The Latin label is mostly modern. Cicero uses praemeditatio futurorum malorum in the third book of the Tusculan Disputations, arguing that grief hits hardest when it arrives unannounced, and citing Anaxagoras, who on being told his son had died said that he knew he had fathered a mortal. A very good line, and also, I suspect, something he thought of afterwards.
Seneca does the exercise constantly and never names it. The clearest statement is in Letter 91, written after fire destroyed Lyon, to a friend from the city.
Therefore, nothing ought to be unexpected by us. Our minds should be sent forward in advance to meet all problems, and we should consider, not what is wont to happen, but what can happen.
Seneca, Letter 91.4, translated by Richard Gummere
Earlier, in Letter 76, he compresses it into five words of Latin:
Praecogitati mali mollis ictus venit.
Letter 76.34
If a bad thing has been thought through in advance, the blow lands softly. He gives a physical version too: days on the cheapest food and roughest clothes, asking yourself whether this is the condition you were afraid of. He wrote that as one of the richest men in Rome. @marginalia/seneca-was-extremely-rich has the numbers.
Seneca, Letters 18.5 to 18.8, 24, 76.35, 91.3. Epictetus, Encheiridion 3 and 11.
In the car park, engine off, four minutes. There is a note on my phone and I tick the boxes, because thinking about a list and doing a list are different activities.
The last two are unticked so you can see which parts I skip. The eating one I skip in a manner that would embarrass me if I were the patient.
This has nothing to do with courage. It changes where a decision gets made. Several small decisions have moved out of the middle of an emergency and into a parking space at 21:40, and the effect is not that I am calmer, it is that I am already walking while other people are deciding to walk. Seneca's claim is about pain: the blow lands softly. I do not find that. I find a claim about speed, which he never makes.
It does not work on the things that happen.
That sounds like a cheap paradox and it is arithmetic. You rehearse out of your existing repertoire, so you rehearse the five things you already know about, and the night goes wrong in a sixth way that was never on the list because it was not in your head to put there. In eleven years I have never rehearsed the specific thing that arrived.
What it does instead is take the anticipation apart, which is worth doing and not what it says on the tin. Between parking at 20:40 and taking the handover there is a stretch of dread with nothing inside it. The checklist gives the dread contents. Contents are workable. Formless dread is not. That is the whole benefit, and worth every shift.
Then the part I want to be careful with. Encheiridion 3 starts with a clay pot: tell yourself it is a clay pot you love, so you are not disturbed when it breaks. Then Epictetus keeps going.
If you are kissing your child or wife, say that it is a human being whom you are kissing, for when the wife or child dies, you will not be disturbed.
Encheiridion 3, translated by George Long
I have done this. I am not going to be superior about it, and I do not think he was cruel; he had every reason to know what loss costs.
But I have been in the room when a child died, and I will say this plainly and then move on. The rehearsal did nothing. Not less than I hoped for. Nothing at all. Whatever premeditation builds is built for the wrong load. It is sized for inconvenience, for losing your position, for illness, for your own death, which is honestly the easiest item in the set because you are not present for the aftermath. It is not sized for that.
Rehearsal and rumination run on the same equipment and the difference is direction. Rehearsal ends in an action you could take. Rumination ends in an image you cannot stop looking at. If you cannot name the action, you are not practising.
Two ways it goes wrong, and I have been down both.
The first is that the rehearsal becomes the condition of leaving the house. It starts as a tool and turns into a rite, and one day you cannot walk onto the unit until you have run it, and at that point it is running you. Seneca at 76.35 has the wise man saying "I knew it" about everything that happens, one small step from a person who cannot get in the car.
The second is worse. You point it at the people you love, because they are what you are most afraid of losing, and it does not inoculate you. It gives you the experience twice, once for free, in advance, in the dark. Rehearsing your daughter's death is not premeditatio malorum; it is intrusive imagery with a Latin name on it, and that difference is something Seneca had no way of knowing and you do.
So use it on the likely and the logistical, and use the philosophical version on your own losses and your own end, where two thousand years of people have found it holds. Do not point it at the people you love.
And if you catch yourself doing that at three in the morning, that is not practice. Get up, go and stand in a corridor, and count something.