The science of vision can tell us something about what is going on in the brain when one is looking at a painting. It remains to explain how this process triggers a properly aesthetic experience. It is possible, I believe, to reconstruct the processes at work in cognizing a painting in such a way as to acknowledge the specific nature of the work of art. It is by understanding pictorial language. In what follows, an account is given of the pictorial language - that is, of the kind of visual experience that is uniquely offered by paintings, as opposed to other objects.

The perception of a work of art, unlike the perception of an image, is such that we usually tend to recognize what we see, thus to see what we already know. Whereas image perception is automatic deciphering, art-sensing happens through the passage from passive to active seeing and sensing; and it takes a particular kind of attention for passive vision to be turned into emotionally resonant, active seeing. The viewer perceiving passively a Rembrandt portrait as an image only, will miss its pictorial emotion. The passage from passive to active perception engages the processes that define "art cognition". Art cognition in the sense given here generates a complex neuronal firing, by which we tend not only to taste but also to recognize by what we already know. The reason for this is that retinal activation triggers associations (percepts) determined by past experiences. The past visual experiences of looking at paintings, reminiscent of other paintings, can trigger a cascade of varied emotions, intensified by the recognition of the pictorial language, thus probably engaging both hemispheres of the brain.

Art cognition requires not only knowledge but discernment, and favourable viewing conditions: without light at its full spectrum (natural light) the perception of colour is falsified. Although art cognition engages all levels, it is first by feeling that it is activated, when a viewer is struck by a work of art conveying a visual experience. A visual experience is immediate and is not necessarily conveyed by subject matter, but by the pictorial language itself.

For example, Chardin’s famous Le Gobelet d'Argent (oil, 1767-68, Paris, Louvre, M.I. 1042) has no story to tell, and yet, it conveys a visual impact. Three apples, two chestnuts, a bowl with its spoon and a silver goblet are the theme of a painting that conveys a moving visual experience, although the subject is indifferent. What moves us is the painting itself.

We are at first struck by the reflection of the apples on the upright silver goblet, the eye is drawn from the reflection of the apples to the apples themselves, and from the apples to the opaque bowl, from its oval rim, to the goblet’s oval rim, and back from the oval to the round apples, two showing their stems and one turned backwards, and finally to the chestnuts. Two oval rims, three apples, two chestnuts, opacity and reflection in a rhythm of three-two - in a sequence of one-two-three and one - the one is the spoon in the bowl, seen from below. Slightly darker and opaque, the back of the spoon handle creates the syncopation and sets the tension in the Gobelet d’Argent.

One can, of course, interpret this painting without sensing it, without seeing it, using it as a document, by carrying it through analogies: the apple’s species, the goblet’s style, its eventual owner, his society, its political implications, and so forth, entering a lengthy cultural discourse. Without saying anything about the painting itself. However, art history is the history of works of art, and was at its beginnings a history of exceptions that perpetuates these exceptions, and teaches seeing, not reading. Viewing a painting at a first glance does not differ much from wine tasting: both engage discernment. It is followed by the formal pleasure derived from the unfolding of the pictorial syntax, which carries the subject or the theme.

Similarly to the function of grammar in a string of words, the pictorial constituents operate the picture - dot, line, form and colour in a state of tension - that underlie depiction. It is analogous to a succession of segmental phonemes that constitute a sentence. A visual proposition, the way in which Chardin’s still life can be turned into a pictorial event, when its formulation follows internal logic, when every dot in it relates to a line, the line to form, the form to space, the centre to edges, the colour to value, harmony to contrast, pull to counterpoint and syncopation. Finally every authentic pictorial continuum has a flow, within its simultaneity, guiding the eye with movements and halts as in music. Furthermore, a sharp line will affect perception differently from a soft one, so that soft and sharp lines together constitute a graphic duet. However, unlike a proposition formed by words, the constitutive pictorial elements are not fixed like musical notes or letters of the alphabet, but are fluctuating marks traced on a surface, inflected by subjectivity. This inflection is the origin of style - it causes Rembrandt’s line to differ from Holbein’s, affecting the perceiver’s feelings distinctly.

Although subjectivity is the mark left by an artist and remains imprinted as style, it is only the root of a graphic or pictorial sequence, similar to the way an axiom is related to the sentence it justifies. And yet, the existence of such a syntax has largely been overlooked, although artists have always known it intuitively. Line, form and colour in concordance can be recognized universally and communicate directly on the visual level by impact, igniting a cascade of feelings or aesthetic emotions. These feelings can be pleasurable or not, depending on the angle of cognition. And this cognition provokes recognition, presumably of beauty. Beauty can be defined as perfection, a state of equilibrium between fragility and potency. It provokes the viewer’s infinite craving - a craving that cannot be quenched.

Imitation and beauty were declared obsolete concepts not only because of overuse, but because of the utopian ideologies that started with romanticism. However, beauty is always there when recognized. On the other hand, mimesis remains a need as in mitosis. One cannot resist the need to hold by graphic or painterly means a figure, a face, or a view that strikes one’s feelings. The fleeing visual event imposes its urgency by which its trace is fixed on a plane. Even a photograph, which is not a trace but only a reflection, can be subjected to an angle and become art, as in the cases of Nadar or Cartier-Bresson - and both moved from painting to photography. Although a photograph is not achieved by the hand, but obtained mechanically, it is still the work of the painter’s eye.

There wouldn’t be perfection in art without the evolution of the hand. The endeavour to capture visual data is manifest from the onset of lithic technology, and was determined by the hand-motion which unfolded continuously in order to achieve perfection. The palaeolithic artist strived for perfection of line in his depictions no less than later artists. The graver by which lines were incised into the rock was soon followed by a tool by which not only the single line would be achieved, but multiple lines - namely the brush. The invention of the brush is as crucial in the evolution of art as the wheel is for motion. They are both permanent and essentially unchanged. Diversifications of the brush remain very narrow: it is still made of animal hair tied to a stick. Without the brush there wouldn’t have been painting. The drawing or painting tool is an extension of the hand, and the first motion a novice has to learn is how to hold and move this tool in order to master it in such a way as to make it transmit the slightest tremor.

It is this tremor that moves the discerning viewer.

We can suppose from palaeolithic paintings that they had methods of holding and moving these early brushes, probably made of an animal’s tail, but written evidence appeared late, first in China, in the Southern Ch’i period (479-591). It implies first of all the exercise of the hand in order to master the brush, which is not unlike a beginner’s first piano lessons, which consist in learning to hold the hands above the keys, and touch, and press, and hammer. The weight and touch are as important in mastering the piano as they are for the brush. The essence of technique is to master the hand before the subject. In Cato’s words: ‘grasp the subject the words will follow’ - Rem tene verba sequuntur. The methods actually didn’t really differ. The intensity of a line demanded the same hand movement for a Lascaux or Altamira artist as they did for Mu’chi, or Dürer.

What remained hidden was the awareness of the pictorial language, of which there is no mention in Western art-treatises prior to the second half of the nineteenth century. Though the notions of beauty, grace and liveliness were there since Antiquity, one did not venture beyond proportion, perspective, technical recipes and perfect execution. Although the pictorial grammar and syntax was, subliminally, always there, it was first formulated as "grammaire et syntaxe de la peinture" by Jacques-Louis David. The notion of a pictorial grammar was carried on by the decorative arts and received an extraordinary impetus in Britain, during the 1840s, following the reform of industrial design, in the battle for good taste in interior decoration. It was started by a number of artists, among whom August Northmore Welby Pugin, Richard Redgrave, and William Dyce, who, in his lecture on ornament delivered to the students of the London School of Design (1849), said:

"Ornamental design is, in fact, a kind of practical science, which, like other kinds, investigates the phenomena of nature with the purpose of applying natural principles and results to some new end".

Although that "new end" was meant to be the mechanical skill, another end beyond that horizon was painting as painting - not painting a tale or a yarn any longer - a principle that would explode during the first three decades of the twentieth century. Modernist theory of abstraction, and above all the spirit that presided over the Bauhaus with Kandinsky and Klee, continued the ideals started by William Dyce, Owen Jones, Christopher Dresser and William Morris. Klee’s investigations into the constitutive elements of the picture gave Modernism its grammar. A painting was not regarded any longer as an illustration but had to be seen as autonomous, through its own language. Klee’s approach was influenced by metaphysics, mysticism and music. He actually deconstructed the constitutive elements of a picture, demonstrating all its hidden formal possibilities and thought that our art-cognition is wider than it was in the past and therefore extends beyond the optical. What he probably meant by "optical" is actually what we name illusionism - Zeuxis’s grapes. Modernism was about non-illusionist painting, up to the appearance of Pop-art, which brought the image back into the picture, doing away with pictorial syntax.

In spite of the fact that art has moved away from the general to the particular, from the collective to the individual, in an accelerating path, since the seventeenth-century, the regression of the 1960s perpetuates a setback, one that influenced art cognition negatively.

It took painting tens of thousands of years to move from the undetermined cavern walls to the determined surface of a painted plane, and not so long ago to painting from observation, rather than from memory. However, the pigments have remained the same. Palaeolithic art attests to a knowledge of minerals and even painting mediums in a speedy technique and graphic as well as chromatic formulation that remains, in many cases, paradigmatic. The caverns’ rugged walls were often treated so as to use their irregularities, which were incorporated in their engraved, drawn or painted elements. These early artists clearly understood that the painted surface ought to be transformed into a pictorial plane, although it is likely that such a concept did not yet exist; but the segmentation of visual data is naturally based on limits, on spatiotemporal edges, which are and were spontaneously detected by the human visual system. The plane is determined by its limits, by its edges, be it a rectangle, a square, an oval or a tondo. It imposes foreground and background, and its edges determine the power of the centre. This fact was recognized by Leon-Battista Alberti, who defined the pictorial plane as "known not by its depth but only by its length and breadth and by its quality. Some qualities remain permanently on the plane in such a manner that they cannot be changed without altering the plane itself."

Hence, it is the shape of the plane that dictates its activation and its eventual transformation into a pictorial space. The formulation - the pictorial syntax - is, however, closely knitted with technique, because the chemical aspect of pigments conditions the visual one. So does the correspondence between colours perceived in reality and the pigments on the palette, that continue to challenge art cognition to the present day.