What it's like to be a bat and the Incarnation
Catholics who read this will probably think that this is yet another post by a Catholic trying to explain how the Church hasn’t actually changed her teaching on this subject, blah blah blah you get it. That is not the topic of this post.
Instead, I want to point out that the doctrine itself in fact has a lot of tension in it that can’t be merely resolved by throwing out Vatican II and Lumen Gentium, and it’s something that the Church has historically recognized.
We can state it something like this:
Premise: Outside of the Catholic Church in union with the Pope of Rome there is no salvation
Premise: God desires all men to be saved
Premise: There are men alive who simply do not have the opportunity to join unity with the Pope of Rome
Conclusion: Either God does not desire all men to be saved (Which would disprove Catholicism anyway) or there is in fact salvation outside of the Catholic Church (which would disprove Catholicism’s claim to unique authority at the very least).
This is a serious and legitimate theological problem that Lumen Gentium and Vatican II actually try to *address* with their nuance. I am going off of memory here – this is not an academic article – but I believe Thomas Aquinas attempted to resolve the tension by positing that those with no opportunity to formally join the Catholic Church would be given the opportunity at the moment of their death. This is a perfectly logical proposition, but never formally defined, and the fact remains that in order for all of the things the Church claims about herself to be true the tension HAS to be addressed somehow.
Vatican II addressed the tension by formally defining a distinction between explicit and implicit unity and positing that men of good will who would reasonably desire to be a part of the Catholic Church if they were convinced of its truth could be said to be members implicitly, which is enough for salvation. This is as perfectly logical of a solution as Aquinas’s and, speaking personally for myself, has always satisfied me.