The wise man is full of joy, cheerful and calm, undisturbed. Now examine yourself: if you are never sad, if no hope disturbs your mind with anticipation of the future, if by day and night the condition of your spirit is even and unvarying, alert and happy with itself, then you have reached the high point of human good. But if you constantly desire all kinds of pleasures, know that you are as far from wisdom as of joy. You want to reach this state, but you are misleading yourself in thinking that you will get there surrounded by wealth and honors; that is, you are looking for joy in the midst of anxieties. The very things you seek as if they would give you happiness and pleasure are the causes of your distress. I mean that all men aim for joy in that way, but they do not know the source of stable and lasting success. One man seeks it from parties and self-indulgence, another from ambition and a sprawling crowd of clients, another from his girlfriend, and yet another from the hollow display of culture and from writing that gives him no healing. All those men are deceived by false and short-lived distractions, like drunkenness which pays for the cheerful craziness of a single hour with the discomfort of a long period, or applause and favor of a supporting crowd, favor won by great anxiety which will have to be atoned for by as much. So think that this is the outcome of wisdom, to achieve evenness in joy. The wise man’s mind is like the universe beyond the moon: there is always fine and calm. So you have another motive to want to be wise, if the wise man is never without joy. Such joy only arises from the awareness of one’s virtues; no-one can rejoice except the brave, just, and temperate man.

From Seneca’s Letter 59 (Book VI) in Selected Letters, translation by Elaine Fantham, Oxford: Oxford University Press, 2009, p. 92.