earned of the
law, or for a surgeon to leave his knowledge at the door when he entered
the operating room. Too often we are bidden to view the larger conceptions
of nature and supernature as something outside the realm of ordered
knowledge too frequently we are given statements upon authority that takes
no account of reason, and we are asked to accept these views whether or not
they accord with the demonstrated facts of common-sense. But those who
have followed the present description of evolution can readily recognize
their obligation to use for the further analysis of higher human life the
means which have given in that doctrine the most reasonable explanation of
the natural phenomena already investigated.

I need hardly say that we now enter upon the most difficult stage of our
progress. The regions we have traversed were more readily explored because
they were remote from the matters now before us; even in the case of man's
mental and social evolution it was possible to take a partially impersonal
view of certain of the essential elements in human life, which we cannot
do now. For ethics and religion and philosophy are groups of ideas that
are familiar to us as the property of mankind alone. Countless obstacles
are in the way. Much mental inertia must be overcome, for it is far easier
to accept the average and traditional judgments of other men--to let well
enough alone--than it is to win our own way to the heights from which we
may survey knowledge more fully. Human prejudices confront us as a
veritable jungle, hemming us in and obstructing our vision on all sides;
and perhaps much underbrush must be cut away if we are to see widely and
wisely. Nevertheless, to those imbued with a desire to learn truth,
anything and everything gained must surely repay a thousand times all
efforts to obtain clearness of vision and breadth of view. With our
perspective thus rectified by our backward glance, we turn to the three
divisions of human thought now to be examined. The conceptions of ethics
come first for reasons that must be apparent from the classification of
the facts of social evolution; just as mental attributes and communal
organization are inseparable, so rules of conduct arise _pari passu_ with
the origin of a biological association. Religion and theology form the
second division, which takes its origin in part from the first, for these
two groups of ideas are largely concerned with the authority for right
conduct and