Ong explains the context for Newman's essay, emphasizing the influence of Joseph Butler's Analogy on Newman's thought. Newman was raised as an Evangelical Protestant but joined the Anglican Church, and in line with the Protestant and Anglican traditions, he believed that the development of doctrine did not exist. Eventually, he accepted the Catholic notion that development of doctrine does exist, and Butler's "sacramental principle" had an influence of this change in Newman's thought.
Ong then analyzes Newman's essay, focusing particularly on Newman's use of the organic life analogy, in which an idea (such as that of the development of doctrine) is likened to a plant: rather than expressing "the truth" from the outset, an idea must be germinated, maturated, and propagated, and this process can often take many centuries to occur. The development of ideas is further complicated by the fact that human knowledge (unlike that of angels, according to Ong) is not absolutely direct but relevant only in relationship to the material world (an idea Ong also explains in "The Meaning of 'New Criticism,'" with a slightly more optimistic take on this reality than presented here).
For Newman, Ong explains, the development of doctrine worked in exactly the same way that the development of other ideas operates. For example, Newman does not believe in a "root idea" of Christianity, but even if one accepts the Incarnation as the most central idea in the religion, Newman asserts that this idea cannot be understood absolutely or only in the abstract sense. Instead, it is understood through various interpretations ("God became man," "Christ as God-Man stands between man and God," and "God has become one of us in the flesh") as well as how those interpretations develop over time.
Ong asserts that although Newman does not directly address the doctrine of revelation in his Essay on Development, readers can conclude that the essay does take a stand on the issue: in fact, the absence of direct discussion is what creates a stand on the issue. By arguing that Evangelical Protestants and Anglicans refused to accept the fluidity of doctrine, something they applied to the issue of revelation, Newman set himself up as someone who accepted revelation wholeheartedly and in opposition to those who did not.
After Ong establishes this assertion, he discusses in more detail the kind of mindset Newman opposed: the positivist. Prefacing this discussion with a section on "first principles" and Newman's concern with them in the whole body of his writing (specifically how Newman's schematic is similar to that of St. Thomas Aquinas, in which abstract ideas are intimately linked to the material world), Ong asserts that the positivist mind is one that cuts itself off from accepting revelation because it works only with one way of accessing the truth (and, even worse, denies that it rejects all but one form of knowing). Interestingly, Newman's long-time friend, William Froude, was a good example of this type of mind, and Newman's correspondence with Froude provides proof that Newman actively tried to convince Froude to adopt new approaches to his work.
Ong also contrasts Newman's approach to that of Hegel, as much an extreme idealist as Froude was an extreme positivist. While Hegel did recognize the weakness in his Idealist philosophy, his work provides more evidence that those people who try to separate the abstract and material realms end up oversimplifying life. In the end, Ong describes Newman as a realist, for he was able to acknowledge both the abstract and material realms and make the transition from the material to the abstract, which Ong believes is required to access revelation. In the conclusion of the article, Ong returns to the importance of Newman's Essay on Development, emphasizing in particular that the essay functioned as an important marker of Newman's shift away from the Protestant and Anglican traditions to Catholicism.