Letter from Thomas Jefferson to John Trumbull

In this brief letter, Thomas Jefferson writes to John Trumbull, an American portraitist and painter famous for his depictions of events during the American Revolution. He requests that Trumbull make copies of his portraits of Francis Bacon, Isaac Newton, and John Locke.

Thomas Jefferson identified Francis Bacon, Isaac Newton, and John Locke as the “three greatest men that have ever lived, without any exception.” Bacon’s Novum Organum was instrumental in developing the modern scientific method; in Newton’s Philosophiæ Naturalis Principia Mathematica, he articulated his eponymous Laws of Motion and the law of universal gravitation, and Locke established the idea of empiricism, the idea that our knowledge comes through our senses and experience. Jefferson credited this trio with “having laid the foundation of those superstructures which have been raised in the Physical and Moral sciences.”

Jefferson is not alone in his appreciation of his scientific trio; John Adams also listed Bacon, Newton, and Locke as thinkers most important to his intellectual development. Adams believed these thinkers’ value was not in providing all the right answers on every scientific issue but that their writings together constituted a sound framework for approaching philosophical and political issues. In a similar vein, James Wilson, one of the six people to sign both the Declaration of Independence and the United States Constitution, listed Bacon, Newton, and Locke as the three minds who began the Age of Enlightenment.

The writings of Newton rejected the Aristotelian-​Christian view of nature guided by teleology, the idea that all things are guided by natural or divine purpose, striving to achieve their preordained ends. Newton instead posited that all living and nonliving things were subject to the same mechanical laws of nature. Newton’s vision of nature was not guided by a deity but by scientific laws that, unlike the will of God, can be explained and expressed. The scientific laws that govern nature can be seen as effects following a particular cause. He famously expressed this principle: “the same natural effects we must, as far as possible, assign the same causes.” Newton’s discoveries and writings inspired Enlightenment thinkers to perceive the universe as a well-​ordered machine that was complex but could be understood rationally.

Rejecting the Scholastic syllogistic reasoning that was then popular, In Novum Organum, Bacon developed a new method for discovering scientific truths. Bacon theorized that by examining experience and collecting and organizing data, we discover patterned relationships between cause and effect. For Bacon, experience and experimentation provided a method of understanding the world that was open to the unaided reason of each and every person. Knowledge of science was no longer reserved for a select few at the top of the hierarchy; in Locke’s words, we no longer need to submit to the “dictator[s] of principles.”

Lastly, John Locke, in his An Essay Concerning Human Understanding, argued that an objective system of ethics can be discovered scientifically, like the Newtonian laws of nature. For Locke, physical laws of nature were discoverable, and moral laws could be discovered by applying Bacon and Newton’s inductive method based on experience and observation. Locke’s view that our natural rights were discoverable by unaided reason became a core belief of the Enlightenment in Europe and the Founding Fathers’ philosophical northern star.

Though the Founding Fathers’ philosophy was based on classical writings and Biblical teachings, they also made ample room for the modern developments of science that occurred during the Enlightenment Period.