light which they shed. Light, in its physical being, is accordingly the
measure of all things in this new philosophy: and if we ask ourselves why
this element should have been preferred, the answer is not far to seek.
Light is the only medium through which very remote or very minute
particles of matter can be revealed to science. Whatever the nature of
things may be intrinsically, science must accordingly express the universe
in terms of light.

These reforms have come from within: they are triumphs of method. We make
an evident advance in logic, and in that parsimony which is dear to
philosophers (though not to nature), if we refuse to assign given terms
and relations to any prior medium, such as absolute time or space, which
cannot be given with them. Observable spaces and times, like the facts
observed in them, are given separately and in a desultory fashion.
Initially, then, there are as many spaces and times as there are
observers, or rather observations; these are the specious times and spaces
of dreams, of sensuous life, and of romantic biography. Each is centred
here and now, and stretched outwards, forward, and back, as far as
imagination has the strength to project it. Then, when objects and events
have been posited as self-existent, and when a "clock" and a system of
co-ordinates have been established for measuring them, a single
mathematical space and time may be deployed about them, conceived to
contain all things, and to supply them with their respective places and
dates. This gives us the cosmos of classical physics. But this system
involves the uncritical notion of light and matter travelling through
media previously existing, and being carried down, like a boat drifting
down stream, by a flowing time which has a pace of its own, and imposes it
on all existence. In reality, each "clock" and each landscape is
self-centred and initially absolute: its time and space are irrelevant to
those of any other landscape or "clock", unless the objects or events