By Dave Dietrich
"To the living we owe respect, but to the dead we owe only truth.”–Voltaire
Writer and author, James C. Thompson, has written extensively on the social-networking relationships between Thomas Jefferson and many of the movers and shakers of the French Enlightenment, people with whom Jefferson became familiar during the period of his Paris years, 1784-1789. Yet one significant mover and shaker Thomas Jefferson never had the pleasure of meeting was François-Marie Arouet, known better to the world as Voltaire. Unfortunately, Voltaire had passed away in 1778, six years before Jefferson arrived in Paris. Even so, history leaves us hints that the contours of much of Jefferson’s thinking might have been influenced profoundly by Voltaire.
François-Marie Arouet (Voltaire) was born in Paris, France on 21 November 1694. He passed away at age 84 on 30 May 1778. Adopting the nom de plume, “Voltaire,” he became the greatest intellectual influence of the 18th century French Enlightenment, the le Siècle des Lumières—the “century of lights,” or “age of illumination.” Noted for his profound wit and polemical satire, Voltaire was the author of poetry, dramas, essays, historical works, and perhaps most significant, the Philosophical Tale, the most famous being the novella, Candide (1759). In his Philosophical Tales, Voltaire critiqued many of the beliefs and institutions of his day through use of metaphor, veiled satire, and double entendre. Voltaire was also noted as a promoter of the sciences, particularly the scientific ideas of the Englishmen Isaac Newton (physics) and Francis Bacon (scientific method). To promote Baconian-Newtonian thinking among the general population, Voltaire worked closely with another great thinker of the day, Gabrielle Émilie Le Tonnelier de Breteuil, the Marquise Du Châtelet (1706-1749). While living together at the Châtelet estate in Cirey, France (1735-1749), Voltaire and “the divine Émilie” helped popularize the Newtonian-Baconian science of the day.
Education of a Sage and Voltairean Discovery: A Background
The other half of the intellectual connection was of course Thomas Jefferson. He was also a student of, and contributor to, the 18th century Enlightenment, the Age of Reason. His formative years and his formal educational experiences occurred during that period. His views and values were greatly influenced by what he experienced in that era, by the education he received, the people with whom he became acquainted, and the events he witnessed. Of note, Jefferson was directly exposed to the American, Anglo-Scottish, and French Enlightenments. He helped shape the American Enlightenment while contributing at least indirectly to the later period of the French Enlightenment.
Beginning in 1760, Thomas Jefferson attended the College of William and Mary in Williamsburg, Virginia. There he studied under Professor William Small (1734-1775), a proponent of Enlightenment thought, particularly in the areas of science, mathematics, and philosophy. It was at William and Mary and under the direction of Small where Jefferson was probably first exposed to the Enlightenment ideas of the English empiricists, namely John Locke, Francis Bacon, and Isaac Newton. Small also introduced Jefferson to the Scottish philosophers, Adam Smith and David Hume, and to the French philosophes, including Voltaire.
During his years in Paris as the United States Ambassador Plenipotentiary to the Court of Louis XVI (1784-1789), Jefferson was exposed further to the ideas of the French Enlightenment. He received this exposure through direct contact with the philosophes, both in private settings and in the salons of Paris. Salons were highly popular in France in the 18th century. Essentially social gatherings of the upper classes, salons were focal points for presentations and discussions on various topics. The philosophes, philosophers of the French Enlightenment known for knowledge, profound analytical acumen, sagacity, and often wit, frequented these salons. Generally, they were renown experts in certain fields of inquiry that included political theory, economics, natural science, and so forth. By far, the philosophe who enjoyed the greatest reputation—even becoming a kind of metaphor for the times—was Voltaire.
As mentioned, by the time Thomas Jefferson was in Paris (1785-1789), Voltaire had been dead for several years. Yet his intellectual reputation and profound influence had survived his death, and Jefferson met Voltaire vicariously in the Salons of Paris, through the vast written legacy generated by him, and though contact with those whom Voltaire had influenced directly.
Voltaire and Jefferson’s Private Library
One significant hint at an intellectual connection between Jefferson and Voltaire, beyond the former’s schooling and association with Parisian salons, can be found in Jefferson’s private libraries. Thomas Jefferson owned copies of many of Voltaire’s published works, and his Voltairean holdings were in fact quite extensive. Most of these works were kept among the approximately 7,000 books that made up Jefferson’s private library at Monticello. Others works were part of a smaller private library of approximately 1,000 books, maintained at Jefferson’s retreat home of Poplar Forest, near Lynchburg, Virginia.
In all, Jefferson’s library holdings of Voltaire’s published works included, among others:
Commentaire sur Le Livre des Délits et des Peines: Par un Avocat de Province (1766), (English title translation: Commentary on the Book of Offenses and Punishments: by a Provincial Advocate)
Mémoires de M. de Voltaire, Ecrits par Lui-Même (1784), (English title translation: Memoirs of M. de Voltaire, Written by Himself)
Dictionnaire Philosophique (1765), (English title translation: The Philosophical Dictionary for the Pocket)
La Philosophie de l'Histoire (1765), (English title translation: The Philosophy of History)
Saül: Tragedie Tirée de l'Ecriture Sainte (1755), (English title translation: Saul: Tragedy from Scripture)
Oeuvres de M. de Voltaire (1775), (English title translation: Works of M. de Voltaire), Geneva—Kehl edition
Œuvres Complètes de Voltaire (1785), (English title translation: Complete Works of M. de Voltaire), Beaumarchais edition
L'histoire de Charles XII: Roi de Suède (1740), (English title translation: The History of Charles XII: King of Sweden)
Oeuvres de Voltaire. Nouvelle Edition, avec des Notes et des Observations Critiques (1792) (English title translation: Works of Voltaire. New Edition, with Notes and Critical Observations)
Henriede, (published in 1723)
An Essay on Crimes & Punishments [by Cesare Beccaria], translated from Italian, with commentary attributed to Voltaire (translated from French). TJ’s copy produced in 1809.
Candide, ou L’optimisme (English title translation: Candide, or Optimism). TJ’s copy produced in 1780.
Histoire de I’empire de Russie sous Pierre le Grand (English title translation: History of the Russian Empire Under Peter the Great). TJ’s copy produced in 1809.
For sure, this extensive private collection provides subtle yet prime-facie evidence of the intellectual influence of Voltaire on the life of Thomas Jefferson.
Voltaire’s Influence on Jefferson’s Systematic Thinking
Although there is scant evidence that Jefferson cited much of Voltaire’s work in his own writings, Voltaire may have influenced Jefferson nevertheless, particularly on the latter’s view of systematic discovery as expressed in the ideas of Francis Bacon and Isaac Newton. Francis Bacon (1561-1626) and Isaac Newton (1642-1727) were Englishmen responsible for advancing mathematics and physics (Newton), and the scientific method (Bacon) during the scientific revolution of the 16th-18th centuries. Voltaire deeply admired them both. Another thinker of the age whom Voltaire admired was John Locke (1632-1704), the father of modern skeptical empiricism. Like Voltaire, Jefferson held these three enlightened thinkers in high regard:
Voltaire wrote in 1733,
“Therefore, as you are desirous to be informed of the great men that England has produced, I shall begin with the Bacons, the Lockes, and the Newtons” and,
“Since, therefore, you desire me to give you an account of the famous personages whom England has given birth to, I shall begin with Lord Bacon, Mr. Locke, Sir Isaac Newton…”
In the parlor of Jefferson’s primary home of Monticello hang the paintings of Newton, Bacon, and Locke, tacit acknowledgement at least of the Voltairean assessment that these three had constituted the greatest minds of the age, particularly as articulated in Voltaire’s Lettres Philosophiques (1733-1734). Perhaps as further hint of that Voltairean influence, Jefferson himself wrote:
“Bacon, Locke and Newton…I consider them as the three greatest men that have ever lived, without any exception, and as having laid the foundation of those superstructures which have been raised in the Physical and Moral sciences…”
Voltaire’s influence on Jefferson can also be seen in his works Jefferson recommended to his friends and acquaintances. As example, in 1785 Jefferson provided to Walker Maury a list of books that included a reference to Voltaire. Ses ouvrages historiques (Translation: Voltaire, his historical works.) In a letter to Richard Mentor Johnson, dated 10 March 1808, Jefferson recommended again Voltaire’s historical works as good history worth reading and reflecting upon.
A Tentative Evaluation
Overall, Voltairean influence on Thomas Jefferson can be seen—albeit somewhat subtly—in the former’s works present in Jefferson’s libraries, in Jefferson’s private letters that reference these works, and in Jefferson’s stated admiration for the same three Enlightenment thinkers that so moved Voltaire. Moreover, the nature of the philosophies that Voltaire himself embraced, developed and promoted, including ideas regarding religious liberty, philosophy—particularly skeptical empiricism, the concept of separation of church and state, belief in God based on reason, particularly as understood from the standpoint of 18th century positive deism, the application of systematic reason, and the falsifiability and testability inherent in modern science, are to be found in the ideals and ideas of the Sage of Monticello, shaped in many ways perhaps by le patriarche, the patriarch of the French Enlightenment—Voltaire.
Finally, in perhaps the greatest testimony that this is most certainly true, visitor’s to Monticello in Jefferson’s day were greeted in the Entrance Hall by the bust of Voltaire, a copy of the bust created originally by the French artist, Jean-Antoine Houdon (1741-1828). Thus, Voltaire occupied a high and noble space in Jefferson’s implied pantheon of heroes. The bust can be seen there still by visitors today.
For sure, both helped shape the modern world.
Dave Dietrich served for over forty years as a professional national security analyst and educator at the international, national, and military service levels. Since his retirement, he has been working both as an Assistant Professor of Political Science and as a volunteer docent at a Thomas Jefferson historical site. He is also a director for the Thomas Jefferson Heritage Society (TJHS). He is also the author of serval TJHS articles on Thomas Jefferson, including: Dissing Thomas: An Apologia (2017); Thomas Jefferson and Abigail Adams: A Singular Correspondence (2018); and Thomas Jefferson and the Enlightenment (2018).
The author acknowledges with gratitude the advisory and research contributions that Anna Berkes (Thomas Jefferson’s Monticello), Endrina Tay (Jefferson Library, Thomas Jefferson’s Monticello), Rachel Honchul (Programs and Education Coordinator at Poplar Forest), and Travis McDonald (Director of Architectural Restoration at Poplar Forest) made to this article.
 James C. Thompson, Thomas Jefferson’s Enlightenment, Pars 1785, (Alexandria, Virginia: Commonwealth Book Publishers of Virginia), 2013, ISBN: 978-0-9854863-1-0
 Jefferson did refer to Voltaire in his book, Notes on the State of Virginia, Query VI, but about Voltaire’s thought regarding the origins of animal shells. See Jefferson, Notes on the State of Virginia, Query VI, A Notice of the Mines and Other Subterraneous Riches; its Trees, Plants Fruits, &C., 1785.
 Voltaire, Philosophical Letters. First published in 1733 as, "Lettres Philosophique" (Philosophical Letters)
 Voltaire, Philosophical Letters, Letter XII- On the Lord Bacon, 1733
 TJ to John Trumbull, Paris, 15 February 1789
 TJ to Walker Maury, 19 August 1785
 TJ to Richard Mentor Johnson, 10 March 1808
 Jefferson was also influenced by Montesquieu.
 Positive deism was the belief that God’s existence and moral laws could be known through nature. Positive deism was opposed by critical deism, which was a denial of any supernatural knowledge.