The concepts of action and reaction before Newton have received so little attention from historians that the unwary student might easily get the impression that Newton was the first to concern himself seriously with the problem. In fact, the subject had a long prehistory extending back to Aristotle and it was actively discussed by physicists during the half-century preceding the publication of Principia mathematica in 1687. Although there is no evidence that Newton himself was much influenced by the views of (...) others on the subject, they formed a part of the intellectual background of the Principia which should not be ignored. (shrink)

Summary In the trial of Galileo there is a small but significant discrepancy between the text of his condemnation by the Holy Office and the text of his recantation, which has been generally overlooked or ignored. The offence that he was required to recant was more serious than the one of which he had been found guilty. The most plausible explanation seems to be that the two texts were drawn up independently of each other by the Inquisitors and the Pope (...) respectively, and that the latter wished to deal more harshly with Galileo than the former. There is some independent evidence for this supposition. (shrink)