In correspondence with Roman Catholics, the issue of infallibility inevitably gravitates toward the center of discussion. This is only natural since Catholics and Protestants are ultimately appealing to opposing authorities to underwrite their beliefs. Any debate therefore tends eventually to put the validity of these authorities at the center of the merry-go-round.
Although Catholics claim that it’s necessary for the Church to be able to teach infallibly, lest it fall into error and apostasy, it’s my contention that the distinction between the Catholic and the Protestant positions is far hazier than it might at first appear. Firstly, ex hypothesi, the infallible Magisterium of Rome has not actually prevented the very thing which Catholics claim it is needed to prevent—namely error and apostasy in the form of Protestantism. Secondly, there is actually no clear difference, in principle, between Roman Catholicism and Protestantism. Both appeal to an infallible teaching authority: Catholics appeal to the Church; Protestants appeal to the Bible.
No infallible teaching authority prevents the teaching of error
Although any infallible authority does not, itself, teach error, nonetheless its infallible teaching must be interpreted, understood, and internalized by individual church elders in order to be taught to the laity. Elders are not themselves infallible, and so will inevitably err in various ways. Thus, in a practical sense, the teaching of error is not mitigated by having elders who submit to the infallible teaching authority of a Magisterium any more than by having elders who submit to the infallible teaching authority of Scripture. This is obviously validated by the numerous disagreements between professional Catholic theologians, just as between professional Protestant ones.
No infallible teaching authority prevents the believing of error
Moreover, even if an elder never errs, even if he counsels his congregation infallibly, the individual members of that congregation will inevitably err in their own interpretation, understanding, and internalizing of his counsel. Thus, the believing of error by the laity is not mitigated by having an infallible teaching authority represented in a Magisterium any more than by having such an authority represented in Scripture. I’d suggest that you validate this for yourself, whether you’re a Catholic or a Protestant, by repeating back to your priest or pastor everything you understood him to be saying during his sermon the next time you’re in church. If, after a couple of Sundays, he hasn’t had to correct you once, you might as well stop going since you are obviously falling asleep before the homily.
In light of the above two facts, which demonstrate that the Roman Catholic Magisterium conveys no obvious epistemic advantages to its believers over and against Protestantism, a major claim of Catholics about the superiority of their church is falsified. But I can go further, and show that Catholicism actually suffers from at least two major disadvantages:
The disadvantage of added complexity
The teachings of Catholicism are very, very complex. Not all Catholics may be aware of this, but compared to Protestantism an enormous extra layer of complexity is added. Now, I’m not a subscriber to Occam’s Razor, but it remains that the Magisterium’s infallible teachings are vastly more complicated and extensive than those of Scripture, and therefore require vastly more specialized knowledge to accurately exegete or even understand. Therefore, the probability of Catholic believers, who subject themselves as best they can to all the teachings of Rome, being in error is actually much higher than for Protestants who subject themselves as best they can to the teachings of Scripture. Moreover, a Catholic has nothing to fall back on if he wants to make sure that his interpretation of some Magisterial teaching is accurate, and so again Rome confers no advantage over Protestantism.
The disadvantage of distance from Scripture
Lastly, Catholicism is more removed from Scripture. The baseline belief of both Catholicism and Protestantism is that the Bible is the inspired and infallible word of God. Catholicism, however, adds an additional fundamental assumption: that the Church is the infallible interpreter of the Bible. This is assumed as a first principle, and so cannot be easily tested by the Catholic himself.
The problem here is that various organizations claim the same thing; and if the Catholic claim is false, then a Catholic is unable to discern which Magisterial teachings are false, or even that any are false, because practicably speaking the Magisterium is taken as a more fundamental authority than Scripture. As I argued in ‘The keys of the kingdom’, Catholics are unable to perform genuine exegesis on Scripture, because the meaning of any given passage must be conformed to presupposed doctrines, rather than being discovered from the text itself. Thus, Catholics are incapable of testing doctrine against Scripture as Scripture itself commands (they cannot even recognize that Scripture commands this). They are entirely reliant on their church for all matters of faith and doctrine; and if that church is wrong they cannot know it. Thus, instead of relying on God’s word, they are relying on man’s word. This is a far less appealing position to be in, because there is not the same guarantee of truth behind it. Of course Catholicism claims that its Tradition is implemented and guaranteed by Christ—but this claim itself rests on Catholic Tradition, and thus is underwritten only by the word of man.
Therefore, I suggest that regardless of whether Roman Catholicism is the “one true church”, it is better to be a Protestant than a Catholic. If Roman Catholicism is false, then Catholics are damned to hell while Protestants will be saved. If, on the other hand, Roman Catholicism is true, then according to Vatican II Protestants are merely doctrinally impoverished Christians, and will still be saved. Either way, Protestants will be saved whereas Catholics may not be. So a sort of wager can be set up wherein it is pragmatically preferable to be a Protestant than a Catholic—barring some infallible proof that Rome is the one true church.