Were it possible for a man to live a hundred years, he could only begin
the exploration of the vast domains of science, and were his life
prolonged indefinitely, his task would remain forever unaccomplished, for
progress in any direction would bring him inevitably to newer and still
unexplored regions of thought.

Therefore it would seem that we are attempting an impossible task when we
undertake in the brief time before us the study of this universal
principle and its fundamental concepts and applications. But are the
difficulties insuperable? Truly our efforts would be foredoomed to failure
were it not that the materials of knowledge are grouped in classes and
departments which may be illustrated by a few representative data. And it
is also true that every one has thought more or less widely and deeply
about human nature, about the living world to which we belong, and about
the circumstances that control our own lives and those of our fellow
creatures. Many times we withdraw from the world of strenuous endeavor to
think about the "meaning of things," and upon the "why" and "wherefore" of
existence itself. Every one possesses already a fund of information that
can be directly utilized during the coming discussions; for if evolution
is true as a universal principle, then it is as natural and everyday a
matter as nature and existence themselves, and its materials must include
the facts of daily life and observation.

Although the doctrine of evolution was stated in very nearly its present
form more than a century ago, much misunderstanding still exists as to its
exact meaning and nature and value; and it is one of the primary objects
of these discussions to do away with certain current errors of judgment
about it. It is often supposed to be a remote and recondite subject,
intelligible only to the technical expert in knowledge, and apart from the
everyday world of life. It is more often conceived as a metaphysical and