Author's note: Much of the following is excerpted from Chapter 5 of my book in progress, The Anti-Copernican Revolution. The book is concerned with the relationship between philosophy and physics, and it spans the period from Copernicus to the present.

Like the lives of individuals, history has its key moments. In Ayn Rand's novel The Fountainhead, the hero, Howard Roark, is asked: “When you look back, does it seem to you that all your days rolled forward evenly, like a sort of typing exercise, all alike? Or were there stops—points reached—and then the typing rolled on again?” Roark answers: “There were stops.”1 Even on the grand scale of history we can see such stops, that is, points at which one period ends, the direction changes, and another period begins.

One historian, Alan Cromer, refers to the extraordinary transition that took place at the end of the 18th century and writes: “In many ways, the decade of the 1780s divides the past from the present.”2 That is a profound truth, in a much deeper sense than Cromer explains. I will argue that this was the point at which the Enlightenment reached its zenith—and at which it was brought down by its one failure.

The Enlightenment is the century between two major figures: Isaac Newton and Immanuel Kant. In The Ominous Parallels, Leonard Peikoff wrote that this period is the only time in modern history that “an authentic respect for reason became the hallmark of an entire culture.”3 Man's nature, most thinkers of the period agreed, was clear from his accomplishments, particularly those in science. He is not the helpless animal described by the skeptics or the depraved animal described by the mystics; he is, as Aristotle said long ago, the rational animal. As such, he is a being with unlimited potential for gaining knowledge and acting to achieve his spiritual and physical well-being. In 1750, French economist and statesman Anne Robert Jacques Turgot expressed the attitude that dominated the era: “At last all clouds are dissipated. What a glorious light is cast on all sides! What a crowd of great men on all paths of knowledge! What perfection of human reason!”4

In physical science, the crowd of great men knew who had cleared their path. “The physics of the eighteenth century,” writes one historian, “provides an example of the profound influence exerted by the work of a single man, Isaac Newton, to a degree that is unique in the development of modern science.”5 Newton had blazed the trail with two works of genius. In the Principia, he had presented the universal laws of motion and gravitation and thus opened men's eyes to the extraordinary power of mathematics. In his Optics, he had provided a tour de force demonstration of how to ask questions of nature and obtain the answers by systematic experimentation. The Enlightenment made the most of both lessons.

By far the greatest contribution to mathematical physics was made by Leonhard Euler. As one physicist puts it: “All branches of mathematics abound with Euler's theorems, Euler's coefficients, Euler's methods, Euler's proofs, Euler's constant, Euler's integrals, Euler's functions, and Euler's everything else.”6 He wrote exhaustive treatises on differential and integral calculus, and he presented the first modern treatment of methods for solving differential equations. He made fundamental contributions to several new areas of mathematics, including the theory of functions of complex variables, the theory of special functions, and the calculus of variations. Furthermore, he invented a great deal of the notation used today in mathematics, including the ubiquitous modern symbols for summations, finite differences, pi, the square root of minus one, the base of natural logarithms, and trigonometric functions.

Above all, Euler did for calculus what Euclid did for geometry. Neither man was the original discoverer, but each made an enormous contribution to his respective field and then presented the theory systematically. The comparison also highlights an interesting difference between the two men. Euclid was more the theorist concerned with logical foundations, whereas Euler was more the “practical” thinker so typical of the Enlightenment. Euler never lost sight of applications to the physical world, and such applications motivated his major innovations in mathematics.

Both logical rigor and applications are crucial. Without the first, we cannot be certain that our statements are true; without the second, it does not matter whether or not they are true. Throughout most of history, however, mathematicians have committed the Platonic error of denigrating applications. Newton's influence caused a profound (and unfortunately temporary) change of attitude. During the Enlightenment, mathematicians celebrated the indispensable role of their science in understanding the physical world. As one historian notes: “Calculus had been created to deal with the problem of motion, and the new mathematical techniques discovered in the 18th century were all responses to the challenges of mechanics. In no other century was mathematics so closely related to physical problems. . . .”7

Euler's work provides the leading illustration of this point. His first important paper, written in 1727, dealt with the optimal design of ship masts; fifty-six years later, on the last day of his life, he worked on the mathematical theory of balloon flight. In the intervening years, he analyzed vibrating strings and membranes, studied air flow through pipes, and designed hydraulic turbines; these physical problems led him to develop the theory of partial differential equations. He analyzed the strength of columns and beams, and designed optical lenses and waterwheels; such problems provided him with the impetus to develop the calculus of variations. He made important advances in cartography, by applying his new theory of complex functions. He improved orbital calculations for the moon and planets, by developing approximation techniques for solving differential equations. He improved calculations of the movement of the Earth's spin axis, by developing a general mathematical theory of rotating solid bodies.

In a sense, Euler was a man of all fields: a physicist, a mechanical engineer, an optical engineer, a cartographer, a ballistics expert, and so on. Yet, in a deeper sense, he was simply a mathematician. His primary purpose never wavered, and it was never merely to solve the particular physical problem at hand. His focus was always on developing general methods for solving any physical problem of a given type. That is what a mathematician is supposed to do. The difference between Euler and most of today's mathematicians is simple: Euler descended from Newton, not from Plato—and so he created methods for understanding the world, not floating abstractions detached from it.

While Enlightenment mathematicians found their inspiration in the Principia, many other researchers found theirs in Newton's Optics. Scientists were quick to apply Newton's experimental method to a new area: electricity.

Recorded observations of static electricity are as old as Western civilization. Thales, the earliest of the famous pre-Socratic philosophers, knew that a piece of amber (fossilized pine resin) rubbed with wool could attract bits of straw and even emit sparks. Our nomenclature reflects this early discovery: The word “electricity” is derived from the Greek word for amber, elektron.

For two thousand years, however, electricity received little attention. Its fundamental role in nature was far from obvious; the attractive force seemed weak, and it was observed only in a few materials. All motivation for investigating electricity was extinguished during the Christian era, when the “city of God” was exalted and the physical world was trivialized. According to the prevailing Christian view, the attempt to understand perplexing natural phenomena was futile; Saint Augustine had insisted that “the frail comprehension of man cannot master [such] wonders of God's working.”8 Consequently, it was seen as a waste of time to study a strange attractive force that was assumed to be unimportant and beyond comprehension. Only after the Renaissance restored man's confidence and rekindled his desire to know the natural world, and after Newton demonstrated how such knowledge could be obtained, did an old mystery suddenly become a new science.

A rapid series of discoveries began in 1729 when Stephen Gray showed that an electrified body can transfer its electrical power to another body by touching it. Earlier observers had missed this fact, because they gripped the second body by hand and thus allowed the electricity to escape through them into the ground. Gray achieved his results with bodies suspended on silk cords. His experiments led him to divide materials into two categories: those that readi≠ly transmit the electrical power (i.e., conductors, such as the human body and any metal) and those that do not (i.e., insulators, such as silk and glass). Gray then realized that the transfer of electricity from one object to another did not require direct contact; it was enough to connect the objects by means of a moist thread or wire. Thus Gray built the first aerial transmission line, which consisted of a moist thread that carried a little bit of electricity over about 700 feet. It was the first ancestor of today's power lines.

Upon reading about Gray's discoveries, the French scientist Charles Dufay embarked on his own investigations. Dufay performed a series of experiments using a thin strip of gold foil hanging from a silk cord. He noted that when an electrified glass tube was brought near, the gold leaf was attracted to the glass as expected (just as straw is attracted to amber electrified by rubbing). However, after touching the glass, Dufay observed that the gold leaf was then repelled by the electrified glass tube. Upon making a few similar observations with materials other than gold and glass, he arrived at a general principle: An electrified body attracts any non-electrified body, and then repels it after transferring electricity to it.

This result led DuFay to suspect that all electrified bodies repel each other. To check the idea, he expanded on the above experiment. After the electrified glass tube touched and repelled the gold leaf, he approached the leaf with a piece of copal (a resinous solid similar to amber) that had been electrified by rubbing. To DuFay's amazement, the electrified copal strongly attracted the electrified gold leaf. Further tests with other substances led to a surprising but inescapable conclusion: There are two different kinds of electrified bodies. Glass, precious stones, and animal fur are electrified in the same way when rubbed; amber, copal, and paper are electrified in a different way. In December of 1733, DuFay announced his greatest discovery: Two bodies with the same kind of electricity repel each other, whereas two bodies with opposite kinds attract.

Researchers were aware of the sometimes inconvenient fact that an electrically charged body in the open air slowly loses electricity, as though “electrical fluid” in the body were evaporating. One amateur experimenter had the idea of keeping electricity in a closed jar to avoid such “evaporation.” In 1745, E. G. von Kleist filled a glass jar with a material that conducted electricity, closed the jar with a cork, and poked a wire (or nail) through the cork and into contact with the conductor inside. Holding the jar in his hands, he repeatedly touched the wire to a body electrified by vigorous rubbing. When he then touched the wire with one hand while still gripping the jar in the other, he made a painful discovery. “The shock stunned my arms and shoulders,” Kleist reported.9 News of this important invention spread quickly. After some improvements to the design, researchers finally had a device in which large amounts of electricity could be stored and accessed at will.

The general public found the new discoveries fascinating, and electricity became the popular rage. Public demonstrations of electrical phenomena drew large crowds, and people were said to be “crowding the students out of their seats” in college lectures.10 Scientists sought to entertain as well as educate; sometimes the power of electricity was demonstrated by electrifying an attractive young woman and daring the men in the audience to kiss her.

The fascination with electricity soon spread to the New World and fueled the investigations of Benjamin Franklin. As we have seen, a great deal had already been discovered: The key concepts of “conductor” and “insulator” and “electric charge” had been developed, and it was known that charges exist in two varieties that give rise to both attractive and repulsive forces. Something essential was still missing, however, something that was required before electricity could properly be called a science. The missing ingredient, which Franklin undertook to supply, was: a theory.

A science is not merely a loose group of facts pertaining to the same subject. Even the broad generalizations discovered by DuFay fell short of raising electricity to the level of a science. In his landmark paper of 1734, he did not discuss such questions as: What is physically happening when a body becomes electrically charged by rubbing, or when charge is transmitted from one body to another? Does the rubbing generate electric charge in the same way that it generates heat, or does preexisting charge simply move between the rubbed bodies? Is electric charge a property of ordinary matter, or a property of some independent electrical stuff? If the latter, how does the electrical stuff interact with ordinary matter? And are there two kinds of electrical stuff, corresponding to the two kinds of charges?

Physical science consists of knowledge integrated into a whole by means of physical theory. Franklin recognized that answers to the above questions were essential to further progress, and he was the first to provide them. He proposed that electricity consists of a special fluid, which can flow from one body to another when they are rubbed together or connected by a conductor. The total amount of fluid always remains the same; it is neither created nor destroyed, but only transferred between bodies. Thus the first fruit of Franklin's theory was a crucial new principle: the conservation of electric charge.

The electrical fluid, Franklin said, is present in all bodies. Electrical forces and their observed effects arise when the amount of fluid in a body deviates from the normal or equilibrium value. A body with an excess of fluid is said to be charged positively, whereas a body with a deficiency of fluid is said to be charged negatively. In its final form, the theory could account for all of Dufay's discoveries by postulating a delicate balance of forces between the electrical fluid and ordinary matter; it claimed that both substances are self-repulsive, while each attracts the other. Franklin was also able to explain the operation of Kleist's jar and the puzzling phenomena of “electrification by influence” (without direct contact). The explanations suggested further experiments, which in turn confirmed essential aspects of the theory.

In the past, electricity had been thought of as a weak force that acts only under special circumstances and in certain materials. In contrast, Franklin's theory claims that the electrical fluid is as common as ordinary matter and is even required to hold matter together. Electrical neutrality, on the other hand, is the result of a precise counterbalancing of forces. If a large imbalance between the electrical fluid and ordinary matter is possible, the theory implies that electrical forces might be quite strong.

Franklin soon demonstrated how strong. Several researchers had noted the observable similarities between lightning and electrical discharges, but without investigating further. Franklin's theory made him particularly receptive to the idea that lightning is an electrical discharge, albeit on a scale that people had previously thought inconceivable. In 1752, he proved this hypothesis by means of his famous kite experiment. Thus Franklin completed the work that brought about a radical change in perspective: In one generation, the subject of electricity developed from the description of a curiosity to a science studying a fundamental force of nature.

Not everyone was happy about such progress.

Some found the Enlightenment too bright and were nostalgic for darker ages. Such an attitude explains the topic chosen by the Academy of Dijon for its annual essay contest of 1750. The prestigious French academy asked: “Has the restoration of the arts and sciences been conducive to the purification of morals?” In effect, they were asking: Was the Renaissance and scientific revolution a step forward or backward, that is, are we better or worse for it?

That such a question was regarded as debatable is incredible enough. It is still more incredible that the prize was awarded to an author who took the negative side, that is, who argued that the arts and sciences—and the rebirth of reason in general—should be rejected as incompatible with moral virtue. The prize went to Jean-Jacques Rousseau.

Rousseau looked at creation—man's creation—and declared that it was evil. Dedicating himself to “directly opposing everything that is now most admired,” he announced his theme: “[T]he effect is certain, the depravity is real, and our souls have been corrupted in proportion as our sciences and arts have advanced toward perfection.”11 His solution to this alleged problem was straightforward. In regard to art and those who create it, Rousseau cried out: “[D]emolish these amphitheaters, break these statues, and burn these paintings; cast out these slaves who hold you in subjection, and whose pernicious arts corrupt you.”12 In regard to natural science, he wrote in praise of ignorance:

Peoples of the earth, know that nature intended to preserve you from knowledge, as a mother snatches a dangerous weapon from the hands of her child; that all the secrets which nature hides from you are so many evils from which she protects you; and that the difficulty you encounter in extending your knowledge is not the least of her blessings.13

Accordingly, he expressed approval of those who in the past had burned libraries and sought to banish the “terrible art” of printing.

Despite the obvious similarities, Rousseau was essentially different from the Christian zealots who held such ideas a millennium earlier. He was not a religious fanatic; he was a modern intellectual. He did not reject the world of the Enlightenment in favor of the kingdom of God; he rejected it in favor of barbarism. It was not heaven he offered to man, but a dark cave.

Rousseau glorified Sparta, and denigrated Athens; he admired the American Indian, and scorned the enlightened European. He created the myth of the “noble savage,” that is, a mindless brute who is entirely ignorant of literature, philosophy, and science—and yet is morally superior to civilized men. According to Rousseau, the savage is noble because he is mindless. Virtue consists of following the heart, not the mind. Since the proper moral code is allegedly “engraved in all hearts,” he claimed:

I have only to consult myself about what I want to do: what I feel to be right is right, what I feel to be wrong is wrong. . . . Reason deceives us all too often, and we have acquired all too good a right to disregard it, but conscience never deceives us.14

Thus the savage has a great advantage: He has not developed the deceptive faculty of reason. He is ruled by his whims—and therefore he acts virtuously.

A primitive man who has not discovered reason may be innocent, but an educated man who abandons reason is not. The latter men are ruled by a particular kind of emotion toward those who create the values that enrich our lives. What they feel is the opposite of love or gratitude. By their own statement, the mindless react with hostility toward efficacious thinkers. In a completely healthy culture, such apostles of unreason have no significant voice or influence. Yet, during the Enlightenment, Rousseau not only championed their cause but won fame and academic prestige by doing so.

Rousseau's success was made possible by the failure of philosophers. Early modern philosophy had started with the fantasies of RenÈ Descartes and ended with the anguish of David Hume. Descartes and his followers attempted to deduce the nature of the world from their arbitrary axioms, thereby making a mockery of reason while posing as its advocates (this school became known as rationalism). Hume and his followers attempted to reduce human cognition to mere sensation, thereby denying the existence of reason (this school became known as empiricism). Thus a void was created, and Rousseau's brand of emotionalism rushed to fill it.

In effect, Rousseau was the intellectual offspring of irresponsible parents. One (rationalist) parent tried to enforce arbitrary rules that had no basis in reality; the other (empiricist) parent did not believe in rules. The unsurprising result was a destructive child who threw temper tantrums. Rousseau got attention, but he did not immediately get his way. Most of his neighbors were still too mature and too civilized to accept emotional outbursts in place of reasoned arguments. Voltaire, who popularized Newton's ideas in France, spoke for rational men everywhere when he replied to Rousseau (1755):

I have received your new book against the human race, and thank you for it. Never was such a cleverness used in the design of making us all stupid. One longs, in reading your book, to walk on all fours. But as I have lost that habit for more than sixty years, I feel unhappily the impossibility of resuming it.15

Rousseau could lead a small and growing counterculture, but he could not yet divert the mainstream.

The case of Jean d'Alembert, however, shows that the mainstream itself was polluted by the ideas of modern philosophy. D'Alembert was primarily a mathematician and physicist, although he also dabbled in philosophy and literature. He edited the famous 18th century French encyclopedia, and he was an enormously popular figure in the salons of Paris. He was arguably the most influential intellectual in Paris during the 1750s.

D'Alembert often expressed the typical Enlightenment confidence in reason. Describing the great progress of his era, he wrote:

The true system of the world has been recognized, developed, and perfected. . . . The discovery and application of a new method of philosophizing, the kind of enthusiasm which accompanies discoveries, a certain exaltation of ideas which the spectacle of the universe produces in us—all these causes have brought about a lively fermentation of minds. Spreading through nature in all directions like a river which has burst its dams, this fermentation has violently swept away everything which stood in its way.16

Unfortunately, when d'Alembert searched for a philosophic foundation for this progress, he settled for what was readily available. His starting point was Descartes, and therefore, he began by looking inward for “clear and distinct” ideas rather than by looking outward at the world. He assumed that generalizations could be established with certainty only if they were based on innate, “a priori” truths—that is, truths known prior to experience—whereas they are always doubtful if derived from experience. The path to knowledge, therefore, is not induction from observation, but deduction from first principles that are grasped by intuition. D'Alembert made his philosophic allegiance clear when he wrote: “[Descartes'] method alone would have sufficed to render him immortal.”17

The Cartesian influence on d'Alembert's physics is unmistakable. He insisted that mechanics was a branch of mathematics, on a par with algebra or geometry. Mechanics is based on “necessary truths” that are allegedly independent of observational evidence. Consequently, he never “deigned to touch a piece of experimental apparatus.”18 He viewed experimenters as manual laborers, while he performed the more exalted role of mathematical architect. Following Descartes, d'Alembert attempted to reduce physics as much as possible to geometry. Nature, he claimed, is explicable solely in terms of movement and shape; bodies are merely “impenetrable extension,” whereas space is “penetrable extension.” Mechanics, according to this view, is restricted to the movement and impact of impenetrable shapes.

This rationalistic scheme was helpless to account for the actual physical world. For example, there was no place for the idea of “mass.” In an insightful biography, Thomas Hankins wrote: “Mass [is] a physical concept and could not be deduced from d'Alembert's disembodied chunks of impenetrable extension.”19 Refusing to accept this obvious truth, d'Alembert stubbornly repeated Descartes' mistake of trying to reduce the idea of “mass” to that of “volume.”

D'Alembert's mechanics also floundered on the concept of “force.” Descartes had taken the concept of “cause” for granted, but d'Alembert's confidence was shaken by the empiricists' attack on the idea of physical causality. In his Treatise of Dynamics, d'Alembert wrote:

All we see distinctly in the movement of a body is that it crosses a certain space and that it employs a certain time to cross it. It is from this idea alone that one should draw all the principles of mechanics when one wishes to demonstrate them in a distinct and precise manner; thus it is not surprising that I have kept away from motive causes to consider only the motions they produce . . . [W]e have no precise and distinct idea of the word “force” unless we restrict this term to express an effect . . . [A]rguments concerning the measure of forces are entirely useless in mechanics and even without any real object.20

As a result, d'Alembert felt compelled to develop his physics without making any essential use of the concept of “force.” Thus he proposed to replace Newton's second law (F = mA) with a law describing how the velocities of impenetrable shapes change upon impact.21

D'Alembert's unsuccessful attempt to reduce force to motion was as futile as his attempt to reduce mass to volume. The futility is particularly obvious in those cases where opposing forces result in no motion (such cases are the subject of the important branch of mechanical engineering known as “statics”). If forces are nothing but the motions they cause, then we must deny the existence of “static” forces. D'Alembert was left in an embarrassing position, asking: “Why, then, when one sustains a heavy body tending to fall, does one feel a resistance that is not felt in all the other directions except the vertical?”22 Only the collapse of philosophy can explain why an intelligent scientist struggled hopelessly with such a simple question.

Descartes escaped skepticism by invoking his “clear and distinct” innate ideas. D'Alembert, however, was unable to consistently follow the Cartesian method that he so admired. When he searched his mind for the crucial first principles, he was honest enough to admit that he could not find them. He described his dilemma in a letter to Voltaire:

I swear that the only reasonable course in all these metaphysical shadows is skepticism. I have no distinct idea, and even less a complete idea, of matter or of anything else; and to tell the truth, when I lose myself in my reflections on this subject, I come to the same conclusion every time I think about it; I am tempted to believe that what we see is only a phenomenon which contains nothing outside ourselves similar to what we imagine; and I am always brought back to the question of the Indian king: Why is there anything? Because that is actually the most surprising thing of all.23

D'Alembert's inability to defend rationalism ultimately drove him toward Humean skepticism. Not surprisingly, he and Hume were good friends during their later years.

In the end, d'Alembert's view was this: Mankind is finally moving forward, astounding progress is being made in all fields, our knowledge is expanding at a tremendous rate, and all obstacles have been overcome—except for one obstacle, namely, that the relationship of consciousness to existence seems to be unknowable, and we cannot have any idea whether our so-called “knowledge” refers to anything real. Unfortunately, this obstacle was more than an inconvenience; it was a land mine, and it could not be side-stepped.

Despite the growing confusion over foundational issues, scientific progress continued as if carried by its own inertia. The strength of Newton's legacy was enough to inspire another generation of brilliant thinkers. Perhaps the best of these thinkers was Antoine Lavoisier, the father of chemistry. In a letter to Benjamin Franklin, Lavoisier wrote that his aim was “to follow as much as possible the torch of observation and experiment.” He added: “This course, which has not yet been followed in chemistry, led me to plan my book according to an absolutely new scheme, and chemistry has been brought much closer to experimental physics.”24

There was no science of chemistry prior to the Enlightenment. There was speculation, and some practical knowledge, but nothing deserving of the name “science.” Recall that the Greeks had supposed that all terrestrial matter was composed of four basic elements: earth, water, air, and fire. Later, some alchemists tried to reduce everything to salt, mercury, and sulphur. Such ideas were unsupported by the observations and incapable of explaining them.

Chemistry became a science when a method was discovered that distinguished between elements and compounds. Lavoisier was the one to explicitly state and emphasize the crucial principle that mass is conserved in chemical reactions. It follows that if a material can be decomposed into two or more other materials with the same total weight, then the original material is a compound or mixture, not an element. Armed with this principle, chemistry was finally freed from arbitrary conjecture; the mass-balance gave an objective verdict.

The “elements” of the Greeks could not withstand Lavoisier's method of quantitative analysis. Water was shown to be a compound of two elements, hydrogen and oxygen. Air was discovered to be a mixture of nitrogen and oxygen. Combustion was understood as the result of combining certain materials with oxygen, not the release of elementary “fire.” Earth was shown to consist of many different materials. In total, chemists of the era identified more than twenty elements.

The concept of an “element” had historically been used to refer to the most fundamental constituents of matter. However, Lavoisier recognized that the data of chemists did not support such a claim. He wrote:

[I]f by the term elements we mean to express those simple and indivisible atoms of which matter is composed, it is extremely probable that we know nothing at all about them; but, if we apply the term elements . . . to express our idea of the last point which [chemical] analysis is capable of reaching, we must admit, as elements, all the substances into which we are capable, by any means, to reduce bodies by means of decomposition.25

Like Newton, Lavoisier went as far as the observations could take him—and no further.

Much of the confusion that had plagued chemistry was built into its termi≠nology. The same name was often used for different substances (e.g., all gases were referred to as various modifications of “air”). Conversely, different names were sometimes used to refer to the same material, depending on how it was synthesized (e.g., the element antimony had at least four names). In other cases, compounds were named after their discoverer or the place where they were found; such names gave no clue to the composition of the material. The situation was made worse by the legacy of the alchemists, who had viewed themselves as a secret cult and therefore used terminology that was intentionally obscure (e.g., “green lion” and “star regulus of Mars”).

Lavoisier took the lead in bringing order to this chaos. He recognized that an objective science requires an objective language. He first distinguished elements from compounds, and then gave names to the compounds that identified the elements of which they were composed. Materials were placed into wider groups according to their essential properties (e.g., acids, alkalies, and salts). He understood that concepts are not arbitrary conventions; they are integrations of similar particulars, and the groupings must be based firmly on the facts. A word that refers haphazardly to a collection of dissimilar things can give rise only to error and confusion. On the other hand, Lavoisier noted:

A well-composed language . . . will not allow the teachers of chemistry to deviate from the course of nature; either they must reject the nomenclature or they must irresistibly follow the course marked out by it. The logic of the sciences is thus essentially dependent on their language.26

He presented his new language—the chemical language we still use today—in a landmark book entitled Elements of Chemistry. The book, published in 1789, was the culmination of two decades of research.

Chemistry was not the only area to reach a great milestone in the 1780s. All the progress made throughout the Enlightenment in various fields seemed to reach a climax at about the same time.

In mathematical physics, Joseph-Louis Lagrange published his landmark book entitled Analytic Mechanics in 1788. Many physical problems are difficult, if not impossible, to solve by a direct application of Newton's laws of motion. Lagrange developed a new method to deal with such cases. Rather than attempting to compute the changing vector forces on a moving body, he showed that Newton's laws imply that a certain scalar function of the motion and position of the body is always minimized. Lagrange's analysis led to a reduction in the number of required equations, and many previously intractable problems became solvable.

Another French physicist, Pierre-Simon Laplace, used new mathematical methods to tackle the outstanding problem in celestial physics. Newton, in a concession to religion, had suggested that it might be necessary for God to occasionally correct the planetary orbits in order to ensure the stability of the solar system. In several important papers published in the 1780s, however, Laplace proved otherwise by showing that the effects of the planets on each other lead to only small periodic variations in their orbits. Many years later, Laplace presented Napoleon with a copy of his magnum opus, Celestial Mechanics. After looking through the book, Napoleon objected: “You have written this huge book on the system of the world without once mentioning the author of the universe.” “Sire,” Laplace replied, “I have no need of that hypothesis.”27 Nature was being recognized as a self-sufficient realm ruled by causality, and consequently, appeals to the supernatural were increasingly regarded as superfluous.

The achievements in theoretical astronomy were matched by advances in observational astronomy. Galileo's best instruments had magnified images by a factor of only thirty. By the 1780s, William Herschel was revolutionizing astronomy by building reflecting telescopes with magnifications of more than six thousand. His instruments enabled him to discover the seventh planet, Uranus, thus overthrowing the long-held view that Saturn was the outermost body in the solar system. He also discovered binary stars revolving around one another, confirming that Newton's law of gravitation was truly universal. Most impressively, Herschel observed stars that are more than two million light-years away. “The great end in view,” he wrote in 1785, “is to increase what I have called the power of extending into space.”28 Herschel was introducing mankind to the universe.

Research in electricity also reached its climax in the 1780s. It finally became a mathematical science when Charles Augustin de Coulomb designed a delicate apparatus that enabled him to measure precisely the force between two electrically charged spheres and the distance between them. He proved that the electric force exerted by charges obeys a law similar to the gravitational force exerted by masses: It is proportional to the product of the charges and inversely proportional to the square of the distance between them. Less than one hundred years after the Principia, physicists had discovered the mathematical law describing another fundamental force in nature.

In addition, science was proving to be of great practical value. Knowledge of gases and heat made possible James Watt's invention of the steam engine, which was first put to practical use in the 1780s. At the same time, the world witnessed the first human flight. It was in a hot-air balloon, and one spectator wrote with awed admiration:

What with the novelty, the dignity of the experiment, the unclouded sky, the attitude of the two men sailing into the blue, . . . and lastly the balloon itself, superb in the sunlight, whirling aloft like a planet or the chariot of some weather-god—it was a moment which can never be repeated, the most astounding achievement the science of physics has yet given the world.29

Science was opening new frontiers, and the potential benefits seemed limitless.

It was an age whose theme was the power of human reason—and that theme has a political corollary. If the source of the values that sustain human life is the individual reasoning mind, then individuals must be free to think and act in accordance with their conclusions. In an age dominated by respect for man as the “rational animal,” it seemed self-evident that the proper purpose of government was to protect each individual's right to life, liberty, property, and the pursuit of happiness. Hence the birth of the United States, the nation founded on these principles.

Exactly one century separates Newton's Principia from the writing of the U.S. Constitution. It was an amazing hundred years, when man's knowledge extended beyond the Milky Way and penetrated into the nature of chemical elements, when man discovered the force that causes lightning and the practical power of heat, when the New World broke its political chains and declared that each individual has the right to think for himself and pursue his own happiness.

The Principia had been prefaced with a call for man to “arise and learn the potency of the human mind.” Scientists, inventors, and statesmen responded to the call with great achievements, but they were not in the business of teaching the potency of the mind. They could only implicitly rely on the ideas of our first teacher, Aristotle—but that foundation had long since been attacked and discarded by philosophers. As a result, the great thinkers of the Enlightenment were writing checks on a philosophic account that no longer existed.

Just as the Enlightenment reached its climax, the debt was called in. It was called by a man who looked and acted much like the stereotypical accountant. He worked in a sparsely decorated office in which hung only one painting to inspire him and remind him of his mission: a portrait of Jean-Jacques Rousseau. In the 1780s, this man completed and delivered the paperwork for the foreclosure of the Enlightenment.

The accountant was Immanuel Kant. The paperwork was entitled the Critique of Pure Reason.

Despite their errors, most philosophers prior to Kant had attempted to validate the capacity of the mind to know reality. Some acknowledged their failure and skeptically gave up in despair. But the skeptics were always followed by others who renewed the effort to show that consciousness could somehow grasp existence. Kant was the first philosopher to renounce, on principle, all such efforts—and to present his renunciation not as a failure but as a profound triumph.

The Sophists of ancient Greece argued that because we perceive things in a way that depends on the nature of our senses, we do not actually perceive the external things, but only their effects on us. Their argument assumed that, in order to be aware of an object, the conscious subject must have no nature of its own. Our organs of perception, and the specific means by which they operate, allegedly prevent us from perceiving an object as it really is. The Sophists concluded that we perceive only subjective appearances, which are in part created by our sensory apparatus and which bear an unknowable relationship to the external objects.

Kant's attack on the efficacy of the mind was a radical extension of this old and familiar idea. If our faculty of perception is invalid because it is not a “blank slate,” what about our faculty of conception? All awareness results from processing the data of cognition, and that processing is done in specific ways that depend on the nature of the conscious entity. If the nature of our sensory apparatus is an insurmountable barrier to perceiving reality, then, by the same reasoning, the nature of our thinking apparatus must be regarded as an insurmountable barrier to knowing reality. Kant concluded that consciousness, by its very nature, is cut off from existence.

The influence of previous skeptics had been mitigated because they confessed their inability to validate human knowledge. But Kant was different: He rejected the criterion by which his philosophy would be condemned as a failure. The standard of truth, he claimed, is not correspondence between our ideas and reality. He banished reality from the realm of human reason and replaced it with a delusion called the “phenomenal world,” a world of appearances created by our minds. He referred to reality as the “noumenal world” of “things-in-themselves,” and he insisted that it is unknowable and cognitively irrelevant. “What the things-in-themselves may be I do not know, nor do I need to know, since a thing can never come before me except in appearance,” he wrote.30 According to Kant, we never perceive reality, and reason is powerless to know anything about it. Reason deals only with the subjective world of its own creation.

The philosophers of the past, Kant claimed, had it backward when they assumed that ideas should correspond to the facts of an independently existing world. “Hitherto it has been assumed that all our knowledge must conform to objects,” Kant wrote. “We [now] make trial whether we may not have more success in the tasks of metaphysics if we suppose that objects must conform to our knowledge.”31 The objects we perceive, says Kant, will always conform to our basic ideas—because they are merely appearances constructed by means of those very ideas, which are inherent in the structure of the human mind.

In a bizarre contortion of language, Kant referred to this fundamental shift of perspective as his “Copernican Revolution.” It was a brazen attempt to usurp that prestigious name and attach it to ideas of the opposite nature. The actual Copernican Revolution was led by men who confidently asserted that reason can grasp reality, and who rebelled against the skeptical tradition of merely “describing appearances.” Because these scientists acknowledged that the physical world is fully real and independent of us, they were able to discover that the universe is not centered on and designed around us. Kant, on the other hand, claimed that the world we observe is created by us. His view of the universe was incomparably worse than the geocentric astronomy—what he offered was an anthropocentric delusion.

Kant's motive was the same as that of the original opponents of the scientific revolution. He recognized that widespread respect for reason was leading to a more secular age, and his goal was to save the fading power of religion. “I have found it necessary to deny knowledge in order to make room for faith,” he announced in the Preface to the Critique of Pure Reason.32 He foresaw that an explicit rejection of reason, like that of Father Tertullian or Martin Luther, would not serve his purpose. “[A] religion which rashly declares war on reason will not be able to hold out in the long run against it,” he noted.33 Kant's strategy, therefore, was to limit reason to the phenomenal world and propose faith as the means of transcending the appearances.

Like Plato and Descartes, Kant based his epistemology on innate ideas. Unlike Plato and Descartes, he denied that such ideas correspond to reality; he insisted that they are merely subjective constructs, inapplicable to “things-in-themselves.” Hence his theory synthesized the worst errors of his predecessors: He combined the arbitrary method of the rationalists with the skeptical content of the empiricists.

Kant put forth an elaborate scheme to explain how our minds create the world of experience. First, he claimed, we have a faculty of “pure intuition” that supplies spatial and temporal relationships, which are the basic ways in which our minds order the appearances. Second, we have twelve innate concepts, which he called “categories,” that function as rules for synthesizing the perceived objects of the phenomenal world, that is, rules for creating the appearances.

Hume had left behind a shattered world. He treated sensations of individual qualities as “separate and distinct,” and therefore, he could not find a world of entities obeying the law of causality. Kant agreed that no such world can be found—outside us. We can never discover any clue about “things-in-themselves,” or how they must act. Nevertheless, he claimed to have solved Hume's problem. The concept of “causality,” according to Kant, is merely one of the “categories”; as such, it applies throughout the subjective world of our experience. Kant wrote: “I do not at all comprehend the possibility of a thing in general as a cause, inasmuch as the concept of cause denotes a condition not at all belonging to things, but to experience.”34 The objects we perceive will always act in strict accordance with the law of causality—because our minds impose this law on the appearances that we create. Likewise, the world we experience conforms to the rules of logic—again, because we construct the world that way. The law of non-contradiction, Kant insists, is applicable only to judgments about appearances, and “has not the least meaning in regard either to nature or to anything in itself.”35 Just as an author of fiction is not surprised by the events in his own novel, we should not be surprised by the order and intelligibility that we find in the world. According to Kant, we put it there.

However, Kant adds, if we apply our method of logic beyond the realm of appearances, then it “soon falls into such contradictions that it is constrained . . . to desist from any such pretensions.”36 Among the issues on which reason allegedly flounders, he identified two questions pertaining to the universe as a whole. He claimed to present “clear, evident and irresistible proofs” that the universe is finite, and that it is infinite—and also that it is eternal, and that it had a beginning in time. Such “antinomies of pure reason,” he explained, do not imply that we have made an error in our reasoning: They are “natural and unavoidable illusions” that result when we attempt to grasp a truth that transcends the appearances.

Of course, there is an alternative to blaming the faculty of reason for these contradictions: We might look for false premises and non sequiturs in Kant's arguments. The search would not be in vain. Among other problems, his arguments are based on a view of space and time that combined two fundamental errors of his predecessors. Newton correctly held that the concepts of “space” and “time” are objective, that is, they are based on facts of reality, which exist independent of us—but he incorrectly regarded space and time as existents that are independent of bodies. The empiricist philosopher George Berkeley, on the other hand, correctly argued that space and time pertain to relationships among bodies, and have no existence distinct from the bodies—but he claimed that the bodies themselves are merely images within consciousness and that none of our ideas refer to a physical world that exists independently.

Kant chose the worst from both sides of the controversy. With Berkeley, he held that space and time are subjective constructs that have no basis in a physical world that exists independent of us. With Newton, he treated space and time as independent of bodies. As Kant put it, “space and time come before all appearances and before all data of experience, and are indeed what make the latter at all possible.”37 His subjectivist view of space led Kant to conclude that an infinite universe is impossible because our minds are incapable of constructing it; his reification of space led him to conclude that a finite universe is impossible because “empty space” cannot be limited. Given his false premises, the contradiction is inevitable.

Rather than being embarrassed, however, Kant was proud of his antinomies; he offered them as further confirmation that the world we perceive is unreal. He wrote:

If the world is a whole existing in itself, it is either finite or infinite. But both alternatives are false. . . . It is therefore also false that the world (the sum of all appearances) is a whole existing in itself. From this it then follows that appearances in general are nothing outside our representations. . . .38

Thus Kant has the distinction of being the first philosopher to cite his own contradictions as proof that he is right.

Kant recognized that his philosophy required the science of physics to be reconceived. We grasp things by means of our subjective human concepts, he claimed—therefore we do not grasp the real things, only the inner objects created by our minds. This premise was the launching point for Kant's attack on every philosophic essential of the scientific revolution. He insisted that the science of physics does not study the nature of a physical world that exists independent of us; instead, he described it as “mathematics applied to appearances.”39

Kant's approach demanded the rejection of Newton's inductive method. Since we create the phenomenal world, we are the authors of its basic laws, not the discoverers. He wrote:

[W]e know nature as nothing but the totality of appearances, i.e., of representations in us; and hence we can only derive the law of their connection from the principles of their connection in us, that is, from the conditions of their necessary unification in a consciousness. . . .40

Those conditions are the innate ideas comprising the categories, from which the fundamental laws of physics must follow. He concluded that “the universal laws of nature . . . are not derived from experience, but experience is derived from them.”41 We allegedly start with the laws and create the experience that obeys them.

In 1786, Kant published a book entitled Metaphysical Foundations of Natural Science, in which he presented his deduction of physics from the categories. The book has four parts, corresponding to his four groups of three innate concepts, and he identified a principle of physics corresponding to each category. In method, it was a regression to the rationalism of Descartes. Kant's goal was to show that the laws of motion and the fundamental forces can be known a priori, that is, independent of experience.

Starting from the innate ideas of “substance,” “causality,” and “community,” Kant offered a priori proofs of Newton's three laws of motion and the principle of mass conservation. He insisted that “these laws, and hence all the propositions of [mechanics], answer exactly to the categories of substance, causality, and community, insofar as these concepts are applied to matter. . . .”42 In his discussion of the third law, which states that interacting bodies exert equal and opposite forces on one another, he wrote critically: “Newton did not at all trust himself to prove this law a priori, but appealed to experience to prove it.”43 According to Kant, the experiments that Newton painstakingly performed were unnecessary. Without any experiments, we can know that the appearances will conform to these laws, because the laws follow from the innate structure of the human mind.

Kant based his analysis of the fundamental forces of nature on the categories of “reality,” “negation,” and “limitation.” Our innate idea of “reality,” he claimed, requires that a body be extended and capable of repelling other bodies from its space. This, in turn, requires that matter be endowed with a basic force by which it repels all other matter. The repulsive force alone, however, cannot explain the existence of bodies, because under its influence matter would continually move further apart. Therefore, another universal force must exist that is attractive. Since the attractive force alone would cause material bodies to entirely collapse, Kant argued that this force corresponds to the category of “negation.” The two forces together make possible the existence of matter in definite “limited” shapes; hence the category of “limitation” underlies the appearance of physical bodies.

Kant went further and claimed that the mathematical form of these forces could be derived from purely geometric arguments that are independent of experience. He argued that the repulsive force must be inversely proportional to the volume into which matter is compressed, whereas the attractive force must spread out uniformly over a spherical surface. He concluded: “Therefore, the original attraction of matter would act in inverse proportion to the square of the distance at all distances and the original repulsion in inverse proportion to the cube of the infinitely small distances.”44 He identified the inverse square attractive force as the law of gravitation, which he derived without considering planetary orbits, falling apples, ocean tides, and so on. Predictably, Kant's deductive method arrived at the correct result in only those cases where Newton had already provided an inductive proof. In the case of the repulsive force, Kant was on his own—and the force he described is purely fictitious.

In his later years, Kant was even bolder about deducing all of physics from his table of innate ideas. Describing Kant's final view, one commentator writes: “By means of the categories, then, one can set up a priori the schema of all possible forces that can affect us and be perceived by us in experience.” Furthermore, Kant argued that “every empirical property that we can know anything about must conform to the categories; therefore this table provides us with a sufficient basis for setting up a priori a schema of the properties of matter.”45 He offered explanations of fluidity and solidity, drop formation and capillary action, crystallization and melting, cohesion, the luster of metals, and so on. After Newton had closed the door on armchair metaphysicians who fancied themselves scientists, Kant opened it again.

In regard to the idea of “matter,” Kant once again adopted the worst from his predecessors. His stated goal was “to explicate the concept of matter . . . only by its relation to the faculty of cognition in which the representation can first of all be given to me. . . .”46 Since “things-in-themselves” are unknowable, the concept of “matter” cannot depend on them. But what is matter, if not the physical stuff of which things are made? “The fundamental determination of a something that is to be an object of the external senses must be motion, for thereby only can the senses be affected,” Kant explained.47 “The concept of matter,” he concluded, “is reduced to nothing but moving for≠ces. . . .”48 According to Kant, matter consists only of a continuum of mathematical points that move and exert attractive or repulsive forces on other mathematical points.

This view of matter is consistent with Kant's metaphysics and epistemology. He began by claiming that because we process the data we receive from reality in specific ways, we are not aware of “things-in-themselves” but only of the creations of our subjective mental processing. His entire philosophy is based on a refusal to distinguish between how we perceive (by a process dependent on the nature of our consciousness) and what we perceive (reality). In essence, Kant discarded the “what” and substituted the “how.” He did the same in physics, by discarding physical entities and replacing them with interactions. In philosophy, he advocated awareness without the (external) object of awareness; in physics, he advocated action without the thing that acts.

Since forces are viewed as irreducible primaries in Kant's theory, they cannot be explained by any underlying mechanism. So, for example, he claimed that the gravitational force of a massive body acts instantaneously on distant bodies by no physical means. In his words:

When the earth directly influences the moon to approach it, it acts upon a thing many thousand miles removed from it, but nevertheless acts immediately; the space between it and the moon may be regarded as entirely empty, for although matter may lie between both bodies, this fact does not affect the attraction. Therefore, attraction acts directly in a place where it is not—something that seems to be contradictory.49

It seems contradictory because it is: It contradicts our common sense (Aristotelian) understanding of causality. There are no “free-floating” actions; things act—and they cannot act where they are not. Such was Newton's reasoning when he wrote:

[T]hat the gravity of one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which the action and force may be conveyed from one to the other, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it.50

However, Kant did fall into this absurdity, and he did so because “action-at-a-distance” is perfectly compatible with his view of causality. If causality is nothing more than an innate rule of the mind that regulates the actions of appearances, then there is no need to explain those actions by reference to unobserved entities.

Kant's view had another clear implication, which he made explicit: He rejected the atomic theory of matter. Many scientists were favorably inclined toward atomism because it had the potential to explain the enormous complexity of the physical world by means of a small number of basic entities. But Kant rejected the goal of such scientists. He wrote:

Natural science will never reveal to us the internal constitution of things, which, though not appearance, yet can serve as the ultimate ground for explaining appearances. Nor does that science need this for its physical explanations. . . . For these explanations must only be grounded upon that which as an object of sense can belong to experience. . . .51

Since the aim of physics is not to understand the nature of the real world, but only to describe the phenomenal world, there is no place for conjectures about atoms. Thus Kant tried to preempt an entire field of research that was on the threshold of success. As a result, physicists and chemists spent the 19th century caught in the cross-fire between scientific evidence in favor of the atomic theory and Kantian arguments against it.

Kant made room for every form of irrationalism.

For those who enjoyed wild speculation detached from reality, Kant gave them the philosophic sanction they needed. Newton had sent such peddlers of the arbitrary into hiding—but now they could reemerge. After all, Kant had allegedly proved that reasoning by its very nature is detached from reality. Anyone is free to start from the ideas in his head and deduce away, so long as he refrains from claiming knowledge of “things-in-themselves.” Descartes' rationalistic game was revived, with one change: This time it was openly acknowledged as a game.

For the skeptics who never tired of saying that wisdom consists of knowing that one does not know, again, Kant gave them what they needed. They too had been embarrassed by Newton's triumph, but now they could once again hold their heads low. Enlightenment intellectuals thought that Newton had discovered fundamental truths about the universe, but Kant showed that it was a delusion. The giant of the Age of Reason had merely devised a clever description of appearances; he knew no more about reality than an illiterate child.

Finally, those who wanted the freedom to believe without the effort of thought, that is, who simply wanted to skip cognition and indulge their emotions, could turn to Kant for a philosophic justification. Recall the purpose of Kant's denial of knowledge: “to make room for faith.” After silencing reason, he declared man free to follow his emotions in accepting the existence of God and the afterlife. He argued that thinking can never give us access to what is real, but feelings can—some feelings are, in effect, messages from the noumenal world. Such messages, for example, tell us our moral duties. On this issue, Kant agreed with Rousseau: Ultimately, feelings are the proper guide to action.

The leader of the anti-Copernican revolution had done his work. The nature of the work did not go unnoticed by everyone. One German philosopher of the Enlightenment, Moses Mendelssohn, bestowed upon Kant an appropriate title: The All-Destroyer.52

With its philosophic foundation already so weakened, Continental Europe could not withstand this assault.

In France, the ideas of Rousseau had been spreading. Paris was once the intellectual center of the Enlightenment; however, by the end of the 1780s it rushed to embrace the new era. One perceptive historian writes:

What [the French Revolution] inaugurated, it was claimed, was the establishment of human life on a basis of pure feeling. . . . In a sense it might be said that the explosion of irrational or subconscious impulses that characterized so many aspects of the revolution was the signal for the Romantic rebellion against Reason.53

The world soon witnessed the grand-scale consequences of such a rebellion. In his political philosophy, Rousseau had combined collectivism with emotionalism. In other words, he had articulated the underlying ideology of a lynch mob. The French Revolution faithfully translated the theory into practice.

Antoine Lavoisier did not escape the mob's wrath.

Lavoisier's degree was in law, not in chemistry, and he never made a living from his scientific work. Furthermore, his career choices were severely restricted under the monarchy. “Almost every opportunity to make money was directly or indirectly in the hands of the government,” notes one historian.54 Nevertheless, the choice he made is open to criticism: For two decades, his main source of income came from administering and collecting taxes for the corrupt regime.

After the revolution, the Committee of General Security ordered the arrest of Lavoisier and many other former tax administrators. There was indecision over what specific charges to bring against them. It would have been an embarrassing hypocrisy to accuse them of wielding absolute power to confiscate the property of citizens, since the revolutionaries were doing just that on a massive scale. Instead, the tax collectors were charged with taking illegal profits in particular cases; however, it turned out that most of these accusations were fabricated by the prosecutors. The defendants were also accused of selling adulterated tobacco at excessive prices; in this case, Lavoisier himself carefully documented the facts and refuted the charge. But facts, logic, and individuals were regarded by the revolutionaries as irrelevant. The men were judged as a group, on the basis of “pure feeling”; since the mob was angry and the new leaders wanted to seize the personal assets of these men, there was no chance of acquittal.

At dawn on May 8, 1794, Lavoisier was searched and physically prepared for the guillotine prior to being taken before the Revolutionary Tribunal. During the group trial, the capital charge of “counter-revolutionary conspiracy” was suddenly introduced, without even the pretense of presenting evidence for it. Although the entire proceeding was a mockery of justice, one document was submitted in Lavoisier's defense. The document was signed by a committee of scientists led by Lagrange, and it testified to the great scientific achievements of Lavoisier and the high esteem in which he was held throughout Europe. The head of the Revolutionary Tribunal dismissed it with contempt, uttering the infamous words: “The Republic has no need for learned men.”55 With that, Lavoisier's fate was decided.

At the beginning of the 18th century, the father of physics had been knighted by the Queen in a culture that revered reason. At the end of the century, the father of chemistry was beheaded in a revolution led by men who despised reason. As Lavoisier and the others were led to the scaffold, one of the victims surveyed the crowd and remarked: “What vexes me is to have such unpleasant heirs.”56 Perhaps he was speaking for the Enlightenment itself.

But, if so, he misidentified his heirs. The new era belonged to a group of men who were incomparably more “unpleasant” than the bloodthirsty crowd in front of the scaffold. It belonged to the new generation of intellectuals in Germany.

Very quickly throughout Germany, Kant gave irrationalism an academic voice and respectability. Radical young Kantians infiltrated the German universities and began their crusade against reason. The hotbed of this activity was the University of Jena located near Weimar. What Berkeley was in the 1960s, Jena was in the 1790s.

It began with a philosophy professor named Karl Reinhold, who started to teach Kant's ideas at Jena in 1787. Reinhold was so enthralled with Kant that he made a prediction: Within one hundred years, he said, Immanuel Kant would have the reputation of Jesus Christ. Reinhold did his part to fulfill this prophecy; he was a very popular teacher, and he attracted to Jena many students who were interested in Kant. Among them was Johann Gottlieb Fichte, who was awarded the chair of philosophy when Reinhold left in 1794.

Fichte achieved fame in Germany when his first major publication appeared unsigned and everyone thought it was a work by Kant. Even though Fichte was a disciple, however, his ideas differed from Kant's in ways that marked out a new direction for philosophy.

First, he emphatically rejected the idea of “things-in-themselves.” Kant had said that there is a real world out there, and it supplies us with the raw data that our minds use to create the subjective world of appearance. By saying this, however, Kant was claiming knowledge about that which he himself insisted was unknowable. It was an obvious contradiction, and Fichte rejected it immediately. There are no “things-in-themselves,” he insisted; that is, there is no existence apart from consciousness—there is only consciousness.

Second, Fichte latched on to one particular idea of Kant's and gave it a new emphasis. Kant had said, in effect, that our passkey to reality was our nature as moral beings with free will. Your capacity to feel morally obligated, and to choose to act in accordance with your moral duties, derives from the real you (not just the apparent you). Fichte took this idea one step further: He insisted that the free “I,” the self, is not only real—it is reality. The physical world exists only because the self creates its own boundaries in order to become self-aware. “The source of all reality is the self,” he wrote. “The non-self, as such, has no reality of its own. . . .”57 Furthermore, Fichte declared that each individual “finite” self is an aspect of one collective, “infinite” Ego. The physical world is a by-product of that all-powerful Ego. Grand-scale events in the world, such as the French Revolution, represent the infinite Ego evolving and asserting itself.

Fichte's philosophy is that of a whim-driven consciousness triumphantly declaring its independence from reality (or, more precisely, declaring that reality consists entirely of its whims). This declaration became the banner for a new school of philosophy called Romanticism (not to be confused with the school of art that goes by the same name).

The essence of Romantic philosophy can be seen in the writings of two famous poets of the so-called “Jena circle.” The first is Friedrich von Hardenberg, who wrote under the pseudonym Novalis. Novalis expressed the typical avant-garde mysticism and contempt for the physical world when he wrote: “We dream of journeys through the universe, but is not the universe within us? We do not realize the profundities of our spirits. Inward is the direction of the mystic path. . . . The external world is the world of shadows.”58

Novalis despised the Enlightenment and idealized the Middle Ages. He held that mechanistic explanations such as those of Newton merely veil the truth, a truth that can be grasped only through the artist's intuition. However, the “truth” that Novalis reached was not very inspiring. After rejecting reality and reason, he took the next logical step and rejected life. He argued that the finite must be destroyed for the sake of merging with the infinite. His most famous work ends with a poem entitled “Yearning for Death,” in which he wrote:

There is no more for us to seek,

The heart is sated, the world is bleak.59

Thus Novalis has the distinction of being the first post-Kantian nihilist. Interestingly, he was also the first to explicitly reject the Copernican revolution. He wrote:

With good cause, the wise Head of the Church . . . prevented bold thinkers from asserting publicly that the earth was an insignificant planet, for he realized that humans . . . would lose respect for their heavenly home and for their race, [and they] would prefer limited knowledge to infinite faith, and would become accustomed to scorning everything great and worthy of wonder.60

He was serious about going back to the Middle Ages.

The other famous poet in the Jena circle was Friedrich Schlegel, whose views appear very contemporary (he would be at home in today's universities). Schlegel celebrated the fact that the intellectual world had finally been set free from cold logic and things-in-themselves, thereby eliminating all constraints on the creativity of artists. The task of the artist, he claimed, is to articulate the ambiguities and contradictions of a chaotic world. Art reaches its highest level, therefore, in a calculated irrationalism that he referred to as “transcendental buffoonery.” To achieve this exalted state, he thought that poetry needed to be based on a new mythology. And he identified the basic ingredients of this new mythology: oriental mysticism and physics. (Here we see the root of the 20th century nonsense expressed in books such as The Tao of Physics.)

Why did Schlegel attach so much importance to physics? For the same reason so many intellectuals today like the subject. He wrote: “I cannot close without urging once again the study of physics. From its dynamic paradoxes the most sacred revelations now emanate from all sides.”61 Schlegel was not recommending Newton; he was recommending the new “romantic physics,” with its deliberate paradoxes.

One might ask: If there isn't a real physical world, how can there be a science of physics? The Romantics, however, viewed non-existence as a blessing rather than a problem. In their view, the independent existence of a physical world would merely complicate the task of the physicist. In that case, a lot of painstaking observation, reasoning, experimentation, and mathematical analysis would be required to discover the nature of these independent entities. On the other hand, if there is only consciousness, and the physical world is merely a mental creation within consciousness, then there is no need for all that effort. The physicist simply has to introspect, identify the mental activities that give rise to this pseudo-physical world, and then deduce the nature of that world accordingly. This saves time and money on mathematical training and laboratory equipment.

What sort of physical science did the Romantics find in their heads? One member of the Jena circle, Friedrich Schelling, made laying out the basic principles his primary goal. He expressed his starting point as follows: “In the mental being there is an original conflict of opposed activities, and from this conflict there first proceeds a real world created out of nothing.”62

He then asked: What does this view imply about the concept “matter”? Obviously, he reasoned, matter is a concept pertaining to consciousness, since there is nothing else. Consciousness, however, is an activity, not a stuff. Therefore, matter must be viewed as an activity—it is a concept of action, not substance. The basic concept of action in physics is “force.” So Schelling, in agreement with Kant, concluded that material entities are entirely reducible to forces. He wrote:

[Physical] objects themselves we can regard only as products of forces, and with this there vanishes the chimera of things-in-themselves, which are supposed to be the causes of our ideas. What, after all, can work upon the mind, other than itself, or that which is akin to its nature?63

Schelling applied this idea consistently. He offered theories in which heat, light, electricity, and chemical elements were reduced to various attractive and repulsive forces. According to romantic physics, all of nature can be understood as a by-product of dueling forces. This absurdity exerted a dominant influence over the next generation of scientists in Germany.

Many essential ideas of Romanticism were soon developed into a full philosophic system by Georg Wilhelm Friedrich Hegel. Hegel was also connected to the “Jena circle”; he was a friend of Fichte and Schelling during the 1790s, and he taught at the University of Jena from 1801 to 1807. However, he does not qualify as a typical romantic. Compared with the other members of the group, he was less of an emotionalist and more of a rationalist. Precisely because of this difference, however, it was Hegel who transformed the movement from a mere irrational outburst into a system of thought that would be very influential for more than a century.

In essence, Hegel provided a complete description of Fichte's infinite Ego (which he renamed the “Absolute Spirit”). According to Hegel, this collective consciousness is quite complicated. It has many different stages of intellectual development, and—although Hegel would not put it this way—it is literally a mess of contradictions. The Absolute is made up of triads of ideas: In each triad, there is a pair of ideas that oppose and contradict one another, and then a third idea that combines the first two, thereby resolving the contradiction while at the same time retaining it. (If this description seems unintelligible, then you have understood it.)

In constructing all of reality, Hegel dealt with physics as a major part of his scheme. He began his career by attacking Newton in his doctoral dissertation. Why was he offended by the father of modern physics?

Newton discovered universal laws that were true anywhere, anytime—and this was unacceptable to Hegel. In Hegel's theory of the Absolute, truth evolves in stages. What is true at one level is superceded by another higher truth at the next level. But Newton proceeded as if reality is one integrated whole with no contradictions—so Hegel claimed that Newton's laws “distort and pervert the truth.”

As an example of Hegel's approach to physics, let us look at his analysis of planetary orbits. Hegel claimed that inertia alone would cause the planets to fly out of their orbits, away from the sun. In contradiction to the law of inertia, the law of fall would cause them to crash into the sun. These two opposite motions are combined and overcome in the generation of the actual orbit. Hegel denies that the orbit is caused by an attractive force of gravitation; instead, in his view, the orbit is free motion that results when the forces of inertia and fall are combined and transcended. He writes: “The movement of the heavenly bodies is not a pulling hither and thither, but free motion; as the ancients said, they go their ways like the blessed gods.”64

If elliptical planetary orbits are free motion, why don't things such as hockey pucks slide freely around in ellipses? Hegel answers that the Absolute has different levels—and what is true at one level is not true at another. He rejected the integration achieved by Newton, and he treated the heavens and Earth as fundamentally different spheres. He wrote: “People think that things should happen in heaven as they do at home, but these finite relationships cannot show forth the infinitude of a sphere of nature.”65

Based on such views, Hegel argued that a horrible injustice had been done in the history of science. The great scientist of the 17th century was not Newton, but Kepler. It was Kepler who discovered the fundamental laws of absolutely free motion, and then Newton came along and confused everyone with his false physical ideas. Furthermore, Hegel claimed, Kepler's theory of the solar system was more fully developed than Newton's theory. Based on Pythagorean mysticism, Kepler had offered explanations for the number of planets and the distances between them—issues on which Newton was silent. Hegel conceded that Kepler was wrong about these details, but he defended the method of starting from mystical insights and deducing the nature of the world.

While Hegel's animosity toward Newton is obvious, he nevertheless expressed it in terms that were mild and polite compared with the vitriolic outbursts of Johann Wolfgang von Goethe.

Goethe is best known for his poetry, particularly for the verse drama Faust; however, he thought that his greatest achievement was in physics. In a lengthy treatise published in 1810, he boasted that he had refuted Newton's Optics. He compared Newton's theory to an abandoned building, and he set himself the goal of “demolishing it wall after wall, arch after arch, the rubbish being cleared away.”66

What Goethe despised most about Newton was his experimental method, which Goethe insisted was a violation of nature. Newton, he claimed, disturbed nature by his experiments; in revenge, nature offered him only a distorted image of herself. In Faust, Goethe wrote:

Mysterious in the light of day,

Nature will not be denied her veil.

And what she does not make manifest to your spirit,

Cannot be forced from her with levers and screws.67

This is the essence of Kantianism, distilled into poetic form. Goethe insisted that our activity in pursuing knowledge is a barrier to grasping reality. Consequently, he favored a passive approach. We should not do the type of controlled experiments that Newton did; instead, we should just carefully observe phenomena under natural conditions. He wrote: “It is, in fact, the greatest evil of the more modern physics that . . . Nature is recognized only in that which artificial instruments demonstrate.”68 One commentator summarizes Goethe's view as follows: “Newton's errors were the price he paid for his methods, mathematicizing nature into abstraction, torturing her with instruments, with telescopes, prisms and mirrors, until she expires like a butterfly on a pin.”69

When one physicist gave Goethe an optical apparatus that would conclusively prove Newton's theory, Goethe refused to use it—just as some Church officials had refused to look through Galileo's telescope. Instead, Goethe made sloppy, qualitative observations with his prism; consequently, he did not see a clear spectrum, but only colored fringes at the edge between white light and darkness. This observation, however, fit perfectly with Goethe's preconceived ideas based on Romantic philosophy. The Romantics said that all of reality is a synthesis of conflicting opposites. Since colors appeared only at the edge, Goethe concluded that they must be the product of the contradicting opposites of light and darkness. This became the fundamental idea in Goethe's theory of colors: He regarded white light as elementary and pure, and colors as a synthesis of light and dark.

One might think that Goethe's approach is so irrational that no reputable scientist could take it seriously. But Goethe's scientific ideas were influential in early 19th century Germany. In addition, although there was a long period thereafter in which they were ridiculed and rejected by scientists, his ideas have enjoyed a popular revival in the last seventy years.

One avid fan of Goethe was Werner Heisenberg, a founder of quantum theory. Accepting Goethe's basic Kantian premise, Heisenberg wrote: “[O]ur experiments are not nature itself, but a nature changed and transformed by our activity in the course of research.”70 Furthermore, he agreed with Goethe that the more we abstract, the more we withdraw from the world of experience and from life. So, according to Heisenberg, neither experiment nor analysis gives us access to reality. As to his evaluation of the work of Newton, he had this to say:

[T]here is good reason for one of the most eminent of men using all his power to combat the achievements of Newton's optics. One can only charge Goethe with a lack of consistency. . . . [H]e should have said that the whole of Newton's physics, optics, mechanics and gravitational theory was the work of the devil.71

Heisenberg made this statement in 1932, the year he was awarded the Nobel Prize in physics.

More recently, in 2002, the popular magazine Physics Today published an article defending Goethe's optics against Newton's optics. The authors argue that Goethe attempted to deal with the full complexity of our visual experience, whereas Newton's controlled experiments merely studied artificially simplified situations. After making their preference for Goethe clear, they conclude as follows: “Which [method] is more productive in a given context depends on many factors, including a field's state of development, the sort of knowledge . . . sought by the physicist, and the complexity of the system being studied.”72 In their evaluation of the two methods, the authors omit one seemingly relevant point: namely, that Newton's method arrived at the truth and Goethe's method generated nonsense. Evasion on this scale is astonishing, particularly when it is published in a reputable journal.

Aside from Goethe's optics, our culture shares other interests with the Romantic era. Both then and now, there was a resurgence of interest in faith healing, telekinesis, and other forms of magic. In 19th century Germany, one leader of this magical revival was Arthur Schopenhauer, a major Romantic philosopher and a vocal proponent of Goethe's optics. Schopenhauer pointed out that the only culture in history to deny the possibility of magic was Enlightenment Europe. He insisted that the Enlightenment was misguided, and it was time to go back to the old beliefs. And Schopenhauer was philosophically astute enough to identify the source of renewed interest in magic, which he explained in the following passage:

[The] change was profoundly prepared for by the transformation in philosophy that was brought about by Kant. In this and in other respects, that transformation establishes a fundamental difference between the education of Germany and that of the rest of Europe. To smile in advance at all magic, we have to find the world completely intelligible. But this we can do only when we look into it with an extremely shallow gaze that admits of no inkling that we are plunged into a sea of riddles and incomprehensibilities and have no thorough and direct knowledge and understanding either of things or ourselves. . . . If our natural way of knowing were such that we were directly furnished with things-in-themselves, and consequently with the absolutely true relations and connections of things, then indeed we would be justified in rejecting all magical influence. But if, as Kant teaches, all that we know are mere appearances whose forms and laws do not extend to things-in-themselves, then such a rejection is evidently premature.73

We have seen an extraordinary transition. We began with the outstanding achievements of Enlightenment science and ended with the revival of magic; in just a few decades, we saw an era led by men such as Franklin and Lavoisier degenerate into an era led by men such as Hegel and Schopenhauer. This collapse is the tragedy of modern history.

Man had stepped up to the gates of an earthly paradise—only to find that he did not have the price of admission. The price is a rational philosophy. Two centuries later, Ayn Rand explained that men cannot live without answers to the basic questions: Where am I (metaphysics)? How do I know it (epistemology)? What should I do (ethics)? When they accept wrong answers, they pursue a course of self-destruction.

Fortunately, a rational philosophy is now available: It is the legacy of Ayn Rand, who is the philosophic antipode of Immanuel Kant. If the men of the Enlightenment had known her answers to those basic questions, there never would have been a collapse and we would be living in a much different world today. If we ever again achieve a culture of reason, it will have the potential to endure and flourish because we now have the foundation to support it.

Recall the man who went to his death alongside Lavoisier, while lamenting the fact that he had such unpleasant heirs. From the widest perspective, I think he was wrong. His heirs were not the mob in the plaza that day, or even the intellectual followers of Rousseau and Kant. The true heirs of the Enlightenment—that is, those who deserve such an inheritance—are the thinkers who seek out a rational philosophy and make the effort to apply it within their fields and throughout their lives. Insofar as such heirs exist, there is hope that future historians will see our age as a major transition point—this time in the right direction.


Acknowledgment: The author wishes to acknowledge the generous support of the Ayn Rand Institute.

1 Ayn Rand, The Fountainhead (New York: Signet, 1993), pp. 542–543.

2 Alan Cromer, Uncommon Sense: The Heretical Nature of Science (New York: Oxford University Press, 1993), p. 5.

3 Leonard Peikoff, The Ominous Parallels (New York: Stein and Day, 1982), p. 102.

4 Richard Panek, Seeing and Believing (New York: Viking Penguin, 1998), pp. 102–103.

5 I. Bernard Cohen, Franklin and Newton (Baltimore: J. H. Furst Company, 1956), quoted from Preface, vii.

6 Petr Beckmann, A History of Pi (New York: St. Martin's Press, 1971), p. 148.

7 Thomas L. Hankins, Science and the Enlightenment (Cambridge University Press, 1985), p. 21.

8 St. Augustine, The Essential Augustine, edited by Vernon Bourke (Indianapolis: Hackett Publishing Company, 1974), p. 114.

9 Duane Roller, The Development of the Concept of Electric Charge (Cambridge: Harvard University Press, 1954), p. 52.

10 Ibid., p. 51.

11 Jean-Jacques Rousseau, The Essential Rousseau (New York: Penguin Books, 1983), p. 210.

12 Ibid., p. 214.

13 Ibid., p. 215.

14 Ibid., pp. 258–259.

15 Bertrand Russell, A History of Western Philosophy (New York: Simon & Schuster, 1945), p. 688.

16 Thomas L. Hankins, Jean d'Alembert: Science and the Enlightenment (London: Oxford University Press, 1970), p. 70.

17 Ibid., p. 88.

18 Ibid., p. 3.

19 Ibid., p. 165.

20 Ibid., p. 153.

21 Ibid., p. 185.

22 Ibid., p. 197.

23 Ibid., p. 129.

24 Thomas L. Hankins, Science and the Enlightenment (New York: Cambridge University Press, 1985), p. 112.

25 The Beginnings of Modern Science, edited by Holmes Boynton (New York: Walter J. Black, Inc., 1948), p. 615.

26 Thomas L. Hankins, Science and the Enlightenment (New York: Cambridge University Press, 1985), p. 109.

27 E. T. Bell, Men of Mathematics (New York: Simon & Schuster, 1986) p. 181.

28 Richard Panek, Seeing and Believing (New York: Viking Penguin, 1998), p. 115.

29 Alan Cromer, Uncommon Sense: The Heretical Nature of Science (New York: Oxford University Press, 1993), p. 4.

30 Immanuel Kant, Critique of Pure Reason, translated by Norman Kemp Smith (New York: St Martin's Press, 1965), p. 286.

31 Ibid., p. 22.

32 Ibid., p. 29.

33 Immanuel Kant, Religion within the Limits of Reason Alone, translated by Theodore M. Greene and Hoyt H. Hudson (New York: Harper & Row, 1960), p. 9.

34 Immanuel Kant, Kant's Philosophy of Material Nature, translated by James W. Ellington (Indianapolis: Hackett Publishing Company, 1985), p. 55.

35 Immanuel Kant, Critique of Pure Reason, translated by Norman Kemp Smith (New York: St Martin's Press, 1965), p. 284.

36 Ibid., p. 385.

37 Ibid., p. 280.

38 Ibid., p. 449.

39 Immanuel Kant, Kant's Philosophy of Material Nature, translated by James W. Ellington (Indianapolis: Hackett Publishing Company, 1985), p. 39

40 Ibid., p. 61.

41 Ibid., pp. 55–56.

42 Ibid., pp. 114–115.

43 Ibid., p. 112.

44 Ibid., p. 73.

45 Ibid., p. 217.

46 Ibid., p. 19.

47 Ibid., pp. 13–14.

48 Ibid., p. 78.

49 Ibid., pp. 62–63.

50 Isaac Newton, Newton's Philosophy of Nature: Selections from His Writings, edited by H. S. Thayer (New York: Hafner Publishing Company, 1953), p. 54.

51 Immanuel Kant, Kant's Philosophy of Material Nature, translated by James W. Ellington (Indianapolis: Hackett Publishing Company, 1985), p. 93.

52 The Encyclopedia of Philosophy, edited by Paul Edwards (New York: Macmillan Publishing Company, 1967), vol. 3, p. 300.

53 H. G. Schenk, The Mind of the European Romantics (New York: Anchor Books, 1969), p. 4.

54 Jonathon Norton Leonard, Crusaders of Chemistry (New York: Doubleday, Doran & Company, 1930), p. 263.

55 Ibid., p. 298.

56 Douglas McKie, Antoine Lavoisier: Scientist, Economist and Social Reformer (New York: Henry Schuman, 1952), p. 406.

57 Johann Gottlieb Fichte, Science of Knowledge, edited and translated by Peter Heath and John Lachs (Meredith Corporation, 1970), pp. 129–130.

58 Novalis, Hymns to the Night and Other Selected Writings, translated by Charles E. Passage (New York: Bobbs-Merrill Company, 1960), p. 66.

59 Ibid., p. 15.

60 Ibid., p. 46.

61 Romanticism and the Sciences, edited by Andrew Cunningham and Nicholas Jardine (Cambridge University Press, 1990), p. 200.

62 F. W. J. Schelling, Ideas for a Philosophy of Nature, translated by Errol Harris and Peter Heath (New York: Cambridge University Press, 1988), p. 177.

63 Ibid., p. 175.

64 Hegel's Philosophy of Nature, edited and translated by M. J. Petry (London: Unwin Brothers Limited, 1970), p. 262.

65 Ibid., p. 246.

66 Goethe's Color Theory, edited by Rupprecht Matthaei (New York: Van Nostrand Reinhold Company, 1971), p. 212.

67 Selected Writings of Hermann von Helmholtz, translated and edited by Russell Kahl (Connecticut: Wesleyan University Press, 1971), p. 65.

68 Werner Heisenberg, Across the Frontiers, edited by Ruth Anshen and translated by Peter Heath (New York: Harper & Row Publishers, 1974), pp. 126–127.

69 Charles Coulston Gillispie, The Edge of Objectivity (New Jersey: Princeton University Press, 1960), p. 195.

70 Werner Heisenberg, Philosophical Problems of Quantum Physics, translated by F. C. Hayes (Connecticut: Ox Bow Press, 1979), p. 71.

71 Ibid., p. 37.

72 Neil Ribe and Friedrich Steinle, “Exploratory Experimentation: Goethe, Land, and Color Theory,” in Physics Today, July 2002, p. 48.

73 Arthur Schopenhauer, On the Will in Nature, translated by E. F. J. Payne and edited by David E. Cartwright (Oxford: Berg Publishers, 1992), pp. 110–111.

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