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.