Principles of Perception by S. H. Hartley (review)

96 Letters surface pattern, at the same time as we see the scene depicted in depth by the artist. (This illusionary depth is less realistic than in a stereoscopic view.) Thus, linear perspective gives a certain spatial pattern on the surface of the painting-not an arbitrary, conventional pattern but one largely based on empirical optical facts. In most paintings, this canvas pattern (of which, as Michael Polanyi says, we are ‘subsidiarily aware’), this flat pattern, does provide the ‘music’ of the painting alluded to by the painter Delacroix. This ‘visual music’ does somehow get mentally integrated with the perception of the scene depicted in depth. How this psychological integration occurs remains rather mysterious, even though it takes place in everyone for most forms of representational art and poetrybut this, as far as I know, had not hitherto been clearly and definitely recognized in the case of the art of painting. All this leads to a vindication of those ‘oldfashioned ’ representational artists who worked during the past centuries and attempted to imitate reality. Their works could not be ‘mere imitations’, in the sense that painting or photography cannot achieve a complete imitation of reality. Those relatively few artists who tried to ‘hold a mirror to nature’ perforce failed, first, because they could only give a version of what they personally saw and, secondly, because ordinary paintings really fail to represent depth realistically. But their endeavours towards a true representational painting led artists eventually to the discovery of linear perspectivewhich , contrary to popular misconceptions, still allowed them an immense amount of freedom in composing their paintings. In the Renaissance, this perspective composition provided the spectator with a new, fascinating visual music, which accompanied their interpretation of the painted reality. Thus, this old-fashioned ‘search for truth’ in painting could, and did, lead to great artistic heightswhile , perforce, failing always to give the complete truth. Photography, useful as it is, especially for documentary representation, has not rendered obsolete the great ‘realistic’ paintings of the past. While abstract or non-figurative artists seem to aim mainly at producing merely an artistically interesting surface pattern on their canvas, oldfashioned painting can give a vivid depiction of reality plus such a canvas pattern and an intriguing one. Thus, the contrast between representational art and ‘abstract’ art is sometimes exaggerated. Whereas the man in the street may find a mere pattern on the canvas quite uninteresting, he will ‘swallow’the pattern on a Piero della Francesca and be influenced by it, even though he may think that he is only interested in the scene depicted. Kennedy gives an accurate summary of the difficulties encountered by artists in the use of exact perspective, especially for the depiction of objects having curved surfaces. He takes, rightly I think, the depiction of a sphere as a crucial example. Even in the Renaissance, artists deviated from strict linear perspective in the case of objects with curved surfaces; this is a complicated fact that sometimes tends to be glossed over. The student of optics and perspective soon experiences the truth of the aphorism that ‘truth is rarely pure and is never simple’. The end of Kennedy’s review, however, I find less easy to understand. He writes: ‘So, perhaps, one should look for the special structure that is information for a sphere in the structure that occurs across time and across viewpoints.’ But the eye at any given instant is necessarily in a given position, so the viewpoint also is in a given position at any given moment. Medieval paintings often give views depicted from different viewpoints in one and the same picture and some cubic paintings give such different projections even of one and the same object. But they fail of course to give the continual series of views changing in time that we have when we walk around an object. And I agree that this is the best way of looking at things-even though it can hardly be used for very distant ones. It would seem to me that the cinema is about the only answer to Kennedy’s wish, for an ordinary painting is necessarilyfrozen-and that is considered one of its attractive features. Again, Kennedy writes...