Here we are only concerned with the generalities
and presuppositions of the theory.

We must dispute even the main justification of the theory, which is sought
for in the old maxim of parsimony in the use of principles of explanation
(_entia_, and also _principia, praeter necessitatem non esse
multiplicanda_), and in Kant's "regulative principle," that science must
proceed as if everything could ultimately be explained in terms of
mechanism. For surely our task is to try to explain things, not at any
cost with the fewest possible principles, but rather with the aid of those
principles which appear most correct. If nature is not fundamentally
simple, then it is not scientific but unscientific to simplify it
theoretically. And the proposition bracketed above has its obvious
converse side, that while entities and principles must not be multiplied
except when it is necessary, on the other hand their number must not be
arbitrarily lessened. To proceed according to the fundamental maxims of
the mechanistic view can only be wholesome for a time and, so to speak,
for paedagogical reasons. To apply them seriously and permanently would be
highly injurious, for, by prejudging what is discoverable in nature, it
would tend to prevent the calm, objective study of things which asks for
nothing more than to see them as they are. It would thus destroy the
fineness of our appreciation of what there really is in nature. This is
true alike of forcible attempts to reduce the processes of life to
mechanical processes, and of the Darwinian doctrine of the universal
dominance of utility. Both bear unmistakably the stamp of foregone
conclusions, and betray a desire for the simplest, rather than for the
most correct principles of interpretation.

There is one point which presses itself on the notice even of outsiders,
and is probably realised even more keenly by specialists. The confidence
of the supporters of the mechanical theories of earlier days, from
Descartes onward, that animals and the bodies of men were machines,
mechanical automata, down to the mechanical theories of Lamettrie and
Holbach, of _l'homme machine_, and of the _systeme de la nature_, was at
least as great as, probably greater than, that of the supporters of the
modern theories. Yet how naive and presumptuous seem the crude and wooden
theories upon which the mechanical system was formerly built up, and how
falsely interpreted seem the physiological and other facts which lent