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Conceptions of Evolution
Yet we must protest against the exaggerated estimate of the
conscious pain which so many read into these millions of years of
struggle. Probably there was no consciousness at all during the
greater part of the time. The wriggling of the worm on which you
have accidentally trodden is no proof whatever that you have
caused conscious pain. The nervous system of an animal has been
so evolved as to respond with great disturbance of its tissue to
any dangerous
or injurious assault. It is the selection of a certain means of
self-preservation. But at what level of life the animal becomes
conscious of this disturbance, and "feels pain," it is very
difficult to determine. The subject is too vast to be opened
here. In a special investigation of it* I concluded that there is
no proof of the presence of any degree of consciousness in the
invertebrate world even in the higher insects; that there is
probably only a dull, blurred, imperfect consciousness below the
level of the higher mammals and birds; and that even the
consciousness of an ape is something very different from what
educated Europeans, on the ground of their own experience, call
consciousness. It is too often forgotten that pain is in
proportion to consciousness. We must beware of such fallacies as
transferring our experience of pain to a Mesozoic reptile, with
an ounce or two of cerebrum to twenty tons of muscle and bone.
One other view of evolution, which we find in some recent and
reputable works (such as Professor Geddes and Thomson's
"Evolution," 1911), calls for consideration. In the ordinary
Darwinian view the variations of the young from their parents are
indefinite, and spread in all directions. They may continue to
occur for ages without any of them proving an advantage to their
possessors. Then the environment may change, and a certain
variation may prove an advantage, and be continuously and
increasingly selected. Thus these indefinite variations may be so
controlled by the environment during millions of years that the
fish at last becomes an elephant or a man. The alternative view,
urged by a few writers, is that the variations were "definitely
directed." The phrase seems merely to complicate the story of
evolution with a fresh and superfluous mystery. The nature and
precise action of this "definite direction" within the organism
are quite unintelligible, and the facts seem explainable just as
well--or not less imperfectly--without as with this mystic
agency. Radiolaria, Sponges, Corals, Sharks, Mudfishes,
Duckbills, etc., do not change (except within the limits of their
family) during millions of years, because they keep to an
environment to which they are fitted. On the other hand, certain
fishes, reptiles, etc., remain in a changing environment, and
they must change with it. The process has its obscurities, but we
make them darker, it seems to me, with these semi-metaphysical
phrases.
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