"It is essential to distinguish architectural aesthetics, as I conceive it, from something else that sometimes goes by the same name, but which one might call, for clarity's sake, architectural theory. Architectural theory consists in the attempt to formulate the maxims, rules and precepts which govern, or ought to govern, the practice of the builder. For example, the classical theory of the Orders, as it is found in the great treatises of Vitruvius, Alberti, Serlio and Vignola, which lays down rules for the systematic combination and ornamentation of the parts of a building, belongs to architectural theory; so too do most of the precepts contained in Ruskin's The Stones of Venice and Seven Lamps. Such precepts assume that we already know what we are seeking to achieve: the nature of architectural success is not at issue; the question is, rather, how best to achieve it. A theory of architecture impinges on aesthetics only if it claims a universal validity, for then it must aim to capture the essence, and not the accidents, of architectural beauty. But such a theory is implicitly philosophical, and must be judged accordingly; we will wish to know whether it succeeds in establishing its claims a priori, by a consideration of the phenomena in their most abstract and universal guise. As a matter of fact it has been characteristic of architectural theorists, from Vitruvius to Le Corbusier, to claim this universal validity for their laws. And no architectural aesthetics can leave such claims untouched. Vitruvius, Alberti, Ruskin and Le Corbusier cannot all be right in believing that their favoured form of architecture is uniquely authorized by the rational understanding. As we shall see, they are all wrong.
It may still be thought that there is no real subject of architectural, as opposed to general, aesthetics. If philosophy is to be as abstract as I claim it is, ought it not to consider the aesthetic experience in its full generality, in isolation from the accidental constraints imposed by particular art forms and particular conceptions of success? Why is there any special need for a philosophy of architecture, other than the purely ephemeral one, that architecture is misunderstood by so many of its present practitioners? Is there not one and the same concept of beauty employed in the discussion of poetry, music, painting and building, and is there not one single faculty involved in the appreciation of all those arts? Once we have made the distinction between architectural aesthetics and architectural theory it may seem that little remains to the former other than the delineation of abstractions that have no special application to the practice of the architect. And it is certainly true that philosophers have approached the subject of aesthetics as though it could find expression only in such comprehensive abstractions, and could make none but passing and inessential references to the individual forms of art.
Now as a matter of fact architecture presents an immediate problem for any such general philosophical theory of aesthetic interest. Through its impersonal and at the same time functional qualities architecture stands apart from the other arts, seeming to require quite peculiar attitudes, not only for its creation, but also for its enjoyment. Generalized theories of aesthetic interest, such as those of Kant and Schopenhauer, tend to give rather odd accounts of architecture, and those philosophers who have treated the problem seriously - among whom Hegel is perhaps the most prominent - have often described the appreciation of architecture in terms inappropriate to the other forms of art. For Hegel, for example, architecture was a medium only half articulate, unable to give full expression to the Idea, and hence relegated to the level of pure symbolism, from which it must be redeemed by statuary and ornament.
It is not difficult to see why Hegel should have thought that. It is natural to suppose that representational arts, such as painting, drama, poetry and sculpture, give rise to an interest unlike the interest aroused by such abstract arts as music and architecture. But it is also natural to suppose that music has expressive, sensuous and dramatic powers in common with the representational arts. Only architecture seems to stand wholly apart from them, being distinguished from the other arts by certain features that cannot fail to determine our attitude
towards it. I shall begin by discussing these features, since a grasp of them will be essential to understanding later arguments, and since they will show what a frail and fragmentary thing is this concept of 'art' that we have inherited."
Scruton, Roger (1979) The Aesthetics pf Architecture. London: Matheuen & Co., pp 4, 5.
"Así pues, podemos asignar al sistema de las artes particulares la siguiente división: 
