nlikely. The improbability will be the greater, the more
complicated the routes; and it will become impossibility, if the zigzags
are infinitely complicated. Now, what is this complexity of zigzags as
compared with that of an organ in which thousands of different cells,
each being itself a kind of organism, are arranged in a definite order?

Let us turn, then, to the other hypothesis, and see how it would solve
the problem. Adaptation, it says, is not merely elimination of the
unadapted; it is due to the positive influence of outer conditions that
have molded the organism on their own form. This time, similarity of
effects will be explained by similarity of cause. We shall remain,
apparently, in pure mechanism. But if we look closely, we shall see that
the explanation is merely verbal, that we are again the dupes of words,
and that the trick of the solution consists in taking the term
"adaptation" in two entirely different senses at the same time.

If I pour into the same glass, by turns, water and wine, the two liquids
will take the same form, and the sameness in form will be due to the
sameness in adaptation of content to container. Adaptation, here, really
means mechanical adjustment. The reason is that the form to which the
matter has adapted itself was there, ready-made, and has forced its own
shape on the matter. But, in the adaptation of an organism to the
circumstances it has to live in, where is the pre-existing form awaiting
its matter? The circumstances are not a mold into which life is inserted
and whose form life adopts: this is indeed to be fooled by a metaphor.
There is no form yet, and the life must create a form for itself, suited
to the circumstances which are made for it. It will have to make the
best of these circumstances, neutralize their inconveniences and utilize
their advantages--in short, respond to outer actions by building up a
machine which has no resemblance to them. Such adapting is not
_repeating_, but _replying_,--an entirely different thing. If there is
still adaptation, it will be in the sense in which one may say of the
solution of a problem of geometry, for example, that it is adapted to
the conditions. I grant indeed that adaptation so understood explains
why different evolutionary processes result in similar forms: the same
problem, of course, calls for the same solution. But it is necessary
then to introduce, as for the solution of a problem of geometry, an
intelligent activity, o