It is the interest of the bird which enables it to build its nest, and in the same way it is the interest of man which enables him to make all that he makes. If man did not have this faculty of taking interest the world would never have evolved; this is why the secret of manifestation and the mystery of evolution are to be found in interest. But at the same time I do not deny the power of indifference. The power of indifference is a greater one still, provided that the indifference is not an artificial one. When a person chooses indifference only because he thinks "it is a good principle, then it is not a virtue; and also there will be no power, for such a man is a captive: on one side he is drawn by interest, and on the other side he wants to show indifference. It is a mistake on his part, for he neither accomplishes anything by the power of interest, nor does he gain the advantages that can be derived from indifference.