Newton stated he had begun working on a form of calculus (which he called "The Method of Fluxions and Infinite Series") in 1666, at the age of 23, but the work was not published until 1737 as a minor annotation in the back of one of his works decades later (a relevant Newton manuscript of October 1666 is now published among his mathematical papers[2]).[3] Gottfried Leibniz began working on his variant of calculus in 1674, and in 1684 published his first paper employing it, "Nova Methodus pro Maximis et Minimis". L'Hôpital published a text on Leibniz's calculus in 1696 (in which he recognized that Newton's Principia of 1687 was "nearly all about this calculus"). Meanwhile, Newton, though he explained his (geometrical) form of calculus in Section I of Book I of the Principia of 1687,[4] did not explain his eventual fluxional notation for the calculus[5] in print until 1693 (in part) and 1704 (in full).
Today, the consensus is that Leibniz and Newton independently invented and described calculus in Europe in the 17th century, with their work noted to be more than just a "synthesis of previously distinct pieces of mathematical technique, but it was certainly this in part".[6]
It was certainly Isaac Newton who first devised a new infinitesimal calculus and elaborated it into a widely extensible algorithm, whose potentialities he fully understood; of equal certainty, differential and integral calculus, the fount of great developments flowing continuously from 1684 to the present day, was created independently by Gottfried Leibniz.
— Hall 1980: 1
One author has identified the dispute as being about "profoundly different" methods:
Despite ... points of resemblance, the methods [of Newton and Leibniz] are profoundly different, so making the priority row a nonsense.
— Grattan-Guinness 1997: 247
On the other hand, other authors have emphasized the equivalences and mutual translatability of the methods: here, Niccolò Guicciardini (2003) appears to confirm L'Hôpital (1696) (already cited):
the Newtonian and Leibnizian schools shared a common mathematical method. They adopted two algorithms, the analytical method of fluxions, and the differential and integral calculus, which were translatable one into the other.
— Guicciardini 2003, on page 250[7]"-- end of quoting.
It seems that the numbers 4 and 8 play important but distinct roles in math.(is this true or false?) Historians have various views on this subject. Would you briefly comment, noting whether Lonergan was "concerned" about this history, John