NECESSITY OF LONG PERIODS. 129 
naturalists, make it their chief objection to these theories, 
that they arbitrarily claim too great a length of time: yet 
the ground of objection is scarcely intelligible. For it is 
absolutely impossible to see what can, in any way, limit us 
in assuming long periods of time. We have long known, 
even from the structure of the stratified crust of the earth 
alone, that its origin and the formation of neptunic rocks 
from water must have taken, at least, several millions of 
years. From a strictly philosophical point of view, it makes 
no difference whether we hypothetically assume for this pro- 
cess ten millions or ten thousand billions of years, Before 
us and behind us lies eternity. If the assumption of such 
enormous periods is opposed to the feelings of many, I regard 
this simply as the consequence of false notions which are 
impressed upon us from our'earliest youth concerning the 
short history of the earth, which is said to embrace only 
a few thousands of years. Albert Lange, in his “ History 
of Materialism,’” has convincingly shown that from a 
strictly philosophical point of view it is far less objec- 
tionable in a scientific hypothesis to assume periods which 
are too long than periods which are too short. Every 
process of development is the more intelligible the longer it 
-is assumed to last. A short and limited period is the most 
improbable. 
T have no space here to enter minutely into Lyell’s great 
work, and will therefore mention only its most important 
result, which is, that he completely refuted Cuvier’s history 
of creation with its mythical revolutions, and established in 
its place the constant and slow transformation of the earth’s 
crust by the continued action of forces, which are still work- 
ing on the earth’s surface, viz. the movement of water and 
VOL, I. K 
