This book—the last in a list that includes several contributions Tutino has devoted to Catholic theological elaboration and doctrinal control—addresses the relationship between truth and demonstration as well as faith and empirical proof in the Roman Church after the Reformation. She privileges two kinds of sources—theological texts and the documents produced by the Congregations of Inquisition and Index—to trace the trajectory of a Latin term of great impact in the Western tradition. This is credulitas, which meant both credulity and credibility. While pagan authors had stigmatized as credulitas the attitude of those who are inclined to believe what cannot be ascertained, Augustine and Aquinas outlined the traditional interpretation of the term. Believing means first of all performing an act of the will to embrace a truth that is not always demonstrable but credible because it is founded on the divine Word and the Magisterium. In the Augustinian-Thomistic interpretation, reason is not sufficient to ground faith; credulitas as the propensity to believe even without seeing or having tangible evidence must therefore be valued (Chapter I). In the Middle Ages, canon law—for which credulity indicated a condition placed between ignorance and direct knowledge of a fact—admitted witnesses not de visu as trial evidence, speaking also of testes and iuramenta de credulitate (oaths of credulity) valid for the matrimonial disputes and the rites of purgatio.

To what extent could one accept uncertainty in judging what to believe and how to act morally? The problem became more urgent in the sixteenth century when humanists, Protestants, and unbelievers—not to mention those who investigated the nature—challenged the Church of Rome, forcing it to respond to unprecedented problems that also arose from the new missionary context. As we read in Chapter II, the canonist Navarro and the Jesuit Francisco Suárez were the first to value credulitas as a resource of the intellect, and not of the will, both for the judgement on matters of conscience (crimes and sins) and for the very act of adhering to the true faith. In controversies with the Church's enemies, it was no longer enough to appeal to the will to obey, but it was useful to make the Catholic choice credible so that the flock could embrace the authentic religion by giving their “reasonable assent” (Súarez, De Fide, modified before printing, 1621). Although theologians such as Juan Maldonado thought otherwise (Chapter III), history, miracle, and missionary success became credible witnesses of the true Church, even if the risk for Catholics was to base faith more on an act of reason and clear evidence than on a willingness to adhere to Christ's saving message by subordinating themselves to the clergy authority. Moreover, by applying the category of credibility, one could believe in the powers of the devil but at the same time criticize witch hunts, as the theologians Adam Tanner and Friedrich Spee did.

But how many aporias, how much uncertainty, how much need to judge religious phenomena and books with flexibility did this inclination to balance faith with credibility engender in the Church leadership? These are the questions answered in the second part of the book, which reports some significant cases from the seventeenth century. In Chapter IV, distancing himself from Ethan Shagan's teleological view (The Birth of Modern Belief, 2018), Tutino analyzes the failed censorship of Thomas Campanella's Atheismus Triumphatus and Hugo Grotius's De veritate religionis Christianae to show that Church institutions were not at all rigid in judging works by controversial authors, who applied reason to ascertain which religion was to be believed. In Chapters V and VI, Tutino addresses the much-debated question of the early modern origins of unbelief and atheism and highlights the cautious attitude of the Roman congregations toward episodes such as that of Muzio Antonazzi, who was questioning the biblical accounts. In the wake of Alec Ryrie (Unbelievers: An Emotional History of Doubt, 2019), she analyses some cases of theological controversy, such as that of a minor author who had reaffirmed the thesis of the double truth regarding the immortality of the soul, ignoring the Lateran V decree against Averroist Aristotelianism; that of a spiritual director who did not consider it a sin to perform acts that the penitent did not consider a sin; and some episodes of unbelief, involving not too learned women and men who had often had a mobile existence and considered themselves sincere Catholics, even though they were troubled by radical scruples.

In Chapters VII and VIII, the book addresses the problem of controlling devotions and deals with cases of tearing images, miraculous statues of the baby Jesus, and alleged saints. How to ascertain the truth of extraordinary phenomena without fuelling scepticism toward divine prodigies? How to sanction the impostures of the laity and clergy without scandalizing the faithful? How to discern falsehood, credulity, and superstition? Above all, how to control the circulation of stories of saints who had performed alleged miracles in the global theater of missions, in a context that favored the circulation of unverifiable news such as those reported in the gazettes but also in the litterae annuae printed by the Jesuits? The stories of the biographers of the missionary “martyr” Marcello Mastrilli and the prophet Giulio Mancinelli (who forced the rules imposed by Urban VIII concerning the writing of the lives of non-canonized saints, thus prompting the Roman Congregations to reformulate them) are emblematic of the contradictions that ran through the Church's leadership—this, in an era of uncertainty in which the demand for evidence and the myriad taste for invention coexisted. All the more so because, for Tutino, a critic (like Brad Gregory) of the old paradigm of secularization and the Enlightenment vulgate, the travails that the institutions of Rome went through in the seventeenth century show that the black legend that relegated the Church to the margins of modernity, interpreting it as a monolith deaf to all doubts, must be abandoned, as the more recent historiography on Early Modern Catholicism, with which she engages in lively dialogue, strives to do.

Perhaps the text could have delved into the concept of fides along with that of credulitas with which it ended up being confused; and perhaps some of the cases reported are less significant than others in demonstrating the book's thesis. But it is an intriguing, well-written, and solid piece of research, useful even to those who would hesitate to share an overly benevolent judgement on the disciplinary and repressive institutions of the Tridentine Church.