I am looking for either a literal Latin adjectival form of "ipso facto," or--more interestingly--an adjective with a very closely equivalent meaning to that of the adverb "ipso facto."
Though there seems to be a superabundance of words related to this concept across the disciplines of philosophy, math, and logic, I am looking for strict equivalence. (Variations on "a priori," "tautological," "self-evident," "axiomatic," "pleonastic"/"superfluous"/"redundant" and all forms of "empty"/"saying nothing" and "necessarily true" are farther than I'd like, semantically, from "ipso facto." The latter has an extremely precise and forceful meaning which I'd like to retain.)
I want to fill in the blank in the sentence
But this truth is _______.
...suggesting, in the manner of the anthropic principle, that something is necessarily true insofar as one is observing it.