That he had really but vague and imperfect conceptions of scientific method is decisively shown by his contemptuous rejection of Copernicus, Galileo, and Gilbert, and by his own plan of investigation into heat. One sentence alone would suffice to show this, namely, his sneer at Copernicus as "a man who thinks nothing of introducing fictions of any kind into nature, provided his calculations turn out well." Bacon did not understand, what Copernicus profoundly saw, that the only value of an hypothesis was its reconciliation of calculations with observations. In his plan for an inquisition into the nature of heat, we see a total misconception of the scientific process; not only does he set about in a laboriously erroneous way, but he seeks that which science proclaims inaccessible, the nature of heat. It is true that he arrives at a hypothesis which bears some resemblance to the hypothesis now accepted, namely, that heat is a mode of motion—"an expansive and restrained motion, modified in certain ways, and exerted in the smaller particles of the body." But those who have been eager to credit him with an anticipation of modern views on the strength of this definition, have overlooked the fact that it is incapable of explaining a single process, includes none of the ascertained laws of phenomena, and is itself an example of the illicit generalization which Bacon elsewhere condemns. It was with some justification, therefore, that Harvey, who knew what science was, and knew better than most men how discoveries were made, said of him that he wrote of science like a lord chancellor.
Indeed, it is to mistake his position and his greatness altogether to attribute his influence on philosophy, which is undeniable, to an influence on science which is more than questionable. Bacon was a philosopher; but because with him philosophy, separating itself from the bondage of theology, claimed to ally itself with science, and sought its materials in the generalities of science, those writers who have never made a very accurate distinction between the two, but have confounded philosophy with metaphysics, and science with physics, have naturally regarded Bacon as the precursor of Newton, Laplace, Faraday, and Liebig. It is in vain that critics oppose such a claim by asserting what is undeniable, that the great discoveries in modern science were neither made on Bacon's method nor under any direct guidance from him—that Copernicus, Galileo, and Kepler preceded him, that Harvey and Newton ignored him—stanch admirers have their answer ready; they know that Bacon was the herald of the new era, and they believe that it was his trumpet-call which animated the troops and led them to victory.
Having thus indicated his position, it will be necessary to give a brief outline of the method which he confidently believed was to be infallible and applicable in all inquiries. This was imperatively needed: "for let a man look carefully into all that variety of books with which the arts and sciences abound, he will find everywhere endless repetitions of the same thing, varying in the method of treatment, but not new in substance, insomuch that the whole stock, numerous as it appears at first view, proves on examination to be but scanty. What was asserted once is asserted still, and what was a question once is a question still, and, instead of being resolved by discussion, is only fixed and fed."
He proposes his new method, that thereby "the intellect may be raised and exalted and made capable of overcoming the difficulties and obscurities of nature. The art which I introduce with this view (which I call the 'Interpretation of Nature') is a kind of logic, though the difference between it and the ordinary logic is great, indeed immense. For the ordinary logic professes to contrive and prepare helps and guards for the understanding, as mine does; and in this one point they agree. But mine differs from it in three points: viz., in the end aimed at, in the order of demonstration, and in the starting-point of inquiry.
"But the greatest change I introduce is in the form itself of induction and the judgments made thereby. For the induction of which the logicians speak, which proceeds by simple enumeration, is a puerile thing; concluded at hazard, is always liable to be upset by a contradictory instance, takes into account only what is known and ordinary, and leads to no result. Now, what the sciences stand in need of is a form of induction which shall analyze experience and take it to pieces, and by a due process of exclusion and rejection lead to an inevitable conclusion."
"Now, my method, though hard to practise, is easy to explain; and it is this: I propose to establish progressive stages of certainty. The evidence of sense, helped and guarded by a certain process of correction, I retain; but the mental operation which follows the act of sense I for the most part reject; and instead of it I open and lay out a new and certain path for the mind to proceed in, starting directly from the simple sensuous perception."
The same dissatisfaction with mediæval philosophy expressed itself in Descartes. The incompetence of philosophers to solve the problems they occupied themselves with—the anarchy which reigned in the scientific world, where no two thinkers could agree upon fundamental points—the extravagance of the conclusions to which some accepted premises led, determined him to seek no more to slake his thirst at their fountains.
"And that is why, as soon as my age permitted me to quit my preceptors," he says, "I entirely gave up the study of letters; and resolving to seek no other science than that which I could find in myself, or else in the great book of the world, I employed the remainder of my youth in travel, in seeing courts and camps, in frequenting people of diverse humors and conditions, in collecting various experiences, and above all in endeavoring to draw some profitable reflection from what I saw. For it seemed to me that I should meet with more truth in the reasonings which each man makes in his own affairs, and which, if wrong, would be speedily punished by failure, than in those reasonings which the philosopher makes in his study, upon speculations which produce no effect, and which are of no consequence to him, except perhaps that he will be more vain of them the more remote they are from common-sense, because he would then have been forced to employ more ingenuity and subtlety to render them plausible."
For many years he led a roving, unsettled life; now serving in the army, now making a tour, now studying mathematics in solitude, now conversing with scientific men. One constant purpose gave unity to those various pursuits. He was elaborating his answers to the questions which perplexed him; he was preparing his method.
When only twenty-three he conceived the design of a reformation in philosophy. He was at that time residing in his winter quarters at Neuburg, on the Danube. His travels soon afterward commenced, and at the age of thirty-three he retired into Holland, there in silence and solitude to arrange his thoughts into a consistent whole. He remained there eight years; and so completely did he shut himself from the world that he concealed from his friends the very place of his residence.