science.
He knows no bounds to geological speculation but those of the intellect.
He reasons back to a beginning of the present state of things; he admits
the possibility of an end.

I have said that the three schools of geological speculation which I
have termed Catastrophism, Uniformitarianism, and Evolutionism are
commonly supposed to be antagonistic to one another; and I presume it
will have become obvious that, in my belief, the last is destined to
swallow up the other two. But it is proper to remark that each of the
latter has kept alive the tradition of precious truths.

CATASTROPHISM has insisted upon the existence of a practically
unlimited bank of force, on which the theorist might draw; and it has
cherished the idea of the development of the earth from a state in which
its form, and the forces which it exerted, were very different from
those we now know. That such difference of form and power once existed
is a necessary part of the doctrine of evolution.

UNIFORMITARIANISM, on the other hand, has with equal justice
insisted upon a practically unlimited bank of time, ready to discount
any quantity of hypothetical paper. It has kept before our eyes the
power of the infinitely little, time being granted, and has compelled us
to exhaust known causes, before flying to the unknown.

To my mind there appears to be no sort of necessary theoretical
antagonism between Catastrophism and Uniformitarianism. On the contrary,
it is very conceivable that catastrophes may be part and parcel of
uniformity. Let me illustrate my case by analogy. The working of a clock
is a model of uniform action; good time-keeping means uniformity of
action. But the striking of the clock is essentially a catastrophe; the
hammer might be made to blow up a barrel of gunpowder, or turn on a
deluge of water; and, by proper arrangement, the clock, instead of
marking the hours, might strike at all sorts of irregular periods, never
twice alike, in the intervals, force, or number of its blows.
Nevertheless, all these irregular, and apparently lawless, catastrophes
would be the result of an absolutely uniformitarian action; and we might
have two schools of clock-theorists, one studying the hammer and the
other the pendulum.

Still less is there any necessary antagonism between either of these
doctrines and that of Evolution, which embraces all that is sound in
both Catastrophism and Uniformitarianism, while it rejects the arbitrary
assumptions of