eptions, but very short
indeed compared with the entire duration of which the life-bearing
season would be only a single era.

Lastly, though men may daringly overleap the limits of time and space
within which their lives are cast, though they may learn to recognise
the development of their own world and of others like it even from the
blossom of nebulosity, they seem unable to rise to the conception that
the mighty tree which during remote aeons bore those nebulous blossoms
sprang itself from cosmical germs. We are unable to conceive the nature
of such germs; the processes of development affecting them belong to
other orders than any processes we know of, and required periods
compared with which the inconceivable, nay, the inexpressible periods
required for the development of the parts of our universe, are as mere
instants. Yet have we every reason which analogy can afford to believe
that even the development of a whole universe such as ours should be
regarded as but a minute local phenomenon of a universe infinitely
higher in order, that universe in turn but a single member of a system
of such universes, and so on, even _ad infinitum_. To reject the belief
that this is possible is to share the folly of beings such as we have
conceived regarding their tiny world as a fit centre whence to measure
the universe, while yet, from such a stand-point, this little earth on
which we live would be many degrees beyond the limits where for them the
inconceivable would begin. To reject the belief that this is not only
possible, but real, is to regard the few short steps by which man has
advanced towards the unknown as a measurable approach towards limits of
space, towards the beginning and the end of all things. Until it can be
shown that space is bounded by limits beyond which neither matter nor
void exists, that time had a beginning before which it was not and tends
to an end after which it will exist no more, we may confidently accept
the belief that the history of our earth is as evanescent in time as the
earth itself is evanescent in space, and that nothing we can possibly
learn about our earth, or about the system it belongs to, or about
systems of such systems, can either prove or disprove aught respecting
the scheme and mode of government of the universe itself. It is true now
as it was in days of yore, and it will remain true as long as the earth
and those who dwell on it endure, that what men know is nothing, the
unknown