h must be sought in the same way as the solution
of any other historical problem.

So far as I know, there are only three hypotheses which ever have been
entertained, or which well can be entertained, respecting the past
history of Nature. I will, in the first place, state the hypotheses,
and then I will consider what evidence bearing upon them is in our
possession, and by what light of criticism that evidence is to be
interpreted.

Upon the first hypothesis, the assumption is, that phenomena of Nature
similar to those exhibited by the present world have always existed; in
other words, that the universe has existed, from all eternity, in what
may be broadly termed its present condition.

The second hypothesis is that the present state of things has had only
a limited duration; and that, at some period in the past, a condition
of the world, essentially similar to that which we now know, came into
existence, without any precedent condition from which it could have
naturally proceeded. The assumption that successive states of Nature
have arisen, each without any relation of natural causation to an
antecedent state, is a mere modification of this second hypothesis.

The third hypothesis also assumes that the present state of things has
had but a limited duration; but it supposes that this state has been
evolved by a natural process from an antecedent state, and that from
another, and so on; and, on this hypothesis, the attempt to assign any
limit to the series of past changes is, usually, given up.

It is so needful to form clear and distinct notions of what is really
meant by each of these hypotheses that I will ask you to imagine what,
according to each, would have been visible to a spectator of the events
which constitute the history of the earth. On the first hypothesis,
however far back in time that spectator might be placed, he would see
a world essentially, though perhaps not in all its details, similar to
that which now exists. The animals which existed would be the ancestors
of those which now live, and similar to them; the plants, in like
manner, would be such as we know; and the mountains, plains, and waters
would foreshadow the salient features of our present land and water.
This view was held more or less distinctly, sometimes combined with
the notion of recurrent cycles of change, in ancient times; and its
influence has been felt down to the present day. It is worthy of remark
that it is a hypothesis whic