The period was coming to an end in which the main activity of development was in the senses, and in coming through the coöperation of the senses to a bodily consciousness of herself in a world of objects, of distances, and directions. Now the baby had to learn to use that body, and explore that world. But before this second great period of activity fully began, there was a transition month, a month of vigorous practice in the powers already gained, and of gathering forces for the new developments. IX THE DAWN OF INTELLIGENCE The sixth month, though it lay between two great development periods,--that of learning to use the senses, and that of learning to carry the body,--was not in itself a period of suspended development. It is true that its progress, being more purely mental, could not be so continuously traced as that which came before and after, but rather cropped up to the surface every now and then in a more or less broken way; still, no doubt, it really went on in the same gradual method, one thread and another knitting together into the fabric of new powers. It was to this month, as I said in closing the last chapter, that the beginnings of adaptive intelligence belonged; and this alone marks it a great epoch. There is a great deal of discussion about the use of the words “intelligence,” “reason,” “instinct,” “judgment,” “inference,” and the like: what these faculties and acts really are, how they come about, where the line is to be drawn between their manifestations (in the minds of animals and of man, for instance), and many other problems. But I think that all agree upon recognizing two types of action that come under the discussion: one, that which shows merely the ability to adapt means to ends, to use one’s own wit in novel circumstances; the other, that which rests on the higher, abstract reasoning power, such as is hardly possible without carrying on a train of thought in words. Whether these two types are to be called intelligence and reason, as Professor Lloyd Morgan calls them, or whether both come under the head of reason, lower and higher, we need not trouble to decide. If we call them adaptive intelligence and higher or abstract reason, we are safe enough. Even if it be true that any glimmer of the higher reason penetrates back into the grades of life below the attainment of speech, it must be only into those just below, and is not to be looked for in our baby for a long time yet. But the mere practical intelligence that I am now speaking of seems to appear in babies close on the completion of a fair mastery of their senses, about the middle of the first year, and it goes pretty far down in the animal kingdom. Darwin thought the lowest example of it he knew was in the crab, who would remove shells that were thrown near the mouth of his burrow, apparently realizing that they might fall in.