The Gifford Lectures at Glasgow, 1916-1918, Vol II.
Book III. The Order and Problems of Empirical Existence
Chapter II. The Order of Empirical Qualities
B. The Order of Qualities
...The conception, once at any rate so widely current, that the ultimate constituents of things are matter and motion,
must be modified. Matter it is thought is not itself a form of motion, or comparable with motion itself. It is so difficult to conceive motion as stuff, without something which moves ; we still suppose a something we call matter which changes its place in empty Space. But this difficulty vanishes when once we have learnt to think of motion as stuff, and as in fact the first form of animated body. For there is no reason to regard matter (whatever we may learn from physicists as to what distinguishes matter from other groups of motion), as other than a complex of motion, that is made out of the original stuff which is Space-Time.
This conception that matter is in the end a complex of motions and not, like motion itself, ultimate, requires more courage (or rashness) to suggest than the last of these general pleas that I have now to urge, that another scientific conception, the ether, becomes unnecessary except possibly as a convenience of expression or imagination.
...If it is asked further by what steps it is that mere motion under the guiding hand of Time leads to the emergence of the material complexes of motion which we find in the world of things ; how a specific motion like that of light is generated, with constant and maximal velocity, and how atoms come into existence as combinations of electrons with or without the distinctively material nucleus, with relatively constant constitutions ; I can only reply that I do not know, and that it is not for the metaphysician to say, in the absence of indications from the physicist himself. Yet it is difficult to refrain from hazarding conjecture by way of asking a question. And so I dare to ask if there may not be in these ages of simpler existence something corresponding to the method pursued by nature in its higher stages, of natural selection ; however natural selection is to be interpreted whether as operating upon insensible variations or upon large mutations. Whether that is to say, nature or Space-Time did not try various complexes of simple motions and out of the chaos of motion preserve certain types. The ground which justifies us in asking this question is that the beginnings of things present phenomena analogous to those of life ; for instance, in the ' organisation ' of the atoms ; in the law that the physical and chemical elements observe certain periods or cycles which are connected with the number of the atomic weights, or " that the properties of an element are shown to be defined by a whole number which varies by unity from one element to the next " ; in the observed transformation of atoms into atoms of other properties ; all phenomena which suggest growth of a certain kind. If it were so the history of life and mind, and we may add societies, would not be so isolated a feature of things as it seems. But all this is rather a question which might be answered by those who know, if they do not dismiss it at once as fanciful, and is not asked as having any further pretension.