The Crisis of the European Mind 1680-1715

by Paul Hazard

  The English school, of which Boyle was a leading light, displayed no less activity. The Royal Society was the admiration of Europe. The sagacious and gifted persons who compose it think much less about showing off their cleverness, or their remarkable memory, than they do of making a solid contribution to the arts and sciences. That being so, the propositions that engaged their attention, into the truth of which they are concerned to enquire, are, by preference, those to which a practical test can be applied; to the rest, they pay little or no heed. Then they seek out causes by a process of reasoning, combined with further experiments, which, one after another, take these eminent naturalists very far afield, as far, in point of fact, as the top of the peak of Teneriffe, where some of them have been to prosecute further researches, after conducting countless experiments at home, and inventing special apparatus for the work.[1]

  The Dutch scientists were past masters in the method that was now coming into fashion; medical men, botanists, naturalists, all worked unsparingly: Swammerdam, Huygens, Boerhaave, Gravesande, and Leuwenhoeck. The last named, with deft fingers, searching eye, and a forward-looking mind, began by perfecting his technique, as we should say to-day. He spared himself no pains till he had manufactured with his own hands, and after innumerable experiments, a microscope more powerful than any which had served his predecessors. He made a success of it; the microscope which he at length contrived to construct, was capable of magnifying objects two hundred and seventy times their actual size. In a single drop of water he beheld a whole world; a world of tiny creatures moving about, struggling, seeking for food. Maybe that drop of water is as full of things as the ocean, palpitating with a whole world of life. He submits various liquids to a similar test, blood, and other fluids. However, his discoveries were contested and, as usual, arguments, rejoinders, opuscula, books and labour untold, were needed before public opinion would acknowledge the truth of what the eye had beheld.

  Then there were the Scandinavians, Olaus Roemer, Thomas Bartholin, Nils Stensen, whose anatomical discoveries gave new life to medical science. There were Germans, too, like Otto van Guericke, who busied himself with the nature and problems of space. Working as disciplined collaborators in a common task, the Germans brought out a specialist publication in the shape of a journal dealing with medico-physics which described the lines on which students of natural science were working. Bayle thought very highly of it, saying that its contributors were rendering most valuable service to scientific research, both by their indefatigable industry and their inventive genius.

  The French also became smitten with natural science. Parisians went to the jardin du Roi to hear Duverney’s lectures on anatomy. They boasted of possessing, in the person of Nicolas Lémery, who began as an apothecary, the man to whom Voltaire was later on to refer as the first intelligent chemist; as well as Mariotte, one of the most famous physicists of the day. “In Paris, a new Nature Office has been opened, for that is what I call the Académie des Sciences: M. l’abbé Bignon, who keeps the key of this office, has declared that nature would appear there quite unadorned, not having thought fit to borrow from the gentlemen of the Académie française any of the finery and bedizenments they have in stock. That was quite right.”[2]

  Spain itself took part in the research movement. A society of physics and experimental medicine was founded at Seville in 1697. Just as in literature, and just as in philosophy, though possibly more promptly, swarms of ideas began to germinate. An illustrious Etruscan doctor, Francesco Redi, published a treatise on animalculae. In it he demonstrated that substances do not go bad when they are kept away from flies, which, if they are not, lay eggs in them: all the learned folk in Europe were interested in his discovery; and, by way of setting a seal on this intellectual co-partnership, it was a Frenchman, Pierre Coste, who translated this work from the Italian and it was in Holland that the translation was published. A Venetian, Paolo Sarrotti, became acquainted with Robert Boyle in London and, fired with enthusiasm for scientific studies, took back with him to Venice, “A couple of young Englishmen who were very adept at handling mechanical appliances used in connection with scientific experiments”. When Père Tachard went on his second journey to Siam, M. Thévenot asked him to look into a matter which struck him as very remarkable, though he had been assured that it was perfectly true. It was that sea-shells were to be found on the top of Mount Sinai. Now was that really so? Greatly daring, Frs. Le Blanc and de Bèze undertook to make the ascent. The chief European journals gave a lot of space to problems in higher mathematics, but more still to the natural sciences. Often the reports sent in by readers do but indicate an inveterate taste for things out of the ordinary, unnatural: A hen that had never laid an egg, being startled by a loud noise, began to cackle in the most extraordinary fashion, and then laid an enormous egg, which was marked, not with a comet, as some people had got the story, but with a lot of stars. Someone caught a butterfly that had a head like a baby’s. A girl vomited a quantity of spiders, caterpillars, slugs and other insects. Such were the sort of “strange events” that took the public fancy. But on the same pages, there were items that bore witness to genuine scientific work; learned men were busy in every country, all animated by a like spirit of enquiry, by a like eagerness to get at the bottom of things: What is the function of sap in trees? What, precisely, are the effects of quinine? What causes fermentation? Then there was the anatomy of the eye; of the stomach; newly discovered tubes in the human heart. Someone comes across a monstrosity of a cat. Well; no use gaping and saying oh, how wonderful! Let’s take and dissect it.

  As with philosophy, as with criticism, when the time was ripe, there appeared on the scene one of those mighty figures for whom the great ages never call in vain: to wit, Newton.

  Is it not clearly a sign of the times that the two men whom Vico described as the outstanding geniuses of the age, Leibniz and Newton, discovered well-nigh simultaneously the infinitesimal calculus. The application of this new method enables us to treat natural phenomena, not as discontinuous, which they generally are not, but as continuous, which they generally are. What an immensely important place in the evolution of human ideas was henceforth taken by science, science which men in those days quite honestly thought they could do without. It has been observed that whenever some great mathematical truth was discovered and brought out, it was made the basis of a theory by which the whole universe was to be explained. Pythagorism was based on arithmetic; Spinozism on geometry; similarly, it was on the infinitesimal calculus that the philosophy of Leibniz was founded.[3] In fact, Leibniz himself declared that mathematics were the main resource of the philosopher, and that he would never have discovered the theory of harmony had he not in the first place established the law of motion. Meanwhile, Newton, in the light of the infinitesimal calculus, was led to discover the law of gravitation.

  It was, in fact, in the year 1687 that his great work, the Principia mathematica philosophiae naturalis, first saw the light. These principles were a long way from being understood when they first appeared. It was not till a generation or so later that their full importance was realized. As in philosophy, so in criticism, so, indeed, in all things, the XVIIIth century was to profit by the discoveries of the latter part of the XVIIth. Such potent substances have to be ingested slowly. Be it added that the Principia regard mathematics, not as the whole of physics, as Descartes would have them, but as the instrument to which physical science has recourse in order to make and verify its discoveries. And be it further added that the immortal book restores to observation and experiment their dignity and importance. Facts attentively observed; due submission to the facts; humble acceptance of the facts; an almost instinctive abhorrence of any theory that cannot stand the test of fact—such were some of the characteristics of Newton’s genius, and his cosmic discovery is, as it were, the astounding illustration of his principles and the reward of his intellectual allegiance. The popular imagination, which pictures Newton sitting under a tree, observing the fall of an apple, and wond
ering what made it fall, is not so wide of the mark, not so trivial as it might seem, when we look on it as symbolizing the method of one who takes the real for his starting-point. He realized, in an eminent degree, the aim which inspired those bands of pioneers whose patient and zealous labours we have lately been reviewing. Begin with the concrete; interpret it in the light of reason; then verify your conclusion by again comparing it with the concrete—such, explicitly stated, is the rule of the science towards which these pioneers were dimly feeling their way.

  When Fontenelle, as Perpetual Secretary of the Académie des Sciences, came to write his panegyric of Sir Isaac Newton, his clear understanding enabling him to explain his discoveries with such lucidity that the man in the street could understand them, or thought he could; when his writing, while losing nothing of its precision or its elegance, took on an added glow and vivacity, as though warmed by the creative breath of the man whose genius he had set himself to extol; then, indeed, we were presented with a parallel that was no mere literary flight of fancy, something “to point a moral or adorn a tale”, but a most accurate and faithful comparison of these two great men, Descartes and Newton. Despite his partiality for Descartes, his master, Fontenelle brings out with admirable clearness the difference in the intellectual attitudes of the two men, both of whom, in their respective ways, marked the limits to which the human mind can soar.

  The two great men who stand forth in such marked contrast, one against the other, nevertheless, had many links between them. Both were geniuses of first order, born to hold sway over the minds of men, and to be the founders of Empires. Both of them, excellent geometricians themselves, saw the need to bring geometry into the domain of physics; both founded their physics on a system of geometry which they owed almost exclusively to their own intelligence. But one of them, soaring aloft in daring flight, sought to take his stand at the fountain-head of all things in the light of a few clear and fundamental ideas, so that when he came to deal with the phenomena of Nature he would be able to treat them as necessary consequences thereof. The other, less daring, or more modest, in his aims, beginning with phenomena as his starting point proceeded therefrom to unknown principles, resolved to treat them as the logic of the consequences might require. The one starts from a clearly formulated idea to ascertain the cause of what he sees; the other starts from what he sees, and goes on to seek out its cause. . . .

  In like manner, when, proceeding with his discourse, he comes to deal with the subject of Optics, as set forth by Newton in the Treatise of Light and Colours, published in 1704, Fontenelle demonstrates the purpose, the difficulty, ay, and the beauty, of those experimental labours:

  The art of experiment, when it is carried out with a certain degree of nicety, is by no means one that is commonly met with. The most trifling effect presented to our senses is complicated by so many others which constitute or modify it, that it is impossible, without the exercise of extraordinary skill, to disentangle all the various strands which compose it, and it requires the most acute understanding even to guess at the various elements which might conceivably enter into it. The sensible fact has to be resolved into other facts, themselves composite, and these in their turn, must be resolved into their constituents, and sometimes, if you chance to miss your way, you find yourself in a maze from which there is no visible issue. The primary and elementary facts seem to have been hidden by Nature from our sight with as much care as the causes thereof, and when we do succeed in catching a glimpse of them, they present an appearance as novel as it is startling.

  We recognize in the coming of experimental physics the formal ratification of a process whose effects were to prove as varied as they were numerous. The brilliant genius of Newton marks the same transition from the transcendental to the positive as Pufendorf had essayed to achieve in the sphere of law, Richard Simon in Biblical exegesis, Locke in philosophy, and Shaftesbury in ethics. He dismissed with confidence any apprehensions that might be entertained about the possible abuse of reason, which, for the time being, seemed purely destructive. He brought about the union—a task so difficult as to be deemed impossible—between the strict demands of the critics and the facts of experience. So once again does man set forth to survey and subdue the universe.

  On the 8th February, 1715, before the Leyden Academy, Boerhaave, a doctor of medicine, delivered a lecture entitled De comparando certo in physicis, in which he summarized the results achieved in the course of the last few years. All attempts to get at the essence of things had been unavailing. First causes, the nature of matter, eluded us. We invented words, we talked about atoms, monads and so forth; but all this got us no farther. We had to make up our minds to it, and recognize that all this talk was just so much guesswork which tomorrow would falsify. Newton himself was careful to state that when he spoke of attraction he had no intention of repeating the error of the schoolmen, who ascribed the action of mysterious properties to all such phenomena as they could not account for. It looked as if all bodies attracted one another; but as to why they did so he was careful not to commit himself. He observed and noted visible and sensible phenomena; he compared and calculated effects; and there he stopped. In consequence, we should consider as out of bounds those metaphysical regions in which so many philosophers have lost their way. Let us be content with the things that experience makes known and confirms. Leave metaphysics alone and stick to physics. Only when we do that shall we begin to find out the real facts about nature which, up to now, have eluded us. So here again is another brand of Pyrrhonism, of defeatist Pyrrhonism, Pyrrhonismus physicus, as Boerhaave himself denoted it. He could never have taken the line he did had not those changes in the intellectual outlook, whose progress we have been endeavouring to trace, already taken place. The great Dutch doctor was but summarizing the principles of a new school of thought, of a general system of philosophy, whose essential tenets had been expounded by Locke. Tired of trying to discover the essential nature of matter, which they had now come to regard as eternally beyond their reach, men addressed themselves to the task of taking stock of the limited domain which they were still able to call their own. To make the most of that; to put up a comfortable abode there, to make work less of a drudgery and more remunerative; to increase their well-being, to find themselves better off every day—this was now their aim in life. And who was to be their guide in the prosecution of their task? Why, the scientist. To him it belonged to instruct mankind in the ordering of their lives. So, to the scientist went all the honours. He is proclaimed as greater than princes, or military conquerors; his praises are sounded in all the seats of learning, and to him are addressed the eloquent tributes that used to be paid to the masters of the pen. And why should he not also take the lead in public affairs? If politics require the nicest calculations, the utmost skill in planning, surely the scientist is the very man for the job. Newton cut no indifferent figure as a Member of Parliament. The historian prides himself on observing the winds of destiny which sway the fate of nations, which call Empires into being, and bring them to the dust. A paltry satisfaction, that, compared with what the man of science can enjoy. “The most striking pages of History could scarce surpass in interest those phosphorescent substances, those cold liquids which, when mixed together, burst into sudden flame, the almost magical properties of the magnet, and all those countless wonders whose secret Science, by a close and watchful scrutiny of Nature, has managed to unveil.”[4]

  What wonder, after that, that Poetry should sing the praises of the microscope, the pneumatic engine, the barometer? What wonder that it should hymn the circulation of the blood and the laws of respiration? The Muse was but paying homage to the Spirit of the Age.

  Science never pauses in her onward march. Today, it is gravitation that has been revealed to us; tomorrow, other men of genius will arise, other secrets will be brought to light; and so, little by little, we shall come to know all the parts of that mighty machine of which, hitherto, we have known nought. And knowledge means power. Even if Science did no
more for us, it would still be useful in that it would teach us how to think with accuracy and precision, and to shape our minds in conformity with her inexorable laws; an accomplishment not to be despised. But theory must needs find expression in practice: theoriam cum praxi.[5] “To know that in a parabola the subtangent is double the corresponding abscissa, is, in itself, a very barren piece of knowledge; nevertheless, it is one step towards acquiring the art of firing shells with precision which we now possess.” “When the foremost geometricians of the seventeenth century addressed themselves to the study of a new curve which they called the cycloid, they had no practical object in view. . . . However, as a result of their continued investigations into the properties of the curve in question, it came to be applied to clocks, and brought measurement of time to its ultimate perfection.” “The application of science to nature will constantly grow in scope and intensity, and we shall go on from one marvel to another; the day will come when man will be able to fly by fitting on wings to keep him in the air; the art will increase more and more till one day we shall be able to fly to the moon.” In a word: “Here is a vast field of knowledge all adaptable to the use and well-being of humanity here below. We know, for example, how to invent new and swift machines that will add to the speed and comfort of travel, how to blend a variety of agents, or materials, so as to obtain new and wholesome products which we can put to profitable use, thus augmenting the sum total of our riches, in other words of things which will add to the comfort and convenience of our daily lives.” Earth will become a paradise. Already, thanks to the toil of that learned sisterhood, Mechanics, Geometry, Algebra, Anatomy, Botany, Chemistry—more potent than the old-fashioned Muses—Death has been forced to retreat.