To read Zahm today is to be astonished by the innocuous nature of his claims, and by the utter unwillingness of his critics to consider the scientific case for evolution. It’s worth recalling that when Zahm’s book appeared there was less support than there is now for Darwin’s theory that natural selection was the engine of evolution. This was before scientists knew anything about DNA, before there was any consensus on how traits were passed from one generation to the next (Mendel’s work had yet to be rediscovered). Since Zahm was one of those who dismissed natural selection, he was never really a Darwinist in the strict sense. The primary complaint of his critics was that he dared suggest Adam and Eve were not the result of a special act of creation but were, like all other living animals, the descendants of prior species—in this case, primates.
But, as Slattery shows, Zahm’s critics were already predisposed to be hostile to any claim for evolution regardless of the scientific evidence in its favor, because their conservative theology was underpinned by a commitment to nineteenth-century Neo-Scholasticism. Slattery delves into the emergence of this movement and its key figures, including the Jesuit Joseph Kleutgen, who had a profound influence on Pope Pius IX’s Syllabus of Errors and his encyclical Dei filius, as well as on Pope Leo XIII’s encyclical Aeterni patris. These three papal documents all anchored reason in the scholastic tradition that grew out of the work of Aquinas.
This tradition wasn’t a blanket adoption of Aquinas’s thought, but rather a new attempt to create an impregnable intellectual system, a form of theological rationalism that could resist all forms of innovation—in philosophy or science. As Slattery describes it:
First, the leaders of the Neo-Scholastic movement insisted on a singular philosophical structure for all Catholic scholarship that was both objective and universal, for doctrine could not exist in a world where the roots of philosophy were being forever debated. Second, the Scholastic interpretation of the philosophy of Aquinas was to be revered as the model of this universal structure, over against any philosophical systems based on Descartes, Kant, Locke, or anyone else in the modern world, as well as over against the theological interpretations of any other theologian, such as Augustine, Bonaventure, or Scotus. Third, Neo-Scholastics argued that by relying on Aquinas and other medieval philosophers, contemporary Catholic philosophy could be constructed as a single objective whole. Fourth and finally, Neo-Scholastics resisted anything resembling a historical approach to philosophical or theological development, for if doctrine could be changed over time, it would be impossible to test its veracity.
It’s difficult to overstate how much damage this bunker-mentality approach to philosophy and theology caused Catholic scholars over the ensuing decades, right up until the papacy of Pius XII when the Church finally accepted, albeit with reservations, the study of human evolution. The disconnect is beautifully demonstrated by a new translation of the Syllabus of Errors that Slattery provides in an appendix. The Syllabus laid the groundwork for Dei filius at the time of the First Vatican Council and established the narrow boundaries within which all Catholic scholarship was expected to proceed.
Slattery’s account of Zahm’s work provides a much-needed bridge between this reactionary era in the Church’s recent intellectual history and the more open era of Catholic thought that preceded the French Revolution (a period well described in Ulrich L. Lehner’s The Catholic Enlightenment). Faith and Science at Notre Dame is an indispensable addition to this history.
Faith and Science at Notre Dame: John Zahm, Evolution, and the Catholic Church
John P. Slattery
University of Notre Dame Press, $27, 292 pp.