The brain comes into the world provided with a great number of impressions upon it. Some of these are quite obscure, some few are distinct. Each ancestor has added his own to those previously existing. Among these impressions, finally, the useless ones must soon be obliterated by those that are useful. On the other hand, deep impressions will, like wounds, leave behind scars, which abide longer; and very frequently used paths of connection between different portions of the brain and spinal marrow and the organs of sense are easier to travel even at birth (instinctive and reflexive processes). Now, of all the higher functions of the brain, the ordering one, which compares the simple, pure sensations, the original experiences, and first sets them in an order of succession, viz., arranges them in time, then puts them side by side and one above another, and, not till later, one behind another, viz., arranges them in space--this function is one of the oldest. This ordering of the sense-impressions is _an activity of the intellect that has nothing to do with speech_, and the _capacity_ for it is, as Immanuel Kant discovered, present in man "as he now is" (Kant) _before_ the activity of the senses begins; but without this activity it can not assert itself. Now, I maintain, and in doing so I take my stand upon the facts published in this book, that just as little as the intellect of the child not yet able to speak has need of words or looks or gestures, or any symbol whatever, in order to arrange in time and space the sense-impressions, so little does that intellect require those means in order to form concepts and to perform logical operations; and in this fundamental fact I see the material for bridging over the only great gulf that separates the child from the brute animal. That even physiologists deny that there is any passage from one to the other is shown by Vierordt in his "Physiology of Infancy" (1877). The fundamental fact that a genuinely logical activity of the brain goes on without language of any sort, in the adult man who has the faculty of speech, was discovered by Helmholtz. The logical functions called by him "unconscious inferences" begin, as I think I have shown by many observations in the newly-born, immediately with the activity of the senses. Perception in the third dimension of space is a particularly clear example of this sort of logical activity without words, because it is developed slowly.