If the plasticity of childhood and the psychical continuity between maturity and immaturity are, in one aspect, portentous, they are likewise heartening. For the fine qualities that children are capable of--their spontaneity, their capacity for reversing themselves, their generosity and affection, their sense of humor, their unabashed candor, their frequently startling objectivity--we of adult years also are capable of. Childhood is not a shut-off room which we are permitted to visit now and then in order to forget the disagreeable apartment in which we are compelled to live; childhood is a part of what we still are! Plasticity, we are learning, though it may decline with the hardening of the arteries, has no dead line. Experiment has disproved the view, held as late as William James, that after adolescence we are practically incapable of learning qualitatively new habits. We can both increase already used powers by further use of them, and also bring into action neglected powers. Anyone who can enter sympathetically into the life of another has capacity for developing in himself the qualities of this other. The fact that our cynicism, our distrust of others, and our doubt of ourselves shrink when we make ourselves companions of the young is a direct evidence of what our nature contains, in however undeveloped form. And who does not grow mellow--who does not experience a measure of regeneration (becoming “as a little child”)--upon witnessing in children such admirable graces as candor, responsiveness to affection, generosity, the habit of laughter--all spontaneous, unreserved, uncalculating? It is because there is something of the child within me that I am capable of entering the Kingdom of Heaven.