The Foundations of Personality [48]
has as one of its functions the preventing of this, and controlled thinking follows associations that are, as it were, laid down by the goal. In fatigue, in illness, in certain of the mental diseases, the failure of the organizing energy brings about failure "to concentrate" and the tyranny of casual associations annoys and angers. The stock complaint of the neurasthenic that everything distracts his attention is a reversion back to the unorganized conditions of childhood, with this essential difference: that the neurasthenic rebels against his difficulty in thinking, whereas the child has no rebellion against that which is his normal state. Minds differ primarily and hugely in their power of organizing experience, in so studying and recording the past that it becomes a guide for the, future. Basic in this is the power of resisting the irrelevant association, of checking those automatic mental activities that tend to be stirred up by each sound, each sight, smell, taste and touch. The man whose task has no appeal for him has to fight to keep his mind on it, and there are other people, the so-called absent-minded, who are so over- concentrated, so wedded to a goal in thought, that lesser matters are neither remembered nor noticed. In its excess overconcentration is a handicap, since it robs one of that alertness for new impressions, new sources of thought so necessary for growth. The fine mind is that which can pursue successfully a goal in thought but which picks en route to that goal, out of the irrelevant associations, something that enriches its conclusions. Not often enough is mechanical skill, hand-mindedness, considered as one of the prime phases of intelligence. Intelligence, en route to the conquest of the world, made use of that marvelous instrument, the human hand, which in its opposable thumb and little finger sharply separates man from the rest of creation. Studying causes and effects, experimenting to produce effect, the hand became the principal instrument in investigation, and the prime verifier of belief. "Seeing is believing" is not nearly so accurate as "Handling is believing," for there is in touch, and especially in touch of the hands and in the arm movements, a Reality component of the first magnitude. But not only in touching and investigating, but in pushing and pulling and striking, IN CAUSING CHANGE, does the hand become the symbol and source of power and efficiency. Undoubtedly this phase of the hands' activities remained predominant for untold centuries, during which man made but slow progress in his career toward the leadership of the world. Then came the phase of tool-making and using and with that a rush of events that built the cities, bridged the waters, opened up the Little and the Big as sources of knowledge and energy for man and gave him the power which he has used,--but poorly. It is the skill of human hands upon which the mind of man depends; though we fly through the air and speed under water, some one has made the tools that made the machine we use. Therefore, the mechanical skill of man, the capacity to shape resisting material to purpose, the power of the detailed applications of the principles of movement and force are high, special functions of the intelligence. That people differ enormously in this skill, that it is not necessarily associated with other phases of intelligence are commonplaces. The dealer in abstract ideas of great value to the race may be unable to drive a nail straight, while the man who can build the most intricate mechanism out of crude iron, wood and metal may be unable to express any but the commonplaces of existence. Intelligence, acting through skill, has evolved machinery and the industrial evolution; acting to discover constant principles operating in experience, it has established science. Seeking to explain and control the world of unknown forces, it has evolved theory and practice. A very essential division of people is on the one hand those whose effort is to explain things, and who are called theorists, and those who seek to control things, the practical