Kant’s thesis can be summed up in a fairly brief sentence: the experience of beauty is constituted by the "free harmonious play of imagination and understanding"; the experience of art is similarly constituted, although with certain added refinements. But what this grand sounding phrase actually means is far from obvious.

The free play of imagination

Kant uses the notion of imagination in a technical sense. In ordinary perception the role of imagination is to draw together or differentiate elements of the visual field according to a pre-conceptual order - that is independently of our grasp of the species of things which we are looking at. In Corot’s picture we could see that the visual texture of the papal palace is unlike that of the foreground - without classifying these as a building or as heath land. Kant thinks of the "synthesis of imagination" as an ordering process which picks up on visual patterns; in a modular conception of the activity of the mind, this process would precede and facilitate the conceptual classification of what we see. The line which marks the second ridge of hills (beyond which we see the dark trees of the river valley) is visually distinctive quite apart from our grasp of it as a ridge.

In art (as in this picture) this kind of sensitivity - to similarities and differences of visual texture - plays a very important role. In the more practical moments of life we work with (but don’t consciously attend to) such operations of the imagination. Consider the gable-end of the rustic building at the lower left of the picture: it has a distinctive apex; in the "synthesis of imagination" this is seen as similar to the (reversed) apex made by the river on the extreme left and a second (reversed) apex to the right of the lone tree - which (in fact) marks the occlusion of some woodland by two hills. The pictorial structure does not, then, depend upon our seeing things together according to conceptual classification. It is a pre-conceptual sense of similarity which holds together these motifs. Artistic composition is necessarily pre-conceptual in that it does not rely on seeing as similar things which belong to the same conceptual class - but, precisely, requires that we see cohesion and kinship across class boundaries. It also requires differentiation (and differentiation, of course, relates the things held apart - since we see them as mutually constituting a difference). Thus the oppositions of visual texture amongst the palace, the foreground and the sky pick out zones of the image which we see in contrast one to the other. And this sense of contrast doesn’t require - it precedes - our grasp of these zones as depicting things: rough ground, a palace, the sky.

The free play of the understanding

Understanding is, in Kant’s language, the process in which we see a particular object as belonging to a general class. When I see the object before me as a tree, I am deploying a general concept "tree". And this concept is such that it can apply equally well to other individual objects. Although we do not do this self-consciously, our minds are deploying a general rule here - and the general rule would be framed approximately like a definition of "tree".

Kant’s suggestion is that in aesthetic experience the understanding is "at play" - and is not quite performing its usual function. What might this "play" of the understanding be? Abstractly, it could be described as the pursuit of generalisation, without its achievement.

Suppose one feels that there is some visual relationship between, say the single tree on the right and the sky. The juxtaposition of this element and aspect of the picture does not strike us as arbitrary. And yet if we try to specify what exactly the relationship is we find we cannot. We cannot, that is, reduce it to a general formulation. And, therefore, we cannot see other instances as repeating quite the same relationship.

In other words we grasp the relationship between the tree and the sky as a relationship - but its "ineffability" remains intact - we can’t sum it up. And, further, we don’t see this relationship as repeatable: it is unique. It is crucial to recall, at this stage, that Kant is not doing phenomenology - he is not trying to tell us about conscious processes. Rather he is attempting to describe sub-personal processes. These underwrite our conscious experience; but it is not an objection to Kant to turn round and say - that doesn’t happen to me when I look at a picture. He is trying to explain how an ordinary capacity of perception - the ability to see an individual as a member of a species - works in a special way when we find something beautiful.

A relationship is, a priori, abstract and can necessarily be instantiated apart from the particular elements it relates. The relation of "to the left of", for example, can obviously be sustained by millions of distinct pairs of objects. What is so beguiling about the relationship between a tree and the sky is, while it is indeed a relationship, the specific character of the relationship cannot be detached from the things related.

Kant’s view was that, in these cases, the mind seeks a more and more specific grasp of the relationship but never arrives at this; we keep on sensing that there is something to be understood - but quite what it is eludes us. And yet we are not frustrated; we experience it - as he puts it - as play.

The harmony of the faculties

The beautiful object, then, strikes us as highly meaningful, as ordered in a rational way - and yet when we try to say precisely what the meaning or order is we find that we cannot. What impressed Kant here was the benign relationship between the object and the mind. The beautiful object presents us, as it were, with an image of a perfectly comprehensible world, one adapted perfectly to our minds; and yet - for this to occur - the meaning cannot be specified, the order cannot be fully codified. If it were the sense of plenitude, the completeness of the object would be compromised. Instead of presenting us with an impression of ‘meaningful order as such’ the object would merely convey one more specific and limited message, would be reduced to a particular and finite order.

In other words, the value and significance of the work depends upon something elusive: a sense of order without any precise codification. Kant thought that this had a theological import. The encounter with the work of art is similar to that of Adam before the Fall. A world created by a loving God lies before us - as yet we have not understood it, we have not conceptualised it, and yet we grasp that it will be comprehensible.

Aesthetic ideas

Kant does not have much to say about the role of content in art - but what he does say is, I think, very helpful. One problem with content is that it allows for multiple instantiation. "Content" is what could be presented in another form. It therefore sits awkwardly with the specific and particular value of works of art. Kant attempted to get round this in an ingenious way.

He places a great deal of emphasis upon the imprecision of genuinely artistic content - in which the work is suggestive, rather than explicit. The idea is fused with its aesthetic presentation. This is a natural extension for Kant: we grasp such content in a mental process closely related to the free harmonious play of imagination and understanding. We don’t quite specify the content, but we keep on circling round it. We can’t pin down what Corot is trying to tell us about the palace. And yet we may be filled with a sense of the past persisting into the present; or it may be that there is a moving contrast between the extraordinary innocence and freshness of the pictorial time and of the drama, distress and divisions to which the city was a witness. But, crucially, these are not presented as a thesis; they are areas or fields of reflection which fuse with the depicted scene.

The kind of mental processes which works of art require for their aesthetic appreciation can be understood as cognitive processes. But Kant is at pains to identify a set of cognitive processes which can do justice to the outstanding features of aesthetic experience: the specificity of the object, its internal cohesion, and the sense of depth of meaning (even though we cannot sum up that meaning).