ypothesis in this
world which has not some fact in connection with it which has not been
explained, but that is a very different affair to a fact that entirely
opposes your hypothesis; in this case all you can say is, that your
hypothesis is in the same position as a good many others.

Now, as to the third test, that there are no other causes competent to
explain the phenomena, I explained to you that one should be able to say
of an hypothesis, that no other known causes than those supposed by it
are competent to give rise to the phenomena. Here, I think, Mr. Darwin's
view is pretty strong. I really believe that the alternative is either
Darwinism or nothing, for I do not know of any rational conception or
theory of the organic universe which has any scientific position at all
beside Mr. Darwin's. I do not know of any proposition that has been
put before us with the intention of explaining the phenomena of organic
nature, which has in its favour a thousandth part of the evidence which
may be adduced in favour of Mr. Darwin's views. Whatever may be the
objections to his views, certainly all others are absolutely out of
court.

Take the Lamarckian hypothesis, for example. Lamarck was a great
naturalist, and to a certain extent went the right way to work; he
argued from what was undoubtedly a true cause of some of the phenomena
of organic nature. He said it is a matter of experience that an
animal may be modified more or less in consequence of its desires and
consequent actions. Thus, if a man exercise himself as a blacksmith,
his arms will become strong and muscular; such organic modification is a
result of this particular action and exercise. Lamarck thought that by a
very simple supposition based on this truth he could explain the
origin of the various animal species: he said, for example, that the
short-legged birds which live on fish had been converted into the
long-legged waders by desiring to get the fish without wetting their
bodies, and so stretching their legs more and more through successive
generations. If Lamarck could have shown experimentally, that even races
of animals could be produced in this way, there might have been some
ground for his speculations. But he could show nothing of the kind, and
his hypothesis has pretty well dropped into oblivion, as it deserved
to do. I said in an earlier lecture that there are hypotheses and
hypotheses, and when people tell you that Mr. Darwin's strongly-based
hypothe