Lives and Opinions of Eminent Philosophers

​one must not believe that our need concerning these matters has not received all the precision that contributes to our tranquility and blessedness. Wherefore, observing in parallel in how many ways the similar occurs among us, we must give causal explanations both for celestial phenomena and for everything unobserved, holding in contempt those who recognize neither that which is or comes to be in a single way, nor that which happens in multiple ways, having overlooked the presentation arising from distances, and moreover being ignorant both in what matters it is not possible to be untroubled 〈and in what matters it is likewise possible to be untroubled.〉 If therefore we believe that it is possible for it to happen in this way too, knowing the very fact that it happens in multiple ways, just as if we also knew that it happens in this particular way, we shall be untroubled.

"In all these matters generally, one must comprehend this: that the most sovereign disturbance occurs in human souls by holding opinions that these bodies are blessed 〈and〉 incorruptible, while simultaneously attributing to them volitions, actions, and causal motives contrary to such a state; and by constantly expecting or suspecting some everlasting terror in accordance with the myths, or even fearing the very lack of sensation in death as though it were an actual state concerning themselves; and by suffering these things not by reasoned opinion but through some irrational impression, whence, failing to define the limit of terror, they take on equal or even intensified disturbance compared to one who merely holds these opinions at random.

​Tranquility, on the other hand, consists in having been released from all these things and in maintaining a continuous memory of the general and most sovereign doctrines. "Hence, one must pay attention to present feelings—to common perceptions in accordance with what is common, and to peculiar perceptions in accordance with what is peculiar—and to all present clear evidence according to each of the criteria. For if we attend to these, we shall correctly assign the cause of the source whence disturbance and fear arose and dissolve them, giving causal explanations both for celestial phenomena and for the remaining occurrences that continually happen, which terrify the rest of mankind to the utmost degree. "These, O Herodotus, are for you the most summary epitomes concerning the nature of all things.

​Wherefore, if this discourse should prove capable of being grasped with precision, I think that even if one does not advance to all the detailed precisions, he will acquire an incomparable vigor in relation to the rest of mankind. For it will of itself make clear many of the points investigated in detail throughout our entire treatise, and these very principles, continuously kept in memory, will provide aid. "For they are of such a kind that even those who already investigate the particulars adequately or completely, by analyzing them into such comprehensive conceptions, make most of their surveys concerning the whole of nature; while as many as do not fully belong to the accomplished class make from these, and in a silent manner, their survey of the most sovereign points simultaneously with thought, toward serenity." And this is his letter on natural philosophy. The one on celestial phenomena is as follows: "Epicurus to Pythocles, greetings.

​Cleon brought me a letter from you, in which you continued to feel affectionately toward us in a manner worthy of our zeal for you, and were striving not unpersuasively to remember the reflections contributing to a blessed life, and requested that a concise and easily circumscribed reflection concerning celestial phenomena be sent to you, so that you might easily remember it; for what has been written by us elsewhere is difficult to remember, even though, as you said, you constantly carry it about with you. We gladly welcomed your request and were held by pleasant hopes.