Let us listen to yet another voice from the ranks of present-day science, expressing a criticism which is symptomatic of our time. It comes from the late physiologist, Professor A, Carrel, who, concerning the effect which scientific research has had on man's life in general, says in his book, Man the Unknown: 'The sciences of inert matter have led us into a country that is not ours. ... Man is a stranger in the world he has created.' Of these utterances, Eddington's is at the present point of our discussion of special interest for us; for he outlines in it the precise field of sense-perception into which science has withdrawn in the course of that general retreat towards an ever more restricted questioning of nature which was noted by Heisenberg. The pertinence of Eddington's statement is shown immediately one considers what a person would know of the world if his only source of experience were the sense of sight, still further limited in the way Eddington describes. Out of everything that the world brings to the totality of our senses, there remains nothing more than mere movements, with certain changes of rate, direction, and so on. The picture of the world received by such an observer is a purely kinematic one. And this is, indeed, the character of the world-picture of modern physical science. For in the scientific treatment of natural phenomena all the qualities brought to us by our other senses, such as colour, tone, warmth, density and even electricity and magnetism, are reduced to mere movement-changes. As a result, modern science is prevented from conceiving any valid idea of 'force'. In so far as the concept 'force' appears in scientific considerations, it plays the part of an 'auxiliary concept', and what man naively conceives as force has come to be defined as merely a 'descriptive law of behaviour'. We must leave it for later considerations to show how the scientific mind of man has created for itself the conviction that the part of science occupied with the actions of force in nature can properly be treated with purely kinematic concepts. It is the fact itself which concerns us here. In respect of it, note as a characteristic of modern text-books that they often simply use the term 'kinetics' (a shortening of kinematics) to designate the science of 'dynamics'.4