Having published a series of articles on the topic of divine action and contemporary science, Ignacio Silva presents us with a coherent and thorough monograph that summarizes his contribution to this field of study. His main point of reference is a continuing debate inspired by the Divine Action Project sponsored by the Center for Theology and the Natural Sciences in Berkeley, CA, and the Vatican Observatory in Rome (1998–2003).

The first chapter of the book offers a brief historical account of the reflection on the nature of divine providence, in which Silva revisits (1) medieval debates over occasionalism (al-Ghazālī versus Averroes, Aquinas versus Avicebron), (2) the development of early modern causal reductionism, atomism, and the notion of laws of nature (inspiring the modern version of occasionalism), (3) theological repercussions of the nineteenth-century debate over determinism versus indeterminism, and (4) the advent of quantum physics, which many saw as a framework allowing for the re-instantiation of God’s providential action in the created universe. Silva concludes his overview with a formulation of the four criteria (desiderata) helpful in assessment of the contemporary (and future) models of divine action. They include (1) God’s omnipotence, (2) God’s involvement in the workings of nature, (3) the autonomy of nature, and (4) the success of natural reason and science (pp. 26–7). He states (in the Introduction) that the main goal of his project is to prove that, unlike the views of other participants of the conversation on God’s providence, ‘Aquinas’s model [of divine action] manages to hold the four of them’ (p. 7).

In the second chapter, Silva introduces some fundamental categories referred to in the debate on divine providence in the age of science – including the notion of general and special divine action and the category of ‘causal joint’ – and explores the basic features of contingency, indeterminism, chance, and randomness. He explains the use of these concepts in an argument for divine providence through the workings of the created indeterminate order. Silva’s critical assessment of NIODA (non-interventionist, objective, divine action) models refers to the ideas offered by John Polkinghorne, Jeffrey Koperski, and Robert J. Russell (concentrating mainly on the last). He states that these models are based on two philosophical assumptions leading to an important theological conclusion. He adds that all three ‘have not yet been thoroughly analysed’ (p. 43) and offers to fill this lacuna. The first philosophical assumption defines cause–effect relationship as (necessarily) deterministic (even if the universe is indeterministic, causality in it is identified with determinism), while the second introduces incompatibilism, assuming that ‘if God is able to act providentially whenever and wherever God wants, then the autonomy of nature in its actions is endangered, and with it the foundations of science’ (p. 46). Silva asserts that these philosophical assumptions lead to a theological conclusion that ‘God has to be conceived as acting as another natural cause’ (p. 47). Following critical remarks of William Stoeger, Taede Smedes, and Michael Dodds, he develops his own sharp criticism of quantum NIODA and says that

The following two chapters offer an assessment of the classical (fourfold) notion of causation and natural contingency (chapter 3) and a presentation of Aquinas’s model of divine action (chapter 4). Concerning the latter, Silva analyses the notion of God as esse purus and God’s power expressed in (1) his creatio ex nihilo, (2) his action in every natural agency, and (3) his action through miracles. Unlike participants of the science-religion dialogue representing other theological traditions who might see this part of the book as novel and significant for their research, the readers familiar with the Aristotelian-Thomistic school of thought are rather unlikely to find it revelatory. Yet, they should certainly pay attention to Silva’s retrieval of Aquinas’s distinction of four aspects of divine action in the universe (De potentia 3, 7), which include (1) giving things powers to act, (2) preserving natural powers of things in existence, (3) applying their powers to act, and (4) using them as instruments in order to bring out something that goes beyond their natural dispositions. Silva classifies (1) and (2) as ‘foundational’ and (3) and (4) as ‘dynamic’ aspects of divine providence. This distinction becomes crucial for the remaining part of the book, in which Silva applies Aquinas’s philosophy and theology to the contemporary divine action debate.

The final, fifth chapter opens with an account of an important parallel between moderate (suppositional) determinism in Aquinas (who sees chance and fortune as ontologically real) and moderate indeterminacy of quantum events (which, nonetheless, are not pure potency). Silva finds God as present and active in both determinate and indeterminate aspects of nature. Most importantly, he criticizes the popular distinction between general divine action, which ‘refers to all events in nature’ and ‘is not involved in particular events’, and special divine action through which God ‘acts directly and immediately in the universe’ (p. 126). In reference to Aquinas’s four aspects of divine action in the created universe, he notes that according to Thomas ‘… when creating, God does not do it only universally, but rather puts each being into existence particularly and individually: “singular things are God’s effects. God causes things in so far as He makes them to be in act (Summa contra gentiles I, 65)”’ (p. 126). In other words, says Silva, Aquinas’s observation that ‘… the operations of secondary causes are within the scope of divine providence, since God orders all singulars by Himself’ (Summa contra gentiles III, 71) should be ‘understood in the terms of the contemporary debate’s special providential action, since it is an action that God does willingly hic et nunc, when each natural efficient cause acts, at any given time and place’ (p. 130).

This conclusion becomes an original and timely response to all models of NIODA, which proves the importance of Silva’s Thomistic contribution to the contemporary divine action debate. At the same time, his response to quantum NIODA may be challenged in at least one way. While his presentation of Aristotle’s and Aquinas’s accommodation of natural contingency is accurate, his reliance on the same authors in their answer to the question concerning the source of contingency in nature might be insufficient. Silva rightly notes (pp. 72–6) that for Aquinas, the natural sources of contingency include (1) the conjunction of independent causal chains, that is, the concurrence of causes not subordinate to each other (concursus causarum); (2) the defect of the agent or lack of active causal powers (defectus agentis); and (3) the lack of proper disposition of matter which makes the recipient unable to receive a specific form from the agent (indispositio materiae). However, this typology was challenged by Robert Russell’s version of NIODA. Russell claims that chance defined in (1) is merely epistemological, and that ‘in a fully deterministic universe, both [causal trajectories] could be predicted if one possessed sufficient knowledge of all the governing forces along with the initial and boundary conditions’ (Robert J. Russell, Cosmology from Alpha to Omega: The Creative Mutual Interaction of Theology and Science, 2008, p. 120). He is thus of the opinion that what we discover at the quantum level is a completely new type of chance (contingency), which is independent of any causal trajectory (1) and is not an outcome of any defect of agent (2) or patient (3). This is a considerable challenge that does not seem to be addressed by Silva in his presentation and criticism of Russell’s version of NIODA.

This critical remark notwithstanding, Providence and Science in a World of Contingency is undoubtedly recommendable reading, which will become one of the important points of reference for all present and future scholars engaging in divine action debate and critically evaluating the Divine Action Project.