by natural selection, because the development of his
mental faculties would render important modifications of its form and
structure unnecessary. It will, therefore, probably excite some
surprise among my readers, to find that I do not consider that all
nature can be explained on the principles of which I am so ardent an
advocate; and that I am now myself going to state objections, and to
place limits, to the power of "natural selection." I believe, however,
that there are such limits; and that just as surely as we can trace the
action of natural laws in the development of organic forms, and can
clearly conceive that fuller knowledge would enable us to follow step by
step the whole process of that development, so surely can we trace the
action of some unknown higher law, beyond and independent of all those
laws of which we have any knowledge. We can trace this action more or
less distinctly in many phenomena, the two most important of which
are--the origin of sensation or consciousness, and the development of
man from the lower animals. I shall first consider the latter difficulty
as more immediately connected with the subjects discussed in this
volume.

_What Natural Selection can Not do._

In considering the question of the development of man by known natural
laws, we must ever bear in mind the first principle of "natural
selection," no less than of the general theory of evolution, that all
changes of form or structure, all increase in the size of an organ or in
its complexity, all greater specialization or physiological division of
labour, can only be brought about, in as much as it is for the good of
the being so modified. Mr. Darwin himself has taken care to impress
upon us, that "natural selection" has no power to produce absolute
perfection but only relative perfection, no power to advance any being
much beyond his follow beings, but only just so much beyond them as to
enable it to survive them in the struggle for existence. Still less has
it any power to produce modifications which are in any degree injurious
to its possessor, and Mr. Darwin frequently uses the strong expression,
that a single case of this kind would be fatal to his theory. If,
therefore, we find in man any characters, which all the evidence we can
obtain goes to show would have been actually injurious to him on their
first appearance, they could not possibly have been produced by natural
selection. Neither could any specially developed orga