Because it’s pink

Although this is a work of art theory, its primary concern is not with beauty, or aesthetic value more generally, but rather with the nature of pictorial representation. After all, before we can judge whether a representational painting achieves aesthetic excellence in the way it depicts something, we must first perceive what it depicts. And John Hyman is interested in how depiction is even possible. This question has fascinated philosophers for a long time, but it can very quickly get a grip on any reflective person. However familiar we are with the business of linguistic communication, for example, it doesn’t equip us with any obvious answers when we stand back and ask ourselves how mere marks on paper or sounds in the air can embody and convey meaning. A similar difficulty arises if we ask how a configuration of lines and colours on a plane surface can possibly succeed in depicting a man or a battle, a forest or a god. Indeed, once we are struck by the sheer mysteriousness of pictorial representation, worries about what makes one picture more aesthetically valuable than another may come to seem secondary in comparison.

Philosophers have taken two rather different approaches to the problem. The first declares that a picture represents an object by copying its form and colour. The second, which arose in reaction to the first, and has become increasingly dominant since the Enlightenment, says that a picture represents an object by producing a special kind of experience or response in the mind of a suitably qualified spectator. Do pictures cause us to see the things they represent because they are likenesses of those things, or do we call them likenesses of those things because they cause us to see them?

If we think of depiction as involving three things – the viewer of the picture, the picture itself and the object that the picture depicts – then we could say that the first doctrine gives primary weight to the (mimetic) relation between the picture and what it depicts, whereas the second gives it to the (causal) relation between the picture and those who view it. In this sense, the first doctrine is objectivist, the second subjectivist; what is in dispute is the nature and significance of the viewer’s share in the business of depiction. Versions of the second doctrine hold sway in recent philosophy of art, as well as in art theory and art history. One of the many virtues of Hyman’s book is that it provides a sustained, rigorous and devastating critique of such subjectivism, and a carefully nuanced defence of his own version of objectivism.

Hyman organises his discussion around three themes: colour, form and reality (or, more precisely, realism). The first two are obviously central, since pictures consist of colours distributed on a plane surface; but the third is closely related, since historians and theorists of art have long wished to account for the impression of reality that some pictures appear to convey more forcibly than others. Once again versions of objectivism and subjectivism form the major poles of the discussion. Hyman engages in detail with a complex array of texts and arguments from the full historical sweep of Western cultural reflection on the nature of pictorial art. The discussion moves rapidly, but clearly and sure-footedly, from Plato to Gombrich, from Kepler to Panofsky, from Pliny to Winckelmann; and a major part of its value is that it carefully traces the ways in which philosophical, psychological, physiological and art historical inquiries into various aspects of these questions have interacted over time, with each taking over discoveries, models and assumptions from the others, for both good and ill (rather more ill than good). I will look in detail at some of the central and overlapping strands in Hyman’s argument, so as to convey the particular flavour of his position.

The first is Hyman’s response to what he calls Galileo’s myth. This states that ‘if ears, tongues and noses be taken away, the number, shape and motion of bodies would remain, but not their tastes, sounds and odours.’ In other words, when we attribute colours to objects, we are always and everywhere mistaken: objects are colourless. Acceptance of this myth has certainly helped to undermine belief in objectivist accounts of depiction, since the suggestion that the colours of a painting might represent the way things are in the world is threatened by the thought that this world is intrinsically lacking in colour. Hyman calls it Galileo’s myth in order to emphasise that the supposed colourlessness of the world is nowadays usually held to be a discovery of modern science. For it was Galileo who first saw that we do not need to assume that seeing redness is a perception of a quality that objects actually possess in order to explain why these experiences occur. And if that is right, so the argument goes, our everyday attributions of colour to objects must be illegitimate.

Hyman aims to demolish this myth by analysing the concept of colour implicit in our everyday attributions of colours. He begins from the apparent truism that an object’s colour is part of its appearance – that is, part of how it looks. Some appearances may be illusory, of course, but others are not; indeed, the primary sense in which something is apparent is that its true nature is manifest or evident. Nevertheless, Hyman’s observation suggests a link between colour and sentience that does not hold between, say, shape and sentience. For something’s actually being round (as opposed to looking round, which is part of its appearance) is not a matter of how it appears to any particular sense, but of whether or not every point on its circumference is equidistant from its centre; whereas something’s being white is precisely a matter of how it looks.

This doesn’t mean that white objects cease to be white if no one is looking at them, or that whiteness would vanish if sentient animals became extinct; something can look a certain way without anyone actually seeing that it does. But it does mean that understanding what it is for something to be white necessarily involves some understanding of what it is for something to be visible, hence some conception of the sense of sight, of what it is for a creature to possess that sense.

This conceptual link between colour and sentience has various consequences. For example, it follows that the final arbiter of an object’s colour is the sense of sight, since looking at things must be the acid test of how they look. We can certainly be mistaken about the colour of what we see; but we can correct such mistakes only by looking again, more carefully, perhaps with instruments, or drawing on another sighted creature’s judgment. Also, an object’s colour cannot affect what happens in the world except as a consequence of its being seen. For how a thing looks can make a difference to the course of events only if it’s seen – by affecting the behaviour of creatures capable of seeing it. But if the behaviour of sentient animals is the bottleneck through which alone colours can affect the world, then colours are explanatorily inert: they are a kind of property that science can have no reason to refer to in its explanations, except insofar as it wants to explain the thought and behaviour of animals equipped with the sense of sight. So they will not figure in physiological or chemical explanations of how it is that such animals have perceptions of colour (although they might form part of a sociological or anthropological explanation of why my daughter chooses one skirt over another – because it’s pink).

According to Hyman, then, the explanatory inertness of colours is not a discovery of modern science at all; it is a conceptual truth that emerges when we reflect carefully on our everyday conception of colour. And the realisation that colours can’t help to explain our colour perceptions doesn’t show that our everyday attributions of colours to objects are uniformly false. That would be true only if those attributions are always made for the particular theoretical purpose of explaining why we have perceptions of colour when we look at those objects. But why should we assume that all attributions of colour have a theoretical purpose – that they always hypothesise the existence of a property in order to explain an observed effect, as we might postulate universal gravitation to explain the orbits of the planets? This is sometimes the case, as when the newly acquired pinkness of my freshly washed shirt leads me to suppose that there was something red in the wash. But on other occasions when we say that something is red, we may be urging a driver to attend to a traffic light, or offering an ironic compliment on someone’s dress sense, or just making an observation. Such uses of colour words do not, on the face of it, grant speculative existence to colours in order to explain anything at all, let alone our perceptions of colour.

Furthermore, attributions of colour simply cannot be postulations designed to explain our colour perceptions; if they were, they would contradict the very conception of colour they utilise. For the principle of the explanatory inertness of colours is part of that conception, and it excludes the possibility of such a theoretical postulation. It is not that material reality chasteningly rebuffs the explanatory presumptions of our attributions of colour; rather, the structure of colour concepts rebuffs the presumption that they were fashioned for explanatory purposes in the first place. Colours can’t be impugned for failing to explain our perceptions of them if they were never intended to do so, and indeed if our basic conception of them actually excludes it. As Hyman puts it, it is bad practice to sack employees for failing to perform tasks that are inconsistent with their job description.

But paintings have properties of form as well as colour; and the objectivist doctrine talks of pictures as resembling their objects by copying both their form and their colour. Is any version of such a resemblance theory defensible? Hyman argues that a suitably qualified version is not only defensible, but the foundation of any proper understanding of depiction. And central to his argument is his response to an apparently devastating objection to resemblance theories.

Here’s the objection. There is an important distinction between what a picture depicts and what (if anything) it portrays – between what Hyman has elsewhere called its internal and external subjects. The internal subject is who or what we see when we look at a picture: for example, a grey-haired, unsmiling, elderly woman wearing a crown. The external subject, if the picture has one, is specified by picking out a particular individual in the real world that the picture portrays – in my imagined case, Queen Elizabeth II. Plainly, one way we recognise the external subject of a picture is by seeing the resemblance between a particular real individual and the picture’s internal subject. But the question the resemblance theory is supposed to answer is not: ‘How does the internal subject of a picture relate to its external subject?’ For that already takes it for granted that we can see the internal subject of the picture – that we can see what it depicts, and now simply wish to know what if anything it portrays. Whereas our original question was: how can we look at a distribution of coloured pigment on a piece of canvas and see a grey-haired, unsmiling woman? There are no obvious points of resemblance between a paint-smeared canvas and an elderly woman: the canvas doesn’t have grey hair, any more than the woman consists of pigment. In other words, resemblance comes into play only when the basic conjuring trick of pictorial representation is done, so any theory of depiction that invokes resemblance must simply have confused the surface of a picture with its content.

Hyman accepts that many philosophers, art historians and artists have mishandled the distinctions in play here, and that many have found the resemblance theory plausible precisely because of that mishandling. But he points out, first, that a theory can’t be judged false merely because it has been accepted for the wrong reasons; and second, that the resemblances that strike us once we have identified the internal subject of a picture may not be the only ones that exist. To be sure, there is typically no need for us to attend first to the marks on a picture’s surface in order to perceive its content – we just look through the canvas, as it were. But its having that pictorial content might nevertheless be explained by resemblances in form and colour between parts of the surface and the objects they depict that just don’t attract our everyday attention.

One such dimension of formal resemblance that Hyman emphasises concerns what he calls ‘occlusion shape’. Imagine looking through a window at the branch of a tree: if you closed one eye and looked at the tip of the branch, with the windowpane perpendicular to your line of sight, the shape of the mark you would need to make on the windowpane in order to occlude the branch is its occlusion shape. The fact that occlusion shape is always relative to a line of sight does not make it subjective or illusory. A circular tabletop seen from the side really does have an elliptical occlusion shape: it is part of its appearance, of how it looks; it can be true both that a tabletop is circular and that a cross-section of the solid angle it subtends to an observer’s eye is elliptical. We can also be mistaken about an object’s occlusion shape – that is, there can be a difference between an object’s apparent occlusion shape and its real occlusion shape. And if we can get it wrong, there is something there to get right.

Making use of this concept, Hyman specifies the following basic principle of pictorial representation. Suppose that O is a depicted object and P is the smallest part of the picture that depicts O: then the occlusion shape of O and the shape of P must be identical. Suitably refined, this principle articulates a central part of the truth in the objectivist doctrine that a picture represents an object by copying its form. It does not, of course, enable us to infer what kind of object is depicted from the shape of the mark that depicts it. The same curved pictorial element might depict a duck’s bill or a rabbit’s ear, although if a drawing can be seen as either a duck or a rabbit, the principle does tell us that both duck and rabbit must have the same occlusion shape relative to the implicit line of sight. But the principle certainly undermines the subjectivist claim that the only thing relevant to understanding a picture’s capacity to depict is its psychological effect on the spectator. For it specifies a precise mimetic relationship between the marks on a picture’s surface and the objects they depict which holds entirely independently of goings-on in the subject.

Hyman identifies a number of other related principles, some formal and others involving colour; and he argues that the development of Renaissance perspective is best understood as a geometrical synthesis of several techniques – overlapping, foreshortening, shading and so on – for depicting non-planar spatial relations by representing such properties as occlusion, occlusion shape, relative occlusion size and aperture colour. The book concludes by demolishing the most popular subjectivist explanation of the success of perspective, which is that it reproduces the geometrical structure of the retinal image, the picture from which our perception of space is naturally derived. This explanation in effect presupposes that visual perception of any kind is always the result of perceiving what a picture represents: the picture produced on our retinae by light reflected from the object of perception. The thought is that the brain is so familiar with adding a third dimension from information given by the flat retinal image that we might expect it to cope with pictures. But this is obviously confused. ‘It implies that the brain stands in the same relation to a picture, when we perceive what it represents,’ Hyman writes, ‘as it does to a retinal image when we perceive the sunlit world before our eyes.’ But when we look at a picture, this, too, involves the production of a retinal image: the picture is just one more object in the world that we perceive by means of the light reflected from it onto our retinae. The subjectivists appear to assume that we perceive the painting itself; in other words, they replace the retinal image produced by the painting with the painting.

In addition, they misunderstand the nature of retinal images. There certainly are such things: with a properly constructed set of instruments, one can indeed see on the retina an image that has been focused by the lens of the eye and then reflected by the surface of the retina. But the presence of pictures in our eyes can’t enable us to discover anything about the world unless we see them, and our retinal images are not visible to us. We simply don’t see them; and nor do they form any part of the causal processes underlying our capacity to see the world. What permits us to see is the light that is absorbed by our retinae (which then affects our photoreceptors and optic nerve in various ways), not the light that is reflected back from them.

Hyman’s argument reveals the insidious and complex ways in which scientific discoveries about perceptual processes can be mishandled by philosophers and art theorists, and in which scientific theorising can be distorted by misunderstandings about visual images elaborated by philosophers and art theorists. It takes a particular kind of skill and insight to disentangle such mutually reinforcing confusions in a way that is genuinely accessible to those working in all three fields. The book is not always successful in this respect (the discussions of Descartes and Nelson Goodman are particularly demanding). But the rigorous clarity and elegant concision of Hyman’s writing – literary virtues to which the best analytical philosophy has always aspired – carry his reader through even the most challenging sections. No one will come away from his book without having learned a great deal about one of the most familiar mysteries of human culture.