Mark S, MASSA. The Structure of Theological Revolutions: How the Fight Over Birth Control Transformed American Catholicism. New York: Oxford University Press, 2018. Reviewed by Pablo ITURRIETA, Dominican University, Ottawa, ON

Mark Massa is a historian of US Catholic thought and practice in the twentieth century. He argues that when Pope Paul VI issued Humanae Vitae, an encyclical on human sexuality and birth control, American Catholics not just ignored and dissented from the teachings of the Church, but also began to question the entire system of natural law theology. Natural law is central to the edifice of Catholic morality, so much so that arguments on contemporary issues such as birth control, abortion, and marriage are based on natural law. That also means that if those Catholics have rejected natural law, they have also rejected all of the moral tenets of Catholic morality, creating a true revolution in their dissent. It is the structure of this “theological revolution” that Massa analyzes in his book. Yet, far from being a description of this change in mentality, Massa argues that Catholic moral teaching is rather provisional and arbitrary on many important issues

One important question arises, then. If God’s nature is unchangeable, how come theology might be a changeable and evolving reality? This is the essential question that Massa sets out to answer in the present book. In order to do so, Massa argues that natural law is just really only a small tradition within the bigger tradition of Catholic theology. Thus, he questions the theological foundations of Catholic teachings on sexuality, birth control, gay marriage and abortion.
It wasn’t until Aquinas structured Catholic theology that natural law became central to its teachings. Yet, according to Massa, this is no more than just the “privileged” way of talking about sexual morality, but not the “only” way. In 1968, this natural law tradition came abruptly to an end, at least in the United States. Massa explores some of the aftershocks that followed in the field of moral theology within the United States.

In presenting the development of this “theological revolution” in the US, Massa applies Kuhn’s famous idea of how scientific revolutions work. Kuhn challenged older understandings of how and why physical science progressed. He rejected the idea that science progressed in a linear developmental fashion. In the same way, Massa argues that Catholic theology also changes in a way that is not linear with respect to the natural law tradition. His main thesis is that “theology does not progress in anything like a linear fashion from generation to generation. . . . Rupture and discontinuity are at least as important as continuity and linear development in narrating the history of Catholic natural law discourse in the United States during the past half century” (p. 4).

For Massa, it means that the smaller or micro traditions of natural law do not build seamlessly on each other. There has been a serious rupture and reformulation in the last fifty years that require a new understanding of theological progress. Thus, the ancient theological model based on Aquinas’ understanding of natural law is to some extent not true and unhelpful in understanding the role of theology today.
Massa then analyzes in the various chapters of the book the work of authors such as John Ford, Charles Curran, Germain Grisez, Jean Porter, and Lisa Sowle Cahill. All of them, according to Massa, presented different “paradigms” of natural law theory which challenge the old natural law tradition the Church inherited from Thomas Aquinas.

Massa’s presentation of how the structure of theological revolutions work is an interesting insight into the debates that followed the publication of Humanae Vitae. From the analysis of different models of natural law, he concludes that there is not a linear tradition in Catholic theology, as all these models of natural law are all dramatically different, and reality is more complex than any natural law model constructed to explain it. Yet, the question every Catholic theologian should make is, are all these models valid examples of natural law?