es which can
never be absolutely harmonised one with the other. Evolution may at
any time break some form which the system-monger regards as finally
established. Darwin himself felt a great difference in looking at
variation as an evolutionist and as a systematist. When he was working
at his evolution theory, he was very glad to find variations; but they
were a hindrance to him when he worked as a systematist, in preparing
his work on Cirripedia. He says in a letter: "I had thought the same
parts of the same species more resemble (than they do anyhow in
Cirripedia) objects cast in the same mould. Systematic work would be
easy were it not for this confounded variation, which, however, is
pleasant to me as a speculatist, though odious to me as a
systematist."[203] He could indeed be angry with variations even as an
evolutionist; but then only because he could not explain them, not
because he could not classify them. "If, as I must think, external
conditions produce little _direct_ effect, what the devil determines
each particular variation?"[204] What Darwin experienced in this
particular domain holds good of all knowledge. All knowledge is
systematic, in so far as it strives to put phenomena in quite definite
relations, one to another. But the systematisation can never be
complete. And here Darwin has contributed much to widen the world, for
us. He has shown us forces and tendencies in nature which make
absolute systems impossible, at the same time that they give us new
objects and problems. There is still a place for what Lessing called
"the unceasing striving after truth," while "absolute truth" (in the
sense of a closed system) is unattainable so long as life and
experience are going on.

There is here a special remark to be made. As we have seen above,
recent research has shown that natural selection or struggle for life
is no explanation of variations. Hugo de Vries distinguishes between
partial and embryonal variations, or between variations and mutations,
only the last-named being heritable, and therefore of importance for
the origin of new species. But the existence of variations is not only
of interest for the problem of the origin of species; it has also a
more general interest. An individual does not lose its importance for
knowledge, because its qualities are not heritable. On the contrary,
in higher beings at least, individual peculiarities will become more
and more independent objects of interest. Knowledg