The limitations of materialism

Materialism cannot admit the existence of anything outside matter. 
.
Because with the acceptance of an imponderable Force – the source and head of all the physical forces – other intelligent forces would have to be admitted virtually, and that would lead science very far. 
.
For it would have to accept as a sequel the presence in man of a still more spiritual power 
.
Entirely independent, for once, of any kind of matter physicists know anything about. 
.
Hence, apart from a hypothetical ether of space and gross physical bodies. 
.
The whole sidereal and unseen space is, in the sight of the materialists, one boundless void in nature – blind, unintelligent, useless.’ 
.
(SD 1:587)