It is easy, perhaps, for a lay Catholic to become intimidated by the sheer volume of dogmatic truths to which we give our assent. The Catechism alone is over 800 pages! Toss in hundreds of pages of Ott and Denzinger and it is pretty easy for my brain to go into system overload. And what about the 3,000 pages of Aquinas’ Summa Theologiae? What do we do? We say we assent to all this stuff, but there is no practical way that we will ever know all the dogmas proposed by the Church or revealed by God, and still less hope of us understanding it all.
Here is the really really good news: we don’t have to understand it all.
That’s not to say that dogma is unimportant. It is important because it is the truth. We assent to it because it is revealed by God or proposed for our belief by the Church that Christ founded. But God does not expect things of us which are genuinely beyond our abilities or which our circumstances make impossible for us. If the Catechism has not been translated into the language of some nation, it would be ridiculous to expect them to be accountable for literally everything in it. It can’t be done.
Again, this is not to say that dogma is unimportant. As I have said before, we cannot love what we do not know. So the more that we know and understand the truth, the better able we are to know and love God. This is something we should all want and strive after, and it is the major reason for the importance of catechesis for children and adults. So these truths are important for us to learn, but they are important for us to learn to the extent that we are able to do so. Children are not going to understand the Incarnation of Christ (lots of us grownups won’t, either!). But that is okay: they are not saved by knowledge. They are saved by Christ. We adults are saved by Christ too, of course. We are not saved by what we understand nor condemned by what we fail to understand. We exercise the theological virtue of faith, given to us by God, which empowers His people to assent to what He has revealed and to what the Church teaches as dogma. If we can, we should by all means seek to understand these truths to the best of our ability. But we hold to them as true by faith, because God is truth and because God has given the Church a charism of infallibility. This is faith seeking understanding. I think it was St. Anselm who said, “I believe in order that I may understand.” This should be our attitude. The contrary attitude—understanding seeking faith—is the attitude of humanism: it makes man the measure of the truth. It is as though we say, “I am not going to believe in [this or that dogma] unless I understand it.” But that attitude is the very contrary of faith! It is appointing ourselves as judges of the truth, rather than humbly receiving the truth from God just because it is God who says it.
So let us consider some practical examples. Years ago I read St. Thomas’ exposition of the doctrine of transubstantiation in the Summa Theologiae. There were a lot of whooshing sounds as his explanations whizzed over my head, to the point where I reached something of a crisis of faith. I did not understand what Aquinas was saying, and to the extent that I did understand it I did not agree with it. This was distressing to say the very least. But then I remembered what I said above: I do not have to understand it. I only have to believe it; I only need to assent to it as true because the Church teaches it as truth. Maybe someday I will comprehend the doctrine. Probably not, but maybe. :-) In the meantime, it is sufficient for me to believe it as true to the best of my ability.
Here is another example: Someone who is mentally handicapped. If a mentally handicapped person is required to know and understand literally all the truths taught by the Church, then there will not be a single mentally handicapped person in heaven. And that is just plain stupid. There is no sin in lacking the capacity to learn the dogmas of the truth.
The fact that we lack the capacity to grasp all the truths taught by the Church should not surprise us. For one thing, God is infinite and we are not. When we have exhausted ourselves learning all we can about Him, we will not even have begun to scratch the surface of all that may be known about Him. So there is a certain practical impossibility with the idea just to start with. Other people may lack opportunity to learn very much, either because they lack the leisure time and financial resources to do so, or because they speak a language for which ecclesial documents are still unavailable, or because they do not know how to read, or any other of a million reasons. We do the best we can. We seek to love and understand God the best that we can. That is sufficient. And if there are truths that we do not understand, or which we have never even heard of, it is not the end of the world so long as it is our sincere intent to believe all that God has revealed and all that the Church proposes for our belief.