whole realm of nature,
and we perceive the dark chaos of matter lighted up by the reflection of a
divine mind. Such views may be right or wrong. Too hasty comparisons, or
too narrow distinctions, may have prevented the eye of the observer from
discovering the broad outlines of nature's plan. Yet every system, however
insufficient it may prove hereafter, is a step in advance. If the mind of
man is once impressed with the conviction that there must be order and law
everywhere, it never rests again until all that seems irregular has been
eliminated, until the full beauty and harmony of nature has been
perceived, and the eye of man has caught the eye of God beaming out from
the midst of all His works. The failures of the past prepare the triumphs
of the future.

Thus, to recur to our former illustration, the systematic arrangement of
plants which bears the name of Linnaeus, and which is founded on the number
and character of the reproductive organs, failed to bring out the natural
order which pervades all that grows and blossoms. Broad lines of
demarcation which unite or divide large tribes and families of plants were
invisible from his point of view. But in spite of this, his work was not
in vain. The fact that plants in every part of the world belonged to one
great system was established once for all; and even in later systems most
of his classes and divisions have been preserved, because the conformation
of the reproductive organs of plants happened to run parallel with other
more characteristic marks of true affinity.(10) It is the same in the
history of astronomy. Although the Ptolemaean system was a wrong one, yet
even from its eccentric point of view, laws were discovered determining
the true movements of the heavenly bodies. The conviction that there
remains something unexplained is sure to lead to the discovery of our
error. There can be no error in nature; the error must be with us. This
conviction lived in the heart of Aristotle when, in spite of his imperfect
knowledge of nature, he declared "that there is in nature nothing
interpolated or without connection, as in a bad tragedy;" and from his
time forward every new fact and every new system have confirmed his faith.

The object of classification is clear. We understand things if we can
comprehend them; that is to say, if we can grasp and hold together single
facts, connect isolated impressions, distinguish between what is essential
and what is merely accidental