"When the babe is born it shows no sign of mind.

For a brief space hunger and repletion, cold and warmth are its only sensations.

Slowly the specialised senses begin to function; still more slowly muscular movements, at first aimless and reflex, become co-ordinated and consciously directed.
There is no sign here of an intelligent spirit controlling a mechanism; there is every sign of a learning and developing intelligence, developing _pari passu_ with the organism of which it is a function.

As the body grows, the mind grows with it, and the childish mind of the child develops into the hasty, quickly-judging, half-informed, unbalanced youthful mind of the youth; with maturity of years comes maturity of mind, and body and mind are vigorous and in their prime.

As old age comes on and the bodily functions decay, the mind decays also, until age passes into senility, and body and mind sink into second childhood.