heories with special
reference to those of W. Roux, the founder of the new "Science of the
Future"--the mechanical, and therefore only scientific theory of
development, which no longer only describes, but understands and causally
explains phenomena ("Archiv fuer Entwicklungsmechanik"). There are two
kinds of mechanism (Hertwig says): that in the higher philosophical sense,
and that in the purely physical sense. The former declares that all
phenomena are connected by a guiding thread of causal connection and can
be causally explained. As such, its application to the domain of vital
phenomena is justifiable and self-evident. But it is not justifiable if
cause be simply made identical with and limited to "force," if the causal
connection be only admitted in the technical sense of the transference and
transformation of energy, and if, over and above, it is supposed to give
an "explanation," in the sense of an insight into things themselves. Even
mechanics is (as Kirchoff maintained) a "descriptive" science. Hertwig
agrees with Schopenhauer and Lotze in regarding every primitive natural
"force" as unique, not reducible to simpler terms, but qualitatively
distinct,--a "qualitas occulta," capable not of physical but only of
metaphysical explanation. And thus his conclusions imply rejection of
mechanism in the cruder sense. As such, it has only a very limited sphere
of action in the realm of the living. The history of mechanical
interpretations is a history of their collapse. The attempt to derive the
organic from the inorganic has often been made. But no such attempts have
held the field for long. We can now say with some reason that "the gulf
between the two kingdoms of nature has become deeper just in proportion as
our physical and chemical, our morphological and physiological knowledge
of the organism has deepened." Mach's expression "mechanical mythology,"
is quoted, and then a fine passage on the insufficiency of the
mathematical view of things in general concludes thus: "Mathematics is
only a method of thought, an excellent tool of the human mind, but it is
very far from being the case that all thought and knowledge moves in this
one direction, and that the content of our minds can ever find exhaustive
expression through it alone."

In his "Theory of Dominants,"(96) Reinke, the botanist of Kiel, has
attempted to formulate his opposition to the physico-chemical conception
of life into a vitalistic theory of his own. Among