Thomas Jefferson rarely wrote philosophical treatises for publication – his views on religion and philosophy survive mainly in his private letters. But in those letters, Jefferson was direct: he called himself an Epicurean by name, he considered Epicurus's actual teaching to have been badly misrepresented by its enemies, and he was relentlessly critical of Plato and of the Platonism he saw grafted onto Christian theology. He also rejected "immaterialism" outright, insisting that only the evidence of the senses gives us anything to reason from.

Below are excerpts from three of his most direct letters on the subject, with links to the complete originals for anyone who wants to read further.

To William Short, October 31, 1819

The letter containing Jefferson's explicit "I too am an Epicurean"

As you say of yourself, I too am an Epicurean. I consider the genuine (not the imputed) doctrines of Epicurus as containing everything rational in moral philosophy which Greece and Rome have left us. Epictetus indeed, has given us what was good of the stoics; all beyond, of their dogmas, being hypocrisy and grimace. Their great crime was in their calumnies of Epicurus and misrepresentations of his doctrines; in which we lament to see the candid character of Cicero engaging as an accomplice.

I take the liberty of observing that you are not a true disciple of our master Epicurus, in indulging the indolence to which you say you are yielding. One of his canons, you know, was that "that indulgence which prevents a greater pleasure, or produces a greater pain, is to be avoided." Your love of repose will lead, in its progress, to a suspension of healthy exercise, a relaxation of mind, an indifference to everything around you, and finally to a debility of body, and hebetude of mind, the farthest of all things from the happiness which the well-regulated indulgences of Epicurus ensure; fortitude, you know is one of his four cardinal virtues. That teaches us to meet and surmount difficulties; not to fly from them, like cowards.

I will place under this a syllabus of the doctrines of Epicurus, somewhat in the lapidary style, which I wrote some twenty years ago.

— Thomas Jefferson

Syllabus of the Doctrines of Epicurus (enclosed with the letter)
  • Physical: The Universe eternal. Its parts, great and small, interchangeable. Matter and void alone. Motion inherent in matter, which is weighty and declining, in eternal circulation of the elements of bodies. Gods, an order of beings next superior to man, enjoying in their sphere their own felicities, but not meddling with the concerns of the scale of beings below them.
  • Moral: Happiness the aim of life. Virtue the foundation of happiness. Utility the test of virtue. The summum bonum is to be not pained in body, nor troubled in mind – i.e., indolence of body, tranquility of mind. Man is a free agent. Virtue consists in: 1. Prudence, 2. Temperance, 3. Fortitude, 4. Justice.

To John Adams, July 5, 1814

On reading Plato's Republic

… I amused myself with reading seriously Plato's Republic. I am wrong, however, in calling it amusement, for it was the heaviest task-work I ever went through. … While wading through the whimsies, the puerilities, and unintelligible jargon of this work, I laid it down often to ask myself how it could have been, that the world should have so long consented to give reputation to such nonsense as this?

The Christian priesthood, finding the doctrines of Christ levelled to every understanding, and too plain to need explanation, saw in the mysticism of Plato, materials with which they might build up an artificial system, which might, from its indistinctness, admit everlasting controversy, give employment for their order, and introduce it to profit, power and pre-eminence. The doctrines which flowed from the lips of Jesus himself are within the comprehension of a child; but thousands of volumes have not yet explained the Platonisms engrafted on them; and for this obvious reason, that nonsense can never be explained.

But why am I dosing you with these antediluvian topics? Because I am glad to have some one to whom they are familiar, and who will not receive them as if dropped from the moon…

To John Adams, August 15, 1820

On matter, spirit, and "immaterialism"

… I was obliged to recur ultimately to my habitual anodyne, "I feel: therefore I exist." I feel bodies which are not myself: there are other existencies then. I call them matter. I feel them changing place. This gives me motion. Where there is an absence of matter, I call it void, or nothing, or immaterial space. On the basis of sensation, of matter and motion, we may erect the fabric of all the certainties we can have or need.

To talk of immaterial existences is to talk of nothings. To say that the human soul, angels, god, are immaterial, is to say they are nothings, or that there is no god, no angels, no soul. I cannot reason otherwise…

Rejecting all organs of information therefore but my senses, I rid myself of the Pyrrhonisms with which an indulgence in speculations hyperphysical and antiphysical so uselessly occupy and disquiet the mind. A single sense may indeed be sometimes deceived, but rarely: and never all our senses together, with their faculty of reasoning. They evidence realities; and there are enough of these for all the purposes of life, without plunging into the fathomless abyss of dreams and phantasms.

Source: excerpted from a much longer collection at EpicureanFriends.com's Thomas Jefferson resources page, which includes several further letters on the same themes.

Last modified: Tuesday, 15 September 2026, 10:00 AM