I should say at once that I am a heretic as to this explanation and that I shall expound to you another explanation based upon some work of my own, an explanation which seems to me to be more in accordance with our whole scientific ideas and with the whole body of facts which have to be explained. It can be paraphrased more exactly by saying that non-Euclidian geometry holds in the neighbourhood of the sun. It was this thesis that Whitehead wanted to replace by his own theory of measurement. Whitehead was convinced that geometry should be distinguished from physics. Geometry represents the uniform elatedness of nature, especially of spatio-temporal relations.
Physics treats the contingent properties of nature.
These convictions were related to his rejection of scientific materialism and of the bifurcation of nature. The space-time in which material bodies are located, in his view of unified nature, is nothing other than that in which the visual images of them are situated. The potential impetus shares in the contingency of appearance. It therefore follows that measurement on his theory lacks systematic uniformity and requires a knowledge of the actual contingent physical field before it is possible. If we are to locate a material body and the visual image of it in the same space, it is necessary that the space should have a uniform structure independent of matter.