Enlightenment philosophy was the philosophy produced during the Age of Enlightenment (late 17th and 18th centuries), originating in France, then western Europe and spreading throughout the rest of Europe. The Enlightenment philosophers included (among others) Baruch Spinoza, David Hume, John Locke, Edward Gibbon, Voltaire, Jean-Jacques Rousseau, Denis Diderot, Pierre Bayle, and Isaac Newton. Enlightenment philosophy was influenced by the Scientific Revolution in southern Europe, arising directly from the Italian Renaissance with people like Galileo Galilei.
Many Enlightenment philosophers viewed themselves as part of a progressive intellectual élite and opposed religious and political persecution, criticizing what they regarded as irrationality, arbitrariness, obscurantism, and superstition in earlier periods. They redefined the study of knowledge to fit the ethics and aesthetics of their time. Their works had great influence at the end of the 18th century, in the American Declaration of Independence and the Declaration of Rights of Man and Citizen.
Enlightenment philosophy saw its climax in the middle of the 18th century. In the most general terms, in science and philosophy, the Enlightenment aimed for the triumph of reason over faith and belief; in politics and economics, the increasing political influence of the bourgeoisie relative to the nobility and clergy.
Enlightenment philosophers had disrupted the old certainties, which resulted in social and political upheaval. The Enlightenment inspired a revolutionary generation, leading to the American Revolution and French Revolution.
Scientific Revolution
Advances in scientific method
The Enlightenment was in large part an extension of the discoveries of Nicolas Copernicus in the 16th century, which were not well known during his lifetime, and more so of the theories of Galileo Galilei (1564–1642). Inquiries to establish certain axioms and mathematical proofs continued as Cartesianism throughout the 17th century.
Gottfried Wilhelm von Leibniz (1646–1716) and Isaac Newton (1642–1727) had independently and almost simultaneously developed the calculus, and René Descartes (1596–1650) the idea of monads. British philosophers such as Thomas Hobbes and David Hume adopted an approach, later called empiricism, which preferred the use of the senses and experience over that of pure reason.
Baruch Spinoza took Descartes's side, most of all in his Ethics. But he demurred from Descartes in ("On the Improvement of the Understanding"), where he argued that the process of perception is not one of pure reason, but also the senses and intuition. Spinoza's thought was based on a model of the universe where God and Nature are one and the same.
This became an anchor in the Age of Enlightenment, held across the ages from Newton's time to that of Thomas Jefferson's (1743–1826). A notable change was the emergence of a naturalist philosophy, spreading across Europe, embodied by Newton. The scientific method – exploring experimental evidence and constructing consistent theories and axiom systems from observed phenomena – was undeniably useful.
The predictive success of Newton’s theories culminated in his masterwork Philosophiae Naturalis Principia Mathematica (1687). As an example of scientific progress in the Age of Reason and the Enlightenment, Newton's example remains unsurpassed, in taking observed facts and constructing a theory which explains them a priori, for example taking the motions of the planets observed by Johannes Kepler to confirm his law of universal gravitation. Naturalism saw the unification of pure empiricism as practiced by the likes of Francis Bacon with the axiomatic, "pure reason" approach of Descartes.
Belief in an intelligible world ordered by a Christian God became the crux of philosophical investigations of knowledge. On one side, religious philosophy concentrated on piety, and the omniscience and ultimately mysterious nature of God; on the other were ideas such as deism, underpinned by the impression that the world was comprehensible by human reason and that it was governed by universal physical laws. God was imagined as a "Great Watchmaker"; experimental natural philosophers found the world to be more and more ordered, even as machines and measuring instruments became ever more sophisticated and precise.
The most famous French natural philosopher of the 18th century, Georges-Louis Leclerc de Buffon, was critical of this natural theology in his masterwork Histoire Naturelle. Buffon rejected the idea of ascribing to divine intervention and the "supernatural" that which science could now explain. This criticism brought him up against the Sorbonne which, dominated by the Roman Catholic Church, never stopped trying to censor him. In 1751, he was ordered to redact some propositions contrary to the teaching of the Church; having proposed 74,000 years for the age of the Earth, this was contrary to the Bible which, using the scientific method on data found in biblical concordances, which conflicted with contemporary biblical chronologies.Jean Stengers 1974. "Buffon et la Sorbonne" in Études sur le XVIIIe siecle, ed. Roland Mortier and Hervé Hasquin. Brussels: Université de Bruxelles. pp 113–24 The Church was also hostile to his no less illustrious contemporary Carl von Linné, and some have concluded that the Church simply refused to believe that order existed in nature.
Encyclopaedic goals At the time, there was a particular taste for compendia of "all knowledge". This ideal found an instance in Diderot and d'Alembert's ("Encyclopaedia, or Systematic Dictionary of the Sciences, Arts, and Crafts"), usually known simply as the Encyclopédie. Published between 1750 and 1770 it aimed to lead people out of ignorance through the widest dissemination of knowledge.
Philosophical themes
Individual liberty and the social contract This effort to research and elucidate universal laws, and to determine their component parts, also became an important element in the construction of a philosophy of individualism, where everyone had rights based only on fundamental human rights. There developed the philosophical notion of the thoughtful subject, an individual who could make decisions based on pure reason and no longer in the yoke of custom. In Two Treatises of Government, John Locke argued that property rights are not held in common but are totally personal, and made legitimate by the work required to obtain the property, as well as its protection (recognition) by others. Once the idea of natural law is accepted, it becomes possible to form the modern view of what we would now call political economy.
In his famous essay Answering the Question: What is Enlightenment? (), Immanuel Kant defined enlightenment thus:
Enlightenment philosophy was thus based on the realities of a systematic, ordered and understandable world, which required Man also to think in an ordered and systematic way. As well as physical laws, this included ideas on the laws governing human affairs and the divine right of kings, leading to the idea that the monarch acts with the consent of the people, and not the other way around. This legal concept informed Jean-Jacques Rousseau's theory of the social contract as a reciprocal relationship between men, and more so between families and other groups, which would become increasingly stronger, accompanied by a concept of individual inalienable rights. Among atheist Enlightenment thinkers, appeals to divine authority were rejected in favor of secular reasoning.
The Enlightenment redefined the ideas of liberty, property and rationalism, which took on meanings that we still understand today, and introduced into political philosophy the idea of the free individual, liberty for all guaranteed by the State (and not the whim of the government) backed by a strong rule of law.
To understand the interaction between the Age of Enlightenment and the Enlighteners, one approach is to compare Thomas Hobbes with John Locke. Hobbes (1588–1679) worked to create an ontology of human emotions, ultimately trying to make order out of an inherently chaotic universe. Meanwhile, Locke (1632–1704) saw in nature a source of unity and universal rights, with the government's assurance of protection. This intellectual shift during the 17th and 18th centuries reflected contrasting views of the relationship between humanity and nature.
In France, this resulted in the spread of the notion of human rights, finding expression in the 1789 Declaration of the Rights of Man and of the Citizen, which greatly influenced similar declarations of rights in the following centuries, and left in its wake global political upheaval. Especially in France and the United States, freedom of expression, freedom of religion and freedom of thought were held to be fundamental rights.
Social values and manifests
Representation of the people The core values supported by the Enlighteners were religious tolerance, liberty and social equality. In England, America and France, the application of these values resulted in a new definition of natural law and a separation of political power. To these values may be added a love of nature and the cult of reason.
Philosophical goals
The ideal figure of the Enlightenment was a philosopher, a man of letters with a social function of exercising his reason in all domains to guide his and others' conscience, to advocate a value system and use it in discussing the problems of the time. He is a committed individual, involved in society, an (Encyclopédie; "Honest man who approaches everything with reason"), (Diderot, "Who concerns himself with revealing error").
The rationalism of the Enlightenment was not to the exclusion of aesthetics. Reason and sentiment went hand-in-hand in their philosophy. The thoughts of Enlightenment philosophers were equally capable of intellectual rigour and sentimentality.
Despite controversy about the limits of their philosophy, especially when they denounced black slavery, many Enlightenment philosophers criticised slavery, or colonialism, or both, including Montesquieu in De l'Esprit des Lois (while keeping a "personal" slave), Denis Diderot in Supplément au voyage de Bougainville, Voltaire in Candide and Guillaume-Thomas Raynal in his encyclopaedic Histoire des deux Indes, the very model of 18th-century anticolonialism to which, among others, Diderot and d'Holbach contributed. It was stated without any proof that one of their number, Voltaire, had shares in the slave trade.
Criticism The Enlightenment was, for all its existence, pulled in two directions by opposing social forces: on one side, a strong spiritualism accompanied by a traditional faith in the religion of the Church; on the other, the rise of an anticlerical movement, critical of the differences between religious theory and practice, which was most manifest in France.
Anticlericism was not the only source of tension in France: some noblemen contested monarchical power and the upper classes wanted to see greater fruit from their labours. A relaxing of morals fomented opinion against absolutism and the Ancient Order. The French judicial system also showed itself to be outdated. Even though commercial law had become codified during the 17th century, there was no uniform, or codified, civil law.
According to Dale K. Van Kley, Jansenism in France also became a source of division.
Voltaire
This social and legal background was criticised in works by the likes of Voltaire. Exiled in England between 1726 and 1729, he studied the works of John Locke and Isaac Newton, and the English monarchy. He became well known for his denunciation of injustices such as those against Jean Calas, Pierre-Paul Sirven, François-Jean de la Barre and Thomas Arthur, comte de Lally.