If ten ordinary men run in a foot-race, the two foremost may
lead by several feet. But if the number of runners be continually
increased the finish will be ever closer until finally but an atom
more wind or muscle or pluck would make all the difference between
winning and losing the prize.

Similarly the million or more young of any species of insect in a
given area may be said to run a race of which the prize is life, and
the losing of which means literally death. The competition is
inconceivably severe. How indefinitely slight will be the difference
between the poorest of the 2,000 or 20,000 survivors and the best
of the more than 900,000 which perish. The very slightest favorable
variation may make all the difference between life and sure death.
And yet these indefinitely slight variations continued and
aggregated through ages would foot up an immense total divergence.
The chalk cliffs of England have been built up of microscopic
shells.

I have tried to give you very briefly a sketch of the essential
points of Mr. Darwin's theory of evolution. But you should all read
that marvel of patience, industry, clear insight, close reasoning,
and grand honesty, the "Origin of Species." I have no time to give
the arguments in its favor or to attempt to meet the objections
which may arise in your minds. I ask you to believe only this much;
that the theory is accepted with practical unanimity by scientific
men because it, and it alone, furnishes an explanation for the facts
which they discover in their daily work. And this is the strongest
proof of the truth of any accepted theory.

Inasmuch as it is accepted by all scientists and largely by the
public, it is certainly worth your while to know whether it has any
bearing on the great moral and religious questions which you are
considering. And in these lectures I shall take for granted, what
some scientists still doubt, that man also is a product of
evolution. For the weight of evidence in favor of this view is
constantly increasing, and seems already to strongly preponderate.
Also I wish in these lectures to grant all that the most ardent
evolutionist can possibly claim. Not that I would lower man's
position, but I have a continually increasing respect for the
so-called "lower animals."

Now if the theory of evolution be true, and really only on this
condition, life has had a history; and human history began ages
before man's actual appearance on the globe, just as America