made to penetrate still
deeper to the ultimate point, the last possible reduction to simpler
terms, by referring all actual "forces" and reducing all movement, and
therewith all "action," to terms of attraction and repulsion, which are
free from anything mysterious, whose mode of working can be unambiguously
and plainly set forth in the law of the parallelogram of forces. Law? Set
forth? Therefore still only description? Certainly only description, not
explanation in the least. Even assuming that it is true, instead of a mere
Utopia, that all the secrets and riddles of nature can be traced back to
matter moved by attraction and repulsion according to the simplest laws of
these, they would still only be summed up into a great general riddle,
which is only the more colossal because it is able to embrace all others
within itself. For attraction and repulsion, the transference of motion,
and the combination of motion according to the law of the parallelogram of
forces--all this is merely description of processes whose inner causes we
do not understand, which appear simple, and are so, but are nevertheless
not self-evident or to be taken as a matter of course; they are not in
themselves intelligible, but form an absolute "world-riddle." From the
very root of things there gazes at us the same Sphinx which we had
apparently driven from the foreground.

But furthermore, this reduction to simpler terms is an impossible and
never-ending task. There is fresh confusion at every step. In reducing to
simpler terms, it is often forgotten that the principle of combination is
not inherent in the more simple, and cannot be "reduced." Or else there is
an ignoring of the fact that a transition has been made, not from
resultants to components, but to quite a different kind of phenomena.
Innumerable as are the possible reductions to simpler terms, and mistaken
as it would be to remain prematurely at the level of description, it
cannot be denied that the fundamental facts of the world are pure facts
which must simply be accepted where they occur, indisputable,
inexplicable, impenetrable, the "whence" and the "how" of their existence
quite uncomprehended. And this is especially true of every new and
peculiar expression of what we call energy and energies. Gravitation
cannot be reduced to terms of attraction and repulsion, nor action at a
distance to action at close quarters; it might, indeed, be shown that
repulsion in its turn presupposes attr