If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Enlightened Thinking

Eighteenth-century intellectual movement that celebrated human rationality continues to have profound influence on modern society

by Rudy M. Baum
November 18, 2013 | A version of this story appeared in Volume 91, Issue 46

CORRECTION: This story was updated on Jan. 21, 2014, to indicate that the Enlightenment occurred from the last decade of the 17th century through the first decade of 19th century.

As scientists, we are all children of the Enlightenment, the 18th-century intellectual movement that simultaneously put human rationality and benevolence and a belief in human progress at the forefront of philosophy while banishing divinity from most assessments of the human condition.

Credit: Wikimedia Commons
“A Phi-losopher Lecturing on the Orrery” by Joseph Wright of Derby, circa 1766, depicts the solar system and the awe produced by science.
A Philosopher Lecturing on the Orrery by Joseph Wright of Derby ca. 1766, oil on canvas. The Orrery caused a stir, as it replaced the Classical subject at the center of the scene with one of a scientific nature. Wright's depiction of the awe produced by scientific "miracles" marked a break with previous traditions in which the artistic depiction of such wonder was reserved for religious events.
Credit: Wikimedia Commons
“A Phi-losopher Lecturing on the Orrery” by Joseph Wright of Derby, circa 1766, depicts the solar system and the awe produced by science.

I’ve never thought that was a particularly radical notion, even though my understanding of the Enlightenment was fairly superficial. I had read works by Immanuel Kant, David Hume, and Edmund Burke in college, but I was almost entirely unfamiliar with the influential French Enlightenment philosophers—Voltaire, Rousseau, Diderot, and their brethren. I didn’t really know how the Enlightenment fit into previous and subsequent intellectual eras. It just seemed obvious to me that a belief in rationalism and human progress was the basis of modernity.

“The Enlightenment: And Why It Still Matters” by Anthony Pagden is a magisterial assessment of the period that stretched roughly from the last decade of the 17th century through the first decade of the 19th century and its staggering impact on human thought and culture. Pagden is distinguished professor of political science and history at the University of California, Los Angeles. He addresses this era of unprecedented intellectual ferment with deep scholarship and a sweeping knowledge of the history of philosophy.

Credit: Anthony Pagden/Random House
The Enlightenment: And Why It Still Matters, by Anthony Pagden, Random House, 2013, 528 pages, $32 hardcover (ISBN: 978-1-4000-6068-9)
Title and author over background painting reproduction.
Credit: Anthony Pagden/Random House
The Enlightenment: And Why It Still Matters, by Anthony Pagden, Random House, 2013, 528 pages, $32 hardcover (ISBN: 978-1-4000-6068-9)

To Pagden, the Enlightenment most definitely still matters. “The Renaissance and the Reformation, although they too transformed the cultures of Europe … in irreversible ways, are for most people today simply periods of history,” he writes in the preface to the book. “Not so the Enlightenment. If we regard ourselves as modern, if we are forward-thinking, if we are tolerant and generally open-minded, if stem-cell research does not frighten us but fundamentalist religious beliefs do, then we tend to think of ourselves as ‘enlightened.’ And in thinking this, we are in effect declaring ourselves to be the heirs, however distant, of one particular intellectual and cultural movement.”

Make no mistake, “The Enlightenment” is not light reading. Pagden is a scholar, and although this book—which is perhaps best described as a work of philosophical history—is meant for a general audience, it demands readers’ full attention.

Why review a work of philosophical history in a magazine published for professional chemists? Modern science is itself a product of the Enlightenment and, in fact, cannot be successfully pursued in “unenlightened” cultures. It is essential, I think, for scientists to understand the philosophical underpinnings of the culture that supports them and allows them to thrive.

And, as Pagden makes clear, the legacy of the Enlightenment remains controversial, and opposition to enlightened thinking remains present in the modern world. As Pagden writes, “Just what exactly the Enlightenment was has been the subject of irate and furious debates ever since the eighteenth century itself. No other intellectual movement, no other period in history, has attracted so much disagreement, so much intransigence, so much simple anger. The key terms of almost every modern conflict over how we are to define and understand ‘humanity’—modernism, postmodernism, universalism, imperialism, multiculturalism—ultimately refer back to some understanding of the Enlightenment.” Understanding the Enlightenment, Pagden maintains, is fundamental to understanding modernity itself.

Contempt for Enlightenment thinking remains prevalent as well. To some, Pagden writes, the “project that had begun in the eighteenth century as a bid to free every individual from his or her dependence upon the rigid social and moral codes by which the powers, secular and religious, of the old regime had kept their subjects in check and to create a fit social world in which all human beings might flourish had, by the twentieth century, evolved into little more than the attempt by a self-convinced European elite to impose its own will, and its own image, upon the entire world.”

The structure of “The Enlightenment” is straightforward and essentially historical. Pagden sets the stage for the dawn of the Enlightenment with a discussion of the Reformation and the Scientific Revolution of the 16th and 17th centuries. The collapse of religious consensus in Europe, the brutal religious wars fought between 1550 and 1650 leading to the Treaty of Westphalia of 1648 (condemned by Pope Innocent X as “null, void, invalid, iniquitous, unjust, damnable, reprobate, inane, empty of meaning and effect for all time”), and the assault on scholasticism led by England’s Thomas Hobbes all contributed to “dethrone theology” from its position as the organizing principle of human society.

“Few, if any, of the men who set out to do this had any real quarrel with the study of God as such,” Pagden writes, “as long as it was confined to the understanding of God—the theos—and made no claims to meddle in the means by which the operations of the natural world were understood, or to dictate the terms by which humans should live their lives or organize their societies.” Which was, of course, precisely why religions had the power they had.

The Scientific Revolution that followed the Reformation, Pagden maintains, “was a true ‘revolution’ in the modern sense of the term. It was not, as so many previous ones had been … a turning back. … This was not a re-evaluation of a hallowed past, of the kind we associate with the Renaissance, an attempt to purify what had become sullied through abuse. This was a radical, decisive, and irreparable break.”

Pagden goes on to observe that the demolition of scholasticism, especially by Hobbes, left an intellectual void. The scholastics, he points out, “made their version of the natural law the basis for a universal moral and political code” that gave humans a dignity not found in this new philosophical vision that “accepted the existence of only one natural right—the right to self-preservation.” Filling this void was one of the explicit goals of Enlightenment philosophers. “The Enlightenment,” Pagden writes, was in part “an attempt to recover something of this vision of a unified and essentially benign humanity, of a potentially cosmopolitan world, without also being obliged to accept the theologians’ claim that this could only make sense as part of the larger plan of a well-meaning, if deeply inscrutable, deity.”

The bulk of “The Enlightenment” shows how a wide cast of mostly European philosophers—some widely known, some obscure—in the 18th century developed the notion of a rational basis for civilization. In a series of long chapters, Pagden addresses the Enlightenment philosophers’ notions of God (most were deists who had little use for the Judeo-Christian God), the development of a “science of man” (essentially, imagined histories of how human civilization came to be that showed that “the final destiny of the species must be the creation of a universal, cosmopolitan civilization”), and the impact on philosophy of European interactions with newly discovered peoples around the Earth ranging from the “savages” in North America and Tahiti to the ancient civilization of China.

What strikes one while reading this book is that the philosophers, jurists, artists, and other thinkers of the 18th century had begun to grapple with the issues of modernity that still concern us today. In the concluding chapters, Pagden traces the evolution of the monarch from despot to servant of the people and the development of the notion of a “social contract” between rulers and their subjects. He devotes many pages to the notion of “cosmopolitanism,” the idea that humans could “mobilize the natural affinity we all feel for one another, so as to reunite all the peoples of the world into some kind of union,” ideas that presage the 20th century’s creation of the League of Nations and the United Nations. He shows that Enlightenment thinkers viewed “commerce … as the final stage of the civilizing process and the sole effective means of refining human relationships.” Commerce between nations would, in fact, lead to a peaceful, global, cosmopolitan world, they maintained.

The culminating event of the 18th century and of the Enlightenment was the French Revolution, the philosophical basis of which was the rationality elevated by Enlightenment thinkers. Pagden does not flinch from the fact that the rational basis of the revolution would also lead to the unspeakable depravations of Robespierre’s terror. In the conclusion of the book, Pagden outlines how many 19th-century thinkers seized on the horrors of the French Revolution to attempt to discredit Enlightenment thinking. Pagden will have none of it, however. He writes: “In its intention to transform the most significant, most lasting insights available to the western philosophical tradition in such a way as to make them usable in a world from which God had been finally and irrevocably removed; by insisting on the changing, unfinished nature of all human action; by insisting, indeed, on its own unfinished nature, the Enlightenment quite simply created the modern world. It is, indeed, impossible to imagine any aspect of contemporary life in the West without it.”

“The Enlightenment” is not without its flaws. It is longer than it probably needed to be. Pagden sometimes allows his erudition to stand in the way of clear writing, leading to sentences like: “Hobbes’s understanding of the natural law had also, as Francis Hutcheson—‘the never to be forgotten Hutcheson,’ as Adam Smith called him—who had been David Hume’s friend and mentor, was perhaps the first to point out, not merely reduced the natural law to a single irrefutable principle, it has also reduced it to a right.”

But such flaws are relatively minor. “The Enlightenment” is a remarkable, sweeping overview of one of the most consequential intellectual movements in human history, one that, indeed, still very much matters.

Rudy Baum is C&EN editor-at-large.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.