character is inconceivable. But if, perchance, experiment should show
that acquired characters are transmissible, it would prove thereby that
the germ-plasm is not so independent of the somatic envelope as has been
contended, and the transmissibility of acquired characters would become
_ipso facto_ conceivable; which amounts to saying that conceivability
and inconceivability have nothing to do with the case, and that
experience alone must settle the matter. But it is just here that the
difficulty begins. The acquired characters we are speaking of are
generally habits or the effects of habit, and at the root of most habits
there is a natural disposition. So that one can always ask whether it is
really the habit acquired by the soma of the individual that is
transmitted, or whether it is not rather a natural aptitude, which
existed prior to the habit. This aptitude would have remained inherent
in the germ-plasm which the individual bears within him, as it was in
the individual himself and consequently in the germ whence he sprang.
Thus, for instance, there is no proof that the mole has become blind
because it has formed the habit of living underground; it is perhaps
because its eyes were becoming atrophied that it condemned itself to a
life underground.[40] If this is the case, the tendency to lose the
power of vision has been transmitted from germ to germ without anything
being acquired or lost by the soma of the mole itself. From the fact
that the son of a fencing-master has become a good fencer much more
quickly than his father, we cannot infer that the habit of the parent
has been transmitted to the child; for certain natural dispositions in
course of growth may have passed from the plasma engendering the father
to the plasma engendering the son, may have grown on the way by the
effect of the primitive impetus, and thus assured to the son a greater
suppleness than the father had, without troubling, so to speak, about
what the father did. So of many examples drawn from the progressive
domestication of animals: it is hard to say whether it is the acquired
habit that is transmitted or only a certain natural tendency--that,
indeed, which has caused such and such a particular species or certain
of its representatives to be specially chosen for domestication. The
truth is, when every doubtful case, every fact open to more than one
interpretation, has been eliminated, there remains hardly a single
unquestionable example of ac