THE SCIENCE OF LIFE
under various sets of influences, takes recourse to various modes of living, and preserves his continuity and individuality under various forms adapted to the varying conditions of the social and physical world. The state, religion, literature, and other manifestations of human life assume in this way different characteristics of form and spirit under different circumstances.
The motive of man in having recourse to social and physical changes of his organism is to adapt these manifestations and weapons of life to the varying needs and conditions of the struggle for existence. Political movements as well as religious propagandism, planting of colonies as well as the development of industries, are thus regulated by the play of a thousand and one forces to which human life is
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