Page:Popular Science Monthly Volume 28.djvu/370

358 ideas never arise singly, but are linked together in their origin; groups of ideas are integrated into trains of thought, and words into corresponding trains of sentences to express them. When a stock of ideas has been formed in this manner, the mental growth is mainly carried forward by the establishment of new combinations among them. The simpler ideas pertaining to the objects and actions of the child's environment being once acquired, the development of intelligence consists largely in associating them in new relations and groups of relations. The perception of likeness and difference is the essential work that is going on all the time, but the comparisons and discriminations are constantly becoming more extensive, more complex, more minute, and more accurate. Thus elementary ideas become fused into one complex idea; by a still further recognition of likeness and difference, this is associated with a new group, and this again with still larger clusters of associated ideas.

"That which occurs at this earliest stage of mental growth is exactly what takes place in the whole course of unfolding intelligence. Simple as these operations may seem, and begun by the infant as soon as it is born, in their growing complexities they constitute the whole fabric of the intellect. What we call the "mental faculties" are only different modes of the mental activity; and as one law of growth evolves all the various organs and tissues of the bodily structure, so one law of growth evolves all the diversified "faculties" of the mental structure. Under psychological analysis, the operations of reason, judgment, imagination, calculation, and the acquisitions of the most advanced minds yield at last the same simple elements—the perceptions of likenesses and differences among things thought about; while memory is simply the power of reviving these distinctions in consciousness. Whatever the object of thought, to know in what respects it differs from all other things, and in what respects it resembles them, is to know all about it—is to exhaust the action of the intellect upon it. The way the child gets its early knowledge is the way all real knowledge is obtained. When it discovers the likeness between sugar, cake, and certain fruits, that is, when it groups them in thought as sweet, it is making just such an induction as Newton made in discovering the law of gravitation, which was but to discover the likeness among celestial and terrestrial motions. And as with physical objects, so also with human actions. The child may run around the house and play with its toys, but it must not break things or play with fire. Here, again, are relations of likeness and unlikeness, forming a basis of moral classification. The judge on the bench is constantly doing the same thing; that is, tracing out the likenesses of given actions, and classing them as right and wrong."

We hence see that by necessity and by the very nature of intelligence the movements of mental growth are from the relatively simple