knowledge has meant a breaking away from the traditional dualism (or
pluralism) and an approach to monism. Ever more clearly are we compelled
by reflection to recognise that God is not to be placed over against the
material world as an external being, but must be placed as a "divine
power" or "moving spirit" within the cosmos itself. Ever clearer does it
become that all the wonderful phenomena of nature around us, organic as
well as inorganic, are only various products of one and the same original
force, various combinations of one and the same primitive matter. Ever
more irresistibly is it borne in upon us that even the human soul is but
an insignificant part of the all-embracing "world-soul"; just as the
human body is only a small individual fraction of the great organised
physical world.

The great general principles of theoretical physics and chemistry are now
in a position to afford to this unifying conception of nature an exact,
to a certain extent, indeed, a mathematical confirmation. In establishing
the law of the "conservation of energy," Robert Mayer and Helmholtz
showed that the energy of the universe is a constant unchangeable
magnitude; if any energy whatever seems to vanish or to come anew into
play, this is only due to the transformation of one form of energy into
another. In the same way Lavoisier's law of the "conservation of matter"
shows us that the material of the cosmos is a constant unchangeable
magnitude; if any body seems to vanish (as, for example, by burning), or
to come anew into being (as, for example, by crystallisation), this also
is simply due to change of form or of combination. Both these great
laws--in physics, the fundamental law of the conservation of energy, and
in chemistry, of the conservation of matter--may be brought under one
philosophical conception as the law of the conservation of substance;
for, according to our monistic conception, energy and matter are
inseparable, being only different inalienable manifestations of one