observed, and by then
reiterating that nevertheless we do observe this non-existent fact.
Unless motion is something as a fact in nature, kinetic energy and
momentum and all that depends on these physical concepts evaporate from
our list of physical realities. Even in this revolutionary age my
conservatism resolutely opposes the identification of momentum and
moonshine.

Accordingly I assume it as an axiom, that motion is a physical fact. It
is something that we perceive as in nature. Motion presupposes rest.
Until theory arose to vitiate immediate intuition, that is to say to
vitiate the uncriticised judgments which immediately arise from
sense-awareness, no one doubted that in motion you leave behind that
which is at rest. Abraham in his wanderings left his birthplace where it
had ever been. A theory of motion and a theory of rest are the same
thing viewed from different aspects with altered emphasis.

Now you cannot have a theory of rest without in some sense admitting a
theory of absolute position. It is usually assumed that relative space
implies that there is no absolute position. This is, according to my
creed, a mistake. The assumption arises from the failure to make another
distinction; namely, that there may be alternative definitions of
absolute position. This possibility enters with the admission of
alternative time-systems. Thus the series of spaces in the parallel
moments of one temporal series may have their own definition of absolute
position correlating sets of event-particles in these successive spaces,
so that each set consists of event-particles, one from each space, all
with the property of possessing the same absolute position in that
series of spaces. Such a set of event-particles will form a point in the
timeless space of that time-system. Thus a point is really an absolute
position in the timeless space of a given time-system.

But there are alternative time-systems, and each time-system has its own
peculiar group of points--that is to say, its own peculiar definition of
absolute position. This is exactly the theory which I will elaborate.

In looking to nature for evidence of absolute position it is of no use
to recur to the four-dimensional manifold of event-particles. This
manifold has been obtained by the extension of thought beyond the
immediacy of observation. We shall find nothing in it except what we
have put there to represent the ideas in thought which arise from our
direct sense-