these scientific conceptions, like other instruments, are hand-made by man in pursuit of realization of acertain interest that of the maxi- mum convertibility of every object of thought into any and every other. It is awonderful ideal jthe ingenuity which man has shown in devising means of realizing the interest is even more marvelous. But these ways of thinking are no more rivals of or substitutes for objects as directly perceived and enjoyed than the power-loom, which is amore effective in- strument for weaving cloth than was the old hand-loom, is a substitute and rival for cloth. The man who is disappointed and tragic because he cannot wear aloom is in reality no more ridiculous than are the persons who feel troubled because the objects of scientific conception of natural things have not the same uses and values as the things of direct experience.