His restated claim is not that faith as the Catholic Church understands it is somehow incompatible with maturity and independent judgment, and thus inherently vicious, which is what Scott Carson and I had taken him to be claiming. Rather, he rebuts only what he takes to be the argument of unnamed Catholic apologists that Protestantism is somehow inherently vicious. Now I'm not sure who, exactly, makes that claim, partly because the claim itself is ambiguous. If what's meant is that any given person is somehow and necessarily acquiring vice, as opposed to virtue, by choosing to be Protestant, than I know of hardly any Catholic apologists who make such a claim. On my own account, I'd say that, in some cases, choosing to be Protestant can actually be a spiritual advance. People like that could plausibly defend themselves the way Evelyn Waugh defended himself; in response to a question why he, a Catholic, was such an unpleasant person, he replied: "I can't bear to imagine what I'd be like if I weren't Catholic." With as much or as little justice, some Protestants could say the same for themselves; and any Catholic apologist who denies that—if there are any—is a very bad apologist. But I don't think it would be charitable to Shane to interpret his claim as one which is, or would be, so uncharitable to Catholic apologists. Rather, he seems to mean something like this: since, according to Catholic apologists, one lacks the virtue of faith insofar as one rejects the authority of the Magisterium, then it is vicious in itself to be a Protestant. That is the claim he rejects. For brevity, let's call it by the acronym 'PIV'.
Now PIV calls for qualification before it can be fairly assessed. For one thing, one needs to consider whether holding PIV is compatible with acknowledging the fact that there are people who, by choosing to be some sort of Protestant, become better people than they would be if they had not so chosen. Without presuming to speak for other "Catholic apologists," I should say it depends. If somebody has been given the grace of valid baptism and has enough knowledge of the deposit of faith to make an act of divine faith, then the question whether they are vicious for choosing to be some sort of Protestant depends on how well they have understood and considered the claims of the Catholic Church—claims which of course I believe to be both true and vitally important. In my experience, most Protestants do not understand, and thus have not considered, the claims of the Magisterium for itself well enough to be held blameworthy for failing to accept them. As I will exhibit below, that includes Shane himself. The phenomenon in question is only to be expected given that, in my experience, the majority of Catholics do not understand said claims well enough to be held praiseworthy for accepting them—assuming they do accept them, which in the case of some Catholics is by no means a safe assumption to make. Speaking from an informed Catholic viewpoint, I'd say there probably are some Protestants whose choice has been made with enough knowledge and clarity to be blameworthy and thus vicious. A good proportion of those, I suspect, are ex-Catholics. But given Catholic life as a basis for comparison and extrapolation, I don't believe such Protestants are very numerous; and I certainly would not presume to identify any in particular, which is only for God to do. Hence, I would deny it's inherently vicious to be some sort of Protestant, if by calling a choice 'inherently vicious' is meant that, ceteris paribus, one causes oneself to be a less good person by making such a choice than one would be if one hadn't. Understood in that sense, PIV is a strawman hardly worth knocking down among duly informed people.
But perhaps I've missed Shane's point once again. He constructs part of his argument by first noting five propositions on which Catholics and Protestants may be presumed to agree:
1) Everyone has a duty to believe the truth of the Gospel.
(2) The original apostles, i.e. the Twelve and Peter, were faithful witnesses to the content of divine revelation and the New Testament is a reliable written record of their testimony.
(3) Realistically speaking, you will never as an individual figure out what you ought to believe on your own.
(4) You must depend on someone or something else to teach you the revealed truths you were incapable of finding out from the Bible by yourself.
(5) Since God requires you to believe the right things, then he must intend on furnishing you with the means by which to come to believe the right things.The problem arises with what he takes to be a further, distinctively Catholic claim:
(6) The one and only way to know with certainty the revealed truths of the Christian faith is the infallible teaching office of the Roman Catholic Church.
Shane says he knows of no "good argument" for (6), and in fact he rebuts a few bad arguments that are either for it or depend on it. And so, he thinks, PIV must be false: it cannot be inherently vicious to disbelieve a claim for which there is no good argument.
Since Shane's subsequent critique of Catholic claims depends on (6)'s fairly representing the Catholic position, we should ask: does it? I'm afraid not. Just as PIV is itself ambiguous as formulated, (6) too is ambiguous. If (6) be taken to mean that the Magisterium is the only way to know that "the revealed truths of the Christian faith" are true, then that is not the teaching of the Catholic Church. Rather, the Church teaches that "Sacred Tradition, Scripture, and the Magisterium are so linked and joined together that none can stand without the others" (Dei Verbum §10). Hence the Magisterium, taken in isolation as "the one and only way to know," does not stand even on Catholic premises. But even aside from that, the question arises whether the sort of "certainty" given us by the three normative sources taken in convergence is that of knowledge or belief. Answering that question depends on how one's epistemology distinguishes between knowledge and belief generally, and hence in the particular case of religious belief. Regardless, however, of which epistemology Shane is inclined to supply on his own account, he is not fairly representing what's entailed by the Catholic idea of faith as a "theological virtue."
Although Shane professes to have read Aquinas on that subject, he does not seem to have taken the lesson. Aquinas clearly says"...it is impossible that one and the same thing should be believed and seen by the same person. Hence it is equally impossible for one and the same thing to be an object of science [i.e. scientia or "knowledge"—ML] and of belief for the same person." And faith, understood as a divine gift by which one believes with certainty what has been revealed, is a kind of belief. Hence neither the Magisterium nor any other source can cause one to "know" that "revealed truths" are in fact truths, where "knowledge" is of the sort of thing that can be demonstrated. No truth of faith, as distinct from truth of reason, is subject to demonstration; and to believe with certainty what God has actually revealed is itself a divine gift. Therefore, it is not a defect of Catholicism that there is no proof, in the strict sense of 'proof', of any distinctively Catholic doctrine—including that about the Magisterium's infallibility when it speaks with the Church's full authority. And so it cannot be inherently vicious to reject any presentation of that doctrine which pretends otherwise. What the Magisterium does, when it teaches with the Church's full authority, is supply the authentic interpretation of Scripture and Tradition as the two other sources by which the faith-once-delivered is transmitted to us. That does not give us knowledge that the faith-once-delivered is true; it merely supplies something necessary for identifying the content of what is proposed as being divinely revealed. As my essay "Faith, Private Judgment, Doubt, and Dissent" argues, the Magisterium is thus necessary, albeit not sufficient, for supplying us with the proximate object of the assent of faith—the ultimate object of course being the Word of God, who is God himself, the Second Person of the Trinity incarnate as a man in Jesus Christ.
It is inherently vicious to disbelieve that only if (a) one has been given the gift of divine faith with the full teaching of the Catholic Church as its proximate object, and (b) one has rejected that gift with full knowledge and consent. As I've already implied, some Protestants may well have done that; but I would be very hard put to argue that many have, and it would be vicious for anybody to presume to identify just who they are. Indeed, as a Catholic I should say that such a person's being Protestant is more likely the result than the cause of rejecting the gift of faith, a rejection they share with many nominal Catholics who would be rather surprised to hear they are guilty of that. Hence, "Protestantism" understood as the state of being Protestant is not inherently vicious, but in some cases is accidentally so. "Protestantism" understood as a definable religious tradition is neither vicious nor virtuous; only persons can be either. Once cannot even say that "Protestantism" is true or false, since some versions of Protestantism contain much more truth than others. So after all the due qualifications have been made, I'm inclined to agree with Shane that "Protestantism" is not inherently vicious. When a person is vicious for being or becoming Protestant, that is usually accidentally not inherently so.
As if most people really cared. The sort of discussion Shane seems to want to have would be more fruitful if he focused on the concept of private judgment as Newman expounded it and as I use it. I don't think Shane has understood that concept, and he's got a lot of company. My brief treatment can be found in the aforementioned essay of mine.