Pleasure, then, we have excluded from playing any rôle in absolutely primitive consciousness. Pleasure and pain could not both be primitive functions, and of the two pain is fundamental, in that the earliest function of consciousness must be purely monitory. Pain alone fulfils primitive demands, and secures struggle which ends in the abatement of pain through change of environment or otherwise. Pain lessens, but pleasure does not come, but unconsciousness instead, for no continuous organic psychic life is yet evolved. As long as pain continues there is effort and self-conserving action; when pain ceases, consciousness ceases, because the need for it is gone. Each fit of pain subsides into unconsciousness as struggle succeeds, and there is no room for even the pleasure of relief which, indeed, must be accounted a tolerably late feeling. As far as the lowest organisms have a conscious life it is a pain life; but they have a Nirvana in a real unconsciousness. The evolution of pleasure must be accounted a distinct problem.
The law of evolution is that origin of function, and all progressive modification is at critical stages. Thus it is in painful circumstances that the origin of mind is to be traced, and the important steps in its development have been achieved in severest struggle and acutest pain at critical periods. Pleasure then is not the original stimulant of will, but is a secondary form. Pleasure has an obvious utility, especially as foreseen, but this is far from being primitive. The pleasure-mode early enters, however, to sharpen by contrast the pain-mode, and it is only by their interaction that any high grade of psychic life could be built up. The development of pleasure cannot be from pain, but as a polar opposite to it. We cannot bring the development of mind into a perfectly continuous evolution from a single germ, as is the case with organs and tissues in biology where such very different elements as muscle and nerve may be traced to a common undifferentiated basis. In a certain sense we may say that pleasure and pain are complementary, like positive and negative electricity, but the comparison cannot be pressed. We cannot, indeed, carry it so far as to believe either absolutely essential to the other. We mention then the
