Perhaps it would be simpler to put it like this: if someone in a separated Christian body has a genuine desire to believe all that the Church founded by Christ taught, then he has a habitual ‘clinging’ or ‘inhering’ to the Catholic Church. This habitual inhering is actualised when he believes revealed truths proposed to him by this separated body, since in proposing such truths the ministers of this body are, formally albeit illicitly, acting as teachers of the Catholic faith. And so the separated brother in good faith, when he believes them, is believing teachers of the Catholic faith, and doing this on account of his habitual desire to believe whatever is taught by the Church founded by Christ. And this seems to fulfil St Thomas’s criteria for supernatural faith, without contradicting the Holy Office.

Fr Feeney’s position thus appears to derive from an insufficiently ‘formal’ reading of St Thomas. He sees that the act of faith is made in dependence on a Catholic teacher, but supposes that this must mean someone who in general has the office of a Catholic teacher, rather than one who here and now is acting as a Catholic teacher, in virtue of teaching Catholic truth.

A minor correction: in the former post I described ‘proposition by the Church’ as part of the formal object of faith. According to Garrigou-Lagrange, Thomists in general describe it as a sine qua non for faith, and not part of the formal object itself.