So it is to-day. We, too, witness a classico-mathematical Renaissance. It is bringing us a new vision of the universe, but also a new vision of human life. That is why it is necessary to insist upon life as a dance. This is not a mere metaphor. The dance is the rule of number and of rhythm and of measure and of order, of the controlling influence of form, of the subordination of the parts to the whole. That is what a dance is. And these same properties also make up the classic spirit, not only in life, but, still more clearly and definitely, in the universe itself. We are strictly correct when we regard not only life but the universe as a dance. For the universe is made up of a certain number of elements, less than a hundred, and the “periodic law” of these elements is metrical. They are ranged, that is to say, not haphazard, not in groups, but by number, and those of like quality appear at fixed and regular intervals. Thus our world is, even fundamentally, a dance, a single metrical stanza in a poem which will be for ever hidden from us, except in so far as the philosophers, who are to-day even here applying the methods of mathematics, may believe that they have imparted to it the character of objective knowledge. I call this movement of to-day, as that of the seventeenth century, classico-mathematical. And I regard the dance (without prejudice to a distinction made later in this volume) as essentially its symbol. This is not to belittle the Romantic elements of the world, which are equally of its essence. But the vast exuberant energies and immeasurable possibilities of the first day may perhaps be best estimated when we have reached their final outcome on the sixth day of creation. However that may be, the analogy of the two historical periods in question remains, and I believe that we may consider it holds good to the extent that the strictly mathematical elements of the later period are not the earliest to appear, but that we are in the presence of a process that has been in subtle movement in many fields for half a century. If it is significant that Descartes appeared a few years after Malherbe, it is equally significant that Einstein was immediately preceded by the Russian ballet. We gaze in admiration at the artist who sits at the organ, but we have been blowing the bellows; and the great performer’s music would have been inaudible had it not been for us.