I think that even a materialist must reach a conclusion not unlike ours if he fairly faces the problem. He will need in the physical world something to stand for a symbolic unity of the atoms associated with an individual consciousness, which does not exist for atoms not so associated—a unity which naturally upsets physical predictions based on the hypothesis of random disconnection. For he has not only to translate into material configurations the multifarious thoughts and images of the mind, but must surely not neglect to find some kind of physical substitute for the Ego. [47] A few days after the course of lectures was completed, Einstein wrote in his message on the Newton Centenary, “It is only in the quantum theory that Newton’s differential method becomes inadequate, and indeed strict causality fails us. But the last word has not yet been said. May the spirit of Newton’s method give us the power to restore unison between physical reality and the profoundest characteristic of Newton’s teaching—strict causality.” (Nature, 1927, March 26, p. 467.) [48] It is fair to assume the trustworthiness of this intuition in answering an argument which appeals to intuition; the assumption would beg the question if we were urging the argument independently. [Pg 316] Chapter XV SCIENCE AND MYSTICISM One day I happened to be occupied with the subject of “Generation of Waves by Wind”. I took down the standard treatise on hydrodynamics, and under that heading I read— The equations (12) and (13) of the preceding Art. enable us to examine a related question of some interest, viz. the generation and maintenance of waves against viscosity, by suitable forces applied to the surface. If the external forces , be given multiples of , where and are prescribed, the equations in question determine and , and thence, by (9) the value of . Thus we find where has been written for as before.... And so on for two pages. At the end it is made clear that a wind of less than half a mile an hour will leave the surface unruffled. At a mile an hour the surface is covered with minute corrugations due to capillary waves which decay immediately the disturbing cause ceases. At two miles an hour the gravity waves appear. As the author modestly concludes, “Our theoretical investigations give considerable insight into the incipient stages of wave-formation”. On another occasion the same subject of “Generation of Waves by Wind” [Pg 317] was in my mind; but this time another book was more appropriate, and I read— There are waters blown by changing winds to laughter And lit by the rich skies, all day. And after, Frost, with a gesture, stays the waves that dance And wandering loveliness. He leaves a white Unbroken glory, a gathered radiance, A width, a shining peace, under the night.