The title of the question pretty much sums it up. I am looking for a Latin phrase for the English expression "It goes without saying." I am not sure if an analogous expression exists- although I would be surprised if it didn't.
You can say: ex se intellegitur (literally: it is understood from itself). An alternative you will sometimes find is per se intellegitur.
Ex se intellegitur me ad tempus advenisse.
It goes without saying that I arrived on time.
Hoc ex se intellegitur.
That goes without saying.
Intellegitur ex se quam laeta est.
I need not tell you how happy she is.
Id [argumentatio] facere oportet cum aut propositio ex se intellegitur aut assumptio perspicua est et nullius approbationis indiget. (Cicero, De inventione, 1.70)
An argument must be made unless the proposition goes without saying or the assumption is obvious and requires no proof.
And there you have another option: perspicuum est (literally: it is obvious)
Perspicuum est natura nos a dolore abhorrere. (Cicero, De finibus, 3.62)
Obviously by our nature we dislike pain.
Another option I found: hoc sua sponte apparet (literally: it appears of its own volition). There are quite a few historical uses but I doubt it is classical.
1If "ex se intellegetur me ad tempus advenisse." is written indirectly, why is "intellegitur ex se quam laeta est." not? Jan 18, 2022 at 13:10
1@tony because, as so often, I made a mistake: it should be quam laeta sit. Jan 18, 2022 at 20:29
Sebastian Koppehel: I have been trying to find examples of subordinate clauses, in indirect speech, introduced by "quam" = "how", with no luck. In Pinkster's notes on relative clauses, p2, (freely available on the net) among all the substantives, adjectives & adverbs used for this purpose, "quam" = "how", is not one of them. Are you sure about this? I would have translated: "intellegetur ex se laetissimam esse." = "I need not tell you that she is supremely happy." Jan 21, 2022 at 13:20
1@tony Look no further than the L & S entry for quam (under letter B). Jan 21, 2022 at 18:22
1Thank you. It's an indirect question! Often puzzling because many of these are not questions at all--nobody is asking anybody anything. In Latin, it seems to be the case that if there's an interrogative with a subjunctive, it's called an indirect question. Thanks again. Jan 22, 2022 at 9:12
A legal expression that has this meaning is:
Res ipsa loquitur
This literally means the thing speaks for itself.