[T]he Holy Spirit will not lead two Christians into contradictory views.
This is true.
However, it is also an indictment of the entire history of Protestantism, and it was fundamental to my own departure from Protestantism. The Holy Spirit does not lie, the Holy Spirit is the court of final appeal for Protestant truth claims, and yet Protestants hold contradictory views. It isn’t the case that every disagreement among them matters: there are certainly things that are adiophora. But it is also indisputably the case that they disagree about things that do matter, and which cannot in any way be reasonably reckoned as matters of indifference.
Even the magisterial Reformers said that in cases of such disagreement the Holy Spirit could only be leading one of the two (or more) parties, but the critical point is that it is impossible for Protestants to distinguish the truth from error in such cases on their own terms. Impossible. No matter what they say. And on points where it matters, it is inconceivable that the Holy Spirit would “leave them in the lurch” (so to speak) if what they say about how He works is true.
Now the usual reactions to this are to ignore it (which is irrational, and probably a sin against truth), or to splinter into ever smaller and more insular groups (hence the Protestant “genius” for division, which only highlights this problem I’m discussing), or to claim that the areas on which the parties disagree are really matters of indifference after all. But the problem with the latter approach is that it reduces the content of what Christians must believe to an absurdly few points. Such a response means (for one glaring example) that the meaning, mode, and even the number (if you include certain Anglicans) of the sacraments is a matter of indifference for the Christian. And this, quite simply, beggars belief. It is not possible. And the same could be said about other areas of Protestant disagreement. Consequently it is inescapable that Protestantism is a self-defeating principle.
They do not say that the Holy Spirit speaks audibly (or in any other publicly verifiable fashion) to disputing parties so as to resolve disagreements; they say that He speaks internally to each man. But it is impossible to distinguish the Spirit’s leading in such a fashion from mere subjectivism. And really, all this does is cement in each party’s mind that his or their view is the correct one, because of course they are quite naturally all completely convinced of their own faithfulness before God, and of their own abilities in exegesis, and so of course it is inconceivable to them that the Holy Spirit would lead them astray. And yet the other parties say the same things about themselves too.
Consequently Protestantism is a self-defeating principle. Consequently I am now a Catholic.