...what, then, guarantees logic?
What must be true in order for logic to exist at all? And BTW, we are presupposing, perhaps even proving, the existence of that something by proceeding down a logical course.
Discussion
The question is semantically invalid. Logic guaeantees itself since otherwise, it could not exist.
Logic is self-existant and volitional? You're nearly there: it is also personal.
"In the beginning was the [logos], and the [logos] was with God, and the [logos] was God.. .. And the [logos] became flesh, and dwelt among us..." [John 1](https://esv.org/John+1).
