The prehistory of the Principia from 1664 to 1686

Since S.P. Rigaud’s pioneering Historical essay appeared in 18381 there have been many, from Rouse Ball, Cajori and Beth down to I.B. Cohen, A.R. Hall, J.W. Herivel and R.S. Westfall in our own day, who have explored how Newton’s Principia came to be. 2 Surely there can be nothing profoundly new to be said about its progress from first conception as an inchoate idea in its author’s mind to the maturity of its first publication in 1687? No and yes. There is now a broad balance of agreement over the main stages in its evolution: one no longer set greatly awry by the nuggets of Principia gold still (if with decreasing frequency and size) to be sieved from Newton’s papers by those willing laboriously to do the panning. Anyone not of the fraternity, however, would surely be surprised to see how much Newton scholars can still at times find to disagree upon in assessing what is now in itself known in such abundance, sometimes even at the most basic level of dating a manuscript. 3 As for the changes that must now be made in the accepted account, these only slowly filter through. How often am I still asked: 'Did Newton use calculus to obtain the theorems in his Principia ?’ How, without seeming to patronize, do you lay the groundwork on which you can reply that the question is ill-formed and therefore meaningless? I will not here go into the reasons why. 4 But I would like briefly to tell anew the tale of how Newton wrote his Principia , embellishing it with some of the freshnesses of insight that have come out of recent research.