The research-worker in the individual sciences can and must give his attention solely to the known and the knowable; but the philosopher must at the same time consider the unknown and the unknowable. With this twofold vision we shall in these pages apply ourselves to some of the problems of the soul; we shall seek to elucidate them, and to solve them, so far as this is possible in the present state of our knowledge; but we shall keep our minds on the alert for the unexplained and the unsolved. Our aim will be not a vague mysticism, but that learned ignorance, that recognition of ignorance of the knowable. Contents: infinity of the soul; individual and his destiny; journey into the past; dramaturgy of life; Americanization of the soul; religion of the future;