d real forces in inorganic nature, the mechanical
forces and their complements, the so-called potential energies, heat,
radiation (light, radiating heat), electricity, magnetism, chemical
energy, are different forms of universal motion, which pass, under
certain conditions, the one into the other, so that in place of those of
the one which disappear, a certain number of the other appear, so that
the whole movement of nature is reduced to this perpetual process of
transformation from one into the other. Finally, the proof first
developed logically by Darwin, that the organic products of nature about
us, including man, are the result of a long process of evolution, from
a few original single cells, and these again, by virtue of chemical
processes, have proceeded from protoplasm or white of egg.

Thanks to these three great discoveries and the resultant powerful
advance of science, we have now arrived at a point where we can show the
connection between changes in nature, not only in specific cases, but
also in the relation of the specific cases to the whole and so give a
bird's eye view of the interrelation of nature in an approximately
scientific form by means of the facts shown by empirical science itself.
To furnish this complete picture was formerly the task of the so-called
philosophy of nature. It could then only do this by substituting ideal
and imaginary hypotheses for the unknown real interconnection, by
filling out the missing facts with mind-pictures and by bridging the
chasms by empty imaginings. It had many happy thoughts in these
transports (of imagination), it anticipated many later discoveries, but
it also caused the survival of considerable nonsense up to the present
time which could not otherwise have been possible. At present, when the
results of the investigation of nature need only be conceived of
dialectically, that is in the sense of their mutual interconnection, to
arrive at a system of nature sufficient for our time, when the
dialectical character of this interconnection forces itself into the
metaphysically trained minds of experimental scientists, against their
will, today a philosophy of nature is finally disposed of, every attempt
at its resurrection would not only be superfluous, it would even be a
step backwards.

But what is true of nature, which is hereby recognized as an historical
process, is true also of the history of society in all its branches, and
of the totality of all sciences whi