I've encountered the phrase datum (sed) non concessum in various English-language books and articles such as:
- The Beauty of God's House, quoted in Theologically Speaking, What Intelligent Design Is and What It Isn't
- Pistrina Liturgica
- Theology in the Russian Diaspora
- ‘A Designer Universe?’: An Exchange (variant: concessum non datum)
- The Bishop Goes to the University
It's clear that datum and concessum are passive past participles in Latin; datum can mean 'given' and concessum can mean 'conceded' or 'withdrawn' among other possibilities.
So the phrase would seem to mean something like, "if we grant the preceding proposition for the sake of argument, without actually conceding that it's true, ..."
But allowing for the moment the truth of this hypothesis, datum non concessum, how is this episcopal collegiality supposed to have shown itself?
However, the critical question was ... One might argue that ... All right, datum non concessum the issue still remained as to why ...
And the other links show similar constructions. Is my understanding (which is based on the meanings of the individual words and on context) correct? Can anyone point me to a standard reference that describes the usage of the phrase?
P.S. There is some question as to whether this counts as an English phrase (idiom), or only a Latin one. (Actually I don't have evidence that the phrase is used in Latin, but that's not the main point.)
That's an open question, but in my favor, there are currently 4850 Google results for "datum sed non concessum". Even given that many of these are duplicates and not all are in English, nevertheless a good many of them appear to be unique, English-language pages. Usage does seem to be concentrated in circles of Catholic theology.