Enlightenment was a period in history when philosophers emphasized the use of reason as the best method of learning truth. The period of the Enlightenment began in the 1600’s and lasted until the late 1700’s. The Enlightenment is also called the Age of Reason or the Age of Rationalism. Its leaders included several French philosophers—the Marquis de Condorcet, Rene Descartes, Denis Diderot, Jean-Jacques Rousseau, and Voltaire—and the English philosopher John Locke.
The leaders of the Enlightenment relied heavily on the scientific method, with its emphasis on experimentation and careful observation. The period produced many important advances in such fields as anatomy, astronomy, chemistry, mathematics, and physics. Philosophers of the Enlightenment organized knowledge in encyclopedias and founded scientific institutes.
The philosophers believed that the scientific method could be applied to the study of human nature. They explored issues in education, law, philosophy, and politics and attacked tyranny, social injustice, superstition, and ignorance. Many of their ideas were taken up as the ideals of the American and French revolutions during the late 1700’s.
The worship of reason.
The philosophers of the Enlightenment believed that human beings have a unique advantage over all other creatures because they can reason. These philosophers credited reason for all the achievements made in science and philosophy. They contrasted reason with ignorance, superstition, and uncritical acceptance of authority—all of which they felt had dominated the Middle Ages. They blamed people in authority, particularly the leaders of the Roman Catholic Church, for keeping others in ignorance to maintain their own personal power.
The philosophers of the Enlightenment were greatly influenced by discoveries in the physical sciences, such as the law of falling bodies discovered by Galileo in Italy and the laws of gravitation and motion formulated by Sir Isaac Newton in England. The philosophers saw that great discoveries like these were made through the use of mathematics. They believed that mathematics yielded absolutely certain conclusions because the mathematical process started with simple axioms (self-evident truths) and moved from one self-evident step to another. Using this method, scholars discovered laws of nature that otherwise would have remained unknown. As a result, the philosophers of the Enlightenment believed mathematics was the model that all other sciences should follow.
Reason was thought to be the power that enables people to “see” mathematical truths just as clearly as they can see a hand before their eyes by visual perception. However, visual perception yields only particular, or contingent, truths. For example, most hands have five fingers. But it is not necessary that every hand have five fingers, because one or more fingers could be lost in an accident. Only reason yields necessary, or universal, truths. An example of such a truth is that 5 plus 5 will always equal 10.
The philosophers of the Enlightenment believed that each person has a rational will, which makes it possible to make and carry out plans. Animals, they declared, are slaves of their emotions. When an animal is afraid of something, it tries to escape. When an animal is angry, it fights. However, people can figure out the best course of action when they are afraid, angry, or in trouble. In addition, people can make themselves do the right thing, instead of doing only what may seem easier or more appealing.
The philosophers realized that people do not always plan ahead but often act on impulse, which they attributed to inadequate education. All people, the philosophers believed, are born with the capacity to reason. Descartes wrote that “the power of forming a good judgment and of distinguishing the true from the false, which is properly speaking what is called good sense or reason, is by nature equal in all men.” Descartes therefore thought that to become rational, a person need only acquire an education that teaches a good method of reasoning.
Locke wrote that reason is “the candle of the Lord set up by Himself in men’s minds” and “must be our last judge and guide in everything.” Locke believed reason teaches that people must unite and form a state to protect their “lives and liberty and property.” He noted that although people must give up some rights when they form a state, they gain more in protection than they lose.
Locke believed that anyone can reason, providing the capacity is allowed to develop. He therefore emphasized the importance of education and insisted on the right of free speech and on toleration for conflicting ideas.
The orderliness of nature.
Philosophers of the Enlightenment believed that nature is vast and complex but well ordered. The English poet Alexander Pope described nature as “a mighty maze, but not without plan.” The philosophers of the period felt that everything in the universe behaves according to a few simple laws, which can be explained mathematically. Their favorite example of such a law was Newton’s law of gravity.
Human nature, the philosophers believed, is as well ordered as the physical universe. In The Spirit of the Laws (1748), the French philosopher Montesquieu wrote: “The material world has its laws, the intelligences superior to man have their laws, the beasts their laws, and man his laws.” Montesquieu thought that a science of human nature was possible, and he became one of the first philosophers to try to formulate the basic uniformities of all human behavior.
Montesquieu believed that climate has an important influence on temperament and thus on conduct. According to Montesquieu, different kinds of government are appropriate for peoples who are living in different parts of the world. The best government for each nation could be planned, he felt, by considering the country’s climate. Montesquieu thought, for example, that free governments are possible in northern latitudes. “People are more vigorous in cold climates,” he wrote, and they have a “greater share of frankness and sincerity.” But, Montesquieu said, the only workable form of government in a hot climate is despotism (rule by a dictator). Although his conclusions were discarded as mere speculation, they are typical of the Enlightenment’s faith in reason.
Literature in the Enlightenment questioned accepted thinking. Writers portrayed human life as changeable and human understanding as partial. Much of the literature was written with self-consciousness and irony. It called attention to conventions and provoked skeptical awareness. The period reached its peak with works such as Pierre de Laclos’ Dangerous Liaisons (1782) and the Marquis de Sade’s Philosophy in the Bedroom (1795). In these novels, rational thought goes as far as possible toward separating the thinking individual from conventional influences and limitations.
Deism.
The philosophers of the Enlightenment were convinced that the universe can be understood by the human mind. This is not an accident, the philosophers emphasized, because God could have created a universe too complex to be grasped by human beings. Instead, God created a universe ideally adjusted to the reasoning powers of people.
Most of the philosophers believed that after God had created the universe, He left it strictly alone. This theory, called deism, rules out the possibility of miracles or other special acts by God. According to deism, God regulated nature so that it proceeds mechanically. Future events are therefore fully predictable on the basis of earlier events. The philosophers liked to think of the universe as a clock that keeps perfect time because it was designed by a superior clockmaker. See Deism .
Influence of the Enlightenment.
The thinkers of the Enlightenment formulated ideals of human dignity and worth. In France, unjust social and political conditions were criticized by a group of philosophers known as the philosophes. This group, which included Diderot, Rousseau, and Voltaire, greatly influenced leaders of the French Revolution. The philosophes and, more importantly, Locke also influenced the leaders of the Revolutionary War in America.
Philosophers of the Enlightenment sometimes disagreed on minor matters, but they all accepted the idea of the English philosopher Francis Bacon that “knowledge is power.” Because they aimed, in Bacon’s phrase, at “the improvement of man’s estate,” they concentrated their efforts on the advancement of knowledge. Their action explains why so many scientific institutes, including the famous Royal Society in England, were founded during the Enlightenment.
The urge to advance knowledge also explains why great effort was made to organize and circulate the results of the scientific research of the time. Many scholars gathered, organized, and published this knowledge. In fact, the Enlightenment could be called the “age of the encyclopedia.” The most famous reference work was the French Encyclopedie, edited by Diderot and Jean d’Alembert, and completed between 1751 and 1772.
To the philosophers of the Enlightenment, progress in human affairs seemed assured. It was only a question of time, they believed, until people learned to let reason—not ignorance, emotion, or superstition—guide them. When people did so, they would be happy. Condorcet expressed this optimism in his Sketch for a Historical Picture of the Progress of the Human Mind (1793-1794).
Criticism of the Enlightenment.
Today, many beliefs of the Enlightenment seem rather naive. Most philosophers now believe that truths discovered by reason are universal only because they are tautologies. A tautology is a statement that merely repeats an idea in different words, without giving any new information. We can say, for example, that “all cats are felines.” The statement is universally true, but only because “cat” means “feline.”
If the rational truths of the Enlightenment are tautologies, they do not tell us anything about nature. They tell us only how words are used. Most philosophers of the 1900’s believe that factual statements about the world are never certain. Such statements are only probable at best, and they may even be false.
The philosophers of the Enlightenment felt it was self-evidently true that governments should preserve their citizens’ property. But in the 1800’s, the German philosopher Karl Marx argued that this view merely reflected the prejudices of the middle class. These people own the property, said Marx, and thus want to preserve it.
The argument that universal truths are only tautologies was stated early in the Enlightenment by the English philosopher Thomas Hobbes. He wrote that reasoning is “nothing but reckoning, that is, adding and subtracting of the consequences of general names.” But few people paid any attention to Hobbes’s views, except to condemn them.
The Enlightenment’s optimistic belief in a rational human will has also been challenged. In the early 1900’s, for example, the Austrian physician Sigmund Freud stated that what we like to consider as “sound reasons” for our actions are only excuses. We act the way we do, Freud said, because of unconscious drives arising from a part of our subconscious mind called the id. We then attribute socially acceptable motives to ourselves to please another part of our subconscious, the superego.
The Enlightenment, however, ended long before Marx and Freud attacked its basic beliefs. Toward the end of the 1700’s, a great change in people’s outlook occurred. They came to value feeling rather than reason and to prefer passion, individuality, and spontaneity to discipline, order, and control. This change marked the beginning of the Romantic movement and the end of the Enlightenment.
