present day,
have consisted in the substitution of processes which are familiar
and the application of those processes, showing how they produce
great results.

When Darwin's "Origin of Species" was first published, when it gave
us that wonderful explanation of the origin of forms of life from
allied forms through the operation of natural selection, it must
have been like a mental illumination to every person who
comprehended it. But after all it left a great many questions
unexplained, as was natural. It accounted for the phenomena of
organic development in general with wonderful success, but it must
have left a great many minds with the feeling: If man has been
produced in this way, if the mere operation of natural selection
has produced the human race, wherein is the human race anyway
essentially different from lower races? Is not man really
dethroned, taken down from that exceptional position in which we
have been accustomed to place him, and might it not be possible, in
the course of the future, for other beings to come upon the earth
as far superior to man as man is superior to the fossilized dragons
of Jurassic antiquity?

Such questions used to be asked, and when they were asked, although
one might have a very strong feeling that it was not so, at the
same time one could not exactly say why. One could not then find
any scientific argument for objections to that point of view. But
with the further development of the question the whole subject
began gradually to wear a different appearance; and I am going to
give you a little bit of autobiography, because I think it may be
of some interest in this connection. I am going to mention two or
three of the successive stages which the whole question took in my
own mind as one thing came up after another, and how from time to
time it began to dawn upon me that I had up to that point been
looking at the problem from not exactly the right point of view.

When Darwin's "Descent of Man" was published in 1871, it was of
course a book characterized by all his immense learning, his
wonderful fairness of spirit and fertility of suggestion. Still,
one could not but feel that it did not solve the question of the
origin of man. There was one great contrast between that book and
his "Origin of Species." In the earlier treatise he undertook to
point out a _vera causa_ of the origin of species, and he did it.
In his "Descent of Man" he brought together a great many minor