those of touch, estimating with the eye the
sensation a thing produces upon the fingers.

By movement alone we learn the existence of things which are not
ourselves; and it is by our own movements alone that we gain the idea
of extension.

Because the child has not this idea, he stretches out his hand
indifferently to seize an object which touches him, or one which is a
hundred paces distant from him. The effort he makes in doing this
appears to you a sign of domination, an order he gives the object to
come nearer, or to you to bring it to him. It is nothing of the kind.
It means only that the object seen first within the brain, then upon
the eye, is now seen at arm's length, and that he does not conceive of
any distance beyond his reach. Be careful, then, to walk often with
him, to transport him from one place to another, to let him feel the
change of position, and, in this way to teach him how to judge of
distances. When he begins to know them, change the plan; carry him
only where it is convenient for you to do so, and not wherever it
pleases him. For as soon as he is no longer deceived by the senses,
his attempts arise from another cause. This change is remarkable and
demands explanation.

The uneasiness arising from our wants expresses itself by signs
whenever help in supplying these wants is needed; hence the cries of
children. They cry a great deal, and this is natural. Since all their
sensations are those of feeling, children enjoy them in silence, when
the sensations are pleasant; otherwise they express them in their own
language, and ask relief. Now as long as children are awake they
cannot be in a state of indifference; they either sleep or are moved by
pleasure and pain.

All our languages are the result of art. Whether there is a natural
language, common to all mankind, has long been a matter of
investigation. Without doubt there is such a language, and it is the
one that children utter before they know how to talk. This language is
not articulate, but it is accentuated, sonorous, intelligible. The
using of our own language has led us to neglect this, even so far as to
forget it altogether. Let us study children, and we shall soon acquire
it again from them. Nurses are our teachers in this language. They
understand all their nurslings say, they answer them, they hold really
connected dialogues with them. And, although they pronounce words,
these words are entirely useless; the child un