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.