The present study intends to demonstrate that there is no logical-formal inconsistency in the Christian Trinity. However, the demonstration requires specific tools, other than those of classical logic. There are many older or newer attempts that try to remove the thesis of the inconsistency of the Christian Trinity. There is often a call for mathematical tools. As far as we are concerned, we will appeal to co -inherence and the nesting relationships specific to the Christian Trinity, as they appear especially (...) in Augustine’s work. We advance the hypothesis that Augustine's metaphor "heaven of heavens" has a foundational role in the logical plane of explanation. In this sense, Augustine points out that in the "heaven of heavens", reason does not know "in part", but it knows everything suddenly, entirely, as in a totality. This totality with a founding role functions as a principle, which we can call the principle of free totality. But the co -belonging of entities in the free and founding totality also expresses co -inherence. Divine persons are an emanation of God. That is why we are talking about co -inherence. The "co" particle points out that the starting point is in the free totality of God, and that this totality logically precedes the rest of the process. Thus, we can consider the term "the Christian Trinity" as a nested term, as co -habitation. The totality of God is not a generalization in the spirit of the Aristotelian abstraction, but rather a particularity, a "personalization" that does not cancel the individual, but it highlights in instantiation. In this sense, the Christian God is not an abstraction, but a divine Being in three persons, in whom He instantiates. The logic of this process is the one of vagueness. (shrink)