Omne Agens Agit Sibi Simile: A "Repetition" of Scholastic Metaphysics (review)

The technical sounding title of this volume could mislead the reader into thinking that it concerns some obscure point of Latin medieval thought, rather than an issue central to medieval metaphysical speculation. In fact, Philipp Rosemann charts the metaphysical theology of a significant number of intellectuals, ranging from Plato to Aquinas, in a dense and perceptive historical narrative that reaches its telos in Aquinas’s view of the emanation from, and return to, God. Too often historians and philosophers atomize specific medieval issues by treating them apart from the textual, historical, and metaphysical context. The classic case of this occurs when the wider web of metaphysical and monastic concerns is neglected in presentations of Anselm’s argument for the existence of God. Rosemann supplies much of this context in a concise yet detailed discussion of Hellenistic and medieval views on causal similitude, i.e., the degree of similarity that must exist between every cause and effect.

The book is divided, as it were, into three equal parts: the first is devoted to the ancient philosophers Plato, Aristotle, Plotinus, and Proclus; the second to Pseudo-Dionysius, Augustine, Eriugena, Peter the Lombard, Avicenna, Averroes, and Albert the Great; and the third to Aquinas. These figures were included for two reasons: first, for contributing views of causal similitude that take into account either a Neo-Platonic emanational causality between different types of beings or/and a peripatetic efficient causality between individual substances; and second, to provide the background for Aquinas’s reconciliation of both types of causality.

In the second part of the book, Rosemann presses his thesis that there is a Trinitarian context to Western metaphysical reflection which must be understood if we are to be clear about the history of Latin medieval thought. His point is that within this context intellectuals produced detailed accounts of a hierarchy of beings each of which stands on a scale closer to or farther away from a single divine “being” (111). Individual beings, including physical objects, both replicate and exteriorize various qualities of the divine (115). From this perspective, Latin medieval inquiry into issues concerning causality and the human mind form at the same time an inquiry into the interior character of a triune God (145, 349). For example, it becomes clear why Eriugena claims that a human being has no direct knowledge of his or her individual essence (125). In imitation of the divine, one reasons about one’s concerns, and only then is one able to reflect on this reasoning. Such reflection yields self-knowledge (124–27). Since human self-knowledge reflects divine self-knowledge, human self-knowledge is required in order to inquire into the mind of God. According to Rosemann, the medievals extend to the divine Socrates’ dictum regarding the unexamined life.

Recent writers have devoted attention to the Neo-Platonic framework of Aquinas’s project. For example, in his important God in Himself (Oxford: Oxford University Press, 1987), Wayne Hankey has clarified the two emanations that structure the first part of Aquinas’s Summa theologiae: the first a procession of three persons internal to God, and the second the procession of creation. The first plays a causal role in regard to the universe while the second mirrors the metaphysical structure of the first. Rosemann places this intellectual achievement in a more precise historical context, carefully isolates Aquinas’s types of causal relations (280–88), and offers a splendid account of the role played by causal similitude in the emanation and return of individual substances to God (262–77). Individual beings bring about effects that are species-specific to the point that they both lead to the flourishing of the species and represent the divine. The higher the type of being, the more elevated and individual the degree of representation. For example, while a stone might express external physical characteristics of strength, a human being can obtain a...