The timing of the appearance of John Henry Newman’s Essay on the Development of Christian Doctrine in 1845 was either brave or foolish; or perhaps it was both. Coming as it did in the same year as Newman’s conversion to Roman Catholicism, it meant that he crossed the Tiber effectively brandishing what Michael Shea calls ‘a new treatise, which was bold, sweeping, and potentially subversive of the unchanging character of Christian truth’ (p. 55). In this book, Shea explores the influence of Newman’s now-lauded theory of the development of doctrine in the first decade of his life as a Roman Catholic: an influence which, he notes, is necessarily an entangled one.

In 1846, the new man Newman was warmly welcomed in Rome. At the time the Jesuit theologian Giovanni Perrone enjoyed the favour of Pius IX, and ‘hegemonic stature’ (p. 67): his writings on the relationship between faith and reason represented Perrone’s own via media, and amounted to ‘one of the best indices for what constituted orthodoxy in Rome at the time’ (p. 89). It was through his engagement with the now-obscure Perrone that Newman came to realise that some of his own statements on faith and reason might be open to misinterpretation.

Owen Chadwick, in From Bossuet to Newman (1957), observed that the reaction to the Essay included outright hostility from plenty of those whom Newman had left behind in the Church of England and suspicion on the part of many—but, crucially, not all—of his new co-religionists in the Church of Rome. Among his supporters was Nicholas Wiseman, who with characteristic enthusiasm had widely overestimated the convert-potential of the Oxford Movement. Even Wiseman’s support, however, was not enough to allay the concerns of Newman’s friends, nor indeed to shield him from attack.

From America Newman’s fellow-convert Orestes Brownson called him a heretic, while in Europe his name became linked, to his dismay, with the heterodoxies of Henry Bautain and Georg Hermes. Shea considers that Newman had left himself ‘vulnerable to the charge of denying a sufficient role to reason’ (p. 90) and in a helpful comparison of his work with that of Bautain and Hermes traces the way in which it might have been possible to make mud stick. A general overview of the state of contemporary Roman theological thought culminates with the convincing suggestion that Pius IX’s inaugural encyclical of 1846, Qui Pluribus, might well have been partly written by Perrone himself.

Qui Pluribus’s damning indictment of those who endorsed rationalism—istos tam misere delirantes—was not extended to Bautainism, which suggests to Shea the influence of ‘a distinction in Perrone’s mind between error and heresy’. He argues that ‘in all respects Newman would have belonged to the former category rather than the latter’ (p. 133), suggests that the Essay was viewed more benevolently at Rome than has formerly been thought, and that it had ‘obtained a full measure of acceptance’ (p. 148) as early as 1847. By then Newman was focussing on his formation as an Oratorian, but Shea also considers the extent to which ‘Newman’s impact by way of Perrone’ (p. 184) in the field of doctrinal development came to bear on the discussions that led up to the dogmatic definition of the Immaculate Conception with Ineffabilis Deus in 1854.

Shea’s conclusion on that point is that although the idea of doctrinal development did not explicitly appear in Ineffabilis Deus, the decree nevertheless allowed an interpretation in which it might at least be involved, and that ‘it is doubtful whether the 1854 decree would have taken the form that it did on doctrine and history without Perrone’s work and Newman’s theory in the background’ (p. 185). This he substantiates with an encouraging letter from Newman’s fellow-Oratorian Richard Stanton, who claimed that the papal favourite George Talbot had indicated that he thought that Newman’s theory was ‘substantially true’, and ‘what is more important, he says, that though it ought not to be publicly talked of, he knows it to be the private opinion of the Holy Father himself’ (p. 188). During his time as the darling of the Pian court, Talbot said many things to many people; some of them may even have been true, and so perhaps it is not unreasonable to allow Shea to take the notoriously disingenuous Talbot’s comments at face value.

The Essay was Newman’s most reworked of all his publications: not only because ‘to be perfect is to have changed often’, but because he wanted above all things to be able to demonstrate that his position, as convoluted as it was, was above reproach in the eyes of the Church. It was a question answered once and for all in 1879, when Leo XIII made him a cardinal, and sealed in 2010 when Benedict XVI presided over his beatification. Shea’s thesis is that the impact of the Essay on the Development of Christian Doctrine did not have to wait that long, however, and that despite its early imperfections Newman’s theory found favour in Rome as early the 1840s and 1850s.

Shea’s revisionist approach is well-presented and convincingly-argued, and it deserves serious attention. That said, there exists in the book a strange dissonance in that, apart from a couple of bibliographical references, its author does not seem to engage in any way with the work of Ian Ker—not even with his Newman and Vatican II (2014), which would seem to be an obvious point of engagement given Shea’s recognition of Newman’s influence upon men like Henri de Lubac and Yves Congar. It seems curious, even baffling, for someone to have written a book of this kind and on this subject without reference to the leading Newman scholar of our time.