Descartes' refusal to assent to anything susceptible to doubt was not the first time ‘the interiority complex’ had appeared in history. Watson, on the other hand, is able to show ideas shifting their freight across cultures and eras. The growth of knowledge itself means that very few professional people know much about the history of their disciplines and the benefits of progress have largely appeased minds troubled by the loss of historical perspective. Only someone working outside the academy (Watson is a broadcaster and independent scholar) would dare to take on a book like this, charting a universal map of knowledge in 800 pages. That he adopts a largely positivist approach - putting philosophy to work in the service of science - adds to the occasional unsteadiness of the spectacle. That is where the tightrope runs which Watson treads in his naturalistic history of man's progress from primitive times to contemporary civilisation. It is countered by the notion that history itself is a kind of knowledge, which one closes the gulf between questions about facts and questions about ideas, which Descartes' philosophy had split wide open. Yet living every day as if it were the first gave rise to a common cognitive ethic which has transformed the world.

Descartes himself had a sharp antipathy to historiography and the new movement of historical thought that sprang up under his ban was implicitly critical of his attempt to redescribe the world as if he were a mathematical Robinson Crusoe. It was only with Descartes' near contemporaries, Bacon and Vico, that we discover anybody bothering to keep tabs on the discipline of thinking.

Wonder was an impediment to knowledge and it never showed much scepticism about Plato's transcendental postulates, to which, as Alfred North Whitehead once wryly remarked, ‘the history of Western thought has been little more than a series of footnotes’. If philosophy traditionally began in wonder, as Aristotle says, after Descartes it had to start all over again, with doubt. Ideas, as Peter Watson admits in the introduction to his ambitious guide to how we understand our understanding of the world, do not have a long history.

Ideas by Peter Watson