It is the ironic paradox of human existence that both suffering and joy can enable a man to pass to a higher plane. How is this possible? Suffering drives him to seek its own end, that is, to seek peace. Thus he is led inevitably and eventually to the quest of Overself. Joy draws him towards its source, which rises ever higher as it becomes more refined. Thus he is brought in time to recognize that the true permanent happiness is in the Overself. The urge to shun misery and experience joy shows itself on every plane and in every kind of condition because it is finally and fully satisfied only in the Overself.
-- Notebooks Category 13: Human Experience > Chapter 1: Situation > # 151