The Enlightenment

The Enlightenment's emphasis on reason shaped philosophical, political and scientific discourse from the late 17th to the early 19th century. Matthew White traces the Enlightenment back to its roots in the aftermath of the Civil War, and forward to its effects on the present day.

The Enlightenment – the great ‘Age of Reason’ – is defined as the period of rigorous scientific, political and philosophical discourse that characterised European society during the ‘long’ 18th century: from the late 17th century to the ending of the Napoleonic Wars in 1815. This was a period of huge change in thought and reason, which (in the words of historian Roy Porter) was ‘decisive in the making of modernity’.[1] Centuries of custom and tradition were brushed aside in favour of exploration, individualism, tolerance and scientific endeavour, which, in tandem with developments in industry and politics, witnessed the emergence of the ‘modern world’.

Porcelain figure of John Wilkes, holding the Bill of Rights and a scroll inscribed ‘Magna Carta’

Porcelain figure of John Wilkes, holding the Bill of Rights and a scroll inscribed ‘Magna Carta’. He is depicted in formal clothing with a pink material draped around one shoulder

This Derby porcelain figurine of the radical politician John Wilkes poses nonchalantly among symbols of English liberty. The plinth upon which he leans has two scrolls, one inscribed ‘Magna Carta’ and the other ‘Bill of Rights’; at his feet a cherub holds a liberty cap and a treatise on government by John Locke.

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The emergence of ‘reason’

The roots of the Enlightenment can be found in the turmoil of the English Civil Wars. With the re-establishment of a largely unchanged autocratic monarchy, first with the restoration of Charles II in 1660 and then the ascendancy of James II in 1685, leading political thinkers began to reappraise how society and politics could (and should) be better structured. Movements for political change resulted in the Glorious Revolution of 1688/89, when William and Mary were installed on the throne as part of the new Protestant settlement.

The Bill of Rights

Manuscript page. Partial image of The Bill of Rights

The Bill of Rights, signed by William and Mary in February 1689, stated that it was illegal for the Crown to suspend or dispense with the law, to levy money without parliamentary assent, or to raise an army in peacetime, and insisted on due process in criminal trials.

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The ancient civilisations of Greece and Rome were revered by enlightened thinkers, who viewed these communities as potential models for how modern society could be organised.[2] Many commentators of the late 17th century were eager to achieve a clean break from what they saw as centuries of political tyranny, in favour of personal freedoms and happiness centred on the individual. Chief among these thinkers was philosopher and physician John Locke, whose Two Treatises of Government (published in 1689) advocated a separation of church and state, religious toleration, the right to property ownership and a contractual obligation on governments to recognise the innate ‘rights’ of the people.

Locke believed that reason and human consciousness were the gateways to contentment and liberty, and he demolished the notion that human knowledge was somehow pre-programmed and mystical. Locke’s ideas reflected the earlier but equally influential works of Thomas Hobbes, which similarly advocated new social contracts between the state and civil society as the key to unlocking personal happiness for all.

Hobbes's Leviathan

Cover illustration for Hobbes's Leviathan, depicting a crowned giant emerging from the landscape, clutching a sword and with the torso and arms composed of over 300 humans

Published in 1651, Thomas Hobbes’s Leviathan helped shape Western political thinking.

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Concurrent movements for political change also emerged in France during the early years of the 18th century. The writings of Denis Diderot, for example, linked reason with the maintenance of virtue and its ability to check potentially destructive human passions. Similarly, the profoundly influential works of Jean-Jacques Rousseau argued that man was born free and rational, but was enslaved by the constraints imposed on society by governments. True political sovereignty, he argued, always remained in the hands of the people if the rule of law was properly maintained by a democratically endorsed government: a radical political philosophy that came to influence revolutionary movements in France and America later in the century.

The Social Contract by Jean-Jacques Rousseau

The Social Contract, a frontispiece depicting Jean Jacques Rousseau

Frontispiece with a portrait of the author in the 1895 edition of Rousseau’s The Social Contract, first published in 1762.

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The Declaration of the Rights of Man and of the Citizen

Painted depiction of the allegorical figures of France breaking her chains and Fame under the eye of God sit atop the Déclaration, which is associated with a red Phrygian cap, a snake biting its tail and a laurel wreath

On 26 August 1789, the French National Constituent Assembly issued the Déclaration des droits de l'homme et du citoyen (Declaration of the Rights of Man and the Citizen) which defined individual and collective rights at the time of the French Revolution. Painted by the artist Jean-Jacques-François Le Barbier (1738–1826), this depiction of the Déclaration celebrates these rights as a crowning achievement of the French Revolution.

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Scientific revolution

These new enlightened views of the world were also encapsulated in the explosion of scientific endeavour that occurred during the 18th century. With the rapid expansion of print culture from around 1700, and increasing levels of literacy, details of experimentation and discovery were eagerly consumed by the reading public.

Margaret Cavendish's Blazing World

First page of Blazing World, with the title The Description of a New World, called The Blazing World

Cavendish’s ground-breaking proto-novel wove original scientific theories into a fictional narrative.

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This growth of ‘natural philosophy’ (the term ‘science’ was only coined later in the 18th century) was underpinned by the application of rational thought and reason to scientific enquiry; first espoused by Francis Bacon in the early 1600s, this approach built on the earlier work of Copernicus and Galileo dating from the medieval period. Scientific experimentation (with instrumentation) was used to shed new light on nature and to challenge superstitious interpretations of the living world, much of which had been deduced from uncritical readings of historical texts.

Copernicus' celestial spheres

Printed page containing a diagram of Copernicus' celestial spheres and text in Latin

First edition of On the Revolutions of the Heavenly Spheres (1543), in which Copernicus argued that the positions of the stars and planetary orbits could be better explained by the sun being at the centre of the universe with the planets rotating around it in a circular motion, as shown in this iconic diagram.

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Galileo's sunspot letters

Handwritten letter by Galileo Galilei about sunspots, folio 15 v

These letters record astronomical observations made by the Italian physicist and astronomer Galileo Galilei in 1612.

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At the forefront of the scientific revolution stood Sir Isaac Newton, whose achievements in mathematics and physics revolutionised the contemporary view of the natural world. Born in 1643, Newton demonstrated a talent for mathematical theory at Trinity College, Cambridge, where his astonishingly precocious abilities led to his appointment as professor of mathematics at the age of just 26. Among Newton’s weighty catalogue of investigations were his treatises on optics, gravitational forces and mechanics (most famously encapsulated in his Mathematical Principles of Natural Philosophy, first published in 1687), all grounded in empirical experimentation as a way to demystify the physical world.

Newton's Principia Mathematica

Title page of Sir Isaac Newton's Principia Mathematica

Title page of the first edition of Newton's Mathematical Principles of Natural Philosophy (in Latin).

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The discoveries of Sir Isaac Newton were complemented by those of a host of equally dazzling mathematicians, astronomers, chemists and physicists (Robert Hooke and Robert Boyle, for example), many of whom were members of the Royal Society (founded in 1660, and active today). Yet it was Newton’s empirical approach to science that remained particularly influential. By embarking on purely rational and mathematical investigations, Newton was able to show that the natural world was ‘amenable to observations and experiment’, engendering a feeling among the scientific community that ‘Nature had finally been fathomed’.[3]

Micrographia by Robert Hooke, 1665

Large detailed illustration of a flea, as viewed through a microscope, printed in Hooke's Micrographia, 1665

Hooke’s Micrographia was the first important work on microscopy, the study of minute objects through a microscope.

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The pursuit of rational scientific knowledge was never the preserve of an educated elite. As well as fertilising a huge trade in published books and pamphlets, scientific investigation created a buoyant industry in scientific instruments, many of which were relatively inexpensive to buy and therefore available to the general public. Manufacturers of telescopes, microscopes, barometers, air pumps and thermometers prospered during the 18th century, particularly after 1750 when the names of famous scientific experimenters became household names: Benjamin Franklin, Joseph Priestley, William Herschel and Sir Joseph Banks, for example.

Ephraim Chambers's Cyclopaedia, 1741

Labelled illustrations of anatomised human bodies, printed in Ephraim Chambers' Cyclopaedia, 1741

Encyclopaedias, grammars and dictionaries became something of a craze in this period, helping to demystify the world in empirical terms. This huge fold-out page contains carefully labelled illustrations of anatomised human bodies.

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Secularisation and the impact on religion

Religion and personal faith were also subject to the tides of reason evident during the 18th century. Personal judgements on matters of belief were actively debated during the period, leading to scepticim, if not bold atheism, among an enlightened elite.

An enquiry into the nature of the human soul

Printed title page from An enquiry into the nature of the human soul

The author, Andrew Baxter argues that all matter is inherently inactive, and that the soul and an omnipotent divine spirit are the animating principles of all life. In making this argument, Baxter is rejecting the beliefs of more atheistic and materialist thinkers such as Thomas Hobbes and Baruch Spinoza.

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These new views on religion led to increasing fears among the clergy that the Enlightenment was ungodly and thus harmful to the moral well-being of an increasingly secular society. With church attendance in steady decline throughout the 1700s, evidence of increasing agnosticism (the belief that true knowledge of God could never be fully gained) and a rejection of some scriptural teachings was close at hand. Distinct anti-clericalism (the criticism of church ministers and rejection of religious authority) also emerged in some circles, whipped up by the musings of ‘deist’ writers such as Voltaire, who argued that God’s influence on the world was minimal and revealed only by one’s own personal experience of nature.

Though certainly a challenge to accepted religious beliefs, the impulse of reason was considered by other contemporary observers to be a complement rather than a threat to spiritual orthodoxy: a means by which (in the words of John Locke) the true meaning of Scripture could be unlocked and ‘understood in the plain, direct meaning of the words and phrases’.[4] Though difficult to measure or quantify, Locke believed that ‘rational religion’ based on personal experience and reflection could nevertheless still operate as a useful moral compass in the modern age.

New personal freedoms within the orbit of faith were extended to the relationship between the Church and state. In England, the recognition of dissenting religions was formalised by legislation, such as the 1689 Act of Toleration which permitted freedom of worship to Nonconformists (albeit qualified by allegiances to the Crown). Later, political emancipation for Roman Catholics – who were allowed new property rights – also reflected an enlightened impulse among the political elite: such measures sometimes created violent responses from working people. In 1780, for example, London was convulsed by a week of rioting in response to further freedoms granted to Catholics: a sign, perhaps, of how the enlightened thinking of politicians could diverge sharply from the sentiments of the humble poor.

Newspaper report of the Gordon riots, 1780

Newspaper report of the Gordon riots, 1780

The Gordon Riots of June 1780 were in response to legislation passed permitting Catholics greater freedom in society (such as being allowed to join the Army). The riots were so bad that 15,000 troops were deployed to quell the disturbances and nearly 300 rioters were shot dead by soldiers.

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First edition of the Letters of the late Ignatius Sancho, an African, 1782

Page 169 from the first edition of the Letters of the late Ignatius Sancho, an African

From his shop in Westminster, Ignatius Sancho witnessed ‘the burnings and devastations’ of the Gordon Riots. He described the ‘ridiculous confusion’ in a series of letters, dated 6–9 June 1780.

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Political freedoms, contracts and rights

Public debates about what qualified as the best forms of government were heavily influenced by enlightened ideals, most notably Rousseau’s and Diderot’s notions of egalitarian freedom and the ‘social contract’. By the end of the 18th century most European nations harboured movements calling for political reform, inspired by radical enlightened ideals which advocated clean breaks from tyranny, monarchy and absolutism.

Late 18th-century radicals were especially inspired by the writings of Thomas Paine, whose influence on revolutionary politics was felt in both America and France. Born into humble beginnings in England in 1737, by the 1770s Paine had arrived in America where he began agitating for revolution. Paine’s most radical works, The Rights of Man and later The Age of Reason (both successful best-sellers in Europe), drew extensively on Rousseau’s notions of the social contract. Paine reserved particular criticism for the hereditary privileges of ruling elites, whose power over the people, he believed, was only ever supported through simple historical tradition and the passive acceptance of the social order among the common people.

Rights of Man by Thomas Paine

Printed title  page from The Rights of Man by Thomas Paine

The Rights of Man (1791) was in part a defence of the French Revolution, and was thus perceived as an attack on the monarchy in Britain.

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Similarly, German philosopher Immanuel Kant (1724–1804) pointed towards the ‘laziness and Cowardice’ of the people to explain why ‘a large part of mankind gladly remain minors all their lives’, and spoke of reasoned knowledge gained from sensual experience as a means of achieving genuine freedom and equality.[5]

Though grounded in a sense of outrage at social and economic injustice, the political revolutions of both America (1765 to 1783) and France (1789 to 1799) can thus be fairly judged to have been driven by enlightened political dogma, which criticised despotic monarchies as acutely incompatible with the ideals of democracy, equality under the rule of law and the rights to property ownership.[6] These new movements for political reform argued in favour of protecting certain inalienable natural rights that some enlightened thinkers believed were innate in all men (though rarely in women as well): in the freedom of speech and protection from arbitrary arrest, for example, later enshrined in the American Constitution.

An Enquiry concerning Political Justice

Printed title page from An Enquiry concerning Political Justice, and its influence on general virtue and happiness

William Godwin’s major text, An Enquiry Concerning Political Justice, explored the idea of dismantling the power of the state in the international context of the French Revolution.

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However, for other observers (particularly in Britain) the violent extremes of the French Revolution proved incompatible with enlightened thought. Many saw the extremes of revolution as a counterpoint to any true notion of ‘reason’. British MP Edmund Burke, for example, wrote critically of the ‘fury, outrage and insult’ he saw embedded in events across the Channel, and urged restraint among Britain’s own enlightened political radicals.[7]

Reflections on the Revolution in France by Edmund Burke

Page 36 from Reflections on the Revolution in France, with discussion of England and the crown

First edition (1790) of Burke’s observations and reactions to the French Revolution.

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Political philosopher David Hume also warned of the dangers he perceived in the headlong pursuit of liberty for all. An ill-educated and ignorant crowd, argued Hume, was in danger of running into violence and anarchy if a stable framework of government was not maintained through the consent of the people and strong rule of law.[8] Governments, he believed, could offer a benign presence in people’s lives only when moderated by popular support, and he therefore offered the extension of the franchise as a counterbalance to the strong authority of the state.

Four Dissertations by Enlightenment philosopher David Hume

Printed title page from Four Dissertations by David Hume

David Hume was an 18th-century Scottish philosopher, known for his empiricism and scepticism. He was a major figure in the Scottish Enlightenment.

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The end of the Enlightenment?

The outcomes of the Enlightenment were thus far-reaching and, indeed, revolutionary. By the early 1800s a new ‘public sphere’ of political debate was evident in European society, having emerged first in the culture of coffee-houses and later fuelled by an explosion of books, magazines, pamphlets and newspapers (the new ‘Augustan’ age of poetry and prose was coined at the same time). Secular science and invention, fertilised by a spirit of enquiry and discovery, also became the hallmark of modern society, which in turn propelled the pace of 18th-century industrialisation and economic growth.

Individualism – the personal freedoms celebrated by Locke, Hume, Adam Smith, Voltaire and Kant – became part of the web of modern society that trickled down into 19th-century notions of independence, self-help and liberalism. Representative government on behalf of the people was enshrined in new constitutional arrangements, characterised by the slow march towards universal suffrage in the 1900s.

Photograph of Annie Kenney and Christabel Pankhurst

Photograph showing suffragettes Annie Kenney and Christabel Pankhurst holding a 'Votes for Women' placard

This photograph shows suffragettes Annie Kenney and Christabel Pankhurst holding a 'Votes for Women' placard.

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Evidence of the Enlightenment thus remains with us today: in our notions of free speech, our secular yet religiously tolerant societies, in science, the arts and literature: all legacies of a profound movement for change that transformed the nature of society forever.


[1] Roy Porter, Enlightenment: Britain and the Creation of the Modern World (London, 2001), p. 3.

[2] Porter, Enlightenment, p. 34.

[3] Porter, Enlightenment, p. 142.

[4] John Locke, The Reasonableness of Christianity (London, 1695), p. 2.

[5] Immanuel Kant, ‘What is Enlightenment’, quoted in Margaret C Jacob, The Enlightenment: A Brief History with Documents (Boston, 2001), p. 203.

[6] Dorinda Outram, The Enlightenment (Cambridge, 1995), p. 110.

[7] Edmund Burke, Reflections on the Revolution in France (1790), quoted in David Williams, (ed.), The Enlightenment (Cambridge, 1999) p. 516.

[8] Williams, The Enlightenment, p. 26.

  • Matthew White
  • Dr Matthew White is Research Fellow in History at the University of Hertfordshire where he specialises in the social history of London during the 18th and 19th centuries. Matthew’s major research interests include the history of crime, punishment and policing, and the social impact of urbanisation. His most recently published work has looked at changing modes of public justice in the 18th and 19th centuries with particular reference to the part played by crowds at executions and other judicial punishments.

The text in this article is available under the Creative Commons License.