c standpoint would have been the prevailing one.
For it is almost a matter of course to regard plants as devoid of
sensation or "psychical" life, and as mechanical systems, chemical
laboratories, and reflex mechanisms, and this way of regarding them has
been made easy by the very marked uniformity and lack of spontaneity in
their vital processes as compared with those of animals. But it is not the
case that mechanical theories have here prevailed. The opposition to them
is just as great here as elsewhere, and from the days of Wigand onwards it
has been almost continuously sustained.(88) Very characteristic is
Pfeffer's "Pflanzen-Physiologie" (1897), which is written professedly from
the mechanist point of view. "Vitalism," according to this authority, is
to be rejected, but instead of "vital force" he offers us "given
properties," and the alleged machine-like collocations of the most minute
elements. In regard, for instance, to the riddle of development and
morphogenesis, we must simply accept it as a "given property," that the
acorn grows in an oak and nothing else. The chemical explanation of the
vital functions of protoplasm is also to be rejected; as a shattered watch
is no longer a watch though it remains chemically the same, so it is with
protoplasm. The available chemical knowledge of the substances of which
protoplasm is made up is insufficient to render the vital processes
intelligible. Here, as everywhere else, we have to reckon with ultimate
"properties (entities), which we neither can, nor desire to analyse
further." "The human mind is no more capable of forming a conception of
the ultimate cause of things than of eternity." If all the views here
indicated were followed out to their logical conclusions, they would
hinder rather than further the process of reduction to terms of
physico-chemical sequences.

Kerner von Marilaun in his "Pflanzenleben" deliberately takes up a
thorough-going vitalist position, and on this point as well as on many
others he opposed the current theory of the school (Darwinism). It is
true, he admits, that many of the phenomena in plants can be explained in
purely mechanical terms, but they are only those which may occur also in
non-living structures. The specific expressions of life cannot be
explained in this way. He shows this more fully in regard to the most
fundamental of all the vital processes in the plant-body--the breaking up
of carbonic acid gas by the chlorophyll to obtain