Letter No. 6 | September 2026
Epictetus Fund · Monthly Letter · Published October 2026
Letter No. 6 | September 2026
On discipline: what it really is
Dear subscribers,
Discipline isn’t about being strict, and it isn’t willpower. It’s refusing to change a decision you’ve already made, for as long as the reasons behind it still hold and nobody has formally amended it. Who you answer to (yourself, a partner, the capital, your country) doesn’t matter much. What matters is that the decision was made before the urge to break it showed up.
The actor and the playwright. Epictetus reminded us that you’re an actor in a play, and the author picks what kind of play it is and how long it runs. Your job is to play the part you’ve been given well. Choosing it is someone else’s business (Enchiridion, 17, Perseus). At Epictetus Fund that’s exactly how the roles split: the Architect writes the play, the Operator plays his part flat out, but doesn’t rewrite the script.
The athlete and the coach. To anyone who wanted to win at the Olympics, Epictetus said: submit to discipline, eat by the rules, give up the sweets, train at the set hour in heat and cold, and put yourself in your trainer’s hands the way you would a doctor’s (Discourses, III.15). An athlete doesn’t decide halfway through the plan that something else feels better. And Epictetus said to start small (Enchiridion, 12).
Knowing and doing. His teacher Musonius Rufus taught that virtue isn’t just knowledge, it’s practice. Think of a doctor or a musician: they don’t just know the craft, they train at it (Lecture VI). A rule you know but don’t follow under pressure hasn’t become a skill yet.
The first jolt and the assent. Seneca drew a line between the involuntary first movement of the soul, which isn’t yet a passion, and assent to it, after which the passion is up and running (On Anger, Book II). Chrysippus called a passion assent to a false judgement, and Epictetus turned that into an exercise: don’t assent to an impression until reason has tested it. The thought “things will go better if I do it differently” is the first jolt. It’s natural and you can’t avoid it. Trading on it is already assent. Discipline lives in the gap between the two.
Tudor in September. On the technical side, the Operator did really well: trimming, swing trades, options several times a day. That added about 7 percentage points of TWR. But how much capital stays untouched as a long, and how much goes into tactics, wasn’t his call. In the moment he reckoned he could see things more clearly and moved that line. Not out of ignorance, because the rule was written down. The first jolt, “this will be better”, got assent without being checked against the order already agreed.
The market answered the way it usually does. The bulk of the rise came in two jumps, +11.9% and +11.0% in a single day, and on those days there was hardly any long on. Had the Operator simply stuck to the rulebook, the result would’ve been bigger and it would’ve taken less effort. Good technique doesn’t make up for crossing the line. It just puts off the bill.
How the system responds to a mistake. Not with punishment, but with a rule. In Addendum No. 9 on 30 September, the Architect fixed a permanent core: a long position in equities that he himself is responsible for. Everything above the core is handed to the Operator in full: options at any pace, intraday in small lots. The line is written so nobody has to guess where it is, and the decision about it has once again been made in advance, not in the heat of the moment. The author has finished the play, and the actor’s part is clearer.
Two practices have been added. The first is Seneca’s: every evening he went over his day before his own tribunal (On Anger, III.36). Now the Operator writes down the market regime before the session opens, and once a month reviews the results in three parts: core, options, intraday. The second is Epictetus’s prosoché, attention to yourself here and now. Before a trade, ask not “what would be better?” but “whose decision is this?”
Discipline starts not with a ban but with clarity about who decides what. The point of the system isn’t to straighten the Operator out with rules, but to let him stand straight on his own. As Marcus Aurelius put it: be upright, not kept upright (Meditations, III.5, Lexundria).
