Theories of Doctrinal Development in the Catholic Church. By MichaelSeewald. Cambridge: Cambridge University Press, 2023. Pp. vii, 213. £85.00.

A strong historical foundation is vital for understanding clearly most disputed topics.Good history can unmask false claims and call into question much that has always been accepted.In performing these helpful tasks, good history is often simultaneously a source of complexity, demonstrating that 'the truth' does not disclose itself lightly and usually differs from facile presumptions.Michael Seewald's study of doctrinal development displays all the admirable virtues of good history, including the refusal to erase all complexity from what tends to be a divisive issue in the life of the Church.The bulk of the book is a detailed discussion of the concept of development through the history of the Christian community, from the biblical authors to the life of the Church in the post-Vatican II era, but the book begins with an exploration of the key terms in 'development of doctrine'.It is worth noting that while the book's title uses 'doctrine', the focus of the introductory chapter, and beyond, is on 'dogma'.'Doctrine' might have appeared to be more accessible to readers than 'dogma', and so more suitable for the title, but the author's analysis does show that the two terms are not interchangeable when properly understood.Indeed, he argues that 'dogma' is either 'a' doctrine or 'the' collective body of doctrines.Seewald's exegesis of 'dogma' leaves little doubt that, from the New Testament onwards, the term has been one with a contested rather than univocal meaning.A core point of the opening chapter is Seewald's claim that 'ordinary' magisterial teaching has at times come to be regarded as 'extraordinary'; in other words, that something once not regarded as dogma has later come to be so regarded.His point in making this observation is that if revelation is the bedrock of all that the Church regards as truth beyond human manipulation, the advance from ordinary to extraordinary teaching could appear to be an instance of the magisterium altering revelation.With this possibility in mind, Seewald raises the question of whether movement could go in the opposite direction: could something long accepted as dogma cease to be so considered?It is a provocative question and an intriguing one.Equally intriguing is Seewald's definition of 'development': the 'unstable simultaneity of continuity and discontinuity'.This description, perhaps somewhat frustrating in its paradoxical nature but nonetheless appealing in its refusal to tie development to a series of easily-identifiable and invariable features, sets the scene for the emphasis on complexity that the author reads in the application of the term through history.Seewald is careful to stress that no development can be understood without a strong grasp of both the origins of a particular doctrine, and the historical contingencies that have exerted an inescapable influence on how the doctrine has been interpreted and received through history.An overarching thesis of Seewald's approach is that dogma is a meeting point of God's revelation and human understanding that always has its embodiment in history.Accordingly, there will always be the need for careful discernment of what might be the divine element of any teaching.The need for this discernment underscores that God's self-communicating grace does not disclose itself outside of humanity's faith-formed relationship with God.Both authentic continuity and authentic discontinuity, then, are elusive and certainly not subject to any mathematical formula that guarantees easy access to certainty.In many ways, of course, this thesis is simply an affirmation of the fact that the Church must live by faith rather than sight, but knowing this truth has not always spared the Christian community from various forms of struggle concerning what is or is not God's revelation rather than human constructions or what is most appealing to various groups of believers.The bulk of Seewald's volume is his detailed survey of the history of dogma and its development.This survey begins with the New Testament's depiction of Jesus.Seewald illustrates the variation between the different New Testament texts and the process by which relationship with Jesus became faith in Jesus.As a corollary of this process, the chapter on the Bible also charts how the text itself and its understandings of Jesus's identity and mission became formative of the Christian community.A subset of both the biblical material and later chapters is a focus on the role of the Holy Spirit, and the ways in which the Church has interpreted-or at times ignored-the work of the Spirit in shaping and developing the Church's faith through history.A distinctive aspect of Seewald's examination of the understanding of development in the early Church is his engagement with Vincent of Lrins.Vincent's maxim-that only what has been believed 'always, everywhere, and by everyone' constitutes the authentic faith of the Church-has long functioned as the yardstick by which to measure development.Without dismissing the maxim, Seewald leaves no doubt that Vincent's principle is not without its own complexities and does not deliver unproblematic certainty.Interestingly, Seewald demonstrates that Joseph Ratzinger as a young theologian was very critical of the maxim, even though Ratzinger's later activities as curial cardinal and pope might suggest the opposite.Seewald's narrative continues through the Middle Ages and Reformation, but it is the nineteenth century that is pivotal for providing a perspective on contemporary understandings of development.In the nineteenth