common property. The essential novelty on which he relied for the infallibility of his mode of interrogating Nature was his method of exclusions. But this ingenious invention implied an impossible preliminary, and rested on a monstrous assumption. The preliminary to its successful operation was the compilation of what he called a "Natural History"; that is, an exhaustive catalogue of all natural phenomena, constituting a vast repository of materials for induction. Until this should be accomplished, he laid down dogmatically that no progress worthy the human race was possible,[1] and declared the history without the method to be infinitely more serviceable to science than the method without the history,[2] The assumption was that the infinite complexity of visible and sensible objects is formed by the varying combinations of a limited number of "simple natures" (such as neat, weight, color, etc.), just as words and sentences in endless diversity are compounded out of a few elementary signs.[3] And as, by learning six-and-twenty letters, we get at the secret of written language, so we have only to construct a complete alphabet of Nature, in order to read her riddles with ease and certainty. Thus the second step in the process was nothing less than to frame a synopsis of all the modes of action in the universe.[4] The peculiar efficacy of the "Exclusiva" now becomes apparent. All "natures" save one being excluded by a series of skillful experiments from causal connection with the phenomenon under investigation, the residual element is negatively, but conclusively, proved to be the "true cause" or "form" sought for.
It was from this special invention, and not from the general application of inductive rules, that Bacon's "Organ" derived its peculiar efficacy. This was the new art of discovery likened by him to a pair of compasses, armed with which the least skillful hand might be guided to define a perfect circle. This was the universal nostrum—the elixir vitæ of science—which had the one drawback common to all methods professing to transcend nature—that its operation was clogged with an impossible condition. It is easy enough for us, from our present point of view, to see that the method of exclusions was tainted with a logical vice. It implied a petitio principii; it presupposed, while promising to impart, universal knowledge. It was not so easy—it was perhaps impossible—for Bacon, for his contemporaries, and even for his immediate successors, to see this. They did not in fact perceive any impossibility in a scheme for tabulating the universe. On the contrary, they looked forward confidently to the time when it should be accomplished. The preparation of a universal history of nature
