This governs the ordinary conditions of a life that is running out: what you do with your days, who you let near you, how much you need, and how you meet illness, loss, and the end. Seneca's single claim is that almost nothing that frightens or exhausts a person is caused by circumstance, so the fix is never a change of setting. He writes as a fellow patient rather than a doctor, so the rules below are ones he tried on himself first, and the last section holds the positions they stand on, claims to accept rather than tasks to perform.

Do

Decide about a person before you make them a friend, then hold nothing back. Lucilius called someone a friend and in the same breath told Seneca not to speak freely around him, which Seneca calls putting the cart before the horse. Think for a long time about whether to admit someone; once you have, welcome them heart and soul and share your worries too. [Source: "Reading Deeply, and Testing a Friend Before Trusting Him"]

Treat the people below you exactly as you want the people above you to treat you. Lucilius was praised for dining with his own slaves, and Seneca answers the standard objection four times over, widening it until it lands on fortune holding the same power over the master. His reading of the silent Roman dinner, where a slave is beaten for coughing, is causal: a household kept mute manufactures the enemies it then fears, while masters who could actually converse with theirs once had men willing to die for them. [Source: "They Are Slaves — But They Are Men"]

Put real poverty in the calendar, several days at a time. During the Saturnalia, with the whole city drunk, Seneca proposes the opposite exercise: plain food and very little of it, rough clothing, and the question of whether this is really what one used to dread. He is explicit that the pallet must be real and the bread hard and grimy, because the rich man's mock poor-room is an amusement, not a trial. [Source: "Rehearsing Poverty During the Saturnalia"]

Choose one specific person of character and act as though they are watching. His instruction is to pick yourself a Cato, or a Laelius if Cato seems too severe, and hold that person's way of life, words, and face constantly before you, on the reasoning that without a ruler to work against you will not get the crooked straight. [Source: "The Blush Wisdom Cannot Cure, and the Witness You Should Carry"]

Close every night as though the course were already run. He borrows Pacuvius's habit of staging his own funeral each evening and repurposes it: go to bed saying you have lived and completed the course fortune allotted you, so that any further day arrives as a windfall rather than as an entitlement. [Source: "Old Age at the Villa Gate, and Rehearsing the Final Verdict"]

Look back over the day before you plan the next one. He opens his own routine to Lucilius as a worked example, sleep, reading, a token run, a barely cold plunge, on the argument that what ruins characters is that nobody reviews their own life, and that planning ahead depends on reading the past honestly. [Source: "A Daily Accounting, and the Case Against Drunkenness by Example, Not Syllogism"]

Test a want by asking whether getting it would end the wanting. His diagnostic is exact: a natural desire can come to rest at some point, while one manufactured by opinion has nowhere to stop, because falsity has no point of termination. If there is always something further away, the want was never yours to satisfy. [Source: "Philosophy Is Necessary Whether Fate, God, or Chance Rules the World"]

Rehearse the disaster you consider impossible, not just the one you consider likely. Lyons, the showpiece of Gaul, burned to nothing in a single night, and Seneca's consolation to Liberalis is that the shock came from its being unlooked for. His instruction is to anticipate not merely what commonly happens but everything conceivably capable of happening. [Source: "The Fire That Erased Lyons in a Single Night"]

Stop collecting other people's sentences and produce a verdict of your own. He refuses Lucilius's request for more quotable maxims and turns it back: Zeno said this, and what have you said, Cleanthes said that, and what have you said, how long will you serve under others' orders. To remember is to safeguard something entrusted to you; to know is to make it yours. [Source: "Stop Quoting and Start Producing Your Own Wisdom"]

Talk less, to fewer people, about less. His list of what makes one person harm another has exactly five entries, hope, envy, hatred, fear, and contempt, each starved by not becoming a plausible target for it. His most concrete measure is keeping quiet, since conversation has a charm that draws secrets out the way love or liquor does. [Source: "Rules for a Quiet Life: Naming the Five Things That Goad Men to Harm One Another"]

Don't

Don't try to fix a life by changing where you live. Lucilius toured extensively and came back with the same melancholy, which is what Seneca expects: what he needed was a change of character, not of air. Socrates' rebuke to a chronic complainer does the whole job, that he carries himself around wherever he goes. [Source: "You Cannot Flee Yourself by Changing Country"]

Don't wear the change instead of making it. Unkempt beards, sleeping on the ground, loudly refusing silverware: he calls these misguided means to self-advertisement that make philosophy look strange rather than admirable. Inwardly everything should be different while the outward face conforms with the crowd. [Source: "Philosophy Without a Costume, and Becoming Your Own Friend"]

Don't wait for quiet before doing the work. He lodged directly above a public bath and catalogues the racket beneath him, grunting weightlifters, slapping masseurs, a shouting ball score, a shrieking hair-plucker, competing food hawkers, and works through all of it. A man who makes his whole household walk on tiptoe still tosses in bed and complains of sounds he never heard. [Source: "Lodgings Over a Bathhouse: Peace Is Internal, Not Acoustic"]

Don't buy the appearance of knowing something. Calvisius Sabinus, who could not keep straight the names of Ulysses, Achilles, and Priam, bought slaves trained to hold Homer and the lyric poets in memory and quoted them at dinner through borrowed mouths. Told each cost a hundred thousand sesterces, Satellius Quadratus observed that bookcases would have been cheaper. [Source: "The Patient Advising the Patient, and the Man Who Bought His Own Memory"]

Don't pick up a habit on the grounds that a lot of people have it. He names imitation as a live cause of trouble: we would not copy certain habits if only a few people did them, but once many do we follow along, as though a practice became respectable by becoming common. Corrosive talk in particular leaves a seed that surfaces long after the company is gone. [Source: "Bad Bread at Alba, and the Danger of Borrowed Vices"]

Don't count a withdrawal as a life. Vatia was famous for the line that he alone knew how to live, and Seneca's verdict on his abandoned estate is flat: what he knew was how to hide. Someone who ran from the world because he could not bear the sight of luckier people is not living for himself, he is living for his belly and his sleep. [Source: "Vatia's Villa, and What Real Retirement Requires"]

Don't stage a grief you are also supposed to be feeling. His standard on Flaccus's death is tears without lamentation, and his charge against extravagant mourning is that it is aimed at an audience, an attempt to prove the loss registered rather than an expression of it. He forfeits his own standing to be stern about it, having wept for Serenus past all control and counting himself among the men grief defeated. His corrections are plain: hold in advance that friends of any age are as liable to death as you are, and afterward look for someone new to love rather than settle beside the loss. [Source: "Grieving Without Excess — and Seneca's Own Failure at It"]

Don't sit in a crowd you cannot leave unchanged. He went to a lunchtime arena show expecting light entertainment and found unarmed condemned men made to kill each other in sequence while the crowd screamed for the reluctant to be whipped forward. He came home, he records, more selfish and less humane for having only watched. [Source: "The Crowd and the Arena"]

Hold

Death is the same condition as the time before you were born. His asthma attacks, which his doctors nicknamed rehearsing death, gave him the argument: a lamp is no worse off after being put out than it was before it was lit, and death precedes as well as succeeds. Held, mortality stops being an event waiting ahead of you and becomes a state you have already been in. Refused, you spend a whole life bracing against the one half of your non-existence that happens to lie in front of you. [Source: "Asthma, and Death as the Lamp Before It Was Lit"]

A life is complete at whatever length it reaches, and length is not the measure. He argues it through the death of Marcellinus, worn down by a chronic and incurable illness, whose friends offered timid deference or flattery until one put the question properly, that staying alive is something every animal manages and what is worth doing is ending well. His own formulation is that a life runs like a play, where what counts is not how long the acting lasts but how good it is, so where a short life stops matters far less than whether it is rounded off. Held, a life that feels unfinished stops being an argument for more time. Refused, duration is the thing you accumulate and no amount of it settles the account. [Source: "Death Is Never Untimely — Marcellinus's Chosen Ending"]

The fault furthest along is the one you can no longer feel. A sprained ankle eventually forces an admission of gout, but with afflictions of the spirit the worse a person is the less they notice, the way light sleep still admits dreams while heavy slumber blots them out. Nobody confesses their failings, he says, because they are still deep in them. Holding this makes your own sense of being fine weak evidence. Refusing it makes that feeling proof. [Source: "Seasickness, and Why We Never Notice Our Worst Faults"]

Some of what you are will never yield to training. A talented young man blushed under the strain of an unrehearsed conversation, and Seneca predicts it will follow him even once he is wise. Sulla flushed with anger, Pompey blushed in public, Fabianus blushed before the Senate, and trained actors who can produce grief, fear, and a downcast gaze on command cannot produce a blush. Holding this stated limit on what self-mastery covers saves you fighting your own physiology instead of your judgment. [Source: "The Blush Wisdom Cannot Cure, and the Witness You Should Carry"]

Which force actually runs the universe does not change your assignment. Lucilius raised the standard objection, that planning is pointless if fate or God or chance already decides. Seneca refuses to settle the metaphysics and makes it irrelevant: submit cheerfully under providence, bear it with defiance if events are random, and either way the work of ordering your own conduct is unchanged. Held, the question stops being a prerequisite for acting. Not held, it becomes a permanent reason to wait. [Source: "Philosophy Is Necessary Whether Fate, God, or Chance Rules the World"]

Loss, betrayal, and burial are the standing terms, not the exceptions. Lucilius was rattled that his slaves fled during a business crisis, and Seneca refuses to call it an injury: being put out by it is as ridiculous as grumbling about being spattered in the street. You will part from one companion, bury another, and come to fear a third, and his translation of Cleanthes puts the choice in one line, that fate leads the willing and drags the unwilling. Holding it changes only whether you arrive at the same place upright. [Source: "Willing What Must Be: Runaway Slaves and Cleanthes' Hymn"]

Nothing arranged around you is any part of you. A gilded bit does not improve a horse, and a lion with his mane gilded for the arena is diminished next to a wild one. A fine house and a handsome retinue are not in a man, they are around him, and the only thing genuinely his is his spirit and the perfection of his reason in it. Held, this tells you which losses are actually losses. Refused, you defend the whole arrangement with equal urgency and spend yourself on the parts you were only lent. [Source: "The God Within, and Praising Only What Is Truly Your Own"]

Everyone is serving something, and the only disgraceful version is the one you chose. A slave's rank is fortune's assignment rather than a fact of nature, and his proof is Callistus, sold off among the rejects and later installed as the gatekeeper who refused his former master admission. Seneca then turns the category on his reader: one man serves sex, another money, another ambition, and all of them serve hope or fear. Held, rank stops being evidence about a person. Refused, you read your own position as earned and everyone else's as natural. [Source: "They Are Slaves — But They Are Men"]

Pain that is severe cannot last, and pain that lasts is not severe. Writing from his own chronic catarrh, bad enough in his youth that only his father held him back from ending his life, he names three burdens of illness, the fear of dying, the physical suffering, and the interruption of pleasure, and dismantles each. Concentrated pain goes numb quickly, and past a certain intensity registers as stupefaction rather than pain. Holding it removes the imagined version of suffering, which is the version that is actually unlimited. [Source: "How to Endure Illness: Pain Is Either Brief or Bearable"]

Nature's demands are small; the unlimited ones came from us. Against Posidonius, who credited philosophy with inventing weaving, farming, and architecture, Seneca insists ordinary ingenuity did all that, and that whoever discovers a saw is not thereby wise. His preferred figure is Diogenes smashing his own cup after seeing a boy drink from cupped hands, and his charge is that we made everything hard to come by through disdain for what was easy. Held, scarcity becomes a thing you can partly opt out of. Not held, every rung of comfort silently becomes the new floor. [Source: "Philosophy Did Not Invent the Loom, the Bakery, or the Golden Age"]

The one line

Nothing you can travel away from is the problem, almost nothing you need is expensive, and the clock on all of it is shorter than you are behaving as though it is.