order from diverse time-systems must harmonise with one spatial
order in each instantaneous space. In this way also diverse time-orders
are comparable.

We have two great questions still on hand to be settled before our
theory of space is fully adjusted. One of these is the question of the
determination of the methods of measurement within the space, in other
words, the congruence-theory of the space. The measurement of space will
be found to be closely connected with the measurement of time, with
respect to which no principles have as yet been determined. Thus our
congruence-theory will be a theory both for space and for time. Secondly
there is the determination of the timeless space which corresponds to
any particular time-system with its infinite set of instantaneous spaces
in its successive moments. This is the space--or rather, these are the
spaces--of physical science. It is very usual to dismiss this space by
saying that this is conceptual. I do not understand the virtue of these
phrases. I suppose that it is meant that the space is the conception of
something in nature. Accordingly if the space of physical science is to
be called conceptual, I ask, What in nature is it the conception of? For
example, when we speak of a point in the timeless space of physical
science, I suppose that we are speaking of something in nature. If we
are not so speaking, our scientists are exercising their wits in the
realms of pure fantasy, and this is palpably not the case. This demand
for a definite Habeas Corpus Act for the production of the relevant
entities in nature applies whether space be relative or absolute. On the
theory of relative space, it may perhaps be argued that there is no
timeless space for physical science, and that there is only the
momentary series of instantaneous spaces.

An explanation must then be asked for the meaning of the very common
statement that such and such a man walked four miles in some definite
hour. How can you measure distance from one space into another space? I
understand walking out of the sheet of an ordnance map. But the meaning
of saying that Cambridge at 10 o'clock this morning in the appropriate
instantaneous space for that instant is 52 miles from London at
11 o'clock this morning in the appropriate instantaneous space for that
instant beats me entirely. I think that, by the time a meaning has been
produced for this statement, you will find that you have constructed
what is in fact a