times, but which have
now been definitely formulated and supported by evidence.

The Conservation of Matter and Energy.

1. The whole mechanical theory is based upon a law which is not strictly
biological but belongs to science in general--the law of the conservation
of matter and energy. This was first recognised by Kant as a general
rational concept in his "Critique" and in the "Grundlegung der Metaphysik
der Naturwissenschaft," and was transferred by Robert Mayer and
Helmholtz(59) to the domain of natural science. Just as no particle of
matter can come from nothing or become nothing, so no quantum of energy
can come from nothing or become nothing. It must come from somewhere and
must remain somewhere. The form of energy is continually changing, but the
sum of energy in the universe remains invariable and constant. Therefore,
it seems to follow, there can be no specific vital phenomena. The energies
concerned in the up-building, growth, and decay of the organism, and the
sum of the functions performed by it, must be the exact resultant and
equivalent of the potential energies stored in its material substance and
the co-operative energies of its environment. The particular course of
transformations they follow must have its sufficient reason in the
configuration of the parts of the organism, in its relations to the
environment, and the like. An intervention of "vitalistic" principles,
directions and so forth, would, we are told, involve a sudden obtrusion
and disappearance again of energy-effects which had no efficient cause in
the previous phenomena. From any point of view it would be a miracle, and
in particular it would be doing violence to the law of the constancy of
the sum of energy.

Apart from the inherent general "instinct"--_sit venia verbo_, for no more
definite word is available--which is the quiet Socius, the concealed but
powerful spring of the mechanistic convictions, as of most others, this
law of the conservation of energy is probably the really central argument,
and it meets us again more or less disguised in what follows.

The Organic and the Inorganic.

2. What is on _a priori_ grounds demanded as a necessity, or set aside as
impossible, on the strength of the axiom of the conservation of energy,
must be proved _a posteriori_ by investigation. It must be shown in detail
that the difference between the organic and the inorganic is only
apparent. And it is here that the mechanical