On the surface, the most apparent cause of the Enlightenment was the Thirty Years’ War. This horribly destructive war, which lasted from 1618 to 1648, compelled German writers to pen harsh criticisms regarding the ideas of nationalism and warfare. These authors, such as Hugo Grotius and John Comenius, were some of the first Enlightenment minds to go against tradition and propose better solutions.
At the same time, European thinkers’ interest in the tangible world developed into scientific study, while greater exploration of the world exposed Europe to other cultures and philosophies. Finally, centuries of mistreatment at the hands of monarchies and the church brought average citizens in Europe to a breaking point, and the most intelligent and vocal finally decided to speak out.
The Enlightenment developed through a snowball effect: small advances triggered larger ones, and before Europe and the world knew it, almost two centuries of philosophizing and innovation had ensued. These studies generally began in the fields of earth science and astronomy, as notables such as Johannes Kepler and Galileo Galilei took the old, beloved “truths” of Aristotle and disproved them. Thinkers such as René Descartes and Francis Bacon revised the scientific method, setting the stage for Isaac Newton and his landmark discoveries in physics.
From these discoveries emerged a system for observing the world and making testable hypotheses based on those observations. At the same time, however, scientists faced ever-increasing scorn and skepticism from people in the religious community, who felt threatened by science and its attempts to explain matters of faith. Nevertheless, the progressive, rebellious spirit of these scientists would inspire a century’s worth of thinkers.
The first major Enlightenment figure in England was Thomas Hobbes, who caused great controversy with the release of his provocative treatise Leviathan (1651). Taking a sociological perspective, Hobbes felt that by nature, people were self-serving and preoccupied with the gathering of a limited number of resources. To keep balance, Hobbes continued, it was essential to have a single intimidating ruler. A half century later, John Locke came into the picture, promoting the opposite type of government—a representative government—in his Two Treatises of Government (1690).
Although Hobbes would be more influential among his contemporaries, it was clear that Locke’s message was closer to the English people’s hearts and minds. Just before the turn of the century, in 1688, English Protestants helped overthrow the Catholic king James II and installed the Protestant monarchs William and Mary. In the aftermath of this Glorious Revolution, the English government ratified a new Bill of Rights that granted more personal freedoms.
Many of the major French Enlightenment thinkers, or philosophes, were born in the years after the Glorious Revolution, so France’s Enlightenment came a bit later, in the mid-1700s. The philosophes, though varying in style and area of particular concern, generally emphasized the power of reason and sought to discover the natural laws governing human society. The Baron de Montesquieu tackled politics by elaborating upon Locke's work, solidifying concepts such as the separation of power by means of divisions in government. Voltaire took a more caustic approach, choosing to incite social and political change by means of satire and criticism. Although Voltaire’s satires arguably sparked little in the way of concrete change, Voltaire nevertheless was adept at exposing injustices and appealed to a wide range of readers. His short novel Candide is regarded as one of the seminal works in history.
Denis Diderot, unlike Montesquieu and Voltaire, had no revolutionary aspirations; he was interested merely in collecting as much knowledge as possible for his mammoth Encyclopédie. The Encyclopédie, which ultimately weighed in at thirty-five volumes, would go on to spread Enlightenment knowledge to other countries around the world.
In reaction to the rather empirical philosophies of Voltaire and others, Jean-Jacques Rousseau wrote The Social Contract (1762), a work championing a form of government based on small, direct democracy that directly reflects the will of the population. Later, at the end of his career, he would write Confessions, a deeply personal reflection on his life. The unprecedented intimate perspective that Rousseau provided contributed to a burgeoning Romantic era that would be defined by an emphasis on emotion and instinct instead of reason.
Another undercurrent that threatened the prevailing principles of the Enlightenment was skepticism. Skeptics questioned whether human society could really be perfected through the use of reason and denied the ability of rational thought to reveal universal truths. Their philosophies revolved around the idea that the perceived world is relative to the beholder and, as such, no one can be sure whether any truths actually exist.
Immanuel Kant, working in Germany during the late eighteenth century, took skepticism to its greatest lengths, arguing that man could truly know neither observed objects nor metaphysical concepts; rather, the experience of such things depends upon the psyche of the observer, thus rendering universal truths impossible. The theories of Kant, along with those of other skeptics such as David Hume, were influential enough to change the nature of European thought and effectively end the Enlightenment.
Ultimately, the Enlightenment fell victim to competing ideas from several sources. Romanticism was more appealing to less-educated common folk and pulled them away from the empirical, scientific ideas of earlier Enlightenment philosophers. Similarly, the theories of skepticism came into direct conflict with the reason-based assertions of the Enlightenment and gained a following of their own.
What ultimately and abruptly killed the Enlightenment, however, was the French Revolution. Begun with the best intentions by French citizens inspired by Enlightenment thought, the revolution attempted to implement orderly representative assemblies but quickly degraded into chaos and violence. Many people cited the Enlightenment-induced breakdown of norms as the root cause of the instability and saw the violence as proof that the masses could not be trusted to govern themselves. Nonetheless, the discoveries and theories of the Enlightenment philosophers continued to influence Western society for centuries.