Delineating beauty: On form and the boundaries of the aesthetic

Philosophical aesthetics has recently been expanding its purview— with exciting work on everyday aesthetics, so-maesthetics, gustatory aesthetics, and the aesthetics of imperceptibilia like mathematics and human character— reclaiming territory that was lost during the nineteenth and twentieth centuries, when the discipline begun concentrating almost exclusively on the philosophy of art and restricted the aesthetic realm to the distally perceptible. Yet there remains considerable reluctance towards acknowledging the aesthetic character of many of these objects. This raises an important question— partly made salient again by the ongoing expansion of the aesthetic domain, and partly by the fact that many still seem resistant to this aesthetic diversification— which aestheticians seem to avoid: what, if anything, constrains the scope of beauty or the aesthetic? I argue that form, construed as comprising a degree, however minimal, of experienceable complexity, is necessary and sufficient for an object's candidature for the possession of aesthetic properties. Such a condition serves to discriminate between attempts to expand the scope of the aesthetic that are legitimate and those that are not. If correct, my view suggests that the aesthetic realm, though not limitless, is very broad indeed— but this, I think, is as

| 3 PARIS that form, understood thus, is both necessary and sufficient for the possession of aesthetic properties; in other words, that it delineates the aesthetic domain.Finally, I respond to objections, by way of demonstrating that my claim withstands reflective scrutiny.

| FORM AND THE AE S THE TI C : SOME BACKG ROUND
The idea that beauty and form are linked is not new.Indeed, in antiquity, beauty was identified with properties that are quintessentially formal, like symmetry, proportion, harmony, and order (Čelkytė, n.d.;Tatarkiewizc, 1972).Nor was this link severed by eighteenth-century thinkers who otherwise instituted a break with the classical theory of beauty; though they no longer saw beauty as consisting in form, they still thought that it was somehow dependent on it (see, e.g., Hutcheson, 2008Hutcheson, /1725;;Hume, 1975Hume, /1771, p. 291;, p. 291;Shaftesbury, 2001Shaftesbury, /1711, p. 226), p. 226).
Over two millennia, then, most philosophers were united in thinking that form is a precondition for beauty and marks the limits of the aesthetic realm.At the same time, with few exceptions, these same philosophers welcomed a strikingly diverse array of objects into the aesthetic realm, including natural, human, artistic, moral, and mathematical beauty, among others.And yet, especially since the nineteenth century, the notion of form has also been implicated in the considerable narrowing of the aesthetic domain, when it was appropriated by formalists like Bell (1927), whose contemporary proponents have staunchly defended the view that the aesthetic depends on the strictly perceptible (Zangwill, 2001).
It seems strange that one and the same property-form-should be responsible for both such an inclusive and exclusive conception of the aesthetic.But what all parties to this debate appear to accept is that form does delineate the aesthetic realm, a claim which, despite its antiquated resonance, still strikes me, like many others, as intuitively plausible.Something must have gone wrong along the way.I propose to examine two things: first, how we should understand "form"; and, second, whether the claim that form is the gateway to the aesthetic is true.If it is, then it will settle debates over what can and cannot be aesthetic or have aesthetic properties, which currently seem, frankly, directionless.

| UNDER S TANDING FORM
If we are to show that form is both necessary and sufficient for the possession of aesthetic properties, we need to define form.Contemporary analytic philosophers rarely develop accounts of form-often proceeding either by assuming a general understanding of the concept, or by employing a working conception. 5Either way, they are relying on what I take to be the default conception in contemporary aesthetics, which seems to be based on three characteristics.
First, form is concerned with interrelations among the different elements or parts of a given object.This is plausible, and can be glimpsed from the fact that words used to describe or evaluate form, or the aesthetic qualities that we tend to think of as formal, including unity, complexity, elegance, gracefulness, economy, symmetry, uniformity-in-variety, and so on, all pertain to relations or qualities of relations between elements of a thing (cf.Budd, 1995;Carroll, 1999;Paris, 2018b;Zangwill, 2001). 5There are exceptions, of course.Carroll (1999); Lorand (2000); Kivy (2009); Lichtenstein (2019) are among them.However, their accounts are either too specialised or not focused on beauty.For instance, although Lichtenstein (2019) focuses on beauty, his account is primarily of historical interest and concerns Kant's and Heidegger's aesthetics, and Lorand's is distinctively Kantian.Carroll (1999) and Kivy (2009) focus not on beauty, but on art.

PARIS
Second, and much more restrictively, form is not a matter of just any element and relation, but only of such as are "given to the senses" (Stecker, 2019), which is usually interpreted as being perceptible, especially through the distal senses (Parsons & Carlson, 2008;Zangwill, 2001).Call this the "perceptibility constraint".Third, form is contrasted with properties like meaning, kind, and function, not only conceptually, but also in terms of the aesthetically relevant experiences or values it can ground.Thus, for instance, Parsons and Carlson (2008), in defending "functional beauty", on which looking fit for function is a kind of beauty, spend considerable time arguing that understanding an object's function can inform its form, as does Forsey (2013) in developing an aesthetics of design.Similarly, Stecker defines aesthetic experience partly as the experience of attending in a particular way to "forms, qualities or meaningful features of things" (2019, p. 23).All of these ways of handling form presuppose its distinctness from function, meaning, etc.
Jointly, these three features give us what I take to be the contemporary default conception of form, namely: FORM (DEFAULT) = the ensemble of an object's perceptible elements and their interrelations. 6  Now, prima facie, this may seem like a plausible conception, particularly when our focus is on the visual arts, as it is for most of the philosophers who have been proceeding with something like FORM (DEFAULT).After all, as already mentioned, all of the properties associated with, or evaluative of, form seem to presuppose relations among parts or elements.Moreover, when describing or evaluating an object's form, we use "form" to isolate those features of the object that are distinct from its function, meaning, purpose, etc.Now, FORM (DEFAULT), besides being the default conception of form among many contemporary aestheticians, has also been more or less explicitly taken to delineate the aesthetic realm by those who espouse it.Indeed, it is still thought to do so by its proponents, including not only Zangwill (2001), who still explicitly rejects that non-perceptual objects can have aesthetic character or that functional considerations can be aesthetically relevant (cf.Zangwill, 2009), but even by some who have defended theories like functional beauty (e.g., Parsons & Carlson, 2008;cf. Forsey, 2013) or everyday aesthetics (e.g., Saito, 2007).This is presumably why Parsons and Carlson take pains to argue that knowledge of function "can play a role in our perception of, and hence our aesthetic appreciation of, [an] object" (2008, p. 91, emphasis added), and Saito states that "[i]n order for a quality of an object to be aesthetically relevant, … it has to be perceivable or have the power to affect the perceivable features" (2007, pp. 110-111, emphasis added). 7  Yet, as mentioned earlier, many have also sought in recent years to go beyond FORM (DEFAULT), arguing that much besides the (distally) perceptible can possess aesthetic character.In the first place, the perceptibility constraint has come under intense scrutiny on numerous grounds.Briefly, the perceptibility constraint seriously mischaracterises aesthetic experiences and descriptions of the aesthetic character of artforms like literature, where it also results in highly counterintuitive results, such as the view that translated novels cannot share their aesthetic properties with originals, and that all that is aesthetically relevant in artforms like poetry is the sound of the words read aloud (Costello, 2013, pp. 296-297;Gaut, 2007, pp. 124-126).Moreover, it fails to seriously heed both ordinary usage and usage by experts in non-artistic domains.As many have argued, we ought to take seriously the fact that people speak of beautiful moves in football or chess, let alone the fact that scientists are adamant that objects like mathematical proofs or theories in physics can possess aesthetic properties, including beauty and ugliness (Hardy, 1992; Rovelli, 2015; Wilczek, 2015). 8  6 Beardsley (1981); Bell (1927); Budd (1995); Levinson (1996); Stecker (2019); Zangwill (2001); and others mentioned in the last few paragraphs all seem to hold something like this. 7Though, admittedly, elsewhere Saito seems to embrace a disjunction whereby the aesthetic includes "any reactions we form towards the sensuous and/or design qualities of any object, phenomenon, or activity" (2007, p. 9), which would suggest that purely intelligible design can have aesthetic character (cf.Paris, 2020).Nonetheless, throughout her work, there are appeals to the perceptibility constraint, which, if anything, indicates the hold that this criterion, and FORM (DEFAULT), still have over many aestheticians. 8There are several other objections to the perceptibility constraint, but I take the above to be both central and decisive, especially if, as I shall argue shortly, there is a suitable alternative that avoids such problems.

PARIS
Proponents of the perceptibility constraint often respond to such objections by claiming that talk of beauty, etc., in cases like the aforementioned is loose and/or metaphorical (e.g., Zangwill, 2009Zangwill, , 2001)).Yet this response is unsuccessful.For this seems obviously false in the case of literature, whilst in many other cases there simply seems to be no reason to think that the relevant usage is metaphorical besides a prior commitment to the perceptibility constraint.Such a commitment, in turn, has been criticised as being unfounded and as having been arrived at through use of limited examples-overwhelmingly drawn from visual art and architecture-the aesthetics of which are bound to have a perceptual character (Paris, 2018b, pp. 720-722).
Besides arguments against the perceptibility constraint, many philosophers have also developed more targeted defences of the aesthetic status of various domains and objects.For instance, drawing on existing accounts of functional beauty, whereby an object's appearing (or, on some construals, being) well-formed for its function is sufficient for being aesthetically appealing, Roberts (2022) argues that experiences of haptic touch have aesthetic character; elsewhere, I (Paris, 2020) have argued analogously for character traits. 9Others too have offered arguments for the aesthetic character of non-perceptual art (e.g., Carroll, 2004;Shelley, 2003).
While such arguments have done much to advance aesthetics in recent years, we still appear to lack an agreed-upon, principled way of working out what does and what does not possess aesthetic character, viz., a suitable replacement for FORM (DEFAULT).This is because such a delineation principle would consist of a set of necessary and sufficient conditions for having aesthetic character, whereas most accounts seeking to expand the aesthetic in various ways tend to fall short of providing these for a number of reasons, including the following.10First, as already suggested, many subsume a certain phenomenon under an existing aesthetic framework, as does Roberts (2022), for instance, by arguing that the aesthetics of haptic touch qualify for functional beauty, and as do I (Paris, 2020) in arguing analogously for moral, as well as mathematical and literary beauty.While this does the trick, it works by recruiting a sufficient condition for beauty, which, assuming there are non-functional aesthetic properties (cf.Sauchelli, 2013, p. 43), cannot be generalised into a set of necessary and sufficient conditions for aesthetic candidature.Second, some appeal to general considerations, such as linguistic practices, or phenomenology to show that a target phenomenon has aesthetic character.For instance, Gaut (2007Gaut ( , 2010) ) appeals to the philosophical tradition, phenomenology, and linguistic usage in defence of moral beauty.And Shelley (2003) seeks to show that non-perceptual artworks, like Duchamp's Fountain, whose value does not stem from their perceptible properties, can still possess aesthetic properties insofar as what's essential about aesthetic properties is not that they are perceptible via the five senses but that they "strike us with their presence" (2003, p. 372) as opposed to having to be inferred.Again, whilst such arguments are plausible, they do not yield a delineation principle.Though Shelley's may seem a promising proposal, it is at best a necessary condition for possessing aesthetic properties, since there are things that strike us without being aesthetic properties, like the revelation that we have been fired or won the lottery.Indeed, it may not even be necessary for aesthetic candidature, since there are plausibly objects that are suitable candidates for aesthetic appreciation and yet are indifferent, and of which it would be counterintuitive to say that they strike us in any way.11Third, some appeal to empirical evidence, as do both Doran (2021Doran ( , 2022) ) and myself (Paris, 2018a) in defence of moral beauty.However, such evidence tends to not concern itself with the criteria subjects employ in making their judgements, and even if it did, these would still only tell us what people think about the relevant issues, not whether or not they are right.Fourth, others use a specific theoretical framework, as does Costello (2013) who employs Kant's aesthetic theory to argue for the possibility of non-perceptual art.While this strategy could potentially yield the relevant conditions, it will inevitably be 9 See also my (Paris 2017) for an account of deformity-based ugliness that can accommodate the ugliness of imperceptibilia like mathematical proofs and moral vices.PARIS linked to a specific philosophical system; be that as it may, Costello does not seem to be proposing anything like a delineating principle of the aesthetic. 12Finally, as I have already suggested, there are many who still cling onto FORM (DEFAULT) or some equivalent even while seeking to broaden our aesthetic horizons (e.g., Forsey, 2013;Parsons & Carlson, 2008;Saito, 2007, pp. 110-111).
Consequently, available accounts do not as yet suggest an adequately inclusive set of necessary and sufficient conditions the satisfaction of which renders an object potentially beautiful or ugly.By contrast, those who espouse FORM (DEFAULT) as the basis of the aesthetic claim to possess such a condition. 13Indeed, it may be the fact that it seems to provide such a simple and attractive way of delineating the aesthetic that has enabled it to persist for well over a century despite serious problems like those summarised above.Now, if we wish to welcome objects like character traits, mathematical proofs, and the like into the aesthetic realm, as I think it's clear we should, then we must reject FORM (DEFAULT) as a delineating principle for the aesthetic.But this need not mean abandoning the notion of form altogether.Elsewhere I (Paris, 2018b) have considered conceptions of form under which character traits can be beautiful or ugly, with a view to offering a sufficient condition for the possession of beauty.There, I distinguished between "descriptive" and "evaluative" form and considered accounts of these.My account of descriptive form is essentially a variant of FORM (DEFAULT), except that I drop the perceptibility criterion.That of evaluative form comprises an object's "ensemble of elements and their interrelations designed to realise [its] end" (p.716).In that article, I ultimately opted for the latter, evaluative conception, on the grounds that it is more substantive and restrictive, while the descriptive account is too permissive.However, it is important to bear in mind that what I was after at the time was a sufficient condition for the possession of beauty.Here, instead, I am looking for a set of necessary and sufficient conditions for candidature for beauty and ugliness.Hence my (Paris, 2018b) evaluative conception of form, albeit pertinent to my aim at the time of furnishing a backdrop against which moral beauty and ugliness makes sense, as well as useful in aesthetic evaluation more generally, will not do for our purposes here.This is for reasons already adumbrated, including that it is too restrictive in presupposing the possession of functions, whilst there are arguably many objects that possess aesthetic character but lack functions (at least in any ordinary sense), like rocks, water, the sky, etc. 14 Nonetheless, I think that my account of descriptive form is still relevant insofar as it points us in the right direction, viz., of dropping the perceptibility criterion.This gives us: FORM (UNRESTRICTED) = the ensemble of an object's elements and their interrelations.
This may seem an improvement over FORM (DEFAULT).But this judgement would be premature, for talk of an object's elements and their interrelations is both vague and wildly inclusive.We know that objects are made of microscopic particles, and that even the air we breathe contains interrelated elements.Yet it is a stretch to say, without qualification, that air could be beautiful, elegant, etc.A plausible explanation for this is that we simply cannot experience the structure of air, nor indeed can we experience the subatomic particles, etc., that make up the rest of the physical world.It is starting to look like the perceptibility requirement was serving a useful purpose, after all.But perhaps it went a little too far.If so, then maybe what we need is something that plays the role that perceptibility played in FORM (DEFAULT), but allows us to say that certain abstract objects, like mathematical proofs, for instance, have form.
12 Although he does consider complexity as an important factor for aesthetic candidature, in line with my account below. 13Unsurprisingly, then, this tends to be something that sceptics often recruit to rebut defences of the aesthetics of various things.For instance, Todd (2008) argues that without an account of what counts as an aesthetic response (or, presumably, of what qualifies as being aesthetically appreciable), we have no good reason for thinking that mathematicians' talk of beauty, elegance, etc., are genuine aesthetic appraisals, as opposed to undercover epistemic ones. 14This, then, is yet another case where the relevant principle employed to argue for the expansion of the aesthetic does the intended trick, but cannot be generalised to delineate the aesthetic.

PARIS
As I already hinted, the problem with things like air or subatomic particles appears to be that, at least in ordinary, everyday encounters, we cannot experience them.Presumably, if we could, either by using a special microscope or by developing a sense that allows us to experience air particles (oxygen, etc.), then it may not have been odd to claim that they possess aesthetic character (see also the related discussion in section 5 below).Now, plausibly, mathematical properties and other kinds of imperceptibilia, like human personality traits can be experienced through being thought, contemplated, etc. (cf.Paris, 2018b).And to the extent that aesthetics is linked to experience, it is presumably partly in virtue of this fact that many philosophers have granted them aesthetic standing.In light of these considerations, I propose that we replace perceptibility with experience-ability in our conception of form, as follows: FORM (AESTHETIC) (henceforth AE-FORM) = the ensemble of an object's experienceable elements and their interrelations.
With this, we do have something that is shared among visual artworks but also intelligible and other objects that have entered contemporary aesthetics, like the body, character traits, food, ideas, beer, wine, etc., and can plausibly be claimed to partly explain why they are legitimately said to have aesthetic character.Let us consider AE-FORM's relation to the aesthetic.

| FORM AND C AND IDATURE FOR B E AUT Y
Insofar as AE-FORM comprises experienceable elements and relations, it's equivalent to the possession of some degree of experienceable complexity-whether that's understood quantitatively, i.e., to do with spatiotemporal or numerical proportions, etc., or qualitatively, i.e., to do with felt values or features like affective valence, etc.With this in mind, a number of considerations support the claim that AE-FORM is necessary and sufficient for candidature for beauty.
First, AE-FORM is a common denominator among a striking diversity of objects that people call beautifulproofs, fish, buildings, arguments, paintings, mountains, dances, actions, snowflakes, characters, machines, people, symphonies, game moves, to name but a few.I do not think that this is a coincidence.Although none of these objects are beautiful simply by possessing AE-FORM, their possession thereof introduces the possibility of aesthetic evaluation and experience.Anything possessing AE-FORM can, in principle, be balanced, symmetrical or asymmetrical, unified or incoherent, etc., all of which properties seem quintessentially aesthetic.This is because anything possessing complexity will, ipso facto, possess related qualities, like balance, unity, order, disorder, etc., which, when experienceable, are aesthetic, though they may be possessed of objects that are generally indifferent and hence whose aesthetic character does not interest most people.
Second, the best candidates for formlessness in our sense are the only things that plausibly lack aesthetic character altogether.Candidates here are few, but may include purely abstract concepts (though not the abstract entities that they pick out); mere facts (that the French Revolution occurred in 1789; that I am on an island writing this paper, etc., as opposed to thoughts representing these facts); simple sensations that are localisable but lack intentionality, or experientially undifferentiated objects, like the component particles in the air that we breathe.Third, all beautiful objects have AE-FORM and there simply seem to be no counterexamples of formless beautiful objects-indeed, almost no experienceable objects in general, strictly speaking, whether abstract or concrete, are formless.Though this may seem to suggest that AE-FORM is a necessary condition, it also implies that AE-FORM comprises adequate, albeit minimal, ingredients for aesthetic concoctions.
Finally, virtually all of the qualities traditionally identified with or otherwise linked to beauty (arguably the aesthetic property par excellence)-including uniformity in variety, unity in complexity, coherence, unity, harmony, 14679329, 0, Downloaded from https://onlinelibrary.wiley.com/doi/10.1111/rati.12388 by Welsh Assembly Government, Wiley Online Library on [21/08/2023].See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions)on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License symmetry, balance, proportion, order, clarity, elegance, gracefulness-as well as their contraries (linked to ugliness), are predicable only of objects displaying some degree of experienceable complexity.Thus, it seems plausible that AE-FORM is both necessary and sufficient for candidature for beauty: everything that can be beautiful has AE-FORM, and nothing that lacks AE-FORM can be beautiful (cf.Budd, 1995, p. 179, who sees "structure" as necessary for being aesthetically appreciable).

| OBJEC TI ON S AND RE S P ON S E S
The above make plausible the suggestion that AE-FORM is necessary and sufficient for candidature for beauty.
Here, I strengthen my case for this suggestion by defending it against three objections.
First, Sherri Irvin has questioned the claim that complexity, entailed by AE-FORM, is a necessary condition for aesthetic consideration.She writes: … surely the actual placement of elements within a complex structure is not necessary for the elements to be considered aesthetically.A monochrome painting has aesthetic impact even though it is about as simple as a painting can be … Simplicity and complexity lie on an aesthetically relevant spectrum of properties; simplicity can itself be an aesthetic quality, and can contribute to the aesthetic merit of an artwork.The fact that an experience is simple, then, cannot disqualify it from having an aesthetic character.(2008, p. 40) I set the monochrome painting aside for a moment, since this example raises the important question of whether individual colours can have aesthetic properties, which I shall discuss separately.Besides this, in the quoted passage, Irvin is trying to vindicate the claim that experiences, including smells, tastes, and even tactile ones like scratching an itch, can have aesthetic character, even if they are, by some accounts (specifically Dewey's, in Irvin's case) simple.
One of Irvin's examples involves petting her cat, smelling the fur, and enjoying this experience.Now, whether or not this experience is simple depends on whether by "simple experience" we mean an ordinary or everyday experience, as do proponents of "everyday aesthetics " (e.g., Saito, 2007).In this sense, Irvin's examples are certainly of simple experiences, but AE-FORM has nothing to say about this sense of a simple experience's aesthetic status.By contrast, in the sense of complexity pertinent to AE-FORM, Irvin's examples clearly do count as complex experiences, insofar as they can be said to possess AE-FORM.The smell of a cat's fur is complex, as is virtually every scent and, even if we do not, as Irvin puts it, create eau de chat, or dwell on the different notes, we still experience its complexity in the smelling act. 15After all, experienceable complexity need not be consciously or reflectively considered as such, though proper appreciation does require that it be grasped and savoured in the experience.The experience of petting the cat too, is complex: the texture of the fur as it meets the skin and skeleton of the body underneath it, perhaps the cat's purring response, etc.Even simpler sensations, like scratching an itch, an experience with duration, complex qualitative character, and the interplay between frustration and sensations of relief, when dwelt upon, reveal a considerable degree of complexity.Indeed, it is, I think, partly this fact that makes turning our conscious attention to seemingly simple, mundane experiences, aesthetically rewarding: for their qualitative richness then becomes available to us for savouring.Irvin is correct, of course, that simplicity and complexity are on a scale, but the simple in the sense of the totally undifferentiated, or formless, is, I maintain, lacking in aesthetic character. 15Indeed, Irvin acknowledges this, which makes the fact that she discusses these examples somewhat curious.Yet it is still worth discussing this case, since it also serves to illustrate "the pervasiveness of the aesthetic in ordinary experience", as Irvin (2008, p. 29) nicely puts it, that AE-FORM accommodates and accounts for.

PARIS
It is now time to turn to a second, important objection, also raised by Irvin, which concerns the aesthetic status, or lack thereof, of colours.I think that most laypersons, but also artists, take it as self-evident that simple colours can be beautiful.However, it may appear that the view that AE-FORM is a necessary condition for beauty rules this out.So AE-FORM cannot be necessary for beauty candidature.Indeed, this was an early objection to the classical account of beauty, which identified beauty with form or some species of wellformedness. 16Interestingly, both Kant (e.g., 2001Kant (e.g., /1790, pp. 108-109) , pp. 108-109) and Hutcheson (e.g., 2008Hutcheson (e.g., /1725, pp. 22, 26, pp. 22, 26, though elsewhere he speaks of certain beautiful colours, e.g., pp.34, 72) who also upheld a connection between beauty and form similar to the one I am defending, thought that colours cannot themselves be beautiful, but only contribute to the beauty of objects they adorn.
In response, I reject the assumption that colours are simple, no matter how uniform.This is not only because I find the claim that some colours are beautiful eminently plausible, but also partly because I have been convinced of the complexity of colours through personal experience in artistic training.And because, more generally, artists and appreciators are often vividly aware of such complexity, discerning and making use of different qualities of different colours even in monochrome paintings (Albers, 1975;cf. Dewey, 1980, p. 125).
Indeed, although colours and colour perception are still very much objects of investigation (colour blindness was only discovered just over two hundred years ago), their complexity is now widely recognised among colour theorists.It is important to clarify here wherein such complexity lies, for there is a tendency to simplify talk of colour, ignoring a distinction between two senses thereof.In one sense, "colour" may refer to hue, viz., that quality through which normal individuals distinguish between, say, red, green, and blue; in another sense, "colour" also refers to particular instances of colour, like the yellow or purple of a specific object.We may call the first sense a classificatory one, and the latter an experiential one.The claim that colours are complex concerns colour in the experiential sense, since the classificatory sense only picks out one dimension or aspect of colours.
More precisely, we nowadays know that individual colours have three qualities or dimensions, namely hue (viz., "colour" in the classificatory sense), colourfulness or saturation, and brightness (also known as lightness or value) (Kernell, 2016, pp. 2-3).In other words, individual colours vary not just in terms of hue, but also in colourfulness and brightness.Importantly, these qualities are independently experienceable, and adequately experienced or suitably trained individuals can be quite sensitive to their combinations and variations within and between individual colours.This is supported both by testimony and also from simple experiments with colours, where one and the same colour can appear different, or different colours can appear the same, through interaction with other colours, partly due to interplays between their lightness and saturation (see the highly instructive examples in Albers, 1975).It is also supported by the fact that certain kinds of localised brain damage affecting colour perception can cause inability to see, for instance, different hues or perceive luminance contrast, while retaining the ability to use colour contrast (Kernell, 2016, p. 172).This should be unsurprising, since our visual system comprises three kinds of vision, corresponding to the perception of different qualities of colour, two of which enable daylight vision (which registers achromatic lightness contrasts, as well as hues) while a third is used for night vision (and comprises a high sensitivity to light "at the cost of other visual capacities") (Kernell, 2016, p. 100).Though the former are often lumped together, they use "different neuronal networks and, at least partly, their messages travel from eyes to brain along different portions of the visual pathway" (Kernell, 2016, p. 100).
It may be objected here that I am smuggling in a notion of complexity that is distinct from that entailed by AE-FORM.For all that the account of colour above seems to imply is that individual instances of colour can be placed on a three-dimensional coordinate of hue, saturation, and brightness.But this is not sufficient for possessing AE-FORM.Indeed, if it were, a tiny point in space, or a dot, would also have form, since it too can be placed on either a two-or, if suitably extended, three-dimensional coordinate space.But it would be odd to claim that a tiny point in space has form, let alone that it possesses aesthetic character. 16Versions of this objection date back at least to Plotinus.See Tatarkiewicz (1972).In response, it is important to distinguish two issues raised by this objection: on the one hand, whether a point is space can be said to have form in the relevant sense; and, on the other, whether or not the complexity of colour is simply a matter of being traceable to a point in a coordinate.Let us tackle these in reverse order.Assume for the sake of argument that the objector is right about the dot, and that its only claim to complexity is its being placeable on a geometric coordinate.Even so, this would not show that it has AE-FORM.This is because it still lacks experienceable complexity.By contrast, although colours can of course be placed on a coordinate-after all, that's what colour wheels are for-they are additionally constituted by the aforementioned three elements.These, in turn, as I have been arguing, are like ingredients, which can be experienced by sensitive enough perceivers, albeit imperfectly and fused into gestalt colour experiences.Hence colours possess a kind of experienceable complexity, which we may call intrinsic complexity, over and above what we might call extrinsic complexity, which is a matter of external relations which is shared by all spatiotemporally extended objects, events, and even voids, which lack AE-FORM and hence aesthetic properties.
But the objector is also in some ways wrong about the status of the point in space, or dot.For, depending on our viewing conditions, such a point in space may indeed appear to be lacking in any kind of experienceable complexity (we may not be in a position to judge its colour, shape, etc.), and hence aesthetic character.And yet it also belongs to a class of objects that are either invisible to or barely visible to the naked eye, but which may yet possess AE-FORM, and hence aesthetic character, under certain descriptions or viewing conditions.Consider tiny snowflakes, also known as diamond dust crystals.Under certain descriptions or viewing conditions (against the background of a bright sky, say), these too may appear to lack AE-FORM (and so to lack aesthetic character).However, under different descriptions or viewing conditions (namely magnified), not only are they revealed to possess intricate AE-FORM, but to be aesthetically marvellous (cf.Budd, 2002, pp. 16, 107-108).Our tiny dot may not be as aesthetically fortunate as snowflakes, but to the extent that it too can be revealed to possess AE-FORM, I submit that it thereby also possesses aesthetic character, even if that character turns out to be rather bland.Some things are simply too small for their complexity to be appreciated by us under some descriptions or viewing conditions, and so may appear to lack AE-FORM.However, in many of these cases, it may be possible, through magnification or other forms of redescription, 17 to experience their complexity and so be in a position to appreciate in them qualities that are otherwise inaccessible.Perhaps in magnifying or redescribing such objects we are further exploring what Irvin calls "aesthetic affordances" (2017), i.e., their capacity to display a rich aesthetic character beyond what a casual encounter-or an encounter inhibited by pre-existing aesthetic standards or prejudices-might reveal.Technology can help us explore such affordances in many objects of our experiences. 18This clearly contrasts with other examples, like mere facts, voids, etc., that cannot be said to have such features at all.Hence, while ultimately unsuccessful, this objection has offered an opportunity to clarify my proposal and to explain how certain objects' AE-FORM can be revealed at different levels of description or through different experiential conditions.
A third worry is this.Some aesthetic properties, like ugliness or sublimity, are said to be linked not to form but to formlessness, i.e., the lack of form (see Gracyk, 1986).If so, then AE-FORM cannot be necessary for aesthetic candidature.
Going into the many and complex theories of the sublime would take us well beyond the remits of this paper.However, it seems plausible that neither ugly nor sublime objects are such as cannot be experienced or lack complexity.
17 "Other forms of redescription" is intended broadly, as a catch-all term for suitable experiential re-adjustments, including to allow for another interesting possibility in the case of abstract objects, like concepts.For perhaps these too may possess an aesthetic character, once we have analysed them philosophically and can contemplate them under the guise of a given analysis.For instance, "love" strikes me as a concept that many would find beautiful, at least under certain guises.
18 However, while it is appropriate to treat the examples in this paragraph as cases of objects our appreciation of which can be enhanced by viewing them under different descriptions or conditions, it is also important to note that there are certain objects-notably works of art and other artefacts-whose aesthetic character can only be appreciated under normatively specified conditions.Experiencing such objects otherwise cannot, I think, be thought of as seeking out their aesthetic affordances.However, such considerations take us beyond the remit of this essay, as they concern how we correctly assess objects aesthetically, rather than what conditions make aesthetic appreciation possible in the first place.

PARIS
With regards to ugliness and its subspecies, these have traditionally been identified with deformity, rather than formlessness.Insofar as deformity is a property evaluative of form, this means that ugliness too depends on AE-FORM, albeit negatively assessed (cf.Paris, 2017;Sibley, 2001).Talk of "formlessness" in cases of ugliness is thus plausibly used synonymously with "deformity", as Augustine confesses to have used it before becoming convinced, albeit on religious grounds, that he could not "conceive the absolutely formless" (2009/401, p. 248).
As for the putative formlessness of objects described as sublime, far from lacking AE-FORM, it may well be their unfathomable complexity or proportions that make talk of formlessness seem apposite (cf.Gracyk, 1986).
In other words, talk of formlessness in both cases of ugliness or the sublime is not descriptive, but evaluative, implying a complex but ultimately positive evaluation of AE-FORM in the case of the sublime, and a negative one in the case of ugliness.
Hence, the claim that AE-FORM is necessary and sufficient for the possession of aesthetic properties withstands reflective scrutiny.Form, then, is indeed what marks the boundaries of the aesthetic, leaving within that realm a rich and diverse array of objects, the aesthetics of many of which lay as yet unexplored.

| CON CLUS ION
I have argued that form, understood as AE-FORM which consists, roughly, in experienceable complexity, is both necessary and sufficient for possession of aesthetic character.This proposal allows us to delineate the scope of the aesthetic in a principled way, and to explain why, pace some contemporary formalists, certain objects that are imperceptible or that are perceptible through proximal senses, like character traits, thoughts, emotions, mathematical proofs, scientific theories, food, drink, etc., can possess aesthetic properties, while some other things cannot.In doing so, it also preserves the kernel of truth in formalism, understood as the view that form and the aesthetic are inextricably entwined.Given the relative sparsity of accounts seeking to better understand the aesthetic as such, I submit that my proposal marks an important step forward in our systematic exploration of that realm.

ACK N OWLED G M ENTS
I am grateful to my colleagues at Cardiff University-especially Anneli Jefferson and Alessandra Tanesini,and to Ryan P. Doran and S. Orestis Palermos for very helpful feedback on earlier versions of this article.I am also grateful to an anonymous referee for this journal for very insightful comments that greatly improved this paper.