The Catechism of the Catholic Church affirms the following:

In the [Catholic Church] subsists the fullness of Christ's body united with its head; this implies that she receives from him “the fullness of the means of salvation” (CCC #830).

It goes further to explain the following:

The Church is catholic: she proclaims the fullness of the faith. She bears in herself and administers the totality of the means of salvation (CCC #868).

It is now a world that no longer takes delight in such absolute statements. These statements, for the many relativists of various degrees one meets in the intellectual arena, are too arrogantly certain. Such protestors say, “We must never take any one group or denomination of believers to be in full possession of the truth”.

This statement usually means that every group has some fraction of the entire body of truth, and that full truth is found only when one embraces the sum of all these fractions of truth. And many actually audaciously call this “ecumenism” - to be sure, many Catholics are guilty of this too.

Underlying this statement is to be found a series of logical fallacies.

I
For a person to refute the possibility of absolute and complete possession of the deposit of faith is to also assume that he himself possesses the full truth to the extent that he is able to recognise the lack of completeness in others’ beliefs.

Many claimants of this statement do not realise that such an assumption is intrinsic to their argument. The nature of his claim, that no one body of truth encompasses truth in its completeness, presupposes that the claimant himself knows what a complete body of truth must look like. If he himself had no possession of the full truth, he should not know what the full truth is like. And if he possesses not the full truth, he has no logical basis - without first having known full truth - of knowing that other groups have incomplete bodies of truth. If every body of belief, as he claims, is incomplete, then there would be no standard of fullness by which all other bodies of faith claims are to be measured. This would render his own claim arbitrary at best and defective at worst.

Therefore, the fallacy in this position lies in its self-contradiction. It is found in the assumption that the knower knows the extent of truth propositions required to constitute a “fullness” of truth. Even if he does not yet possess the full truth, it assumes that he at least possesses the capacity to collate the sum of truths found in every group of believers, and consequently emerging with a set of full truths. Furthermore, even if he has not yet attained the sum of truths or the fullness of truth, this position must necessarily assume that he can and will one day attain the fullness of truth.

But in the first place, if such fullness of truth was at all possible, then why would this knower be the only one for whom it was possible to attain that fullness? Why would it not be possible for any one group of believers to have attained it prior to the claimant’s attainment of this fullness?

II
Another presupposition underlying this statement is that although all these groups’ bodies of truth are incomplete, they do not contradict one another and can therefore be brought together in totality to form a coherent whole.

In reality, certain beliefs held by the various groups, even if they are all Christian, may be mutually exclusive because they totally contradict one another. In such cases, someone must be wrong, and the other right. One cannot therefore assume that all the different truths of the various groups of believers can be indiscriminately taken together to form a greater whole.

In this sense, to almagamate the various bodies of truth to form a complete whole, one would have to in the process purge these various bodies of truth from their errors before merging them together. But such an enterprise, again, actually assumes that one is in possession of the complete body of truth in order to recognise truth from error. And the irony is, if one already possessed that complete body of truth, he would not have a need to bring together the various bodies of truth to form a greater whole in the first place.

Hence, when one makes such a statement, the question must arise as to who or what constitutes the final arbiter of completeness and orthodoxy. The one who makes such a relativistic claim is not very much of a relativist himself after all, because his claim implicitly implies completeness in the claimant’s own body of faith claims.

Such a relativistic viewpoint of the deposit of faith shows itself to be a logical fallacy on various accounts when one thinks deeper about these claims. In saying “we must never take any one group or denomination of believers to be in full possession of the truth”, it refutes exclusive claims to completeness. But it refutes exclusive claims in a very exclusive way. It accepts exclusively people who reject exclusive claims, and rejects people who accept exclusive claims. In the final analysis, it shows itself to be more exclusivistic than those who make exclusive claims but acknowledge that others’ exclusive claims may not be in agreement with their own.

To set the record straight, I am not objecting to any group of believers’ claim over absoluteness and completeness in their “deposit of faith”. In fact, I am arguing in favour of it. Because this would be the only way by which one can judge any other belief to be incomplete. It takes a claim to complete knowledge of the deposit of faith to recognise incompleteness.

And so this is the Catholic position – we assume (no, we believe!) that our body of truth, our deposit of faith, is complete. And we hope that our dialogue partners would assume the same about their own bodies of faith. Otherwise there would be no grounds for dialogue, only grounds for teaching and evangelisation.

I call this logical fallacy dialogical relativism.