No sooner is the nerve-energy of a lower center set free than at once it tends to discharge itself into action. Thus every sensation, perception, feeling, emotion, thought, or belief, if left uncontrolled, tends to be translated into some appropriate movement, action, or reaction. The physiological process of setting free the nerve energy in a central ganglion, or in a system of central ganglia, is accompanied by activity in the simpler, but more organized, more integrated nerve centers, and by the lower psychic functions of simple sentience, sensibility; and in the more complex, but less integrated, less organized centers, by the higher psychic functions of consciousness, such as sensations, precepts, images, ideas, and emotions.
Turning now to the superior or the highest nerve-centers, we find that they are characterized by the highest mental functions, thought and reasoning, choice and will. A number of impressions, sensations and precepts reach those thought and will-centers; then a critical, a sifting, a selecting, a controlling or inhibitory process begins. Some of the mental states are modified and are permitted to develop within certain limits, others are given full play, while still others, and possibly the majority of them, are rejected and inhibited, not taking effect in reactions and adjustments to the environment.
The inhibited states belong to the great number of possible states with their reactions out of which selection is made by the critical thought and will-centers. These mental states, images, ideas, and feelings with their end-reactions, out of which selection is made, Gal- ton aptly terms "the antechamber of consciousness." They are on the margin of consciousness, and are partly of a conscious and partly of a subconscious character. To quote from Galton: "Although the brain is able to do fair work fluently in an automatic way, and though it will of its own accord, strike out sudden and happy ideas, it is questionable if it is capable of working thoroughly and profoundly without past or present effort. The character of this effort seems to me chiefly to lie in bringing the contents of the antechamber more nearly within the ken of consciousness, which then takes comprehensive note of all its contents, and compels the logical faculty to test them seriatim before selecting the fittest for a summons to the presence of the chamber. The thronging of the antechamber is, I am convinced, beyond my control."
Mental activity in its rational or integrative aspects whether logical, moral, or aesthetic, is essentially selective in character. The logical process draws definite conclusions from given premises; the
