The next step was to create a method for determining the particular configuration on which any given property of matter depends. If such a problem could be solved at all, it would be by some new system of practical analysis. Bacon did not see this because he was a Schoolman, emancipated, indeed, from ecclesiastical authority, but retaining a blind faith in the power of logic. Aristotle’s Organon had been the great storehouse of aids to verbal disputation; it should now be turned into an instrument for the more successful prosecution of physical researches. What definitions were to the one, that Forms should be to the other; and both were to be determined by much the same process. Now Aristotle himself had emphatically declared that the concepts out of which propositions are constructed were discoverable by induction and by induction alone. With him, induction meant comparing a number of instances, and abstracting the one circumstance, if any, in which they agreed. When the object is to establish a proposition inductively, he has recourse to a method of elimination, and bids us search for instances which, differing in everything else, agree in the association of two particular marks.[541] In the Topics he goes still further and supplies us with a variety of tests for ascertaining the relation between a given predicate and a given subject. Among these, Mill’s Methods of Difference, Residues, and Concomitant Variations are very clearly stated.[542] But he does not call such modes of reasoning Induction. So far as he has any general name for them at all, it is Dialectic, that is, Syllogism of which the premises are not absolutely certain; and, as a matter of nomenclature, he seems to be right. There is, undoubtedly, a process by which we arrive at general conclusions from the comparison of particular instances; but this process in its purity is nothing more nor less than induction by simple enumeration. All other reasoning requires the aid of universal propositions, and is therefore, to that extent, deductive. The methods of elimination or, as they are now called, of experiment, involve at every step the assumption of general principles duly specified in the chapter of Mill’s Logic where they are analysed. And wherever we can rise immediately from, a single instance to a general law, it is because the examination of that single instance has been preceded by a chain of deductive reasoning.
The confusion of Induction, properly so called, and Elimination under a single name, is largely due to the bad example set by Bacon. He found it stated in the Analytics that all concepts and general propositions are established either by syllogism or by induction; and he found some very useful rules laid down in the Topics, not answering to what he understood by the former method; he therefore summarily dubbed them with the name of Induction, which they have kept ever since, to the incalculable confusion of thought.
In working out his theory of logic, the point on which Bacon lays most stress is the use of negative instances. He seems to think that their application to reasoning is an original discovery of his own. But, on examination, no more seems to be meant by it than that, before accepting any particular theory, we should consider what other explanations of the same fact might conceivably be offered. In other words, we should follow the example already set by Aristotle and nearly every other Greek philosopher after Socrates. But this is not induction; it is reasoning down from a disjunctive proposition, generally assumed without any close scrutiny, with the help of sundry conditional propositions, until we reach our conclusion by a sort of exhaustive process. Either this, that, or the other is the explanation of something. But if it were either that or the other, so and so would follow, which is impossible; therefore it must be this. No other logic is possible in the infancy of enquiry; but one great advantage of experiment and mathematical analysis is to relieve us from the necessity of employing it.
The value of experimentation as such had, however, scarcely dawned on Bacon. His famous Prerogative Instances are, in the main, a guide to simple observation, supplemented rather than replaced by direct interference with the phenomena under examination, comparable to that moderate use of the rack which he would have countenanced in criminal procedure. There was, perhaps, a deeper meaning in Harvey’s remark that Bacon wrote about Nature like a Lord Chancellor than the great physiologist himself suspected. To Bacon the statesman, science was something to be largely endowed out of the public treasury in the sure hope that it would far more than repay the expenditure incurred, by inventions of priceless advantage to human life. To Bacon the lawyer, Nature was a person in possession of important secrets to be wrested from her by employing every artifice of the spy, the detective, the cross-examiner, and the inquisitorial judge; to Bacon the courtier, she was a sovereign whose policy might be discovered, and, if need be, controlled, by paying judicious attention to her humours and caprices. And, for this very reason, he would feel drawn by a secret affinity to the Aristotelian dialectic, derived as it was through Socrates and Plato from the practice of the Athenian law-courts and the debates of the Athenian assembly. No doubt the Topics was intended primarily for a manual of debate rather than of scientific enquiry; and the English Chancellor showed true philosophic genius in his attempt to utilise it for the latter purpose. Nevertheless the adaptation proved a mistake. It was not without good grounds that the Socratic dialectic had been reserved exclusively by its great founder, and almost exclusively by his successors, for those human interests from the discussion of which it was first derived. And the discoverers, who in Bacon’s own lifetime were laying the foundations of physical science, employed a method totally different from his, because they started with a totally different conception of the universe. To them it was not a living whole, a Form of Forms, but a sum of forces to be analysed, isolated, and recombined, in fact or in idea, with a sublime disregard for the conditions under which they were presented to ordinary experience. That very extension of human power anticipated by Bacon came in a manner of which he had never dreamed. It was gained by studying, not the Forms to which he attached so much importance, but the modes of motion which he had relegated to a subordinate place in his classification of natural causes.[543]
It has been said that, whatever may be the value of his logic, Bacon recalled men from the construction of baseless theories to the study of facts. But, here also, he merely echoes Aristotle, who said the same thing long before him, with much greater terseness, and with the superior authority of one who teaches by example as well as by precept; while the merit of reviving Aristotle’s advice when it had fallen into oblivion belongs to another Bacon, the author of the Opus Majus; the merit of acting on it, to the savants of the Renaissance, to such men as Vesalius, Cesalpino, and Tycho Brahe.
But, towards the close of the sixteenth century, the time for amassing observations was past, no further progress being possible until the observations already recorded were interpreted aright. The just instinct of science perceived this; and for nearly a century after Cesalpino no addition of any magnitude was made to what Bacon called ‘History,’ while men’s conceptions of natural law were undergoing a radical transformation.[544] To choose such a time for developing the Aristotelian philosophy was peculiarly unfortunate; for that philosophy had become, both on its good and on its bad side, an obstacle to progress, by encouraging studies which were not wanted, and by fostering a spirit of opposition to the Copernican astronomy.
The mere fact that Aristotle himself had pronounced in favour of the geocentric system did not count for much. The misfortune was that he had constructed an entire physical philosophy in harmony with it; that he had linked this to his metaphysics; and that the sensible experience on whose authority he laid so much stress, seemed to testify in its behalf. The consequence was that those thinkers who, without being professed Aristotelian partisans, still remained profoundly affected by the Peripatetic spirit, could not see their way to accepting a theory with which all the hopes of intellectual progress were bound up. These considerations will enable us to understand the attitude of Bacon towards the new astronomy; while, conversely, his position in this respect will serve to confirm the view of his character set forth in the preceding pages. The theory, shared by him with Aristotle, that Nature is throughout composed of Form and Matter reached its climax in the supposition that the great elementary bodies are massed together in a series of concentric spheres disposed according to some principle of graduation, symmetry, or contrast; and this seemed incompatible with any but a geocentric arrangement. It is true that Bacon quarrelled with the particular system maintained by Aristotle, and, under the guidance of Telesio, fell back on a much cruder form of cosmography; but his mind still remained dominated by the fancied necessity of conceiving the universe under the form of a stratified sphere; and those who persist in looking on him as the apostle of experience will be surprised to find that he treated the subject entirely from an à priori point of view. The truth is that Bacon exemplified, in his own intellectual character, every one of the fundamental fallacies which he has so picturesquely described. The unwillingness to analyse sensible appearances into their ideal elements was his Idol of the Tribe; the thirst for material utilities was his Idol of the Den: the uncritical acceptance of Aristotle’s metaphysics, his Idol of the Theatre; and the undefined notions associated with induction, his Idol of the Market.
III.
We may consider it a fortunate circumstance that the philosophy of Form,—that is to say, of description, definition, classification, and sensuous perception, as distinguished from mathematical analysis and deductive reasoning,—was associated with a demonstrably false cosmology, as it thus became much more thoroughly discredited than would otherwise have been possible. At this juncture, the first to perceive and point out how profoundly an acceptance of the Copernican theory must affect men’s beliefs about Nature and the whole universe, was Giordano Bruno; and this alone would entitle him to a great place in the history of philosophy. The conception of a single finite world surrounded by a series of eternal and unchangeable crystal spheres must, he said, be exchanged for the conception of infinite worlds dispersed through illimitable space. Once grant that the earth has a double movement round its own axis and round the sun, and Aristotle’s whole system of finite existence collapses at once, leaving the ground clear for an entirely different order of ideas.[545] But, in this respect, whatever was established by the new science had already been divined by a still older philosophy than Aristotle’s, as Bruno himself gladly acknowledged,[546] and the immediate effect of his reasoning was to revive the Atomic theory. The assumption of infinite space, formerly considered an insuperable objection to that theory, now became one of its chief recommendations; the arguments of Lucretius regained their full force, while his fallacies were let drop; Atomism seemed not only possible but necessary; and the materialism once associated with it was equally revived. But Aristotelianism, as we have seen, was not alone in the field, and on the first symptoms of a successful revolt, its old rival stood in readiness to seize the vacant throne. The question was how far its claim would be supported, and how far disputed by the new invaders. It might be supposed that the older forms of Greek philosophy, thus restored to light after an eclipse of more than a thousand years, would be no less hostile to the poetic Platonism than to the scientific Aristotelianism of the Renaissance. Such, however, was not the case; and we have to show how an alliance was established between these apparently opposite lines of thought, eventually giving birth to the highest speculation of the following century.
Bruno himself acted as a mediator between the two philosophies. His sympathies with Platonism were strongly pronounced, he looked with admiration on its mediaeval supporters, especially David of Dinan; and regretted the time when Oxford was a focus of realistic teaching, instead of being what he found her, devoted to the pedantic humanism of the Renaissance.[547] He fully accepted the pantheistic conclusions towards which Platonism always tended; but in proclaiming an absolute principle whence all specific differences are evolved, he is careful to show that, while it is neither Form nor Matter in the ordinary sense, it may be called Matter in the more refined signification attached to that term by Plotinus and, indeed, by Aristotle himself. There is a common substance underlying all abstract essences, just as there is a common substance left behind when the sensible qualities of different bodies are stripped off; and both are, at bottom, the same. Thus monism became the banner round which the older forms of Greek speculation rallied in their assault on Aristotle’s philosophy, though what monism implied was as yet very imperfectly understood.