第10章

But what are now the defects of the nervous system in those animals whose consciousness seems most highly developed? Chief among them must be instability.The cerebral hemispheres are the characteristically 'high' nerve-centres, and we saw how indeterminate and unforeseeable their performances were in comparison with those of the basal ganglia and the cord.But this very vagueness constitutes their advantage.They allow their possessor to adapt his conduct to the minutest alterations in the environing circumstances, any one of which may be for him a sign, suggesting distant motives more powerful than any present solicitations of sense.It seems as if certain mechanical conclusions should be drawn from this state of things.An organ swayed by slight impressions is an organ whose natural state is one of unstable equilibrium.We may imagine the various lines of discharge in the cerebrum to be almost on a par in point of permeability - what discharge a given small impression will produce may be called accidental , in the sense in which we say it is a matter of accident whether a rain-drop falling on a mountain ridge descend the eastern or the western slope.It is in this sense that we may call it a matter of accident whether a child be a boy or a girl.The ovum is so unstable a body that certain causes too minute for our apprehension may at a certain moment tip it one way or the other.The natural law of an organ constituted after this

fashion can be nothing but a law of caprice.I do not see how one could reasonably expect from it any certain pursuance of useful lines of reaction, such as the few and fatally determined performances of the lower centres constitute within their narrow sphere.The dilemma in regard to the nervous system seems, in short, to be of the following kind.We may construct one which will react infallibly and certainly, but it will then be capable of reacting to very few changes in the environment - it will fail to be adapted to all the rest.We may, on the other hand, construct a nervous system potentially adapted to respond to an infinite variety of minute features in the situation; but its fallibility will then be as great as its elaboration.We can never be sure that its equilibrium will be upset in the appropriate direction.In short, a high brain may do many things, and may do each of them at a very slight hint.But its hair-trigger organization makes of it a happy-go-lucky, hit-or-miss affair.It is as likely to do the crazy as the sane thing at any given moment.A low brain does few things, and in doing them perfectly forfeits all other use.The performances of a high brain are like dice thrown forever on a table.Unless they be loaded, what chance is there that the highest number will turn up oftener than the lowest?

All this is said of the brain as a physical machine pure and simple.Can consciousness increase its efficiency by loading its dice ? Such is the problem.

Loading its dice would mean bringing a more or less constant pressure to bear in favor of those of its performances which make for the most permanent interests of the brain's owner; it would mean a constant inhibition of the tendencies to stray aside.

Well, just such pressure and such inhibition are what consciousness seems to be exerting all the while.And the interests in whose favor it seems to exert them are its interests and its alone, interests which it creates , and which, but for it, would have no status in the realm of being whatever.We talk, it is true, when we are darwinizing, as if the mere body that owns the brain had interests; we speak about the utilities of its various organs and how they help or hinder the body's survival; and we treat the survival as if it were an absolute end, existing as such in the physical world, a sort of actual should-be , presiding over the animal and judging his reactions, quite apart from the presence of any commenting intelligence outside.We forget that in the absence of some such superadded commenting intelligence (whether it be that of the animal itself, or only ours or Mr.Darwin's), the reactions cannot be properly talked of as 'useful' or 'hurtful' at all.Considered merely physically, all that can be said of them is that if they occur in a certain way survival will as a matter of fact prove to be their incidental consequence.The organs themselves, and all the rest of the physical world, will, however, all the time be quite indifferent to this consequence, and would quite as cheerfully, the circumstances changed, compass the animal's destruction.In a word, survival can enter into a purely physiological discussion only as an hypothesis made by an onlooker about the future.But the moment you bring a consciousness into the midst, survival ceases to be a mere hypothesis.No longer is it, "if survival is to occur, then so and so must brain and other organs work." It has now become an imperative decree: "Survival shall occur, and therefore organs must so work!" Real ends appear for the first time now upon the world's stage.The conception of consciousness as a purely cognitive form of being, which is the pet way of regarding it in many idealistic-modern as well as ancient schools, is thoroughly anti-psychological, as the remainder of this book will show.Every actually existing consciousness seems to itself at any rate to be a fighter for ends , of which many, but for its presence, would not be ends at all.Its powers of cognition are mainly subservient to these ends, discerning which facts further them and which do not.