G. D. Martin is an omnivorous reader as well as a single-minded writer, and his new book-a successor to Language, Truth and Poetry-bears the marks of one feature as much as the other. On the one hand, he argues a single case for the unique importance of art as a cognitive instrument: 'art is not for art's sake alone. It is about reality and it is for perception. It is awareness-enhancing and consciousness-expanding.' On the other, he bases his case not only on a wide range of examples from English and French literature but on a considerable acquaintance with recent work in the human sciences and the philosophy of natural and social science. An omnivore does not always digest every part of his diet equally well and, if I have a stylistic criticism to make of Martin's generally well-argued book, it is that his use of numerous, substantial quotations is excessive. Too often they disrupt more than they illustrate or integrate the argument.

The argument is single but hardly simple. Its complexity mirrors the complexity of the real world whose features art is said to help us to descry. This world is 'constructed' from our perceptions, understandings and misunderstandings alike. Originating in the experience of consciousness it is re-presented in accordance with a necessary but always fallible system of generally accepted categories and classifications. However we apprehend it, we must always represent the world as a world of types. However, 'Classification is like a medieval cannon: it ...