Because organic tensions and depressions are periodic and are dependent upon the activities of glands and tissues not within our control, the desires may never be completely squelched and may arise as often as some outer stimulus brings them into activity, to plague and disorder the life of the conscious personality.
3. With this preliminary consideration of instinct, we pass on to certain of the phases of intelligence. How to define intelligence is a difficulty best met by ignoring definition. But this much is true: that the prime function of intelligence is to store up the past and present experiences so that they can be used in the future, and that it adds to the rigid mechanism of instinct a plastic force which by inhibiting and exciting activity according to need steers the organism through intricate channels.
Instinct, guided by a plan, conveniently called Nature's plan, is not itself a planner. The discharge of one mechanism discharges another and so on through a series until an end is reached,--an end apparently not foreseen by the organism but acting for the good of the race to which the organism belongs. Intelligence, often enough not conscious of the plans of Nature,[1] indeed, decidedly ignorant of these plans, works for some good established by itself out of stimuli set up by the instincts. It plans, looks backward and forward, reaches the height of reflecting on itself, gets to recognize the existence of instinct and sets itself the task of controlling instinct. Often enough it fails, instinct breaks through, takes possession of the means of achievement, accomplishes its purpose--but the failure of intelligence to control and the misguided control it attempts and assumes are merely part of the general imperfections of the organism. A perfect intelligence would be clearly able to understand its instincts, to give each of them satisfaction by a perfect compromise, would pick the methods for accomplishment without error, and storing up the past experiences without loss, would meet the future according to a plan.
[1] We are at this stage in a very dark place in human thought.
We say that instincts seek the good of the race, or have some racial purpose, as the sexual instinct has procreation as its end. But the lover wooing his sweetheart has no procreation plan in his mind; he is urged on by a desire to win this particular girl, a desire which is in part sexual, in part admiration of her beauty, grace, and charm; again it is the pride of possession and achievement; and further is the result of the social and romantic ideals taught in books, theaters, etc. He may not have the slightest desire for a child; as individual he plans one thing,--but we who watch him see in his approach the racial urge for procreation and even disregard his purposes as unimportant.
Who and what is the Race, where does it reside, how can it have purposes? Call it Nature, and we are no better off. We must fall back on an ancient personalization of forces, and our minds rest easier when we think of a Planner operating in all of us and perhaps smiling as He witnesses our strivings.
As we study the nervous systems of animals, we find that with the apparent growth of intelligence there is a development of that part of the brain called the cerebrum. In so far as certain other parts of the brain are concerned--medulla, pons, mid-brain, basal ganglia cerebellum--we who are human are not essentially superior to the dog, the cow, the elephant or the monkey. But when the neopallium, or the cerebrum, is considered, the enormous superiority of man (and the superiority of the higher over the lower animals) becomes striking. Anatomically the cerebrum is a complex elaboration of cells and fibers that have these main purposes: First, to record in perfect and detailed fashion the EXPERIENCES of the organism, so that here are memory centers for visual and auditory experiences, for skin, joint and bone experiences of all kinds, speech memories, action memories, and undoubtedly for the recording in some way not understood of the pleasure-pain feelings. Second, it has a hold, a grip on the motor mechanism of the body, on the muscles that produce action, so that the intelligence can nicely adapt movement to the circumstances, to purpose, and can inhibit the movements that arise reflexly. Thus in certain diseases, where the part of the brain involved in movement is injured, voluntary movement disappears but reflex action is increased. Third, the neopallium, or cerebrum, is characterized by what are known as association tracts, i.e., connections of intricate kinds which link together areas of the brain having different functions and thus allow for combinations of activity of all kinds. The brain thus acts to increase the memories of the past, and, as we all know, man is probably the only animal to whom the past is a controlling force, sometimes even an overpowering force. It acts to control the conduct of the individual, to delay or to inhibit it, and it acts to increase in an astonishing manner the number of reactions possible. One stimulus arousing cerebral excitement may set going mechanisms of the brain through associated tracts that will produce conduct of one kind or another for years to come.
We spoke in a previous chapter of choice as an integral function of the organism. While choice, when two competing stimuli awake competing mechanisms, may be non-cerebral in its nature, largely speaking it is a function of the cerebrum, of the intelligence.
