In insisting that the philosophical point of view is the only possible platform from which the facts which art criticism deals with can be adequately correlated, I am aware that I am advancing a somewhat novel proposition. It is also one which I do not think it advisable to defend in detail on the present occasion. The present volume is the outcome of an attempt to apply this point of view. So far as all that has gone before is in harmony with my intentions, it is an exemplification of the practical usefulness of such a working hypothesis, but the subject seems to me to call for full and free discussion, and I hope on a suitable occasion to revert to it. At present I hope it will be sufficient if I say that art criticism, if it is to be regarded as a form of knowledge, can have only one consistent aim, and that is intellectual satisfaction. And the subject-matter of art criticism is essentially a form of communication, and therefore is concerned only with certain aspects of the formed world of human experience. And in dealing with any aspects of the ‘world of discourse’ with a view to the satisfaction of our intellectual requirements of coherency and consistency of thought, the terms and ideas used in our non-systematised everyday thought and language are certainly inadequate, and those in use in all the special sciences, though valid enough when confined within the limits prescribed by their initial assumptions, are no less unsatisfactory for our purpose. For the artist to regard nature as anything but an existing reality independent of individual experience and given ready-made in immediate perception must, no doubt, be exceedingly difficult. Both the original bent of his mind and the whole course of his professional training and practice have tended to consolidate his spatial intuitions into something apparently primary and instinctive. But an artist, as an artist, is not called upon to undertake the business of art criticism. The difficulty, however, remains nearly as great for the art critic, for he also is necessarily one whose visual faculties have received early and special development. When even an art critic looks at the familiar objects with which he is surrounded and notices their sharply defined forms and colours, he finds it hard to believe that the very distinctness of these perceptions is the result of a long process of education which his own faculties have undergone. The clearness seems so unmistakably to belong to the objects. Yet however difficult the step, it must be taken. We are bound to admit that animals and infants cannot have the same ordered visual image of space definitely stretching away all round them which we are apt to regard as one of the primary and fixed constituents of the external world. But if the spatial system into which objects of perception fall so easily has to be constructed in some way by each human being for himself, it follows that pictorial art,