As time is the very condition of the possibility of Progress, it is
obvious that the idea would be valueless if there were any cogent
reasons for supposing that the time at the disposal of humanity is
likely to reach a limit in the near future. If there were good cause
for believing that the earth would be uninhabitable in A.D. 2000 or
2100 the doctrine of Progress would lose its meaning and would
automatically disappear. It would be a delicate question to decide
what is the minimum period of time which must be assured to man for
his future development, in order that Progress should possess value
and appeal to the emotions. The recorded history of civilisation
covers 6000 years or so, and if we take this as a measure of our
conceptions of time-distances, we might assume that if we were sure
of a period ten times as long ahead of us the idea of Progress would
not lose its power of appeal. Sixty thousand years of HISTORICAL
time, when we survey the changes which have come to pass in six
thousand, opens to the imagination a range vast enough to seem
almost endless.

This psychological question, however, need not be decided. For
science assures us that the stability of the present conditions of
the solar system is certified for many myriads of years to come.
Whatever gradual modifications of climate there may be, the planet
will not cease to support life for a period which transcends and
flouts all efforts of imagination. In short, the POSSIBILITY of
Progress is guaranteed by the high probability, based on astro-
physical science, of an immense time to progress in.

It may surprise many to be told that the notion of Progress, which
now seems so easy to apprehend, is of comparatively recent origin.