The author demonstrates that the arguments of the sceptic about induction extend by force of logic to scepticism about perception and knowledge of the past, an extension by which the sceptic is shown to refute himself on all counts. This, however, is not the clear-cut resolution it may seem to be, for the author now contends that scepticism in epistemology should yield to metaphysical perplexity, his arguments being such as to bring into play the underdetermination of belief by evidence, the role of necessary conditions within a system, and the nature of the conscious mind. This latter is exhibited as the surface of an ocean in which the non-conscious, on the author's definition of the term, conceals an inaccessible realm: that of the intentional. Peddle's theory of consciousness is perhaps the most startling aspect of the present work, related as it is to his theory of the limits of knowledge, beyond which is mystery. The book is written in such a way as to appeal both to academics and to the general reader, this achieved by a combination of humour, much of it irreverent, and personal reminiscence, much of it moving, together with, in places, a lyricism that deepens into prose-poetry and culminates in the final chapter: on the meaning and the mystery of life, the last words of which are, in the strictest sense, sublime.