Cornelius Senecio ate a good dinner and went to bed a wealthy man. He was a Roman knight Seneca knew, risen from nothing to real money, still busy compounding it. By daybreak he was dead; a quinsy had closed his throat in the night.
Seneca sat down and wrote to Lucilius about it. Senecio had been the very picture of the man on the way up: healthy, capable, sure of his years. He had a night.
Memento mori is the discipline that follows from taking that seriously. Remember that you will die. Most people file the thought under morbid and move on; the Stoics filed it under time.
The founder’s version of Seneca’s letter arrives now as a name in a group chat. On a Friday night in December 2023, SenseTime told the market that Tang Xiaoou, the professor who co-founded the company in 2014 and helped build one of China’s best-known AI firms, had died of an illness. He was fifty-five. He was still the man designing the company’s research strategy. The stock fell on Monday.
He was one of many. Megvii’s chief scientist, Sun Jian, died at forty-five. Yidu Tech’s co-founder, He Zhi, died at forty-one. Southeast Asia keeps a name on the same list: Chevy Beh grew the Malaysian health platform BookDoc across five countries and twenty cities, and died in August 2022 at thirty-seven, the company still open on his desk.[^1] Read the list and the ages are what stay with you: forty-five, forty-one, thirty-seven.
None of them were slowing down. Tang was still running research when SenseTime posted the notice; Beh had BookDoc live in twenty cities the month he died. The company keeps moving without them. It reprices, appoints an interim, and holds the roadmap. That is the part memento mori makes you look at: the machine you are building will run the morning after you stop, and it will not miss you for long.
The founder reads these and feels the wrong thing. The instinct is to go faster, to out-run the clock that took them. It is the same instinct a twenty-two-year-old at Pinduoduo was running on when she collapsed walking home at half past one in the morning, on the six-day, nine-to-nine schedule, in December 2020. The build had eaten the exact thing it was supposed to buy her.
Runway is money you can raise again; the Tuesday you spent is gone.
Runway is money you can raise again; the Tuesday you spent is gone.
This is where the discipline gets uncomfortable, because memento mori turns out to be a scheduling instruction. The dinner you keep moving. The parent you will see properly once the round closes. The year you have promised yourself on the far side of the exit. That is the account, and Senecio’s evening is somewhere on your own calendar too, undated. Balance it while the entry is still yours to make.
Postpone nothing, and balance life’s account every day.
Seneca ended the letter on the practice itself. Order the mind as though you had already reached the end. Put the finishing touches to the day while you hold it. Postpone nothing, and balance life’s account every day.
[^1]: The list keeps its own ledger, and the numbers do not read like old age: Sun Jian at forty-five in 2022, Tang at fifty-five in 2023, He Zhi at forty-one in 2024, an image-processing academic, Quan Yuhui, at thirty-nine in 2025. One researcher in the field said the quiet part plainly: the industry moves too fast, and the competition is too fierce.