The Sleepwalkers: A History of Man's Changing Vision of the Universe

by Arthur Koestler

We are in the habit of visualizing man’s political and social history as a wild zigzag which alternates between progress and disaster, but the history of science as a steady, cumulative process, represented by a continuously rising curve, where each epoch adds some new item of knowledge to the legacy of the past, making the temple of science grow brick by brick to ever greater height. Or alternately, we think in terms of ‘organic’ growth from the magic-ridden, myth-addicted infancy of civilization through various stages of adolescence, to detached, rational maturity. In fact, we have seen that this progress was neither ‘continuous’ nor ‘organic’. The philosophy of nature evolved by occasional leaps and bounds alternating with delusional pursuits, culs-de-sac, regressions, periods of blindness, and amnesia. The great discoveries which determined its course were sometimes the unexpected by-products of a chase after quite different hares. At other times, the process of discovery consisted merely in the cleaning away of the rubbish that blocked the path, or in the rearranging of existing items of knowledge in a different pattern. The mad clockwork of epicycles was kept going for two thousand years; and Europe knew less geometry in the fifteenth century than in Archimedes’ time.