01
The idea
Marcus repeatedly performs an exercise on himself that amounts to deliberate under-description. Take the impressive thing and describe its parts. Take the frightening thing and say what it physically consists of. He does it to fine food, to purple robes, to applause, and to his own mortality, and the effect each time is the same: the surplus meaning falls off, and what is left is manageable.
The modern form is the camera test. Write what a camera and a microphone would have captured, with no motives, no adjectives of character, and no history. Then write everything else you believe about the situation on a second line.
The gap between the two lines is almost always startling, and it is where nearly all the distress lives. Not because the second line is false — some of it will be true — but because it was arriving disguised as the first line, which meant it was never examined.
02
Why this matters
People do not usually act on events. They act on descriptions, and descriptions are assembled fast, under pressure, by a mind with a strong interest in the outcome.
The technique is portable in a way that most of Stoicism is not. It requires no metaphysics, no commitment about virtue, and no belief about the cosmos. You can hand it to a sceptical colleague in thirty seconds and it works.
And it is the prerequisite for everything downstream. Choosing a virtue, deciding what is up to you, judging what action fits — all of it operates on the description. Get the description wrong and the rest is well-executed error.