The tendency of modern religion to make itself at home in the world and to enter into intimate relations with civilization is not due solely to the puritan confidence of victory over life. It is partly due to the influences of a sentimental and optimistic evaluation of human nature which came to the modern church through Rousseau and romanticism. It is also a product of the evolutionary optimism which has characterized religious thought since ethicists and religionists have learnt to overcome the melancholy conclusions implicit in the Darwinian theory and to see the bright side of evolution. Traditional religion is other-worldly. The modern church prides itself on its bright and happy worldliness. It is more interested in transforming the natural and social environment of personality than in persuading the soul to transcend all circumstances and find its happiness in inner peace. The modern church regards this mundane interest as its social passion. But it is also the mark of its slavery to society. Whenever religion feels completely at home in the world, it is the salt which has lost its savor. If it sacrifices the strategy of renouncing the world, it has no strategy by which it may convict the world of sin. A movement which detaches religion from life to give it perspective and power over life must on the other hand run the risk of centering the interests of men on other than social problems. Religion thus faces a dilemma which is not easily solved. A religion of social amelioration easily becomes a beautiful romance which obscures the unlovely realities of life. A religion of detachment from the world may persuade the soul to find both happiness and virtue in defiance of physical and social circumstances and thus to regard all social problems as irrelevant to its main purpose. This dilemma is not due to any specific or historic weaknesses in types of religion but arises out of the nature and constitution of religion as such.