Enlightenment Thinkers and Thomas Jefferson

From the lecture series: America's Founding Fathers

By Allen C. Guelzo, Ph.D., Gettysburg College

The Scientific Revolution led to people wondering about the structure of the human society. Enlightenment thinkers like John Locke and Adam Smith wrote books about their thoughts and discoveries. How did these books influence Thomas Jefferson’s political philosophy?

Photo of some old books and reading glasses on a desk.
Thomas Jefferson included books by Enlightenment thinkers to his list of favorite reading suggestions. (Image: Sandra Cunningham/Shutterstock)

The Scientific Discovery

Galileo Galilei concluded that the physical movements of the moon and the planets were not governed by moral relationships of superiority and inferiority to each other. Later, Isaac Newton explained that the movement of all physical objects was due to a simple and entirely measurable force called gravity. These developments left Europeans wondering whether the same rules which shattered the hierarchy of physical nature might not be applied to the hierarchy of human society.

The task of discovering such political laws fell especially to the Englishman John Locke, the Scot Adam Smith, the Italian Cesare Beccaria, and the Frenchman Charles-Louis de Secondat, the Baron Montesquieu.

This is a transcript from the video series America’s Founding Fathers. Watch it now, Wondrium.

John Locke’s Thought Experiment

The front of the Locke's book 'Two Treatises of Government'.
Locke explained the natural laws of politics in his book. (Image: Unknown/Public domain)

Locke asked his readers in his Two Treatises of Government to perform a thought experiment.

Suppose several of us were shipwrecked on a desert island. The first fact that would impress itself on us would be hunger: where was the next meal to come from? We would need at once to begin harvesting fruit and berries, and then, long-term, plant crops, which we could harvest. Investing our labor in producing food from the land is what sanctions our calling this land our property.

But another fact would soon impress itself on us, and that is that some people would rather steal other people’s harvest or property than do the work themselves. So, it would become necessary to improvise some form of social organization, or risk descending into cannibalism and murder.

Thrust onto our island, we are in what Locke called a state of nature, and in the state of nature, we’re free to do whatever we wish.

If we are successful, we manage to plant crops, hunt game, and build shelter. But in order to get security for our property, we have to leave the state of nature; we have to surrender a portion of that freedom we’ve enjoyed in the state of nature and enter a political society.

Learn more about John Locke, the revolution in knowledge.

The Natural Laws of Politics

John Locke explained the natural laws of politics. Every society emerges as an organized whole because people need to look out for their property, not because some royal lawgiver imposes a divine order from the top down.

Beccaria echoed the same thoughts in On Crimes and Punishments in 1764:

Weary of living in a continual state of war, and of enjoying a liberty rendered useless by the uncertainty of preserving it, they sacrificed a part so that they might enjoy the rest of it in peace and security.

Emergence of Government

Thus, there was nothing mysterious or occult about government. Whenever a society decays or is diverted from that basic purpose of protecting rights and property, the people who made that society can devise something entirely new in its place.

Locke was perfectly happy for British society to remain a monarchy, since he regarded the British monarchy as the mildest form of monarchy in the world. But there had always been more radical voices, arguing that monarchs of any sort were an unnatural imposition on the sovereignty of the people, and therefore the only true and natural form of government was a republic.

Economics in Societal Setup

What was true for politics might also be true for economics. So long as society was conceived of as a hierarchy, kings were assured of the top spot, followed by nobles and the commons.

The idea that there might be another class, composed of tradesmen and merchants and bankers, excited only disdain from the kings and nobles, and resentment from the commons.

Until Adam Smith, there was no longer any inherent virtue in kings or nobles. If there was any virtue to be found in human society, it was in that much-despised commercial class, whose sober concentration on profit and trade was the real means of enriching everyone in society.

Adam Smith’s Contribution to Enlightenment

Just as the protection of property explained to Locke the reason for government, trade explained to Adam Smith what made societies happy and prosperous. He wrote in The Wealth of Nations:

Commerce and manufactures gradually introduced order and good government and with them, the liberty and security of individuals, among the inhabitants of the country, who had before lived in a continual state of war with their neighbors, and of servile dependency upon their superiors.  

Montesquieu, in his Spirit of the Laws, agreed with Smith.

Taken together, this new understanding of society and the new understanding of the physical universe created what the Germans called the Aufklärung, and what was known in English as the Enlightenment.

Learn more about Adam Smith’s argument for free trade.

Jefferson’s Education at William & Mary

Portrait of Thomas Jefferson.
Jefferson was much influenced by George Wythe and Francis Fauquier. (Image: Rembrandt Peale/Public domain)

James Blair, the first president of William & Mary, corresponded with John Locke. But little in the college’s curriculum reflected that connection, and when Jefferson arrived there in 1760 as a student, the tiny faculty were preoccupied more with adapting the new sciences to the rule of the old logic rather than emancipating the sciences from the old logic.

Jefferson’s real education came from two sources with only tenuous ties to the College. One was George Wythe, under whom he studied law, and the other was Virginia’s lieutenant governor Francis Fauquier.

Jefferson became part of Fauquier’s circle and owed much instruction to the habitual conversations around Fauquier’s table.

The Enlightenment Thought and Jefferson

How much that instruction revolved around Enlightenment poles can be seen from the first book list Jefferson compiled for a London bookseller, which ordered “Locke on Government” and Oeuvres de Montesquieu. And there was also a much longer reading list he drew up a year later listing Locke, Montesquieu, and Adam Smith.

Thirty-six years after that, his favorite reading suggestions were still “Locke on Government,” Smith’s Wealth of Nations, and Beccaria On Crimes and Punishments.

Thomas Jefferson had read his way into the Enlightenment.

Common Questions about Enlightenment Thinkers and Thomas Jefferson

Q: According to John Locke, why do people enter a political society?

According to John Locke, in order to get security for their property, the people have to leave the state of nature. They have to surrender a portion of that freedom they have enjoyed in the state of nature and enter a political society.

Q: According to Adam Smith, what made societies happy and prosperous?

Adam Smith believed that trade made societies happy and prosperous. “Commerce and manufactures gradually introduced order and good government,” Smith wrote in The Wealth of Nations, “and with them, the liberty and security of individuals.”

Q: Which books did Thomas Jefferson repeatedly include in his reading suggestions?

Thomas Jefferson’s favorite reading suggestions were “Locke on Government”, Smith’s Wealth of Nations, and Beccaria On Crimes and Punishments.

Keep Reading
Thomas Jefferson’s Books
History of the United States: Thomas Jefferson’s Idea of Self-Reliance
Diderot’s Encyclopedia: The Spirit of Enlightenment