Limbo is the clearest case in this collection of a doctrine that large numbers of people are certain the Catholic Church taught, and which it never defined.
The problem it was built for
If baptism is necessary for salvation, and infants are born in original sin, what becomes of an infant who dies unbaptised? Augustine followed the logic strictly and concluded they were damned, though as mildly as damnation permits. Medieval theologians found that intolerable and proposed a middle condition: no punishment of sense, no vision of God, but the natural happiness proper to a human being. Aquinas developed it, and it became the ordinary teaching of the schools and of catechesis for centuries.
The peg was a formula in Cantate Domino, the bull issued at Florence in 1442 for the reunion with the Copts: those who die in original sin alone descend to hell, but are punished with unequal punishments. Theologians took "unequal" to leave room for a state without positive suffering. The council had said something about inequality of punishment. The inference to a place of natural happiness was theirs.
It was never defined
No council decreed it. No creed contains it. It does not appear in the Catechism of the Catholic Church, which instead speaks of entrusting such children to God's mercy and notes that the funeral rites the Church provides for them express hope.
What the 2007 document did
The International Theological Commission published a study, approved by Benedict XVI, concluding that there are serious grounds in scripture, liturgy and theology for hoping that infants who die without baptism are saved.
Press coverage reported that the Church had abolished limbo, or closed it, or emptied it. None of that is accurate, and the inaccuracy matters:
- It did not abolish limbo, because there was no dogma to abolish.
- It did not define that such infants are saved. It said there are grounds for hope, which is a considerably weaker and more careful claim.
- It did not forbid the older opinion. Limbo remains a permissible theological view; the commission simply declined to teach it.
Why the confusion is instructive
The episode shows how a hypothesis can become, in popular understanding, an article of faith, purely by being taught consistently for long enough, and how hard it then is to set aside without appearing to reverse something. The Church did not reverse a doctrine in 2007. It recommended hope in place of a guess, and was widely reported as having done something it lacked the material to do.