In Micraelius, Lexicon philosophicum (1662), I find this definiion of "duratio":

DURATIO est mora seu permanentia rei in essentia

For "mora", I find "delay", which does not quite make sense.

I find a similar expression in Eustache de Saint-Paul:

DURATIO, quae dici potest permanentia seu mora rei in suo esse...

Has "mora" acquired new shades of meaning (so to say) in early modern scholastic philosophy?

4 Answers 4


I will remark on the OP's entire comment:

Would you accept a translation such as : " duration is the lasting or permanence of things in being/ essence "? . I cannot find any other equivalent, but this sounds a bit like a tautology.

  • dūrātiō appears to be completely unattested before the 14th century, and is strictly a piece of late medieval scholastic jargon, while "duration" is a perfectly common and normal English word, so the two aren't equivalent translations. In contrast to 'duration' it doesn't mean "a span of time", but is deverbal from the classical meaning of dūrāre "to hold out, persist". "Persistance" is therefore a good equivalent.
  • mora is a delay, and in the expression mora temporis means "a typically short and well-defined period of time, envisaged as a stand-still". Medievally it's also used by itself to mean "intervening period, lapse of time, time required".
  • permanentia is a noun to the action permanēre "to remain, persist", while in English "permanence" is not a noun to any action (*permain), but normally expresses the quality of being permanent, fixed (I'm aware that English words can take on Latinate meanings in specialised literature, but this needs to be somehow signalled). DMLBS translates "continued existence", which is good.

Therefore DURATIO est mora seu permanentia rei in essentia means "persistence is the time during which a thing lasts, or it's remaining in existence" - a distinction is being drawn between persistence as a time-delimited (perfective) action and as a continued (imperfective) process, though seu rather says that either definition works.

Notice that my approach is to abstract away from the words' visual similarity, avoid English words with habitual and everyday meanings - both of which avoids false equivalence - and to rely on descriptive visualisation - which creates the appropriate equivalence and is also a feature of the Latin scholastic style.


The meaning "duration" or "space of time" was already there in Classical Latin: see Lewis and Short, section IIB.

  • 1
    Would you accept a translation such as : " duration is the lasting or permanence of things in being/ essence "? . I cannot find any other equivalent, but this sounds a bit like a tautology. Jan 23 at 10:47
  • @TKR, do we have classical references for mora in this sense without temporis attached?
    – d_e
    Jan 23 at 15:48
  • @d_e Good question -- the L&S entry seems to suggest not.
    – TKR
    Jan 24 at 17:21

The Eustache de Saint-Paul expression I would translate as

DURATION, that can mean the permanence or span of time for that a thing exists.

This sounds tautological, but since you are translating a lexicon entry, you should keep in mind that the text is meant for a reader who does not know what "DURATIO" means, or is in search of a better understanding of that word. So you could say that every lexicon entry has to be tautological.


In addition to the existing answers, I think it is worth adding that the term mora was used by Johannes Kepler in the early 17th century to denote basically the duration or time.

William H. Donahue, who translated his great work Astronomia Nova, found it noteworthy to add entry on the term mora in the glossary; there he writes Mora is "literally delay"", and then expends on the sense given by Kepler in that work. Maybe I over-read here, but it seems to suggest that this sense of mora - as given in the question - became natural quite later - in the medieval period.

Mora in Astronomia Nova

  • 1
    That's right, the use in question developed medievally as a technical term; the closest meaning that existed in antiquity referred to syllabic length distinctions, which were also called tempus (ūnum, duo tempora) - hence En. 'mora'. Jan 23 at 18:25

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