x c i i I N T R O D U C T I O N T O V O L U M E 1 5 many leading physicists and mathematicians. He asked whether Einstein would be willing to send a “a message of good wishes” to the gathering, given his admiration for Newton (Doc. 492). Einstein obliged, but his short text did not reach the secre- tary of the Royal Society, James H. Jeans, in time to be read at the event (Doc. 494). This was not the only occasion for Einstein to praise Newton in the months lead- ing up to the bicentenary. Indeed, as he complained to Paul Feldkeller in the spring of 1927 (Doc. 496), he had been overwhelmed by similar requests. In the end, in addition to the message for the Grantham gathering, a translation of which would be printed in Nature (Doc. 504), Einstein wrote more expansive articles for Die Naturwissenschaften (Doc. 503), published in English in the Manchester Guardian, and for the journal Nord und Süd (Doc. 506), the latter being the manuscript for a radio broadcast read by Einstein on the day of the bicentenary. In each of these three texts, Einstein presented Newton as the champion of strict causality in physics, which he identified with the ability to deduce the state of mo- tion of a system from its immediately preceding state (Doc. 503). He stated that Newton was the first to express the causality requirement in a rigorous manner by writing the laws of physics in the form of differential equations. “What has hap- pened since Newton in theoretical physics,” Einstein wrote, “is the organic devel- opment of his ideas.” He presented the introduction of the concept of a field in the nineteenth century as the next significant step in this development. Newton’s dif- ferential equations found their natural continuation in the partial differential equa- tions governing fields. It is only in quantum theory “that Newton’s differential method becomes inadequate, and indeed strict causality fails us.” But he expressed the hope that the “last word has not yet been said” and that “the spirit of Newton’s method” would eventually be restored (Doc. 494). This aspiration was voiced about two months before Einstein presented, and then retracted, a paper in which he tried to modify Schrödinger’s wave mechanics so that, had it been successful, it would arguably have led to a recovery of strict causality as defined in his texts on Newton (see sec. VIII of this Introduction). Intriguingly, in his message to the Grantham meeting, Einstein first wrote down and then decided to strike a phrase that he had already used in a slightly different form in a letter to Max Born, one that would later become iconic: “God does not play dice” (Doc. 426). He concluded his paper in Naturwissenschaften by writing: “[W]ho would be so venturesome as to decide today the question whether causal law and differential law, these ultimate premises of Newton’s treatment of nature, must definitely be abandoned?” (Doc. 503).