The term "Enlightenment" is often given to the intellectual quickening of the eighteenth century. As is the case with all intellectual movements of great importance and duration, it is difficult to say where, when, and how it began, and when it ended. In addition, any satisfactory definition of the Enlightenment would be so cumbersome and all-embracing as to be almost useless; any concise definition would certainly fail to take into account many thinkers and ideas of the period. Still, some generalities may be made which will prove useful.

The Enlightenment may best be considered the intellectual offspring of the scientific and philosophical movements of the seventeenth century. In turn, these movements would have been impossible were it not for the Renaissance, which saw the spirit of secular inquiry revived in Western Europe. The Reformation also made its contribution, in its destruction of what operated as a monolithic Church. This is not to say that the thinkers of the Renaissance and Reformation succeeded in viewing the world totally objectively, without dogma; rather, they aided in tearing down the medieval world view, a necessary precondition for the construction of a new one.

To these factors must be added the growth of nationalism and the rise of the middle class. Again, neither the national monarchs or the growing merchant class were necessarily scientifically oriented. They were more interested in this world than the next, however, and many of their actions and ideas supported a natural rather than a supernatural explanation of phenomena.

What did these movements and groups have in common? All stressed individualism and, by implication, reason. The Renaissance man needed to be free in order to fully exercise his faculty of reason. The religious reformer of the Reformation based a good deal of his protest on the Church's lack of individual interpretation of the Bible and its control over the secular activities of man. The nationalist stressed the uniqueness of his nation-state, as opposed to the universality of the Church. The market demanded that the merchant use reason in his dealings or be out-competed in trades that required the full use of his senses. During the Middle Ages, the intellectual stress was on the unity of man under God, the universality of the Church, the corporate nature of man (a member of a class rather than an individual in his own right), and the rewards of heaven. The stagnation of this period was shattered by the Renaissance and Reformation, by the nationalists and the middle class.

During the seventeenth century, synthesizing attempts were made to preserve some of the tenets of the old order, while admitting to the virtues of the new. After all, St. Thomas used reason in coming to his conclusions; even if the conclusions were unacceptable, his methodology was not. The scholastics of the fifteenth century believed their faith could be reasonably demonstrated, as did the scientists of the seventeenth century.

Three of the most important thinkers of the seventeenth century-and the intellectual fathers of the eighteenth century Enlightenment-were Rene Descartes (1596-1650), Sir Isaac Newton (1642-1727), and John Locke (1632-1704). Descartes attempted to create a system of philosophy by first sweeping away all preconceptions, and starting with the concept he held to be the only absolute, "I think, therefore I am." With the use of mathematics and the deductive method, Descartes went on to reconstruct the universe. God existed, he said, but only as a first mover and creator of matter and mathematical laws. "Give me extension and motion," he said, "and I will construct the universe." As a later critic remarked, "The Cartesian (follower of Descartes) attempts to explain all the phenomena of nature by matter and motion; requiring only that God should first create a sufficient quantity of each, just enough to set him at work." Thus, Descartes did away with the need for a supernatural God to explain earthly events, as well as the human soul itself.

Sir Isaac Newton built upon this philosophical foundation, attempting to formulate universal mathematical laws to explain all physical phenomena. He said, for example, that "every particle of matter in the universe attracts every other particle with a force varying inversely as the square of the distance between them and directly proportional to the product of their masses." The implication was clear; God existed-it was He who created these laws-but the universe acts in accordance with the laws, and not with His whims of the moment. Man may not be able to understand God, but he can understand these naturalistic laws. Consequently, to understand God, man must explore science and this world, and not theology and the supernatural.

Locke was an influential philosopher-his political ideas helped lay the basis for the American and French Revolutions-but his epistemological theories are what concerns us here. At birth, he said, the human mind is blank, a tabula rasa. The child receives simple ideas, which are later integrated to form complex ideas. Sensations give the mind its raw materials, and reason makes them meaningful. Thus, Locke ignores "revelation" and "spiritual truths," in his theory of knowledge. Also implicit in his philosophy is the belief that man possesses a volitional consciousness, that is, he has the capacity to choose and determine his course of action. God has given man a brain and reason, but he may use them freely.

Descartes, Newton, Locke, and their seventeenth and early eighteenth century followers provided the basis for the Enlightenment. At the same time, the student must remember that their ideas were not completely original, but based in part upon the work of the later scholastics. St. Thomas may not have agreed with any of their conclusions, but he would have recognized and accepted their methods.

The basic beliefs of the Enlightenment may be analyzed under four headings: (1) trust in reason; (2) disbelief in original sin; (3) the infallibility of scientific laws; (4) trust in the "simple" and "natural" methods and ways of life.

The thinkers of the Enlightenment believed that all knowledge was attainable through human reason. God gave man a brain and the free will to use it. If man used his mind correctly, he could comprehend the universe, and God himself. St. Augustine had said that man's function on earth was to create an earthly city as close to the City of God as possible, but contented that perfectibility was unattainable. The thinkers of the Enlightenment said that this perfect knowledge was within their grasp, and were supremely optimistic and self-confident.

The men of the Enlightenment denied the assertion, made by both Catholics and Protestants, that man was born with original sin and therefore was incapable of perfection. Instead, the Enlightenment thinkers believed that man was born without preconceptions, and was capable, through his reasoning faculty, of attaining both knowledge and virtues. The Enlightenment believed in progress, a rapid progress which took full advantage of the newly liberated human mind.

The uniform nature of the universe fascinated the men of the Enlightenment. The one who unlocked its secrets could use nature's laws to attain unlimited power. Everything was within man's grasp once the key to knowledge was discovered and used.

What was called "civilization" was, to many Enlightenment thinkers, the dead hand of the past upon the present. Institutions were encrusted with ideas and forms which may have once seemed useful, but which needed to be examined afresh, to determine whether or not any of it was meaningful. From this premise the Enlightenment men proceeded to discard most of organized religion, many concepts of the nation-state, war, economic institutions, etc. In the past, reformers had been content to patch the fabric of society; in the future, the premise went, the rotten foundations must be torn down and the task undertaken anew.

The key word of the Enlightenment, then, was reason. Through the use of reason, man would be able to uncover the natural laws set down by God, the great mathematician. If the laws were followed, then limitless progress would result. The turmoil and suffering of the world might have led others to extreme pessimism; to the man of the Enlightenment, each bit of suffering represented the opportunity to use reason to bring order, progress, and happiness to man. Thus, the Enlightenment, while deploring the present, was extremely optimistic about the future.

Copyright 1963-1990 by Simon & Schuster, Inc.

Voltaire, Works of Voltaire: The Philosophy Of The Enlightenment, Monarch Notes, 1963.