The great convert/cardinal’s 1879 speech is a barn-burner and is reviewed in this article from Catholic World Report.

An excerpt.

There is truly nothing new under the sun. That’s the pedestrian conclusion at which I arrived after recently re-reading the address given by one of the nineteenth century’s greatest theologians, Blessed John Henry Newman, when Pope Leo XIII made him a cardinal on May 12, 1879.

Known as the Biglietto Speech (after the formal letter given to cardinals on such occasions), its 1720 words constitute a systematic indictment of what Newman called that “one great mischief” against which he had set his face “from the first.” Today, I suspect, the sheer force of Newman’s critique of what he called “liberalism in religion” would make him persona non grata in most Northern European theology faculties.

When reflecting upon Newman’s remarks, it’s hard not to notice how much of the Christian world in the West has drifted in the directions against which he warned. Under the banner of “liberalism in religion,” Newman listed several propositions. These included (1) “the doctrine that there is no positive truth in religion,” (2) “that one creed is as good as another,” (3) that no religion can be recognized as true for “all are matter of opinion,” (4) that “revealed religion is not a truth, but a sentiment and a taste; not an objective faith, not miraculous,” and (5) “it is the right of each individual to make it say just what strikes his fancy.”

Can anyone doubt that such ideas are widespread today among some Christians? Exhibit A are the rapidly-collapsing liberal Protestant confessions. Another instance is that fair number of Catholic clergy and laity of a certain age who shy away from the word “truth” and who regard any doctrine that conflicts with the post-1960s Western world’s expectations as far from settled. Yet Newman’s description of liberal religion also accurately summarizes the essentially secular I’m-spiritual-not-religious mindset.

At the time, the directness of Newman’s assault on liberal religion surprised people. It wasn’t for idle reasons that the speech was reprinted in full in The London Times on 13 May, and then translated into Italian so that it could appear in the Holy See’s own newspaper L’Osservatore Romano on 14 May. Everyone recognized that Newman’s words were of immense significance.

The newly-minted cardinal had hitherto been seen as someone ill-at-ease with the Church’s direction during Pius IX’s pontificate. Newman’s apprehensions about the opportuneness of the First Vatican Council formally defining papal infallibility were well-known. Not well-understood was that concerns about Catholics being misled into thinking they must assent to a pope’s firm belief that, for example, the optimal upper-tax rate is 25.63 percent, didn’t mean that you regarded religious belief as a type of theological smorgasbord.

Those who had followed the trajectory of Newman’s thought over the previous fifty years would have recognized that the Biglietto Speech harkened back to a younger Newman and a consistent record of fierce opposition to liberal religion. In 1848, for instance, Newman had lampooned liberal religion in his novel Loss and Gain (1848). One character in the book, the Dean of Nottingham, is portrayed as someone who believes that “there was no truth or falsehood in received dogmas of theology; that they were modes, neither good nor bad in themselves, but personal, national, or periodic.”

Such opinions mirror the views of those today who primarily regard Scripture, the Church and Christian faith as essentially human historical constructs: a notion that invariably goes hand-in-hand with a barely-disguised insistence that the Church always requires wholesale adaptation to whatever happens to be the zeitgeist. The end-result is chronic doctrinal instability (and thus incoherence) and the degeneration of churches into mere NGO-ism: precisely the situation which characterizes contemporary Catholicism in the German-speaking world.

Another of the novel’s characters is Mr. Batts, the director of the Truth Society. This organization is founded on two principles. First, it is uncertain whether truth exists. Second, it is certain that it cannot be found. Welcome to the world of philosophical skepticism which, Newman understood, is based on the contradiction of holding that we know the truth that humans really cannot know truth.

Newman’s antagonism towards liberal religion, however, also reflected another side of his thought that, I suspect, some today would also prefer to ignore. This concerns Newman’s critical view of liberalism as a social philosophy.