for us, they make a mistake, and it is a mistake that obscures something difficult about the usefulness of perception.^[11]

The gods invent hearing for the same reason that they invent sight: it is so we can restore the order in our souls. Here is what Plato says:

We can give the same account of sound and hearing [as was given concerning sight]: they have been given by the gods for the same reason and for the sake of the same goal. For speech was designed for the same purpose, and it makes the greatest contribution in achieving it. As much music that uses audible sound is also given for the sake of harmony. Harmony, when it has an affinity to the motions in our souls, was given by the Muses not to the one who uses it for irrational pleasure, which people nowadays think it is useful for, but to the one who uses it with intelligence, as an ally in restoring the orbits to an unharmonious soul and bringing it into symphony with itself. Rhythm has been given to us too as assistance on account of the disorderliness and the lack of grace in the conditions of most of us (47c–e).

Remarkably, one could read this passage and forget that hearing is also a cause of the disorders that the Muses want to correct by giving it to us. We learn here that we can restore the harmony of our soul not only by observing the heavenly bodies but by listening to orderly sounds. This passage still supports the view that the objects of useful perception are examples we should follow in restoring harmony, and these objects are not restricted to the heavenly bodies. There is more going on here. The claim that speech is the most useful part of hearing means not only that we hear other people’s speech as orderly examples we should follow, but also that hearing speech prompts us to be orderly in our speech. Conversations do not merely provide a model for us to follow but, additionally, require us to impose some order on our thoughts when participating.^[12]

This passage about hearing complicates the picture on which it is perception specifically of the heavenly bodies that is useful for us. That picture was initially attractive because the motions of the heavenly bodies are the same motions we should restore in our own soul. The passage about hearing forces us to widen the account to include all cases of orderly objects of perception, which explains why hearing and sight are the two senses most privileged by Plato. However, the problem that will occupy us in the next section is that Plato throughout the corpus argues that the perfection of our soul depends on observations of confusing and disorderly sensible objects. The Timaeus is exceptional by stressing perception of order, but there is a moment where Plato shows that this other view is present here, too:

For this reason, we must distinguish between two kinds of causes: on the one hand, the divine; on the other hand, the necessary. As for the divine, we must search for it in all things for the sake of possessing a fulfilling life (εὐδαίμονος βίου), as much as it is possible for our nature. We must search for the necessary for the sake of the divine, since we have determined that, without the necessary, the divine causes, about which we are serious, cannot be understood or partaken of on their own (Ti. 68e–69a).

We must investigate the necessary before we can understand the divine.^[13] The divine in the Timaeus includes the heavenly bodies: elsewhere, we are told that we should imitate the motions of the god (47c) and that our happiness depends on it (90c–d); this is consistent with Plato thinking that the created world is a god (34b, 92c). This passage widens the scope of objects that we must perceive beyond just the orderly. One of the aims of 68e–69a might be to explain why so much of the dialogue is dedicated to discussions of necessity. Whereas the appeal of studying the orderly cosmos is natural to someone who strives to imitate that order, it is harder to see why we would have to study the necessary. Looking first at the theory of recollection and then the Republic’s account of summoners will shine some light on how perception of disorderly objects can be useful.

2 Recollection and the Need for Perception

Recollection is described in the Phaedo as the process whereby we come to have in mind a Form by perceiving things that strive to be, yet fall short of being, that Form. At the heart of the theory is our ability to recognize objects as, say, beautiful or just, despite that this ability could not have been acquired while embodied.^[14] After years of philosophical training, an expert might be able to even explicitly compare sensible objects with the Forms that they fall short of, thinking “what I see wants to be like something else that exists but falls short and is unable to be like that thing” (74d).^[15] This knowledge cannot have come from perception because we never perceive the other object in the comparison, the Form. What we encounter are only the deficient sensible objects that want to be like the Forms. This fits with the dialogue’s opening denouncement of perception as deceptive and affirmation that the Forms will be grasped only by those who approach them without the body and with reason alone (65–66).

Yet, that opening denouncement does not seem to fit with how important perception is in the process of recollection.^[16] Plato’s discussion of equal sticks and stones brings this to light vividly.^[17] There, he says: “as long as when you see one thing, you have something else in mind, whether similar or dissimilar, it would necessarily be recollection” (74d–e; emphasis mine).^[18] On the one hand, we recover the knowledge we lost at our birth by “using our senses” (ταῖς αἰσθήσεσι χρώμενοι) (75e). On the other hand, philosophers can grasp the Forms only when “not dragging perception into their reasoning at all, and when they are using their pure thought itself by itself” (αὐτῇ καθ᾽ αὑτὴν εἰλικρινεῖ τῇ διανοίᾳ χρώμενος) (66a). Let us for now note this problem, and we will return to it shortly.

The theory of recollection is also presented in the Meno, where it is developed as a theory of learning that escapes Meno’s paradox.^[19] The paradox is that we cannot search for either what we know or what we do not know (80d–e). If we know it, then there is no need to search for it. If we do not know it, then we do not know what to look for. The theory of recollection is proposed to explain the possibility of de novo inquiry – precisely by denying that it is de novo. We begin with some latent awareness.^[20] The process of recollection in the Meno is illustrated by a question-and-answer session, rather than by an episode of perception triggering the recollection, as we might expect from the Phaedo.^[21] Still, perception does play an important role: the visual diagram that Socrates and the slave-boy use is present for a reason. Some scholars have denied this to the point that they believe the inclusion of the diagram is evidence that the slave-boy is conducting the inquiry improperly.^[22] However, I think that it is a desideratum of interpretations of the Meno that they paint generally the same picture as the (perception-dependent) one in the Phaedo. For the Phaedo refers to the Meno when it comes to recollection. In the former, Cebes and Simmias are familiar with the theory of recollection, and the text seems to implicitly call back to the earlier dialogue or perhaps even draw upon the same Pythagorean or Orphic source (72e–73b). When Socrates is reminding Simmias about the theory, he even says that perception triggers recollection (73c). To say that perception is not a feature (or even that it is a bug) of the theory in the Meno generates an inconsistency at a point in the corpus when Plato clearly relies on consistency and familiarity.

Perception is important, but the theory of recollection is built on the impossibility of explaining our cognitive lives if we think we had only perception. Instead, the Phaedo claims that we acquired knowledge of the Forms of justice, beauty, and so on, before we were born, lost it at the moment of our birth, and then ought to spend our lives recovering it (75c–e). The Meno and Phaedrus back this claim up. In the former, Socrates appeals to what he has heard about the soul’s immortality and the afterlife from priests (81b–e). In the latter, Socrates tells a complicated myth on which disembodied souls move in the circles of the gods in chariots and try to glimpse the Forms: those who see them can enter into a human body, and during their lifetime, they can use “reminders” of the Forms to recollect what their souls saw before they were born (249a–250b).

I take it that the heart of the theory of recollection is captured by the Meno’s claim that the “truth of the things that are (τῶν ὄντων) is always in our soul” (86b).^[23] We are meant to use perception to trigger the process of recovering these things, and this is not foreign to the Timaeus’ idea of restoring our original condition: there is something buried in us that we ought to recover. The Timaeus left the usefulness of perception at the notional level, whereas the theory of recollection develops it at greater length, but we are left with a question that we briefly explored earlier in this section: it is not clear how perception manages to do this, especially following the denouncement of perception earlier in the Phaedo. Scholars have puzzled over this for decades.^[24] Hackforth (1955, 75), in fact, responds by denying that perception is what triggers recollection. Gulley (1954, 199) argues that the “inconsistencies are due to Plato’s failure to realize the full implications of [the theory of recollection].”^[25] I will argue in the next section that there is no tension or inconsistency at all: perception is useful for restoring the correct condition of the soul, or (equivalently) for facilitating recollection precisely because its objects are deficient, which is why perception is denounced in the Phaedo. This account is meant to add to the Timaeus’ discussion: Timaeus focused on orderly objects, whereas the Phaedo and, as we shall see, the Republic focus on disorderly objects.

3 Summoners

The pivotal text for us is the discussion of the summoners (τὰ παρακαλοῦντα) in Republic VII (522–525).^[26] These are objects (or, more precisely, properties that objects have) that summon our understanding by confusing the soul. For example, one finger might be longer than a second finger but shorter than a third. Our soul would be confused by the combination of shortness and length in one and the same finger: the finger in question is both short and long. In contrast, the property of being a finger is not a summoner since a finger does not appear to the soul to also not be a finger in the way that it appears to be both tall and short. These perceptions are “adequate” (ἱκανόν) (523b). Plato thinks that a discussion of summoners is crucial for understanding the soul’s cognitive development in the Republic, which portrays education as a reorientation of the soul. Summoners accomplish just this reorientation. There is, however, a difficult question of what summoners summon. Socrates gives an array of answers: they summon our νοῦς (523d4, 523d8, and 524b4), our διάνοια (524d2), and our λογισμός (524b4).

The abundance of answers reflects the variety of possible summoners. Summoners help our soul move upwards on the divided line. There, the lowest category is imagination (εἰκασία), then belief (πίστις), then thought (διάνοια), and the highest is reason (νοῦς). Our soul can be summoned from, say, belief to thought or from thought to reason, but the summoners in each case will be different. Someone who has stagnated at the level of πίστις might be confused by sensible objects and have their διάνοια summoned, but someone who has graduated to διάνοια would be confused not by sensible but by mathematical objects, which would summon their νοῦς instead.^[27]

The Republic’s discussion bears this out: Plato spends more time discussing mathematical summoners than sensible objects. He initially defines summoners in terms of perceptions but then uses that schema to understand how to reach the highest mode of cognition, which first requires a lengthy study of mathematics.^[28] For most of the time that someone is enrolled in Plato’s education system, they will have already turned towards mathematics and away from the sensible world, which explains why the focus in this section is on mathematics. The phenomenon of summoning is clarified by sensible objects, which are more obviously contradictory in nature than mathematical objects are. Summoning is said to occur “whenever perception no more presents one thing than its opposite” (523c).^[29] The example of a finger being long and short, or of Helen of Troy being beautiful and ugly, illustrates this well (525a). The conclusion that Plato draws from this is that the art of calculation is essential for the philosophers-in-training because it will lead their souls upward.

However, by focusing too much on the way that Plato plans to use summoners in his education system, we miss that the confusion that prompts summoning is ordinary. The text says that summoning can initiate our cognitive development: sight, for example, perceives big and small together in the same sensible object, which prompts us to reflect on how this can be, and it is “from these cases that it first (πρῶτον) crosses our mind to ask what the big is and what the small is” (524c). The more decisive evidence that the confusion is ordinary is that the properties Plato lists as examples are all ordinary: e.g., dark, pale, thick, thin, hard, and soft (523e). The fact that there are also complicated mathematical properties such as one and unlimited reflects that summoning is useful at multiple stages of our education, and the ambiguity of what is being summoned (e.g., νοῦς or διάνοια) captures this too.

Yet, it does not follow from the ordinariness of the confusion that summoning happens frequently. The discussion of summoning begins with this remark about the art of counting:

It [that is, the art of counting] might very well be one of the subjects we were seeking after that lead to reasoning (νόησιν), but nobody uses it correctly, even though it is in every way suited for dragging someone towards being (523a).

If mere perception of something both big and small led to cognition of the Forms, then everyone would be a philosopher, so here Plato explains why very few, if anyone, have the highest kind of cognition: summoners are not being used to summon. This anticipates an important point, namely, that it is not the perception that is doing the work. It is the reflection prompted by the perception. Lovers of sights and sounds, for instance, are living as if in a dream (476c). The summoners might rouse them from this dream – and, indeed, the Republic’s theory of cognitive development explains how this rousing happens – but it will not be because they perceive enough beautiful things. It will be because they reflect on how those things can be both beautiful and ugly.

It is in this context that Plato has been accused of misunderstanding how relations work.^[30] The criticism is that Plato infers from ‘x is beautiful in comparison to y’ and ‘x is ugly in comparison to z’ that x is both beautiful and ugly and thus that the sensible world is filled with contradictions, and that this move is illegitimate. The problem is treating a relation as though it were a property. This criticism is mistaken, at least as far as concerns the discussion of summoners, and seeing how it is mistaken clarifies how summoners work. Plato’s claim here is that perception presents a finger to us as, say, thick. The content of the perception is an unqualified report. We do not ordinarily perceive things as bigger than other things, unless we are perceiving one thing right next to another.^[31] Consider as well when we taste some food: we do not taste the food as more delicious than some other food. We taste the food as delicious. When Plato is talking about properties here, he is talking about them as perception reports them to us.

It is true that we can resolve the confusion caused by perceiving a finger as both big and small by specifying in relation to what (πρός τι). This does not mean that Plato is mistaken when he represents perception of bigness as perception of a property instead of a relation. In fact, the discussion of summoners requires that he not be making this elementary mistake. We are supposed to resolve the confusion by thinking about what perception tells us. We are supposed to specify πρός τι. This is the cognitive action that ought to follow confusing perceptions: we should think about the big and the small and use them to make sense of what we perceive.^[32] The criticism that Plato has treated a relation as a property does not hit its mark, for his point was that perception reports relations as properties, and the confusion that this generates is resolved by further reflection on how this works and, eventually, the Forms. It is precisely because the relational nature of, say, thickness or deliciousness is so unclear that our reason is summoned when the soul reflects on it. We need the Forms to make sense of what we perceive.

It is also unclear how we should understand perception’s report that, say, this finger is big or this finger is small. Scholars have sometimes interpreted the position in this passage to be that perception alone, with no help from anything else in the soul, can make judgments.^[33] This is usually paired with a view that Plato first distinguishes between perception and belief only in the Theaetetus.^[34] This interpretation misreads Plato’s vocabulary. His choice of verbs here matters: he will often speak of perception as presenting (δηλόω) two opposed properties. Perception presenting something to us does not entail that it has made a judgment, whatever that might mean. Yet, the other reading is correct that there does have to be a judgment here. Summoning is a description of a familiar moment: we are presented with something, make a judgment about it, and then think ‘wait, that cannot be right’, and then think through our initial judgment and confusion. The hope is that we end up in a better condition than where we started, and in the Republic, this is ensured by the regimented education system that guides our reflection and revision. If we do not make any judgments, we have nothing to think through. It just does not follow that perception alone is making the judgment, especially when Plato’s vocabulary does not suggest that.^[35]

Perception is useful for us because confusion (ἀπορία) is useful for us. There is something familiarly Platonic, or Socratic, about using ἀπορία as a constructive pedagogical tool. When we consider the character Socrates’s use of ἀπορία generally, we see that he tends to use it to initiate a process of learning.^[36] Summoners are the first step. They provide a template for the kind of education that the ideal city’s guardians should receive. They might even provide a helpful way of thinking about Platonic dialogues. Some scholars have recently argued that the contradictions within and between Plato’s texts are not unlike the way that sensible objects are apparently contradictory, and that these contradictions are intended as prompts for us to think for ourselves.^[37]

It would be a mistake to think that everything we perceive is a summoner. I said above that there are so-called adequate sensible properties that are not always accompanied by their opposites, such as being a finger. Moreover, there is the discussion of model sensible objects in the Timaeus that we explored in the first section: the harmonies that we perceive in the cosmos and that we hear furnish us with a model for restoring our own disordered souls. We might even, for a moment, think that Plato is optimistic about the sensible world, but, in fact, his point is that our cognitive development is so important that we should use every tool at our disposal. Let us imitate harmonious music and the motions of the celestial bodies when we can. The ordinary person, however, will not be naturally disposed to see the celestial bodies as something we should or even can imitate at all. To get to that higher stage in our development, we should first be summoned by the confusion of the sensible world. The confusion is the way that perception harms us. The invitation to think through the confusion, hopefully with guidance, is the way that it helps us.^[38]

4 The Soul’s Instrument

Now that we have seen that perception is useful for our soul’s perfection, we should discuss the body generally as the soul’s instrument.^[39] We need the body to be presented with sensible objects that trigger recollection in the Phaedo. We need the body so much, in fact, that we might forget that the reason we need the body in the first place is that embodiment disrupted our psychic functioning. At the end of the second section above, we saw that scholars have puzzled over how the Phaedo could value perception so little while also holding it up as the spark of recollection. Plato’s reasoning makes sense if we view the disruptive moment in perception as prior to the constructive moment when we reflect on perception’s confusions. Moreover, the larger point is that perception is instrumental. The discussion of summoners in the Republic advances this idea by speaking explicitly about correctly using ontological deficiency as a tool for our soul’s perfection.

We know from the Timaeus that our bodies are created by the gods and that each part of our body achieves a purpose for us: the eyes, for example, allow us to see the heavenly bodies and thus do philosophy. Some of Plato’s writings, though, give the impression that the soul itself is somehow responsible for the body being what it is. Indeed, there are times when Plato speaks like our soul determines our body in some specific, focused way. Consider the way that Thersites’ soul “clothes itself as a monkey” in the myth of Er (Resp. 620c). Another example is living in a way that earns a reincarnation as a shellfish (Ti. 92b). The general principle is that we choose our own bodies, and thus that our soul and body are well-suited to each other. Thersites had lived such a buffoonish life by criticizing Agamemnon in the Iliad that he would never have chosen any other body: there is an appropriate kind of fit between body and soul here. The body depends on the soul in the way that, if Thersites’ soul had been different, so would his body be different.

That we have exactly the body that we need to have is what Plato captures by saying that the body is our tool or instrument. The eschatological and theological contexts here are essential. In the first section above, Plato argued that the gods gave us eyes so that we could see the motions of the heavenly bodies and apply them to the disordered motions of our own soul. This is a clear example of our having the body that we need to have. When we consider myths in which we ourselves choose our bodies (such as the myth of Er), we choose the bodies we think we need to have, in the sense of what bodies we think are good for us, whereas the human body constructed by the gods is the only one that is, in fact, useful for us. The body of a shellfish is a punishment precisely because it is not useful for us. Atalanta was a famous huntress who chose to be reborn as a man because she wanted the honors that she thought she could get only as a man (Resp. 620b). Agamemnon chooses to be an eagle because he hates humanity (ibid.). These are examples of people choosing bodies that they think they need: the bodies are useful for getting what they want out of life, whether that is honor or just avoiding being born by a woman, like the misogynistic Orpheus when he chose to be a swan (620a).

It is an interesting historical fact, then, that Aristotle in De Anima criticizes proponents of reincarnation for not developing a tight enough relationship between soul and body:

Something absurd follows for this account concerning the soul and for most others, for they attach the soul to the body and place it in the body without specifying the cause of this or what the body is like. However, this might seem to be necessary: for on account of their relationship (κοινωνία), one acts and the other is affected, and one moves and the other is moved, none of which belongs to (ὑπάρχει) things that just happen to be related to each other. But these accounts merely try to say what the soul is, without specifying the body that is about to receive the soul, as if it were possible, like the Pythagorean myths say, for the soul to be clothed in any body whatsoever. For each body seems to have its own distinct form and shape, but what they say is nearly the same as saying that carpentry could clothe (ἐνδύεσθαι) itself in flutes; for it is necessary that a craft use its tools (τοῖς ὀργάνοις) and that a soul use its body (I 3.407b14–27).

Plato is the target of this criticism. Firstly, there is the reference to the myth of Er: Thersites’ soul clothed itself in the body of a monkey, which Aristotle thinks is almost as absurd as saying that carpentry could clothe itself in flutes. There cannot be such a mismatch between soul and body, the criticism says. Secondly, the words ‘this account’ in the first sentence single out Plato’s psychology, especially in the Timaeus, which was the focus for the past few pages in the same chapter and which Aristotle had named specifically as his target at the start of the round of criticism (I 3.406b26).

The criticism is that Plato and others who believe in reincarnation allow bodies and souls to be mismatched. A belief in reincarnation as other kinds of animals requires a belief that bodies and souls are so separable that a soul can go from being in the body of a human to being in the body of a monkey or a shellfish. Aristotle is not criticizing other theories on which a human soul will be reincarnated necessarily as a human again and again.^[40] The first part of the criticism claims that Plato does not adequately explain the relationship (κοινωνία) between soul and body; there is, therefore, a lack in Plato’s psychology.^[41] The second part is that, without specifying this relationship, Plato misses the fact that the soul uses the body like a craft uses its tools and that we cannot explain how the two move and affect each other.

I submit that Aristotle’s criticism misses its mark: it might successfully undermine Pythagorean theories, which he also identifies as a target here, but it misrepresents Plato’s psychology. The foregoing discussion of perception confirms that we have exactly the body we need to have: the body’s perceptual capacities are designed for the soul’s well-being. As well, the liver is designed to help reason rein in the appetites (Ti. 71a–b). The spleen exists as a napkin to clean up the liver (72c). The coiled intestines allow us to go longer without food, or else we would be such a slave to our appetites that doing philosophy would have been impossible (73c). The lower gods are carrying out the Demiurge’s order that they “make our species as excellent [ἄριστον] as possible” (71d). The lower gods “bound organs inside the body out of complete forethought for the soul” (45b). Accordingly, we can point to every single constituent of the body with reference to how it serves our soul. The most interesting for us in this study has been the eyes, which let our soul perceive the heavenly bodies and so restore our soul’s original condition. Aristotle is missing this teleology or instrumentality. Some scholars have claimed that at the heart of Aristotle’s criticism is a complaint that Plato cannot explain why our souls do not end up in, say, a book.^[42] If this is the right interpretation, then Aristotle is missing the way that the gods have carefully designed the system of reincarnation and the way that we choose our own bodies.^[43] There is no randomness so long as we bear in mind the teleology of soul-body relationships.

I suspect that part of the disagreement is that Aristotle believes that one function of the soul is to manage the body, whereas Plato thinks that the body functions as the tool of the soul.^[44] The various bodily systems were set up by the gods in order to serve the soul; the soul does not contribute to that. Of course, there is another class of bodies that our souls are not suited for in the same sense, even though we might end up in them: namely, animal bodies. There is no doubt that animal bodies frustrate the soul’s activity much more than being born in a human body, but that is precisely the point. The gods have designed the system of reincarnation such that there is a perfect fit between soul and body yet again, but it is not a helpful, constructive sort of fit. Instead, it is punitive. A human is reborn as a shellfish whose “penalty for extreme stupidity is the extreme dwelling place” (92b). Another fate is being reborn as a land animal whose head is close to the ground because they did not spend the time as a human studying the cosmos (91e). It is not only that this is a punishment but that these are the bodies we choose: we choose to be a land animal by choosing to neglect the cosmos. Thersites chooses to be a monkey because he is just that buffoonish. He is suited for this body in the sense that it reflects who he has made himself, although his soul’s proper activity is not served by this body. The gods have carefully provided for animal bodies as much as for human bodies, but the aim of the provision is different: instead of carefully stewarding the soul back to its original condition, animal bodies punish us for our choices.

It is for this reason that focusing on the instrumentality of the body for the soul is key. The ethical dimension of this relationship stresses that the body is something that our souls use and ought to use well. There is a protreptic quality to this account. The most important statement of this as Plato’s position comes in the Alcibiades (129e) at a point when Socrates is convincing Alcibiades to care for himself.^[45] The body is not what we are, but it is our tool. There is something defective about a person who cares for the body as an end in itself or as his or her self, rather than caring for it as an instrument. People who use their soul to satisfy the needs of the body, instead of using the body to satisfy the needs of the soul, have made a great error. Plato does not have the worked-out vocabulary that would allow him to think about the soul-body relationship as necessary or contingent. What he settles on instead is a middle position of instrumentality: a relationship that is so tight that our body is as well-suited to our souls as possible but weak enough that we can aspire to the permanent separation of soul and body.