Different, however, as science and technology may be, they are also closely related. Technology draws on many other than scientific sources; it draws upon common sense, upon existing technologies, upon pre-scientific practise; but it draws continually upon science. Science, in its turn, is furthered by technology. The pursuit of a practical end often reveals some defect of theoretical knowledge; and the repairing of this defect, itself a contribution to science, may perform more than it promised, may in fact open up some wholly new field of scientific enquiry. That is the nature of the relation; and at first sight the advantage seems to lie with technology; for if the technologist needs the aid of science, he also appears capable of supplying for himself the science that he needs; he has only, for a little while, to shift his attitude, and the science is forthcoming. Where, then, would be the loss if pure science, with its "unreal" and "abstract" concerns, went by the board, and we all became practical together?
In answer to this question there are two things to be said. We must remember, in the first place, that every technology is limited by its end. When a technological need suggests a problem in pure science, the suggestion bears directly upon the need out of which it arises, and upon that need only; when the need is satisfied, there is no further sanction, within the technology, for purely scientific work. If, in other words, the progress of science were made dependent upon the progress of technology, and theory were never invoked save for the sake of practise,—if such a state of things were conceivable,—then our scientific knowledge would perforce remain scrappy and partial, so scrappy and so partial that a halt would ultimately be called to the advance of technology itself. An all-embracing technology, starting out with things as they are today, would no doubt be able to maintain itself for a relatively long time; theory is, in general, so far ahead of practise that, though science now stopped short, technological advance would long be possible. It is this fact, of course, which gives a plausible coloring to the demand that science leave its heights and come down among "every-day people," and that the man of science, instead of adding to his store of observed facts, use his scientific capital for "practical" and "vital" purposes. Sooner or later, however, the capital would be exhausted; sooner or later, progress would slow down to stagnation; the needs of technology, occasional needs of a circumscribed activity, would not suffice in the long run for the advancement of science. And then there is the other side of the shield! Technology, we said, draws from many sources, but is continually drawing upon science; each separate technology, we may here add, upon many sciences. Now if any induction from the history of human achievement is secure, it is surely this: that there is nothing in science so abstract, or so remote from matter of fact, or so indifferent to common sense, that it may not, some day or other, prove of service to
