Russell's theory of space is of great value in understanding the confused concepts of the scientists. He, in the conclusion of a philosophical discussion on space, states: "We have, on this view, two spaces, one subjective and one objective, one known in experience and the other merely inferred. But there is no difference in this respect between space and other aspects of perception, such as colours and sounds. All alike, in their subjective forms, are known empirically; all alike in their objective forms are inferred by means of a maxim as to causation. There is no reason whatsoever for regarding our knowledge of space as in any way different from our knowledge of colour and sound and smell."[1]
The two kinds of space interpreted by Russell can be called perceptual space and conceptual space. The Jain metaphysical Ākāśa can be compared to the conceptual space of Russell, while the space of the physicists is akin to the perceptual space of Russell. But, on logical basis, without accepting the reality of conceptual space, the problem of substratum of substances cannot be solved.