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