Intellectual requirements and requirements in aptitudes, experience, and training vary, of course, with every kind of work, and almost with every particular job. One most valuable division of people intellectually is as to capacity of intellect. Some people have fine intellects, capable of great accomplishments in the way of education and training. They are particularly fitted for intellectual work; they have mental grasp; they comprehend; they reason; they have good judgment; they learn easily; they remember well. In every way their intellects are active, energetic, capable. Other people have only moderate intellectual capacity. They express themselves best in physical activity or in the direct, man-to-man handling of others. Their few intellectual activities may be exceedingly keen and accurate—or slow, dull, and vague. People with small intellectual capacity sometimes have remarkable vigor and clearness of mind in some one direction—such as finance, promotion, commerce; judgment of people, horses, cattle, or other living beings; mechanics, invention, music, art, poetry, or some other narrow specialty. Some intellects, in other words, are simply incompetent—others, merely narrow.
People can also be divided, intellectually, into two other classes, the theoretical and the practical. The man with a theoretical intellect is thoughtful, meditative, reflective. His mind works slowly; it is interested in philosophy, in theories, in abstractions, and is capable of dealing with them. On the other hand, it is not particularly well qualified for observing practical things, and for making a practical application of the theories it learns so easily and in which it takes so great an interest. This is the intellect of the philosopher, the dreamer, the educator, the preacher, the writer, the reformer, the poet. This is particularly the intellect of reason, of logic, of ideas and ideals. Whether found amongst the world’s leaders or in the lowliest walks of life, its function is always that of dealing with theory, finding out reasons, putting together logical arguments, teaching others and dealing with abstractions. Oftentimes this type of intellect is so impractical that its possessor never possesses anything else. Literature abounds in the tragic tales of philosophers, poets, reformers, and dreamers who starved beautifully and nobly. Every-day life sees thousands more blundering along, either cursing their luck or wondering why Providence withholds its material gifts from people so deserving as they.
Over against this is the practical, matter-of-fact, analytical intellect—the intellect which demands facts and demands them quickly; the intellect which is quick in its operations, impatient, keen, penetrating, intolerant of mere theories and abstractions, not particularly strong in reason and logic, but exceedingly keen and discriminating in regard to the facts. This is the intellect which deals with things, with the material universe, with laws and principles, based upon accurately determined facts. This is the intellect of the preeminently practical man.