differences--differences so many and so great as to justify our
classing them in distinct categories so long as we have regard to
the daily purposes of life without looking at remoter ones.

If the above be admitted, we can reply to those who in an earlier
chapter objected to our saying that if Mr. Darwin denied design in
the eye he should deny it in the burglar's jemmy also. For if
bodily and non-bodily organs are essentially one in kind, being each
of them both living and non-living, and each of them only a higher
development of principles already admitted and largely acted on in
the other, then the method of procedure observable in the evolution
of the organs whose history is within our ken should throw light
upon the evolution of that whose history goes back into so dim a
past that we can only know it by way of inference. In the absence
of any show of reason to the contrary we should argue from the known
to the unknown, and presume that even as our non-bodily organs
originated and were developed through gradual accumulation of
design, effort, and contrivance guided by experience, so also must
our bodily organs have been, in spite of the fact that the
contrivance has been, as it were, denuded of external evidences in
the course of long time. This at least is the most obvious
inference to draw; the burden of proof should rest not with those
who uphold function as the most important means of organic
modification, but with those who impugn it; it is hardly necessary,
however, to say that Mr. Darwin never attempted to impugn by way of
argument the conclusions either of his grandfather or of Lamarck.
He waved them both aside in one or two short semi-contemptuous
sentences, and said no more about them--not, at least, until late in
life he wrote his "Erasmus Darwin," and even then his remarks were
purely biographical; he did not say one syllable by way of