Wiktionary
ex hypothesi
adv. Following from the hypothesis; in accordance with the hypothesis; by hypothesis; as a consequence of assumptions made; theoretically; supposedly; hypothetically.
Usage examples of "ex hypothesi".
I need hardly add that a situation is thus being produced in which it is intolerably hard to bring up Christian youth in Christian sexual morals (which are ex hypothesi correct morals for all, and which will be lost but which depend upon Christian youth for their maintenance).