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

by Arthur Koestler

The third document is a minute in the Vatican files which seems to contradict the previous two by alleging that Galileo was formally forbidden ‘to hold, teach, or defend in any way whatsoever, verbally or in writing’52 the Copernican doctrine. This minute, of doubtful reliability, has given rise to one of the most embittered controversies in the history of science, which has now been raging for nearly a century. It may be thought that to attribute such importance to the difference between an absolute injunction and an admonition is splitting hairs. But there is, in fact, a world of difference between the admonition not to ‘hold or defend’ a doctrine, and the command not to teach or discuss it ‘in any way whatsoever’. In the first case, it could be discussed as before, in terms of a mathematical hypothesis; in the second case, not (see note 52a).52a