I. Scientific Progress.

     The accumulation and progress of discoveries in science and
     in nature.—They serve as a starting-point for the new
     philosophers.

The first is scientific discovery, admirable on all sides, and beneficent in its nature; it is made up of masses of facts slowly accumulated and then summarily presented, or in rapid succession. For the first time in history the sciences expand and affirm each other to the extent of providing, not, as formerly, under Galileo and Descartes, constructive fragments, or provisional scaffolding, but a definite and demonstrated system of the universe, that of Newton.3101 Around this capital fact, almost all the discoveries of the century, either as complementary or as prolongations, range themselves. In pure mathematics we have the Infinitesimal Calculus discovered simultaneously by Leibnitz and Newton, mechanics reduced by d'Alembert to a single theorem, and that superb collection of theories which, elaborated by the Bernouillis, Euler, Clairaut, d'Alembert, Taylor and Maclaurin, is finally completed at the end of the century by Monge, Lagrange, and Laplace.3102 In astronomy, the series of calculations and observations which, from Newton to Laplace, transforms science into a problem of mechanics, explains and predicts the movements of the planets and of their satellites, indicating the origin and formation of our solar system, and, extending beyond this, through the discoveries of Herschel, affording an insight into the distribution of the stellar archipelagos, and of the grand outlines of celestial architecture. In physics, the decomposition of light and the principles of optics discovered by Newton, the velocity of sound, the form of its undulations, and from Sauveur to Chladni, from Newton to Bernouilli and Lagrange, the experimental laws and leading theorems of Acoustics, the primary laws of the radiation of heat by Newton, Kraft and Lambert, the theory of latent heat by Black, the proportions of caloric by Lavoisier and Laplace, the first true conceptions of the source of fire and heat, the experiments, laws, and means by which Dufay, Nollet, Franklin, and especially Coulomb explain, manipulate and, for the first time, utilize electricity.—In Chemistry, all the foundations of the science: isolated oxygen, nitrogen and hydrogen, the composition of water, the theory of combustion, chemical nomenclature, quantitative analysis, the indestructibility of matter, in short, the discoveries of Scheele, Priestley, Cavendish and Stahl, crowned with the clear and concise theory of Lavoisier.—In Mineralogy, the goniometer, the constancy of angles and the primary laws of derivation by Romé de Lisle, and next the discovery of types and the mathematical deduction of secondary forms by Haüy.—In Geology, the verification and results of Newton's theory, the exact form of the earth, the depression of the poles, the expansion of the equator,3103 the cause and the law of the tides, the primitive fluidity of the planet, the constancy of its internal heat, and then, with Buffon, Desmarets, Hutton and Werner, the aqueous or igneous origin of rocks, the stratifications of the earth, the structure of beds of fossils, the prolonged and repeated submersion of continents, the slow growth of animal and vegetable deposits, the vast antiquity of life, the stripping, fracturing and gradual transformation of the terrestrial surface,3104 and, finally the grand picture in which Buffon describes in approximate manner the entire history of our globe, from the moment it formed a mass of glowing lava down to the time when our species, after so many lost or surviving species, was able to inhabit it.—Upon this science of inorganic matter we see arising at the same time the science of organic matter. Grew, and then Vaillant had just demonstrated the sexual system and described the fecundating of plants; Linnaeus invents botanical nomenclature and the first complete classifications; the Jussieus discover the subordination of characteristics and natural classification. Digestion is explained by Réaumur and Spallanzani, respiration by Lavoisier; Prochaska verifies the mechanism of reflex actions; Haller and Spallanzani experiment on and describe the conditions and phases of generation. Scientists penetrate to the lowest stages of animal life. Réaumur publishes his admirable observations on insects and Lyonnet devotes twenty years to portraying the willow-caterpillar; Spallanzani resuscitates his rotifers, Tremblay dissects his fresh-water polyps, and Needham reveals his infusoria. The experimental conception of life is deduced from these various researches. Buffon already, and especially Lamarck, in their great and incomplete sketches, outline with penetrating divination the leading features of modern physiology and zoology. Organic molecules everywhere diffused or everywhere growing, species of globules constantly in course of decay and restoration, which, through the blind and spontaneous development, transform themselves, multiply and combine, and which, without either foreign direction or any preconceived end, solely through the effect of their structure and surroundings, unite together to form those masterly organisms which we call plants and animals: in the beginning, the simplest forms, and next a slow, gradual, complex and perfected organization; the organ created through habits, necessity and surrounding medium; heredity transmitting acquired modifications,3105 all denoting in advance, in a state of conjecture and approximation, the cellular theory of later physiologists3106 and the conclusions of Darwin. In the picture which the human mind draws of nature, the general outline is marked by the science of the eighteenth century, the arrangement of its plan and of the principal masses being so correctly marked, that to day the leading lines remain intact. With the exception of a few partial corrections we have nothing to efface.

This vast supply of positive or probable facts, either demonstrated or anticipated, furnishes food, substance and impulse to the intellect of the eighteenth century. Consider the leaders of public opinion, the promoters of the new philosophy: they are all, in various degrees, versed in the physical and natural sciences. Not only are they familiar with theories and authorities, but again they have a personal knowledge of facts and things. Voltaire3108 is among the first to explain the optical and astronomical theories of Newton, and again to make calculations, observations and experiments of his own. He writes memoirs for the Academy of Sciences "On the Measure of Motive Forces," and "On the Nature and Diffusion of Heat." He handles Réamur's thermometer, Newton's prism, and Muschenbrock's pyrometer. In his laboratory at Cirey he has all the known apparatus for physics and chemistry. He experiments with his own hand on the reflection of light in space, on the increase of weight in calcified metals, on the renewal of amputated parts of animals, and in the spirit of a true savant, persistently, with constant repetitions, even to the beheading of forty snails and slugs, to verify an assertion made by Spallanzani.—The same curiosity and the same preparation prevails with all imbued with the same spirit. In the other camp, among the Cartesians, about to disappear, Fontenelle is an excellent mathematician, the competent biographer of all eminent men of science, the official secretary and true representative of the Academy of Sciences. In other places, in the Academy of Bordeaux, Montesquieu reads discourses on the mechanism of the echo, and on the use of the renal glands; he dissects frogs, tests the effect of heat and cold on animated tissues, and publishes observations on plants and insects.—Rousseau, the least instructed of all, attends the lectures of the chemist Rouelle, botanizing and appropriating to himself all the elements of human knowledge with which to write his "Emile."—Diderot taught mathematics and devoured every science and art even to the technical processes of all industries. D'Alembert stands in the first rank of mathematicians. Buffon translated Newton's theory of flux, and the Vegetable Statics of Hales; he is in turn a metallurgist, optician, geographer, geologist and, last of all, an anatomist. Condillac, to explain the use of signs and the relation of ideas, writes abridgments of arithmetic, algebra, mechanics and astronomy.3109 Maupertuis, Condorcet and Lalande are mathematicians, physicists and astronomers; d'Holbach, Lamettrie and Cabanis are chemists, naturalists physiologists and physicians.—Prophets of a superior or inferior kind, masters or pupils, specialists or simple amateurs, all draw directly or indirectly from the living source that has just burst forth. This is their basis when they begin to teach about Man, what he is, from whence he came, where he is going, what he may become and what he should be. A new point of departure leads to new points of view; so that the idea, which was then entertained of the human being will become completely transformed.