ached the utmost
limit possible to it, it is not satisfied to rest there, but starts at
once upon its return trip, to bring to notice undiscovered facts hidden
in these mighty generalizations. Thus the pendulum of intellectual
activity unceasingly vibrates between the infinite and the finite, never
resting, because Idea and Matter, the force of Man and the force of
Nature can never be completely identified.

THE PHILOSOPHY OF EVOLUTION.

The intellectual processes of a rational being must proceed according to
some law. They cannot succeed each other at hap-hazard. The notion of
rationality is conditioned upon this regular procedure; if this be
wanting, the essential character of rational action is wanting. But to
say that rational processes are determined by law, and conditioned upon
a regular procedure, is simply to assert that the steps in ratiocination
are so related to each other that the relation of each to every other
may be determined by the application of the law--the difference between
any two steps being analogous to the difference between any other two.
The astronomer determines the orbit of a planet from three observations,
because he thereby determines the law of variation between these points;
from which he assumes that this law will be constant, presenting a
series of terms each differentiated according the series of differences
already determined.

Applying the same principle to mental phenomena, we may determine the
law of intellectual action. Thoughts are discriminated by the presence
or absence of certain attributes. At one extreme we find the _summum
genus_, comprising the fewest possible attributes distinguishing an
idea; at the other extreme we find the individual, comprising any number
of attributes. Between these two extremes we find a regular series of
intermediate terms. The movement of an idea from the general to the
individual is like the motion of a planet through one-half of its orbit;
while the return movement from the individual to the general,
corresponds to the motion of the planet over the remaining half of its
orbit. The same law governs both movements and unites the two halves of
the orbit into a single whole; and a series of observations taken at
equal distances, will, by the uniformity of differences presented,
reveal the operation of the same law in this dual manifestation. Upon
examining the processes of deduction and induction, we find in each the
same series of terms