The Enlightenment (ca. 1650-1800) was a period of unprecedented optimism in the potential for knowledge and reason to enable humanity to understand and improve the world. Since this optimism has persisted right up to the present day, the Enlightenment can be summarized as "the birth of the modern Western outlook".
The Enlightenment could also be summarized as "the age in which humanism reached its fully-developed form". Humanism is an outlook that affirms the importance of two things: critical thought and secular matters (see Humanism). During the Enlightenment (and continuing up to the present), secular subjects flourished like never before, as did the application of critical thought to all knowledge.
The Notion of Progress
During the Enlightenment, the notion of progress came to be a standard feature of the Western outlook; that is, the view that human civilization is becoming ever more advanced (technologically, politically, socially, and so on).3 This can be described as a "linear view" of history. It is often argued that up until the Enlightenment, a "cyclical view" or "static view" of history prevailed; that is, the view that humanity does not truly progress in any direction, but simply undergoes cycles of prosperity and poverty, peace and war, and so on. Perhaps the most important factor in awakening a sense of progress was the dramatic advance of science.
The importance of the notion of progress must not be underestimated; the more widespread it became, the more people believed they could change the world for the better (via knowledge and reason). In greater numbers than ever before, people felt encouraged to pursue education and be innovative. This positive attitude is reflected in the strong educational focus of the present-day Western world, in terms of both institutions (primary, secondary, post-secondary) and popular interest in knowledge (e.g. museums, documentaries, scholarly magazines).A337-38,H881
The Spread of Knowledge
The provision of education to a wide public audience (i.e. the "democratization" of knowledge) was a central Enlightenment preoccupation. This pursuit culminated in the Encyclopédie, a book (edited by Denis Diderot) which aimed to set forth the sum of human knowledge in an accessible manner.A311,H881,K270-71,1 Wikipedia is the 21st-century successor to this work.
Crucial to the spread of knowledge was the massive economic growth of the Early Modern age. This growth drove the expansion of the middle class, which possessed the time and wealth to become literate and pursue scholarly activities.
The Enlightenment, led by France and England, flourished throughout Europe (albeit less strongly in the East) and the United States.H880 Scientists, social scientists, and political reformers were among the most prominent types of Enlightenment thinkers. The two foremost Enlightenment scholars of England were arguably Newton and Locke (described further below); among the Enlightenment scholars of France (often referred to collectively as the "philosophes"), the most famous is Voltaire, known for his scathing political satire.
The Two Pillars of the West
Two pillars of modern Western civilization may be identified: science and liberal democracy. The unprecedented average quality of life in the contemporary world may be credited primarily to these two forces.
In this context, "science" is used broadly to denote any field based on rigorous logic and evidence. This includes the natural sciences (e.g. physics, chemistry) and social sciences (e.g. history, economics). Science only matured during the Enlightenment, when thinkers finally subjected all scholarly claims (e.g. scientific, historical, religious) to constant, unmitigated rational scrutiny (see History of Science).H880,2,3
In the field of science, the outstanding Enlightenment figure is Isaac Newton, who conclusively demonstrated that the physical universe can be explained in terms of quantifiable laws, and that the scientific method is the means of discovering these laws. Encouraged by the victories of scientists in uncovering universal laws of nature, other Enlightenment thinkers created the social sciences in hopes of finding laws governing the functioning of society.2
"Liberal democracy" denotes a form of government that features both democracy (in which the government is comprised of the people, either directly or via representatives) and liberalism (in which the government prioritizes individual freedom). Though democracy dates to ancient Greece, the notion of liberalism did not clearly emerge until the Enlightenment; thus, the combination of these ideas (liberal democracy) also dates to the Enlightenment (see History of Western Philosophy, History of Democracy).
While many Enlightenment thinkers argued in favour of liberal democracy, the outstanding figure is John Locke, known as the "father of liberalism" or "father of liberal democracy". Locke is responsible for fully developing the concepts of liberalism and liberal democracy, and for making them influential throughout the Western world (including the United States). Locke's work thus lies at the foundation of all present-day liberal democracies.4,5
In addition to revolutionary efforts, the Enlightenment embrace of liberalism gave rise to extensive demands for reform of existing Western governments, which were accused of repressing individual freedoms. Passionate denouncements (both direct and satirical) were made against such issues as discrimination (e.g. religious intolerance), censorship (e.g. of political expression), arbitrary imprisonment, and economic restrictions. Importantly (for Enlightenment scholarship), these issues were already less severe in England (and its colonies) than elsewhere in the West (thanks to the efforts of Parliament), thus providing a relatively safe and encouraging environment for innovative thinking.H880,K270-71,1,2
The Enlightenment also featured a rising tide of secularism: the view that religion should be self-contained, and thus not involved in other aspects of society (e.g. government, law, education). Enlightenment thinkers argued that civic institutions should operate according to knowledge and reason, and should therefore be free of religious influence. Since the Enlightenment, secularism has grown to find widespread acceptance in Western nations.
The Present Day
Generally speaking, the Enlightenment outlook continues to flourish in the present-day Western world. In the centuries following the Enlightenment, the sheer monumentality of the world's social challenges has become clearer, and the terrible destructive potential of modern technology has been revealed. Yet consensus remains strong on the potential of knowledge and rational inquiry to benefit society, and humanity is indeed making steady progress in many critical areas, however slow and difficult it may be.
2 - "Enlightenment", Columbia Encyclopedia. Accessed February 2010.
3 - "Enlightenment", Encyclopedia Britannica. Accessed March 2010.
4 - "John Locke", Who2? Biographies. Who2?, 2012.
5 - "John Locke", Oxford Dictionary of British History. Oxford University Press.