There is obviously a greater difficulty in conceiving time as the outcome of relations between different bits of matter than there is in the analogous conception of space.

At an instant distinct volumes of space are occupied by distinct bits of matter.

Accordingly there is so far no intrinsic difficulty in conceiving that space is merely the resultant of relations between the bits of matter.

But in the one-dimensional time the same bit of matter occupies different portions of time.

Accordingly time would have to be expressible in terms of the relations of a bit of matter with itself.