GEORGE HENRY LEWES
Three centuries of modern thought have not sufficed to settle the dispute as to its own origin. Many Englishmen still claim insistently that Lord Bacon, in his Advancement of Learning, and still more positively in his later and greater work, the Novum Organum (1620) started modern scientific method. Present scientists themselves seem inclined to smile somewhat scornfully at the laurels thus placed on Bacon's brow. And as for Frenchmen, they simply refuse to hear the pompous Lord Chancellor mentioned at all. To them René Descartes is the only genuine originator of all modern philosophy. The publication of his Discourse on Method (1637) marks for them the epoch which separates two worlds of thought.
Fortunately, George Henry Lewes, himself a celebrated English critic and the author of a system of philosophy, presents us the two rivals side by side, seeking to explain and balance the honors due to each.
It is very certain that somewhere about this period did originate that mathematical exactitude of method in both thought and experiment which has produced modern science. And modern science has, in its brief but marvellous career of three centuries, altered the face of the globe. It has taught man more than ancient science did in all the preceding centuries; it has touched even our deepest faiths.
Whether its success has been due mainly to the abstract reasoners like Copernicus and the philosophers, or to the practical experimenters like Galileo and Harvey, is perhaps scarcely a practical question.
In the evolution of philosophy, as in the evolution of an organism, it is impossible to fix with any precision a period of origin, because every beginning is also a termination, and presumes the results of a whole series of preceding evolutions. As Mr. Spedding felicitously says, our philosophy "was born about Bacon's time, and Bacon's name, as the brightest which presided at the time of its birth, has been inscribed upon it:
"Hesperus that led
The starry host rode brightest."
"Not that Hesperus did actually lead the other stars; he and they were moving under a common force, and they would have moved just as fast if he had been away; but because he shone brightest, he looked as if he led them." Bacon and Descartes are generally recognized as the "Fathers of Modern Philosophy," though they themselves were carried along by the rapidly swelling current of their age, then decisively setting in the direction of science. It is their glory to have seen visions of the coming greatness, to have expressed in terms of splendid power the thoughts which were dimly stirring the age, and to have sanctioned the new movement by their authoritative genius. The destruction of scholasticism was complete. They came to direct the construction of a grander temple.
There are in these two thinkers certain marked features of resemblance, and others equally marked of difference. We see their differences most strikingly in their descendants. From Bacon lineally descended Hobbes, Locke, Diderot, D'Alembert, Condillac, Cabanis, and our Scotch school. From Descartes descended Spinoza, Malebranche, Leibnitz, Fichte, Schelling, and Hegel. The inductive method predominated in one school, the deductive in the other. These differences we shall recognize more fully later on; at present we may fix our minds on the two great points of resemblance: 1st, the decisive separation of philosophy from theology; 2d, the promulgation of a new method.
The separation of philosophy from theology is made emphatic in the rejection of final causes by both Bacon and Descartes. Perhaps the most effective of their novelties was the effort of Descartes to explain the system of the world by matter and motion only, thus quietly setting aside all causes and metaphysical entities which had hitherto been invoked. The hypothesis of vortices was indeed soon disclosed to be untenable; but the scientific attitude from which that hypothesis proceeded was never afterward relinquished. It was a bold attempt at the application of the objective method, and was only defective in its restriction to cosmology, and its exclusion of biology, which was still left to the subjective method, as I shall presently notice.
The second point on which Bacon and Descartes resemble each other is in their conception of the results to be achieved by a totally new method. Coming as they did on the top of the revolutionary wave which had washed away the old methods, seeing as they saw the striking results of physical research, and foreseeing yet more glorious conquests from the spirit which achieved those results, they yielded themselves to the pleasant illusion that a new method would rapidly solve all problems. Bacon, as the more magnificent and imaginative mind, had grander visions and more enthusiastic faith; but Descartes also firmly believed that the new method was to do wonders. Indeed, it is interesting to note how these great intellects seem quite unconscious of their individual superiority, and are ready to suppose that their method will equalize all intellects. It reminds us of Sydney Smith maintaining that any man might be witty if he tried. Descartes affirms that "it is not so essential to have a fine understanding as to apply it rightly. Those who walk slowly make greater progress if they follow the right road than those who run swiftly on a wrong one." To the same effect Bacon: "A cripple on the right path will beat a racer on the wrong one." This is true enough, but is beside the question. Equipped with good or bad instruments, the superiority of one worker over another is always made manifest; and it is precisely in the right use of a good method that the scientific genius is called upon for its delicate and patient skill.
Into the vexed questions of Bacon's conduct, both with regard to Essex and with regard to bribery, I cannot enter here; but referring the curious to his biographers and critics, I will simply note that he was born in 1561; was educated at Trinity College, Cambridge, where he learned to distrust the Aristotelianism of his masters, and planned his own vast scheme of reform; went to Paris; sat in Parliament as member for Middlesex; was successively appointed of the Privy Council, and lord chancellor; was created Viscount Verulam; was impeached and condemned for corruption as a judge; and died in the spring of 1626. "For my name and memory," said the dying man, "I leave it to men's charitable speeches, and to foreign nations, and the next age."
Posterity has been generous; the fame of Bacon is immense. Admirers have not always been unanimous as to his special claims; but there has been no lack of enthusiasm, no questioning of his genius. He has been lauded for achievements in which he had no part, and has been adorned with titles to which he had doubtful pretensions; while his most important services have been overlooked. But the general recognition of his greatness, and our national pride in it, have not prevented certain attacks on his reputation, which have been answered in a rather angry spirit; and thus from one cause and another there is great difficulty in arriving at any candid and thorough appreciation of the work he did. It seems to some persons that Bacon did very little in rising against the philosophy of his day, and pointing out a new path; and to others it seems that he did nothing of the kind. But whoever looks closely into the writings of Bacon's predecessors will see that what now seems obvious and trivial was then startling and important. As M. Rémusat felicitously says, "Il fallait du génie pour avoir ce bon sens." And to those who deny that Bacon did head the revolution, I would oppose not simply the testimony of nearly three centuries, but the testimony of Gassendi, who, both as contemporary and as foreigner, was capable of judging the effect then produced. It is indeed apparent to anyone familiar with the writings of some of Bacon's immediate predecessors, especially Galileo, that there was little novelty in his denunciations of the erroneous method then popular, or in his exhortations to pursue observation, experiment, and induction. But it is not less apparent that he had wider and profounder views of the philosophy of method than any of them, and that the popular opinion does not err in attributing to him the glory of heading the new era.
In England he is commonly regarded as the "Father of Experimental Philosophy" and the originator of the inductive method. Men profess themselves followers of the "Baconian philosophy," sometimes confounding that with a servile attention to facts and a most unscientific scorn of theories; at other times implying that by the Baconian method is to be understood the one on which science has successfully been pursued. A rigorous investigation of Bacon's claims will disclose the truth of his own statement, that he was rather one who sounded the trumpet-call than one who marshalled the troops. He insisted on the importance of experiment, but he could not teach what he did not himself understand—the experimental method. He exhorted men to study nature; but he could not give available directions for that study. He had fervent faith in the possible conquests of science; but never having thoroughly mastered any one science, he was incapable of appreciating the real conditions of research. He saw clearly enough the great truth that the progress of research must be gradual, but he did not see what were the necessary grades, he did not see the kind of inquiries, and the order they must follow before discoveries could be made.
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.
When the results of this meditative solitude were given to the world in the shape of his celebrated Discourse on Method, and his Meditations—to which he invented replies—the sensation produced was immense. It was evident to all men that an original thinker had arisen; and although this originality could not but rouse much opposition, from the very fact of being original, yet Descartes gained the day. His name became European. His controversies were European quarrels. Charles I of England invited him over, with the promise of a liberal appointment; and the invitation would probably have been accepted had not the civil war broken out. He afterward received a flattering invitation from Christina of Sweden, who had read some of his works with great satisfaction, and wished to learn from himself the principles of his philosophy.
He accepted it, and arrived in Stockholm in 1649. His reception was most gratifying, and the Queen was so pleased with him as earnestly to beg him to remain with her, and give his assistance toward the establishment of an academy of sciences. But the delicate frame of Descartes was ill fitted for the severity of the climate, and a cold, caught in one of his morning visits to Christina, produced inflammation of the lungs, which carried him off.
Christina wept for him, had him interred in the cemetery for foreigners, and placed a long eulogium upon his tomb. His remains were subsequently (1666) carried from Sweden into France, and buried with great ceremony in Ste. Geneviève du Mont.
Descartes was a great thinker; but having said this, we have almost exhausted the praise we could bestow upon him as a man. In disposition he was timid to servility. When promulgating his proofs of the existence of the Deity, he was in evident alarm lest the Church should see something objectionable in them. He had also written an astronomical treatise; but hearing of the fate of Galileo, he refrained from publishing, and always used some chicane in speaking of the world's movement. He was not a brave man, nor was he an affectionate man. But he was even-tempered, placid, and studious not to give offence.
It has already been indicated that the great work performed by Descartes was, like that of Bacon, the promulgation of a new method. This was rendered necessary by their separation from the ancient philosophy and their exclusion of authority. If inquiry is to be independent, if reason is to walk alone, in what direction must she walk? Having relinquished the aid of the Church, there were but two courses open: the one to tread once more in the path of the ancients, and to endeavor by the ancient methods to attain the truth; or else to open a new path, to invent a new method. The former was barely possible. The spirit of the age was deeply imbued with a feeling of opposition against the ancient methods; and Descartes himself had been painfully perplexed by the universal anarchy and uncertainty which prevailed. The second course was therefore chosen.
Uncertainty was the disease of the epoch. Scepticism was widespread, and even the most confident dogmatism could offer no criterion of certitude. This want of criterion we saw leading, in Greece, to scepticism, Epicureanism, Stoicism, the New Academy, and finally leading the Alexandrians into the province of faith, to escape from the dilemma. The question of a criterion had long been the vital question of philosophy. Descartes could get no answer to it from the doctors of his day. Unable to find firm ground on any of the prevalent systems, distracted by doubts, mistrusting the conclusions of his own understanding, mistrusting the evidences of his senses, he determined to make a tabula rasa, and reconstruct his knowledge. He resolved to examine the premises of every conclusion, and to believe nothing but upon the clearest evidence of reason; evidence so convincing that he could not by any effort refuse to assent to it.
He has given us the detailed history of his doubts. He has told us how he found that he could plausibly enough doubt of everything except of his own existence. He pushed his scepticism to the verge of self-annihilation. There he stopped; there in self, in his consciousness, he found at last an irresistible fact, an irreversible certainty.
Firm ground was discovered. He could doubt the existence of the external world, and treat it as a phantasm; he could doubt the existence of a God, and treat the belief as a superstition; but of the existing of his thinking, doubting mind no sort of doubt was possible. He, the doubter, existed if nothing else existed. The existence that was revealed in his own consciousness was the primary fact, the first indubitable certainty. Hence his famous "Cogito, ergo sum" ("I think, therefore I am").
It is somewhat curious, and, as an illustration of the frivolous verbal disputes of philosophers, not a little instructive, that this celebrated "Cogito, ergo sum," should have been frequently attacked for its logical imperfection. It has been objected, from Gassendi downward, that to say, "I think, therefore I am," is a begging of the question; since existence has to be proved identical with thought. Certainly, if Descartes had intended to prove his own existence by reasoning, he would have been guilty of the petitio principii Gassendi attributes to him, viz., that the major premise, "that which thinks exists," is assumed, not proved. But he did not intend this. What was his object? He has told us that it was to find a starting-point from which to reason—to find an irreversible certainty. And where did he find this? In his own consciousness. Doubt as I may, I cannot doubt of my own existence, because my very doubt reveals to me a something which doubts. You may call this an assumption, if you will: I will point out the fact as one above and beyond all logic; which logic can neither prove nor disprove; but which must always remain an irreversible certainty, and as such a fitting basis of philosophy.
I exist. No doubt can darken such a truth; no sophism can confute this clear principle. This is a certainty, if there be none other. This is the basis of all science. It is in vain to ask for a proof of that which is self-evident and irresistible. I exist. The consciousness of my existence is to me the assurance of my existence.
Had Descartes done no more than point out this fact he would have no claim to notice here; and we are surprised to find many writers looking upon this "Cogito, ergo sum" as constituting the great idea in his system. Surely it is only a statement of universal experience—an epigrammatic form given to the common-sense view of the matter. Any clown would have told him that the assurance of his existence was his consciousness of it; but the clown would not have stated it so well. He would have said, "I know I exist, because I feel that I exist."
Descartes therefore made no discovery in pointing out this fact as an irreversible certainty. The part it plays in his system is only that of a starting-point. It makes consciousness the basis of all truth. There is none other possible. Interrogate consciousness, and its clear replies will be science. Here we have a new basis and a new philosophy introduced. It was indeed but another shape of the old formula, "Know thyself," so differently interpreted by Thales, Socrates, and the Alexandrians; but it gave that formula a precise signification, a thing it had before always wanted. Of little use could it be to tell man to know himself. How is he to know himself? By looking inward? We all do that. By examining the nature of his thoughts? That had been done without success. By examining the process of his thoughts? That, too, had been accomplished, and the logic of Aristotle was the result.
The formula needed a precise interpretation; and that interpretation Descartes gave. Consciousness, said he, is the basis of all knowledge; it is the only ground of absolute certainty. Whatever it distinctly proclaims must be true. The process, then, is simple: examine your consciousness, and its clear replies. Hence the vital portion of his system lies in this axiom: All clear ideas are true: whatever is clearly and distinctly conceived is true. This axiom he calls the foundation of all science, the rule and measure of truth.
The next step to be taken was to determine the rules for the proper detection of these ideas; and these rules he has laid down as follows:
1. Never accept anything as true but what is evidently so; to admit nothing but what so clearly and distinctly presents itself as true that there can be no reason to doubt it.
2. To divide every question into as many separate questions as possible; that each part being more easily conceived, the whole may be more intelligible—(Analysis).
3. To conduct the examination with order, beginning by that of objects the most simple, and therefore the easiest to be known, and ascending little by little up to knowledge of the most complex—(Synthesis).
4. To make such exact calculations and such circumspections as to be confident that nothing essential has been omitted.
Consciousness, being the ground of all certainty, everything of which you are clearly and distinctly conscious must be true; everything which you clearly and distinctively conceive exists, if the idea of it involves existence.
In the four rules, and in this view of consciousness, we have only half of Descartes' system; the psychological half. It was owing to the exclusive consideration of this half that Dugald Stewart was led—in controverting Condorcet's assertion that Descartes had done more than either Galileo or Bacon toward experimental philosophy—to say that Condorcet would have been nearer the truth if he had pointed him out as the "Father of the Experimental Philosophy of the Mind." Perhaps the title is just; but Condorcet's praise, though exaggerated, was not without good foundation.
There is, in truth, another half of Descartes' system, equally important, or nearly so: we mean the deductive method. His eminence as a mathematician is universally recognized. He was the first to make the grand discovery of the application of algebra to geometry; and he made this at the age of twenty-three. The discovery that geometrical curves might be expressed by algebraical numbers, though highly important in the history of mathematics, only interests us here by leading us to trace his philosophical development. He was deeply engrossed in mathematics; he saw that mathematics were capable of a still further simplification and a far more extended application. Struck as he was with the certitude of mathematical reasoning, he began applying the principles of mathematical reasoning to the subject of metaphysics. His great object was, amid the scepticism and anarchy of his contemporaries, to found a system which should be solid and convincing. He first wished to find a basis of certitude—a starting-point: this he found in consciousness. He next wished to find a method of certitude: this he found in mathematics.
"Those long chains of reasoning," he tells us, "all simple and easy, which geometers use to arrive at their most difficult demonstrations, suggested to me that all things which came within human knowledge must follow each other in a similar chain; and that provided we abstain from admitting anything as true which is not so, and that we always preserve in them the order necessary to deduce one from the other, there can be none so remote to which we cannot finally attain, nor so obscure but that we may discover them." From these glimpses of the twofold nature of Descartes' method, it will be easy to see into his whole system: consciousness being the only ground of certitude, mathematics the only method of certitude.
We may say therefore that the deductive method was now completely constituted. The whole operation of philosophy henceforth consisted in deducing consequences. The premises had been found; the conclusions alone were wanting. This was held to be true of physics no less than of psychology. Thus, in his Principia, he announces his intention of giving a short account of the principal phenomena of the world, not that we may use them as reasons to prove anything; for he adds: "we desire to deduce effects from causes, not from effects; but only in order that out of the innumerable effects which we learn to be capable of resulting from the same causes, we may determine our minds to consider these rather than others."