Catholicism's simple but irrefutable proofs convinced me of her truth. There is no simple Protestant response to the charge that sola scriptura fails on account of its non existence in the Bible. If there were, Protestant apologists would have picked it up a long time ago. There is no simple reason why Protestants have as much claim on early Church history as Catholics do. If there were, the apologists would have all latched on to it. Instead, every apologist has a different (faulty) reason. Some say that Peter being in Rome meant nothing. Some say that he was never in Rome. Some say Peter himself is irrelevant. Some say the first Christian generation apostatized. Some say it wasn't until the 5th century. In fact, none of these silly theories have attracted a large number of anti-Catholic intellectuals. It reminds me of the Jesus debate. Whereas there are large numbers of anti-Christian intellectuals who deny Christ, there isn't any sort of consensus on a plausible alternative to the truth of the gospels while Christians have simple and powerful reasons to trust them. It should be no surprise then that there are large numbers of anti-Catholic intellectuals with a similar lack of consensus against His bride.
I have run across people (especially reformed) when their theology is refuted by these simple truths, they rebut "you don't understand the reformed faith". I've heard that charge at least four times against former Reformed Christians (who knew their faith well). But if the Reformed theology is so complex that even seminary graduates and former pastors can't understand it enough to defend it against simple Catholic claims, then how true is it anyhow?
If "truth is harmonious", then it shouldn't be any surprise to us that all truth can be expressed in simple terms and in its simplicity, it can withstand even complex attempts at refutation. If any doctrine becomes too complex for comfort, as long as we understand it, an analogy may reduce the truth to the simplest of terms. This is why things which are really true can always be explained to men, (even simple minded men).
But there are simple minds and great minds in all faiths, one will object - and this is true. But we are not, at present, dealing with what caliber of minds a particular teaching has attracted but whether or not its fundamental doctrines may be expressed (and defended) in simplicity. Again, the doctrine of sola scriptura may be stated simply "the bible is the only infallible authority" but there is no simple defense of its refutation - "the bible itself does not say so". Similarly, sola fide may state simply "we are saved by faith alone" but it cannot defend itself in simplicity against the arguments of James - particularly "the demons also believe" and "you are not saved by faith alone" (the latter of which is especially difficult to deal with in simplicity).
Therefore I maintain that Catholicism, in her simple, powerful truth refutes all charges against her and that her simplicity itself speaks of her truth. The complexities and confusion of her enemies speak of against them. I say this because God is not the author of confusion and to recall what Jesus prayed "I praise you, Father, Lord of heaven and earth, because you have hidden these things from the wise and learned, and revealed them to little children."