Feankland. — On the Doctrine of Mind-Stuff. 211 



Psychology is the only science which deals with them ; and even that deals 

 only mth the most complex of them. Therefore the Doctrine of Mind-Stuff 

 can in no way supersede the necessity of, still less can it exclude, these 

 mechanical explanations of the universe. 



But although the principles of rational mechanics, and the hypotheses 

 by which, in conjunction with the former, it is sought fco explain the 

 observed phenomena and structure of the material world, are in no way in 

 conflict with our doctrine, we shall presently see that they may come to 

 have a very important bearing on the determination of the particular form 

 which that doctrine ought to assume. For the doctrine asserts that the 

 possibilities of sensation which constitute a material object, correspond to, 

 and depend for their existence on, some reality outside us or "eject" of 

 which Mind-Stuff units are the elementary constituents. Hence every 

 conception of mechanical science must denote what would be called in 

 mathematics some function of Mind- Stuff. Matter, defined as that which 

 has mass or inertia, must be a function of Mind-Stuff. Motion, force, and 

 energy, must be functions of Mind- Stuff. The interesting question then 

 suggests itself: What functions, severally, are mass, momentum, energy, 

 etc., of the noumenal reahty which we have designated Mind- Stuff. This 

 question has been touched upon in a profound passage of the late Professor 

 Clifford's review of a work entitled " The Unseen Universe." Professor 

 Clifford there indicates that the answer to the question, if it can be 

 answered, must depend on the knowledge we can gain respecting Mind- 

 Stuff itself — knowledge which can only be acquired within the domain of 

 psychology. Our feelings, he points out, have certain relations of contiguity 

 or nextness in space, exemplified by contiguous elements of a visual image, 

 and certain relations of sequence in time, exemplified by all feelings what- 

 ever. " Out of these two relations the future theorist must build up the 

 world as best he may. Two things may, perhaps, help him : there are 

 several lines of mathematical thought which seem to indicate that distance 

 and quantity may come to be expressed in terms of position, in the wide 

 sense of an analysis situs, while the theory of the curvature of space hints 

 at a possibility that matter and motion may be expressed in terms of ex- 

 tension only."* 



* I take this to mean, that if we admit as a possibility that the properties of space 

 may show a sensible divergence from the Euclidean standard, if we consider very small 

 parts of it — we get at a way of defining matter in terms of the space which it occupies. 

 An ultimate atom of matter (perhaps infinitesimal as compared with the chemical atom) 

 would on that view be merely an infinitesimal crumple in space. All physical science 

 would then be reduced to transcendental geometry, and space-elements would be the 

 analogues of Mind-Stuff units. 



The former parts of Professor Clifford's suggestion can only mean, as far as I can 



