THE EVIDENCE

Although in contemporary scholarship, the definition of beauty as summetria of parts with each other and with the whole has not received much attention,Footnote ² this is not due to the lack of evidence, because it has a relatively prominent presence in ancient texts. Arius Didymus, Plotinus, Galen and Cicero record this Stoic definition.Footnote ³ They also typically attribute it simply to ‘the Stoics’. Galen's On the Doctrines of Hippocrates and Plato is the only source suggesting that this definition is attributed to Chrysippus. Galen notes that Chrysippus distinguished between the health and the beauty of the body by stating that health depends on the proportion of elements, while beauty depends on the proportion of parts. Then Galen cites the Chrysippean definition of beauty as follows:

Although Galen attributes the definition of visual beauty as summetria to Chrysippus, he does not explicitly write that Chrysippus is the author. It is possible that Chrysippus was merely working with a definition proposed by Zeno or even some other Stoic. Yet, even if Chrysippus is not the author of this definition, the only clear surviving attribution refers to him; therefore, he must have at least advocated it.Footnote ⁵

Galen's record of the Stoic definition appears to refer to visual beauty alone, as is evident from the fact that he used the term τὸ κάλλος for beauty and the proportionality of the limbs as an illustration. Other sources, however, emphasize that summetria explains both visual and intellectual or moral beauty. Since ethical questions play an important role in the Stoic corpus overall, it is likely that the definition was supposed to account for both the beauty of the body and the beauty of the soul. The extended versions of the definition that include the beauty of the body and of the soul, moreover, are not only more prevalent but also more uniform. Plotinus, for instance, recorded and elaborated the Stoic definition of beauty as summetria of parts with one another and with the whole. This passage, which can be found at the beginning of Plotinus' On Beauty, contains the following statement:

Despite the fact that Plotinus claimed he criticized a view held by ‘almost everyone’, it is generally agreed that the target of this critique was the Stoic definition of beauty.Footnote ⁷ Galen's reference to this definition shows that it was held by the Stoics as early as Chrysippus. The idea criticized is not easily mistakable with the views held by any other ancient philosophical school.Footnote ⁸ Plotinus made it clear that he attacked the theory that posited summetria as the sole explanation for the presence; in his view, summetria can be a part of beauty, but it is not a full explanation. The aim of his attack is an account that suggests that summetria fully accounts for the existence of beauty as the only relevant factor, because, according to Plotinus, beauty cannot be explained by the presence of summetria alone.Footnote ⁹

Yet, perhaps the best reason to assume that Plotinus is citing the Stoic idea is that the definition he recorded can be cross-referenced to other sources, which clearly attribute it to the Stoics. Arius Didymus, for instance, not only records this definition, but also elaborated on the idea that Plotinus only mentioned briefly, namely, that the same phenomenon—summetria—accounts for the beauty of both the body and the soul.Footnote ¹⁰ This fragment is found in Stobaeus' Eclogae, among excerpts from Arius Didymus' Epitome of Stoic Ethics. The Stoic definition of beauty is cited as follows:

Similarly, Cicero, when discussing the notions of health and disease in his Tusculan Disputations,Footnote ¹² stated that, according to the Stoics, good proportion is responsible for both the beauty of the body and the beauty of the soul. It has been shown that Cicero's source for the Tusculan Disputations is very likely Chrysippus himself and, more importantly, that Cicero is using On Emotions, the same treatise as used by Galen in On the Doctrines of Hippocrates and Plato.Footnote ¹³ This is possibly quite a significant fact to take into consideration, because Cicero's formulation of the definition includes some additional conditions not mentioned by Galen as follows:

Here, just as in Plotinus' passage, colour, as well as summetria of limbs, is said to constitute bodily beauty of human beings. The beauty of the soul consists not only of consistency among beliefs but also of stability. It is hard to determine when these conditions were added to the Stoic definition and what role they were intended to play. I have already mentioned that Cicero and Galen very likely used the same treatise by Chrysippus as their source. It might be the case that the conditions present in Cicero but not in Galen are due to Cicero's interpretation. It is worth noting, however, that colour is mentioned by Plotinus as well. Unless Plotinus used Cicero as his source, for which we do not have evidence,Footnote ¹⁵ it is unlikely that it is simply Cicero's interpretation. It is also possible that the colour requirement in visual objects might have been included in response to a criticism. In his Ennead 1.6, Plotinus criticizes the advocates of summetria by arguing that this theory of beauty does not explain how colour can be beautiful.Footnote ¹⁶ This criticism is very pertinent, as it is indeed difficult, if not impossible, to account for the beauty of colour by means of summetria, which typically refers to certain proportionality or ratio. It is quite possible that Plotinus was not the first to point out this shortcoming; therefore, requirement for the ‘charm’ of colour was added by one of the Stoics (possibly even Chrysippus himself) as a response.

The requirement of steadiness and stability for the beauty of the soul is found only in Cicero. It refers to a tranquil state of mind unperturbed by strong emotions and wrong beliefs. One possible reason why the condition is found here would be the context in which Cicero records the Stoic definition, namely, the Stoic treatment of emotions and the Stoic concept of mental health.Footnote ¹⁷ It is quite likely that Cicero put an emphasis on steadiness/stability for this reason, and that is why it is not found in other sources.

In all the cited passages, the central part of the Stoic definition is the simple statement that beauty is summetria or the proportionality of parts with each other and with the whole. The most straightforward and obvious interpretation of the Stoic notion of summetria is that it conceptualizes beauty as proportionality. According to such a reading, summetria of parts with each other and with the whole means that all the parts have a harmonious ratio with each other, such as exemplified by Polycleitus' Doryphoros or described in Vitruvius' De Architectura.Footnote ¹⁸

The harmony of beliefs and cognitive functions required for the beauty of the soul could be interpreted in a similar way. Richard Bett argues that ‘it is clear that, according to the Stoics' conception of the soul, reason or the hēgemonikon has a number of different aspects or functions, and that, in the wise person's soul, these aspects or functions will complement one another and fit together in a felicitous and harmonious way’.Footnote ¹⁹ This understanding of summetria reflects the way in which this term was used in the previous philosophical tradition.

SUMMETRIA BEFORE THE STOICS

After citing Chrysippus' definition of beauty as summetria, Galen claims that it is the same as, or very similar to, the definition of beauty proposed by Polycleitus in his Canon. Scholars tend to interpret Polycleitus' theory as referring mostly to a ratio or an internal composition of an object.Footnote ²⁰ The phrasing used by Galen supports such a reading. After stating that Chrysippus' definition is the same as the definition proposed by Polycleitus, Galen added that Polycleitus was the first to give τὰς συμμετρίας of the body as well as making a statue in accordance with his theory.Footnote ²¹ Since Polycleitus is cited as talking about summetria in the plural, it does seem that in his work this term refers to specific ratios that govern the internal structural properties of a beautiful statue,Footnote ²² provided that Galen is quoting him accurately.Footnote ²³ The term summetria is associated with aesthetic properties by many philosophers as well, most notably Plato and Aristotle. They use this term differently from the Stoics, however. Plato often employs the term summetria to denote good proportion,Footnote ²⁴ measurements or ratioFootnote ²⁵ and even appropriateness.Footnote ²⁶ While these phenomena can be pertinent to the discussions of beauty, none of these passages explicitly describes beauty as nothing over and above summetria. Moreover, in Plato's philosophy, forms play a major causal role. Objects gain such properties as beauty by partaking in the form of beauty.Footnote ²⁷ The unity among partsFootnote ²⁸ is also an important factor. In Platonic metaphysics, then, summetria might be a relevant factor for being beautiful (although it is impossible to assert that with certainty), but it does not fully explain the presence of beauty in an object.

Aristotle, just like Plato, does not equate beauty with summetria entirely, yet summetria features in the passages where Aristotle does some work to define beauty. For instance, in Metaphysics M, in Physics and in Topics Aristotle groups summetria together with order and definiteness as the main conditions for beauty.Footnote ²⁹ Other passages, however, indicate that summetria is not a sufficient condition for beauty. According to Aristotle, the existence of beauty requires the presence of both good proportion (summetria) and magnitude. Without the latter, an object cannot be called beautiful. This is made very clear in Nicomachean Ethics, where Aristotle claims that, in order to be beautiful, a body must possess magnitude and therefore short people can be well proportioned but not beautiful.Footnote ³⁰ The requirement for both summetria and magnitude can be found in Politics Footnote ³¹ and Poetics Footnote ³² as well. This is significantly different from the way in which the Stoics employed the notion of summetria. According to these passages from Aristotle's works, summetria can occur independently of beauty. While it can be found in some beautiful phenomena, beauty cannot be explained by the presence of summetria alone. The Stoic definition of beauty as summetria therefore differs from the ways in which Plato and Aristotle use the term.Footnote ³³

PLOTINUS' CRITIQUE

In Plotinus' Ennead 1.6, the Stoic ideas mostly serve as a foil for presenting Plotinus' own account, yet his critique raises some significant—and possibly enlightening—questions about the Stoic definition of beauty. Plotinus starts Ennead 1.6, traditionally labelled On Beauty, by raising some general questions of whether the nature of beauty is the same in different kinds of objects and what it is that attracts the eye to beautiful things. Then he proposes that there is a principle that bestows beauty on objects, and states that it is the form of beauty.Footnote ³⁴ Before the further exposition of his own ideas, Plotinus presents the following critique of the alternative account:

Plotinus' critique consists of a series of cases that exemplify objects or phenomena, which, according to him, the Stoic definition of beauty could not account for. One of the most significant of these objections is that nothing beautiful can be made of parts that have no beauty themselves.Footnote ³⁶ This criticism raises the question of the metaphysics of the Stoic concept of aesthetic properties. It is an important issue that ought to be addressed in order to understand the implications of the Stoic definition of beauty.

In addition to this, Plotinus asks how summetria can account for the beauty of such phenomena as laws, customs, virtue and even intellect itself. He writes that his opponents cannot mean that these phenomena are beautiful in virtue of being ‘in harmony’, because vices and wrong beliefs can be in harmony with each other as well and thus they ought to be beautiful too.

This is a powerful critique, possibly designed to showcase the strengths of Plotinus' own theory. In Ennead 6.7, Plotinus states that an uglier living man is more beautiful than a statue of a beautiful man, because ‘the living is more desirable; and this is because it has soul; and this is because it has more the form of good; and this means that it is somehow coloured by the light of the Good, and being so coloured wakes and rises up and lifts up that which belongs to it, as far as it can makes it good and wakes it.’Footnote ³⁷ According to Plotinus' theory, the form helps to establish an exclusive relationship between beauty and the good. Plotinus employs the notion of forms in order to account for the phenomena that, according to him, summetria cannot account for.

The Stoics are indeed committed to the view that there is a connection between the good and aesthetic properties, and vices are not able to form such a connection; consequently, Plotinus' critique is very relevant. There is, for instance, extant evidence showing that Chrysippus and other Stoics employ syllogisms to prove that only the beautiful is the good.Footnote ³⁸ These arguments show the Stoics maintaining that there are important connections between beauty and morality. There is another pertinent piece of evidence in Plutarch's Against the Stoic on Common Conceptions. When criticizing the Stoic theodicean argument that even apparently bad things are not truly bad, Plutarch argues that the Stoics are contradicting themselves, because they also state that evils are not good or useful for human beings, as follows:

The fact that the Stoics deny the assignment of beauty to vice raises the question of whether they could have defended themselves against Plotinus' accusation that their definition of beauty does not rule out the possibility of vices, as well as of virtues, being beautiful. As Plotinus rightly notes, mere good composition and the fitting together of parts do not sufficiently explain why abstract and especially moral objects are beautiful,Footnote ⁴⁰ and if the Stoic theory had no answer to this problem, it would constitute a serious shortcoming. Thus Plotinus raised two problematic questions: how is it possible that the whole is beautiful when parts lack beauty, and how could the Stoics say that virtues—but not vices—possess beauty.

SUPERVENIENCE

Plotinus argues that the Stoic conception of beauty implies that aesthetic properties depend on bases that are unrelated to these properties. If Plotinus' critique depicts Stoic claims accurately and they account for beauty in this way, then they subscribe to the view that aesthetic properties supervene on non-aesthetic properties. Such a claim is not necessarily a drawback, despite the fact that it is presented as such by Plotinus. Conceptualizing aesthetic properties in this way would have been not only an original stance but also a very substantial theoretical contribution to ancient aesthetics.

The verb ἐπιγίγνεσθαι, found in several sources on Stoic views on virtue, shows how the Stoics employ the notion of supervenience.Footnote ⁴¹ Diogenes Laertius, for instance, records that one of the Stoic definitions of the good is ‘the natural perfection of a rational being qua rational’, adding that such a thing is virtue, virtuous acts and men. Then it is added that joy and gladness supervene on virtue. Similarly, despair and moroseness supervene on everything that partakes in vice.Footnote ⁴² Joy and gladness, then, are novel properties that are dependent on virtue. An even more revealing passage comes from Cicero's On Ends. Here, the Stoics are reported as claiming that the property of being ‘artistic’ is unlike the property of being ‘wise’, because the former is applicable only subsequent to the activity, whereas the latter is applicable from the outset. This is due to the fact that the wise act is an end in itself. Some actions are said to be bad owing to their consequence, but others bad in themselves, so the virtuous actions can be judged right from their inception.Footnote ⁴³ The example chosen as a contrast to a virtuous act in this passage is especially illuminating. Virtuous actions are done for the sake of themselves and the virtue of such actions depends on the agent; consequently, virtue follows from virtue. The property of being artistic, by contrast, depends on properties that cannot properly be called artistic; presumably the examples of such non-aesthetic properties would be the stone for the statue; consequently, the aesthetic properties of a finished artwork would follow from non-aesthetic properties. There is, in addition to this, an explicit statement in Stobaeus that beauty supervenes:

Although this passage is not attributed to any specific Stoic, Teun Tieleman convincingly argues that it is quite probably based on Chrysippus' On Virtues, with a minor variation.Footnote ⁴⁵ The central argument here is the juxtaposition of power (δύναμις) and expertise (τέχνη). It is best understood as a claim that ‘certain qualities of the soul cannot be directly influenced by reason, i.e. through acts of assent. Strength of character and inner harmony lend an additional quality to mental life; hence they are said to supervene on the theoretical virtues.’Footnote ⁴⁶ Beauty, health and strength are ‘powers' that depend on training. The passage precedes the definition of beauty as summetria by Arius Didymus cited above, which states that summetria of limbs and summetria of beliefs are responsible for the beauty of the body and the soul respectively. In both cases, beauty supervenes on the composition of parts. In the case of bodily beauty, the composition or structure of limbs renders a body beautiful. In the case of the soul, it is the structure, arguably a coherent structure, of beliefs that renders it to have a certain aesthetic property as well.

If beauty is conceptualized as a kind of property that supervenes, then it can depend on non-aesthetic properties, and the Stoics could be defended against the charge of Plotinus. The second criticism issued by Plotinus, however, presents another challenge. Summetria, as it was shown above, is typically understood as proportionality of parts. If this is the case, as Plotinus' critique implies, then vice can be beautiful as well, since nothing seemingly prevents a vicious mind to be harmoniously vicious. I would argue, however, that the Stoic definition could be defended even against this criticism, if it is read as stating that beauty supervenes not on just any kind of proportionality of parts but on the proportionality which enables an object to perform its function well.

FUNCTIONAL COMPOSITION

Functional beauty, in this case, is the idea that beauty depends not only on the structural properties of an object, such as the ratio among parts, but also on how those structural properties allow the object to fulfil its role as that kind of object.Footnote ⁴⁷ Different ratios and proportions, for example, are generally considered to be beautiful in a family house and a Gothic church. The properties of these two kinds of buildings would differ based on their respective functions, and beauty in each case would depend not merely on being well-proportioned but on being well-proportioned with regard to what is appropriate to that kind of building. Whereas a high ceiling and good acoustics typically contribute to the beauty of Gothic churches, very different properties are typically found in family houses that are deemed good and beautiful. Beauty is functional in the sense that it depends not only on the internal structural properties of an object but also on how well those properties enable their owner to function as an object of that kind.

It is not uncommon to discuss functionality as one of the aspects of beauty in Greek philosophy. Plato's Hippias Major contains a discussion of functional beauty, although, ultimately, this account is rejected.Footnote ⁴⁸ A similar attempt to theorize beauty can be found in Xenophon's Memorabilia.Footnote ⁴⁹ Aristotle uses the term τὸ καλόν when describing teleological functionality of animals.Footnote ⁵⁰ I will argue that this notion plays an important role in the Stoic conceptualization of beauty.

The notion of functional beauty can be read as a teleological claim, but I would argue that in these cases it is more appropriate to adopt the language of an excellence. The concepts of telos and excellence are, of course, related, but excellence is a particularly useful notion for discussing aesthetic properties.Footnote ⁵¹ When writing about Aristotle's use of τὸ καλόν, Kelly Rogers notes that one of its references is ‘functional excellence’. She illustrates this meaning of τὸ καλόν by citing a passage from Xenophon's Memorabilia, in which Socrates described the shield as beautiful, because it did not impede the use of hands while protecting vulnerable parts.Footnote ⁵² While all the shields have the same end, their excellences may vary. Both a hoplite's shield and a primitive woven shield, for instance, protect their bearers, so both of them achieve their end, but the hoplite's shield has certain advantages that make it excel at its function. Beauty, therefore, can be understood as resulting not just from achieving a certain end but also from achieving that end particularly well, that is, having a certain excellence.

The notion of aesthetic functionality can be found in the Stoic notion of τὸ πρέπον (decorum in Latin), attributed to Panaetius. Possibly the best source for Panaetius' views, including this one, is Cicero's On Duties. It is clear that τὸ πρέπον has aesthetic, and functional, meaning in the following passage, which portrays τὸ πρέπον as analogous to bodily beauty:

The analogy with visual beauty indicates that τὸ πρέπον is an equivalent of the bodily proportionality (‘appropriate arrangement of limbs', to be precise), but it belongs to the sphere of action. Human beings delight in τὸ πρέπον of actions in the same way as they delight in the arrangement of limbs. It is not very easy to pinpoint what exactly τὸ πρέπον is. A useful definition is offered by Andrew Dyck, who suggests that it ‘is a concept without a content of its own; it merely sets up a proportional relationship between two terms'.Footnote ⁵⁴ I would argue that this relationship can be described as functionality, in the sense that an act which exhibits τὸ πρέπον is in accordance with the agent's nature or function. The passage cited above as well as a number of other remarks in On Duties indicate that the notion of τὸ πρέπον is tied to what is natural or in accordance with the nature of human beings. The source of τὸ πρέπον—regardless of whether the issue is a human body or mind—are nature's laws.Footnote ⁵⁵

The functional aspect of τὸ πρέπον is also evident in the comparison of the appropriate character in poetry and real life. The poets are said to observe seemliness ‘when what is said and done is worthy of the role’.Footnote ⁵⁶ When some immoral phrase or speech fits the character of the immoral person in a play, it is applauded and admired because of τὸ πρέπον (yet, this would not be the case if the same was uttered by a noble character). This claim is immediately succeeded by the further clarification that in poetry, unlike in real life, τὸ πρέπον can apply to various characters, including the bad ones. In real life, on the contrary, τὸ πρέπον applies only to virtues, because ‘our parts have been given to us by nature: since they are the ones of constancy, of moderation, of restraint, of a sense of shame’.Footnote ⁵⁷ The beauty of the soul, as explained by τὸ πρέπον, then, derives from achieving our telos—or fulfilling our ‘function’—of living in accordance with our nature as rational virtuous agents.

One might raise the question of whether it is permissible to use the notion, typically attributed to Panaetius, to interpret the definition of beauty advocated by philosophers as early as Chrysippus. Giovanni Lombardo in his L'Estetica Antica, for instance, reserves functional connotations to the term τὸ πρέπον and suggests that summetria refers to internal structural properties alone.Footnote ⁵⁸ Cicero's On Duties contains a comparison between τὸ πρέπον and honestum, the Latin equivalent of τὸ καλόν, but τὸ καλόν, the beautiful, is not the same as τὸ κάλλος, beauty. Τὸ καλόν plays an important role in ethics, as it has ethical connotations, whereas τὸ κάλλος tends to be used when describing visual beauty. Despite their differences, I would argue that it is possible to treat them as related for the purposes of the current paper, and especially with regard to functionality. The main piece of evidence for this is Diogenes Laertius' passage, which states the following: ‘the reason why they characterize the perfect good as beautiful is that it has in full all the measures required by nature or has perfect proportion’.Footnote ⁵⁹ Here, the good is said to be beautiful because it has perfect proportion, that is, it is summetros. It is quite probably a reference to the definition of beauty as summetria. After all, most of the surviving evidence for the definition of beauty as summetria states that it accounts for beauty both in the body and in the soul. The beauty in the sphere of ethics (τὸ καλόν/honestum), then, can be treated as an example of the summetria of the soul.

Now let us consider the relation between honestum and τὸ πρέπον in order to determine whether the functional connotations of the latter also apply to the former. In On Duties, honestum and τὸ πρέπον are described as distinct,Footnote ⁶⁰ but the difference between τὸ πρέπον and honestum is hard to outline clearly, partly because of textual difficulties and partly because of conceptual vagueness, since the difference between them is said to be more easily grasped than explained.Footnote ⁶¹ Despite the conceptual distinction between the two, there is also a strong connection, because what is τὸ πρέπον is honestum and what is honestum is τὸ πρέπον. Moreover, everything just is πρέπον, but what is unjust is lacking in honestum and is unseemly.Footnote ⁶² According to Andrew Dyck, ‘Panaetius evidently regards to prepon as an infallible sign of the presence of the kalon … Moreover, unseemly behaviour would, according to 94, appear to be a sure sign of the absence of the kalon.’Footnote ⁶³ It follows, then, that honestum is a necessary and sufficient condition for τὸ πρέπον and it is not reasonable to treat these two notions separately. We can distinguish them conceptually (just as On Duties indicates), but they necessarily coincide.

Although it has been argued that τὸ πρέπον was introduced by Panaetius specifically, there is no need to treat this notion as strictly existing outside the conceptual framework of the early Stoics. Functional interpretation of beauty may very well have predated Panaetius within the Stoic tradition, and τὸ πρέπον can be said to be Panaetius' notion in the sense that he put a special emphasis on it. If summetria is a feature of honestum, and honestum necessarily coincides with τὸ πρέπον, a notion with a strong functional aspect, then summetria can be related to the functional theory of beauty as well. This is not, however, the only evidence for the functional aesthetics in Stoicism.

The world more generally is described as exhibiting a certain functionality, according to some Stoic arguments. Some support for the functional theory of beauty can be found in Cicero's De Natura Deorum, among the theological arguments presented by Balbus, the Stoic spokesperson. Balbus mostly advocates the view that the world was generated rationally by the god and not by an arbitrary motion of atoms, as the Epicureans claim. One of the proofs for the Stoic theory is the argument from the beauty of the world.Footnote ⁶⁴ Balbus' arguments, furthermore, contain a number of descriptions of the beauty of the world, and some of these descriptions link functionality with beauty.

For instance, when attempting to prove that the world was made for humans' sake, Balbus argues that the motions of the sun, the moon and the rest of heavenly bodies are not only functional (by contributing to the maintenance of the world) but also beautiful.Footnote ⁶⁵ Providence or the world-mind, according to Balbus, has three objectives: ‘to secure for the world, first, the structure best fitted for survival; next, absolute completeness; but chiefly, consummate beauty and embellishment of every kind.’Footnote ⁶⁶ The world could not have been better with regard to either utility or beauty as its parts exhibit exceptional coherence.Footnote ⁶⁷

The functionality of the world can be described in metaphysical terms. Plutarch reports that, in his On Motion, Chrysippus argued that ‘the world is a complete body, but the parts of the world are not complete because they are in certain ways relative to the whole and are not per se’.Footnote ⁶⁸ The category of being relatively disposed, the fourth category in the Stoic theory of genera, explains the relationship between the world as a whole and its constituent parts. Being relatively disposed refers to a kind of property that can appear and cease to exist without qualitative alteration but in reference to something external.Footnote ⁶⁹ Usually this category is explained by a simple example, such as ‘a man on the left’. But Plutarch's passage shows that it can have a much more complex use. If the parts of the world are relatively disposed, then it means that they are to be understood in reference to the cosmos as a whole. They have a nature, or function, with regard to the nature of the cosmos.

Similarly, in the Stoic definition of beauty as summetria, an object is said to be beautiful if its parts are summetros not only with each other but also with the whole. If being relatively disposed on a cosmic level has a certain functional meaning, then being disposed ‘to the whole’ on a smaller scale also quite plausibly has a functional meaning. There is, of course, a controversy within the Stoa regarding the category of ‘relatively disposed’ and its connection to virtue. On the one hand, Aristo argues that virtue is essentially only a single thing, and different kinds of virtues, such as courage and prudence, are relative dispositions. Chrysippus, on the other hand, argues that every virtue constitutes its own quality, as it is ‘qualified’ (τὸ ποιόν).Footnote ⁷⁰ In the Chrysippean conceptual framework, beauty of the soul would arguably be a matter of a further differentiation of an already qualified thing with regard to an external factor, that is, the role assigned to human beings by the rational cosmic principle.

The category of relative disposition can be used to explain proper functions as well.Footnote ⁷¹ The proper functions (τὰ καθήκοντα) are actions in agreement with nature and can be interpreted as a functional notion. The most common definition of a proper function states that it is an act in accordance with nature.Footnote ⁷² The most broad and general understanding of this concept does not have aesthetic underpinnings. Animals and plants have proper functions,Footnote ⁷³ and certain simple actions performed by humans are proper functions as well,Footnote ⁷⁴ yet none of these exhibits any kind of beauty. The proper functions do acquire certain aesthetic aspects, however, when the acting agent is a perfectly rational wise man.

In Cicero's On Ends, the Stoic spokesperson Cato explains that the first proper function is to preserve one's constitution, while the second is to pursue things that are in accordance with nature and to avoid those that are not. Once a person is able to perform this in a way that is fully consistent with his nature, he observes the regularity and harmony of such a conduct (uiditque rerum agendarum ordinem et, ut ita dicam, concordiam) and gains the understanding of the highest human good, which is praiseworthy and desirable for its own sake. This is the actual human good and honestum itself.Footnote ⁷⁵ The harmony of behaviour described here seems to be similar to the beauty of the soul described in the Stoic definition of beauty as summetria; or at least a person who is acting for the sake of honestum can be meaningfully described as having beauty of the soul. And if this is the case, here the phenomenon of beauty has quite clearly functional connotations.

This claim is also supported by a passage from Stobaeus that contains the Stoic definition of a right action as a proper function that possesses all the measures or numbers (τοὺς ἀριθμούς).Footnote ⁷⁶ The importance of the phrase ‘all the measures' is highlighted by A. Long in his article ‘The harmonics of Stoic virtue’. The ‘proper functions' are especially often described as having ‘all the numbers' of virtue,Footnote ⁷⁷ and Long argues that this phrase refers to a musical theory as follows:

The proper functions can, therefore, be a part of the phenomenon of beauty—and it seems fairly clear that the phenomenon described here is beauty—when the agent in question is wise. But, even more importantly, the beauty described here consists in functionality, in the sense that it consists in living and acting in a way which is not only well-structured but also in accordance with nature, both the individual and the cosmic one. It could be argued that the definition of beauty as summetria of parts with each other and with the whole already implies that aesthetic properties supervene on functionality. On the one hand, the definition clearly refers to the structure of a beautiful object, on the other hand, there is a condition of being summetros with the whole. As I argued above, the ‘whole’ referred to here might very well have the same meaning as in Chrysippus' claim that the parts of the world are relatively disposed to the whole, and thus it can be interpreted as a claim about functionality.Footnote ⁷⁹ That is to say, this part of the definition implies that beauty too is functional, and that, in order to be beautiful, an object has to perform adequately the role that this kind of an object ought to fulfil. The requirements of structure and functionality are not two distinct conditions for beauty but two aspects of compositionality. The parts of a beautiful object are well composed not just in any respect but in virtue of enabling the object to function as that kind of object. A composition, therefore, is only properly summetros if it has a functional structure.Footnote ⁸⁰ While ‘the summetria of parts with one another’ refers to an internal relationship between parts within an object, ‘the summetria of parts with the whole’ concerns the role that an object has from the functional perspective and how the composition of its parts contributes to its playing of that role.

If this reading is accepted, then it also helps to clarify the Stoic position regarding the problem of attributing aesthetic properties to virtues but not to vices. As I mentioned above, if it is assumed that beauty is produced when the parts simply ‘fit together’ and ‘complement each other’, then Plotinus is right in pointing out that the Stoics have trouble explaining why virtue, but not vice, is beautiful, as nothing seems to prevent vices from fitting together harmoniously.

This problem could be tackled by denying that vices have the capacity to coexist in a harmonious way. There is some evidence showing that this might have been the approach the Stoics took. In the Tusculan Disputations, for instance, viciousness (uitiositas) is described as a character that is ‘inconsistent in the whole of life and out of harmony with itself’ (a se ipsa dissentiens).Footnote ⁸¹ A similar claim is recorded by Stobaeus. Here, ignorance is said to be vice which is contrary to moderation and which makes impulses unstable and fluttering (ἀκαταστάτους καὶ πτοιώδεις).Footnote ⁸² An unstable and fluttering impulse is defined as a passion (πάθος) by the Stoics.Footnote ⁸³ Vices such as ignorance can be shown to be innately inharmonious by appealing to the description of passions. For instance, Galen, citing Chrysippus' On Passions Book 1, records an elaborate explanation of the definition of passion as the excess of impulse that includes the following vivid illustration: ‘When someone walks in accordance with his impulse, the movement of his legs is not excessive but commensurate with the impulse, so that he can stop or change whenever he wants to. But when people run in accordance with their impulse, this sort of thing no longer happens. The movement of their legs exceeds their impulse so that they are carried away and unable to change obediently, as soon as they have started to do so.’Footnote ⁸⁴ The very nature of vice, then, is chaotic, and one could quite plausibly argue that, for the Stoics, the notion of harmonious vices would be an oxymoron. If vices cannot coexist in a way that can be called harmonious, then they cannot be beautiful either. There is another, somewhat related way to deny that vices can harmoniously fit together and form beauty. In fact, if the Stoic conception of beauty is read as referring to the functional structure of a beautiful object, then their definition allows restricting the supervenience of aesthetic properties to those structures that properly fulfil the function of an object.Footnote ⁸⁵ The Stoics maintain that the best in human beings is their rationality and it is in their nature to be rational.Footnote ⁸⁶ Vice, meanwhile, is the cause of an unnatural and unhappy life.Footnote ⁸⁷ Acting in a rational manner, therefore, constitutes acting in accordance with human nature and, therefore, fulfilling human functions. Subsequently, if it is accepted that beauty supervenes not just on any harmonious structure but on a functional structure, it follows that vices cannot contribute to beauty, because they do not contribute to the human telos. The Stoics could deny that it is possible to act in a harmoniously vicious way, because vice is not functional in virtue of being not in accordance with the human nature. Fitting vices together in a harmonious fashion for the Stoics is a bit like performing a dance number at a singing competition. It can be a very good dance number, but it cannot win, because that is not what the competition is all about. Accordingly, acting viciously cannot be summetros with the function of a human being.

The two components of the Stoic definition of beauty render it a very flexible concept. This definition takes into account more than the internal coherence of parts within an object. Beauty has a functional aspect, since, in order to be beautiful, an object must have appropriate properties for that kind of an object. This stance has important philosophical implications. Chrysippus proposed what in contemporary terms is called broad aesthetic supervenience. This kind of supervenience differs from narrow aesthetic supervenience with regard to its scope of relevant factors. In contemporary aesthetics, broad supervenience is used to explain why an original masterpiece is aesthetically more valuable than its copy, even if the copy is very good. In virtue of having identical structural properties, both pieces ought to have identical supervening aesthetic properties. In order to support an intuition that the original piece of art has different aesthetic properties than its copy, broad supervenience is necessary, because this notion of supervenience takes into account the contextual and relational properties as well as the intrinsic properties of an object.Footnote ⁸⁸

The Stoic definition of beauty, when interpreted as referring to functional structures, has other interesting aspects in the context of more general discussions about aesthetic properties. The fact that this definition conceptualized some properties in a way which is very similar to a notion of supervenience, for instance, is important for understanding how it formulates the requirements for the presence of beauty. The accounts that posit specific formulae as the conditions for aesthetic properties are often criticized through claiming that no particular properties are capable of accounting for all the instances of beauty. Frank Sibley, for instance, argued that ‘there are no sufficient conditions, no non-aesthetic features such that the presence of some set or number of them will beyond question logically justify or warrant the application of an aesthetic term … We cannot make any general statement of the form “If the vase is pale pink, somewhat curving, lightly mottled, and so forth, it will be delicate, cannot but be delicate.”’.Footnote ⁸⁹ The Chrysippean notion of beauty—summetria of parts with each other and with the whole—challenges Sibley's conclusion that it is impossible to find a single formula for beauty in two respects. By concentrating on the compositional rather than on the particular properties of an object, Chrysippus' definition picks out the common feature of objects and phenomena of very different kinds (that is, all the beautiful objects, no matter what their ontological status is, are summetros). Beauty supervenes not on particular features but on a composition of whatever features an object might have. A summetros composition is a flexible concept that could be a catchall theory of beauty and thus save Chrysippus' definition from Sibley's criticism.

INSTEAD OF CONCLUSION

In his famous and widely-discussed article ‘The modern system of the arts: a study in the history of aesthetics: part I’, Oskar Kristeller argues that it is not possible to talk meaningfully about ‘ancient aesthetics’, because ‘ancient writers and thinkers, though confronted with excellent works of art and quite susceptible to their charm, were neither able nor eager to detach the aesthetic quality of these works of art from their intellectual, moral, religious and practical function or content, or to use such an aesthetic quality as a standard for grouping the fine arts together or for making them the subject of a comprehensive philosophical interpretation’.Footnote ⁹⁰ If one agrees with Kristeller's conception of aesthetics as the discipline devoted to studying pure aesthetic properties by themselves, then the Stoics, among other ancient philosophers, cannot be said to have an aesthetic theory, since they talk about beauty, as far as we know, only in the reference to the bearers of beauty, without singling out aesthetic properties per se.

There are, however, quite a few reasons not to accept Kristeller's critique of ancient aesthetics at face value. This restrictive definition of ‘aesthetic’ has been criticized in numerous ways, with special emphasis on the fact that Kristeller's own conception stands on shaky ground.Footnote ⁹¹ Another reason not to dismiss ancients in general and the Stoics in particular is the recent surge of interest in functional aesthetics or everyday aesthetics.Footnote ⁹² These theories do not fit Kristeller's conception either, but it would be strange to claim that they do not belong to the discipline of aesthetics. These theories are illuminating and interesting, and they show that the highly restrictive concept of aesthetics is neither necessary nor the only productive way of exploring the nature of aesthetic properties.

With this in mind, the fragments on the Stoic views about the beauty of the body and the soul can be read as not only belonging to the history of aesthetics but also contributing to the tradition. While it is true that the Stoics, as well as other ancient philosophers, had neither the restrictive concept nor a terminology of ‘aesthetic’ in the sense that Kristeller advocates, they none the less discussed the issues pertinent to our understanding of the aesthetic phenomena in general. Perhaps one of the most interesting aspects of their definition of beauty is providing a reference point from which a composition can be judged to be ‘good’. Functionality is a reference point for composition, thus aesthetic properties in any given object depend on the composition of parts attuned to the purpose of that object as a whole. Such a conceptualization of aesthetic properties allows the Stoics to present a flexible and multi-layered theory that can account for the presence of beauty in both physical objects, such as human bodies, and complex abstract objects, such as virtue. The Stoic definition of beauty, therefore, represents an interesting and significant development in ancient aesthetics.Footnote ⁹³