understanding or explanation of the phenomena concerned; for example, the work of the wind in sweeping sand across a desert and whirling dust high into the air may be seen in operation; or the behavior of rivers in draining their basins and in transporting land waste may be closely studied by direct observation: hence wind action and river action may in these respects come to be understood by induction alone. But the larger action of these agents, as in the erosion of elaborate valley systems by rivers, and in the sculpture of peculiar desert forms by the winds, demand much unseen work in long past time; and even if induction on a widely extended basis could ultimately bring forth the full explanation of such problems, the mind is too impatient to wait for so long postponed a result, and seeks other means of reaching the same end.
Search for Theoretical Explanation.—One sometimes meets inductive investigators who say that they believe it best not to enter upon the speculative aspects of their work, even in complicated problems, until all the facts have been gathered; but such caution is unwise, even if it be mentally possible in one who is capable of conducting an original investigation. An unintelligent person may indeed see various outdoor facts, and continue to observe, collect and record them, and yet never ask himself or anyone else about their cause; but such a person is not mentally fitted to undertake the investigation of new problems, such as are here considered. On the other hand, when an earnest investigator comes upon facts of a complicated nature, he can not help wondering how they came to be what they are; he is not satisfied with the slow progress of induction toward their explanation; he inevitably feels some curiosity as to their invisible origin, that is, as to so much of their history as has already passed; he is discontent to remain ignorant; his mind is alert to find hidden meanings, just as his eyes are watchful to see visible features. He wishes to know about past facts which, in their time, were as veritable as are the facts of to-day, and which taken with to-day's facts assume that reasonable relation which we call explanation. This is precisely as it should be. If by good fortune the student's wonder and curiosity are so much aroused by what he sees, that they excite the invention of a possible explanation for his novel facts, the part of wisdom is surely not to turn his mind away from this invention, which may prove to be an extremely useful one, but merely to refuse immediate belief in it, before its value has been tested. The danger here lies not in the wish for explanation, nor in any ingenious invention of an explanation, but in the acceptance of such an invention as if it were the final truth. That is truly a serious error; an error that is not to be guarded against by stifling the inventive faculty, but, as will be shown below, by arousing the critical faculties to a rigorous examination of any suggestions that the inventive faculty may bring forth.