What Constitutes Total Repudiation of the Catholic Faith?

Apostasy is typically defined as ‘total repudiation of the Catholic/Christian faith.’ What would that include?

(This is indirectly related to Sedevacantism but I’m not going to bring that up in the replies).

Rejecting faith in Christ–say, if a Catholic became a Muslim or an atheist, etc.


What if a Catholic becomes a Mormon?

Same, since they don’t even acknowledge God (theirs is a glorified creature)–and Jesus is therefore not the incarnate divine Word. It’s why their baptisms are invalid–they are not intending to do what is done in the Christian religion.

No doubt there can be gray area between heresy and apostasy–at the end of the day, they both are contrary to faith and break the bonds of visible unity and we should avoid each.


The old online Catholic Encyclopedia gives a full explanation (link below).

These days we seem to see the word “apostasy” only when a Muslim is referring to another (former) Muslim who converted to one of the Christian churches. Presumably a Christian who converted to Islam would similarly be considered an apostate from the Christian point of view.

I’m pretty sure I’ve never seen the term applied to an atheist, that is, to a Christian who ceased to be a believer but who didn’t convert to a non-Christian religion.

Formally converting to a non-Christian religion.

I guess the question comes down to what religions are and aren’t Christian. Also ‘formally converting’ means different things in different religions so it seems unclear. In some ways it’s like a ‘I know it when I see it’ type of situation.

That would be the list of faiths that have a valid Trinitarian baptism, vs. those that do not.

I think it would be difficult to prove apostasy if someone just kinda started going to a Hindu Temple instead of Mass. Until 2009, in Canon Law, there was the notion of an Act of Formal Defection from the Catholic Faith, which involved some paperwork and your local bishop. While there are no effects remaining of a Formal Defection, it is still possible to go through the motions. I think that is typically the only way one would qualify for Apostasy in the eyes of the Church.

That one is not difficult, the Church recognizes baptism or it does not. No grey area.

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