But doubt, which is thus social and imbued with a living sympathy, and which though requiring sacrifice does not destroy belief, but only makes belief active and reality an achievement, may be viewed here in still another way. It shows mankind using or spending [p.258] instead of either hoarding or throwing away any of the resources of knowledge and faith, of developed habit and personal association, which life accumulates. Some doubters, as men say in the business world, invest what they have; some speculate. Some are conservative, even timorous; some are very rash. Yet doubt as expenditure is necessary to all who would enjoy the proper, natural increase of their possessions, and while the rash, be they transgressors or reformers, sensualists or materialists, or equally impractical idealists, at a throw may win or lose great riches of mind or spirit, the timorous and ultra-conservative, the "practical" and conventional, are not less dependent on chance. There are the new rich, too, and the aristocratic poor, and both remind us strongly that the real use of what we have is not only a duty, but also a very sober duty. To hoard blindly or spend rashly is to risk unwisely, perhaps to lose all, or, if to win, to win idly; while to use well, to doubt clearly and honestly, to doubt even in one's belief, to doubt only for fuller meaning, for broader and deeper life, for richer companionship, is personally to earn lasting spiritual treasure.
Modern science, whose knowledge comprises merely working hypotheses, the means to truth, not truth itself, or if truth, then only a living, growing truth, affords one of the best examples of this. Modern science is a great faith, a great belief, but only because it is a life, not a status or possession, only because it is a constant spending, a constant using of knowledge, that earns interest, even compound interest, as regularly as the years go by. And experience in [p.259] general, as well as science, is also a great belief, and also only because always doubting and so always using and always earning.
Doubt, in a word, is more than a necessity of experience; it is distinctly a duty. Experience itself is but another name for that hard master who says to every unprofitable servant: "Thou wicked and slothful servant, thou knewest that I reap where I sowed not, and gather where I did not scatter; thou oughtest therefore to have put my money to the bankers, and at my coming I should have received back my own with interest. Take ye away therefore the talent from him and give it unto him that hath the ten talents."