In this day of testing, when so few have been found lacking in courage and the capacity for self-sacrifice, it seems peculiarly fitting that spiritual values and beliefs be boldly thrown into the arena, there to prove themselves. In the years after the Great War, mankind must build its life afresh and it will be wisest to see that the foundation is a sound one. And, as a matter of social psychology, I doubt that a people which is unwilling to look carefully to the framework of its social and spiritual edifice can build a noble mansion. Mechanical efficiency and cleverness will not be enough for this task of spiritual creation. We must find lasting values around which to build a humane life. And this, also, is a kind of warfare. Some have expressed to me a doubt whether America is prepared for this effort at reconstruction of a basic, yet intangible, sort. I have hopes, although not blind ones. I refuse to take the vulgarities and ignorances of popular evangelists as completely diagnostic of America's soul. In the following pages, which are devoted to a clear statement of the new view of man and nature which, in its essentials, has come to stay, I shall act according to this law of personality, to wit, spiritual courage. I shall explain the spiritualized naturalism to which we are ascending in the same spirit that the scientist presents his facts--impersonally, calmly, and simply. {3} Such, at least, is my purpose and desire. What I write here is in its way a confession of faith. The values and loyalties which I shall proclaim as true, redemptive and invigorating are those which my own life and concrete reflection have selected. In them I see the possibility of high spiritual attainment. The new view of the universe is founded upon, influenced by, and has for its necessary setting, the exact knowledge which the various special sciences, mental as well as physical, have been accumulating. This knowledge is rounding into something of the nature of a whole whose interpretation does not admit of doubt. Incomplete in detail though his knowledge be, man is no longer in the dark as to the main features of the world and his own origin and destiny. He knows that he is an inhabitant of a small planet in one of the many solar systems of the stellar universe, that he is the product of an age-long evolution in which variation and survival have been the chief methods of advance, that his mind as well as his body has its natural ancestry. While it will always remain a wonder, so to speak, that there is a universe in which and to which we awaken, it is equally certain that the only sensible thing to do is to seek to find out its character and laws. Is it not like exploring the chambers and corridors of a house in which one shall live for a stated period?