But how would it have been if, instead of turning on its axis once in
twenty-four hours, the earth had taken a year about it; if the year had
been nearly four hundred years; if man's life had been no longer than it
is, and for the initial steps of astronomy there had been nothing to
depend upon except observations recorded in history? How many ages would
have passed, had this been our condition, before it would have occurred
to any one, that, in what they saw night after night, there was any kind
of order at all?

We can see to some extent how it would have been, by the present state
of those parts of the science which in fact depend on remote recorded
observations. The movements of the comets are still extremely uncertain.
The times of their return can be calculated only with the greatest
vagueness.

And yet such a hypothesis as I have suggested would but inadequately
express the position in which we are in fact placed toward history.
There the phenomena never repeat themselves. There we are dependent
wholly on the record of things said to have happened once, but which
never happen or can happen a second time. There no experiment is
possible; we can watch for no recurring fact to test the worth of our
conjectures. It has been suggested fancifully, that, if we consider the
universe to be infinite, time is the same as eternity, and the past is
perpetually present. Light takes nine years to come to us from Sirius:
those rays which we may see to-night, when we leave this place, left
Sirius nine years ago; and could the inhabitants of Sirius see the earth
at this moment, they would see the English army in the trenches before
Sebastopol, Florence Nightingale watching at Scutari over the wounded at
Inkermann, and the peace of England undisturbed by "Essays and Reviews."