Stoicism is not a doctrine you understand but a practice you do. The Stoics knew that and prescribed exercises: small, repeatable acts meant to let an insight sink from your head into your reflexes.
Below are the nine that survive best. For each one: where it comes from, what it does, and how you carry it out today. None of them asks for more than a few minutes.
Source: Epictetus, Enchiridion 1
The basic exercise all the others rest on. Epictetus opens the Enchiridion with it: some things are in our power, others are not. In our power: our judgment, our intention, our desire, our aversion. Not in our power: our body, our property, our reputation, our office.
How to do it. Take one thing that is troubling you today and split it out loud in two. What happened, and what are you making of it? What can you do tomorrow, and what lies with someone else? The exercise is not the answer but the splitting; most unrest comes from confusing those two.
Source: Seneca, Letters 91 and 107; Marcus Aurelius, Meditations II.1
Premeditatio malorum: the habit of calmly considering at the start of the day what might go wrong. Marcus did it every morning and noted that he would meet difficult people that day. Seneca wrote that fortune can take back everything it has given, and that whoever knows this is never ambushed.
How to do it. Take one minute before your day begins. What could go wrong today, and what would you do then? Once, concretely, and then done. The difference with worrying is that worrying ends nowhere and this ends in a plan.
Source: Seneca, On Anger III.36
Seneca describes going over his day every evening once the light was out and his wife had fallen silent: what did I improve today, where did I fall short, what can I do differently tomorrow. He stresses that it is not about punishing yourself but judging yourself the way a judge who knows the case would.
How to do it. Three questions at the end of your day, out loud or on paper. What went well? Where did I fall short? What will I do differently tomorrow? Strict on the behaviour, gentle on the person; that distinction is the whole art.
Source: Marcus Aurelius, Meditations VII.48, IX.30, XII.24
Marcus repeatedly moves himself to a great height and looks down on the world: the weddings, the lawsuits, the markets, the armies, the funerals, all at once and all small. The exercise lifts you out of your own perspective and returns your case to its actual size.
How to do it. Imagine looking down on your own situation from a great height, then zoom out further: your street, your city, the country, the century. Where does the thing that woke you this morning sit? Not to make it unimportant, but to give it back its right proportion.
Source: Seneca, Letters 18; Musonius Rufus, Discourse 6
Seneca advised living deliberately simply for a few days a month: the plainest food, the roughest cloak, a hard bed, and then asking yourself whether this was what you had feared. Musonius had his students get used to cold and hunger, not out of self-punishment but to move the threshold.
How to do it. Pick something small and uncomfortable and do it deliberately. A cold shower, a day without coffee, the stairs instead of the lift, a meal that amounts to nothing. The point is not the suffering but the discovery: this is bearable, and so my fear of it has less ground than I thought.
Source: Marcus Aurelius, Meditations VI.13; Epictetus, Enchiridion 3
Marcus takes things apart into their components: the expensive wine is fermented grape juice, the purple robe is sheep's wool dyed with the blood of a shellfish. Epictetus asks the same of what you love: name what it is, so that you are not shattered when it breaks.
How to do it. Take something you desire or something you cling to, and describe it as plainly as possible. Not to belittle it, but to see whether the desire survives without the shine that advertising, habit or comparison have laid around it.
Source: Hierocles, in Stobaeus
Hierocles drew the person as the centre of concentric circles: yourself, your household, your family, your city, humanity. His instruction was to keep drawing the outer circles one ring inward: treat the fellow townsman as an acquaintance, the stranger as a fellow townsman.
How to do it. Pick one person today from an outer ring: the courier, the cashier, the driver coming the other way. Think of one thing that person shares with you, and act on it. The other usually notices little; you notice that irritation gets less grip.
Source: Seneca, Letters 11 and 25; Epictetus, Enchiridion 33
Seneca advised choosing someone you admire for his judgment and living as though he were watching. Not out of shame, but because it lifts you out of your own perspective at the moment that perspective is worst informed.
How to do it. In the heat of a moment: picture someone whose judgment you trust, and ask what he would do now. Often you know the answer immediately, and that is exactly the proof that you already knew it.
Source: Cleanthes, in Epictetus, Enchiridion 53; Epictetus, Discourses IV.1
Cleanthes wrote the line Seneca later translated: fate leads the willing and drags the unwilling. The image behind it is a dog tied to a cart; it goes along either way, and the only difference is whether it walks or is dragged.
How to do it. Take something definitively settled: a verdict, a diagnosis, something in the past. Notice where you are still fighting it, and where that fighting costs you energy you need elsewhere. Accepting here is not agreement but withdrawing your troops from a lost front.
These nine exercises are what the Stoics wrote down. What has been added since is the ability to repeat the first of them hundreds of times without opening a book:
Yours, Not Yours · A Stoic practice ground · All cases · Questions or suggestions