Gaius Cassius Longinus — yes, that Cassius, later one of Julius Caesar's assassins — had recently become a follower of the Epicurean school when this exchange with Cicero took place. Cicero, a committed Stoic / Academic Skeptic sympathizer, teases Cassius about his new philosophical loyalties — and Cassius answers with one of antiquity's clearest defenses of Epicurean ethics against the common charge that pleasure and virtue are opposites.

The letters below are given roughly in their exchange order: Cicero opens with a bit of gentle mockery, and Cassius replies with a serious philosophical defense worth reading in full.

Cicero to Cassius

Rome, January, 45 B.C. — Letter 15.16

I expect you must be just a little ashamed of yourself now that this is the third letter that has caught you before you have sent me a single leaf or even a line. But I am not pressing you, for I shall look forward to, or rather insist upon, a longer letter. As for myself, if I always had somebody to trust with them, I should send you as many as three an hour. For it somehow happens, that whenever I write anything to you, you seem to be at my very elbow; and that, not by way of visions of images, as your new friends term them, who believe that even mental visions are conjured up by what Catius calls spectres (for let me remind you that Catius the Insubrian, an Epicurean, who died lately, gives the name of spectres to what the famous Gargettian [Epicurus], and long before that Democritus, called images).

But, even supposing that the eye can be struck by these spectres because they run up against it quite of their own accord, how the mind can be so struck is more than I can see. It will be your duty to explain to me, when you arrive here safe and sound, whether the spectre of you is at my command to come up as soon as the whim has taken me to think about you — and not only about you, who always occupy my inmost heart, but suppose I begin thinking about the Isle of Britain, will the image of that wing its way to my consciousness?

But of this later on. I am only sounding you now to see in what spirit you take it. For if you are angry and annoyed, I shall have more to say, and shall insist upon your being reinstated in that school of philosophy, out of which you have been ousted "by violence and an armed force." In this formula the words "within this year" are not usually added; so even if it is now two or three years since, bewitched by the blandishments of Pleasure, you sent a notice of divorce to Virtue, I am free to act as I like. And yet to whom am I talking? To you, the most gallant gentleman in the world, who, ever since you set foot in the forum, have done nothing but what bears every mark of the most impressive distinction. Why, in that very school you have selected I apprehend there is more vitality than I should have supposed, if only because it has your approval. "How did the whole subject occur to you?" you will say. Because I had nothing else to write. About politics I can write nothing, for I do not care to write what I feel.

Cassius to Cicero

Brundisium, latter half of January, 45 B.C. — Letter 15.19

I hope that you are well. I assure you that on this tour of mine there is nothing that gives me more pleasure to do than to write to you; for I seem to be talking and joking with you face to face. And yet that does not come to pass because of those spectres; and, by way of retaliation for that, in my next letter I shall let loose upon you such a rabble of Stoic boors that you will proclaim Catius a true-born Athenian.

I am glad that our friend Pansa was sped on his way by universal goodwill when he left the city in military uniform, and that not only on my own account, but also, most assuredly, on that of all our friends. For I hope that men generally will come to understand how much all the world hates cruelty, and how much it loves integrity and clemency, and that the blessings most eagerly sought and coveted by the bad ultimately find their way to the good. For it is hard to convince men that "the good is to be chosen for its own sake"; but that pleasure and tranquillity of mind is acquired by virtue, justice, and the good is both true and demonstrable. Why, Epicurus himself, from whom all the Catiuses and Amafiniuses in the world, incompetent translators of terms as they are, derive their origin, lays it down that "to live a life of pleasure is impossible without living a life of virtue and justice."

Consequently Pansa, who follows pleasure, keeps his hold on virtue, and those also whom you call pleasure-lovers are lovers of what is good and lovers of justice, and cultivate and keep all the virtues. And so Sulla, whose judgment we ought to accept, when he saw that the philosophers were at sixes and sevens, did not investigate the nature of the good, but bought up all the goods there were; and I frankly confess that I bore his death without flinching. Caesar, however, will not let us feel his loss too long; for he has a lot of condemned men to restore to us in his stead, nor will he himself feel the lack of someone to bid at his auctions when once he has cast his eye on Sulla junior.

And now to return to politics; please write back and tell me what is being done in the two Spains. I am terribly full of anxiety, and I would sooner have the old and lenient master [Caesar], than make trial of a new and cruel one. You know what an idiot Gnaeus is; you know how he deems cruelty a virtue; you know how he thinks that we have always scoffed at him. I fear that in his boorish way he will be inclined to reply by wiping our turned-up noses with the sword. Write back as you love me, and tell me what is doing. Ah! how I should like to know whether you read all this with an anxious mind or a mind at ease! For I should know at the same time what it is my duty to do. Not to be too long-winded, I bid you farewell. Continue to love me as you do. If Caesar has conquered, expect me to return quickly.

On March 15th, 44 B.C., Caesar was killed in the senate-house by a group of senators, led by Brutus and Cassius. The next letter, written by one of the conspirators, describes the situation in Rome a few days later (the exact date is disputed).

Source: the complete correspondence between Cassius and Cicero, including the letters that follow Caesar's assassination, is collected at EpicureanFriends.com's Cassius Longinus resource page.

Last modified: Tuesday, 15 September 2026, 4:35 PM