1740 made the
experiment of cutting a "hydra" in two, and showed that each of the halves
became a complete animal, so that obviously each of the two halves of the
soul grew into a new hydra-soul. And Trembley's hydra was only the
precursor of all the cut-up worms, of the frogs, birds, and guinea-pigs
that have been beheaded, or have had their brain removed, or their nerves
cut, and have furnished further examples of this divisibility of "souls."

If the independence of the spiritual is thus shown to be a vain
assumption, the alleged difference between the animal and the human Psyche
is much more so. Not from the days of Darwinism alone, but from the very
beginning, naturalism has opposed this claim to distinctiveness. But it is
due to Darwinism that the fundamental similarity of the psychical in man
and animals has come to be regarded as almost self-evident. The mental
organisation of man, as well as his corporeal organisation, is traced back
through gradual stages to animal antecedents, and in thus tracing it there
are two favourite methods of procedure, which are, however, apt to be
mutually destructive.

On the one hand, some naturalists regard the animal anthropomorphically,
insist on its likeness to man, discovering and extolling, not without
emotion, all the higher and nobler possessions of the human mind,
intellectual capacities, reason, reflection, synthesis, fancy, the power
of forming ideas and judgments, of drawing conclusions and learning from
experience, besides will in the true sense, ethical, social and political
capacities, aesthetic perceptions, and even fits of religion in elephants,
apes, dogs, down even to ants and bees, and these naturalists reject
old-fashioned explanations in terms of instinct, and find the highest
already contained in the lowest. Those of another school are inclined to
regard man theriomorphically, to insist on his likeness to animals,
explaining reason in terms of perception and sensation, deriving will from
impulse and desire, and ethical and aesthetic valuations from physiological
antecedents and purely animal psychological processes, thus, in short,
seeking to find the lowest in the highest. (We have already met with an
analogous instance of a similarly fallacious double-play on parallel
lines.) So it comes about that both the origin and the development of the
psychical and spiritual seem to be satisfactorily cleared up and
explained, and at the same time a new proof is addu