In law, ex post facto is used to refer to something done after the fact. I'm interested to know what Latin phrase would mean done during or simultaneously with the fact.

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    I'm not sure the question as such makes much sense to me. Ex post means "after", yes, but this usually refers to knowledge, a motive, a point of view or things like that, and in direct opposition to ex ante. It only makes sense in comparison. What exactly is it you are trying to express?
    – Ingmar
    Mar 5, 2020 at 8:20
  • " in flagrante delicto" suits some occasions.
    – Hugh
    Mar 5, 2020 at 13:50
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    Hi @Ingmar, I'm trying to express that instead of a behaviour happening after another event has completed, that that behaviour is happening at the same time as the other event.
    – Poul
    Mar 6, 2020 at 9:26
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    Sorry for even more information @Ingmar, ex post facto is also used in another sense where a judge gives reasons for his decision 'ex post facto', ie, not the reasons that were the operative or actual reasons for his decision, but which were thought up afterwards. I'm interested in a slightly different sense, where a judge thinks up misleading reasons as he goes along, ie say he's biased for whatever reason, then he thinks of a misleading basis for his decision that he updates as the case goes along to account for any new evidence.
    – Poul
    Mar 6, 2020 at 13:18

1 Answer 1


Perhaps surprisingly, ex post factō isn't actually a valid Latin phrase on its own: it's got two prepositions in a row, and Latin doesn't allow that.

So why do people use it? Well, in legal Latin, a law made after the fact is a postfactum, a "thing-made-after". So a punishment originating from one of these laws comes ex postfactō, "from a thing-made-after".

If you want to adapt this phrase, you could use the adverb simul, "at the same time". Something made at the same time as another thing could, perhaps, be a *simulfactum, or a simultāneum; I like the second option more because it's attested in mediaeval Latin and rolls off the tongue a bit better. And a punishment originating from one of these could, perhaps, come ex simultāneō.

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    Post can be an adverb, so the phrase is valid Latin (though I don't know if it's classically attested).
    – TKR
    Mar 5, 2020 at 23:33
  • @Draconis, I really like this answer. Could it be used in the sense described above (see comment in response to @Ingmar), ie to describe a misleading account of a judge's decision that the judge thinks of (and updates) as the case goes along, rather than thinking of it only after all the evidence has been heard?
    – Poul
    Mar 6, 2020 at 13:23
  • @Poul Legal terms aren't my specialty, but I would say yes, it could be.
    – Draconis
    Mar 6, 2020 at 16:37
  • @Poul To me this was an interesting question. It seems you are pleased with the answer you were given, and be that the case, I would kindly advise you select the answer as your chosen one.
    – Canned Man
    Mar 6, 2020 at 19:35

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