Most of my current work focuses on the topics of causation and causal powers in the medieval and early modern periods. Nearly all medieval thinkers agreed that substances were the agents which caused changes in the world and that substances acted through inherent active powers. Yet there were fascinating debates about what powers are, how they operate, and how God’s causal activity relates to the activities of creatures. My research recovers the conceptually fruitful theories and arguments advanced on these topics. The goals of my work are to show how medieval theories can contribute to contemporary discussions and to highlight the historical importance of medieval debates for understanding the emergence of modernity and the scientific revolution.

Here are a few of my current projects:

Aquinas on Causal Powers and Efficient Causation (monograph)

My main current project is a monograph which recovers Aquinas’s intriguing views on efficient causation. Aquinas did not write an extensive treatise on the topic, so I am reconstructing his views from discussions interspersed throughout his corpus. My work also examines medieval critiques of Aquinas’s positions by subsequent thinkers such as Henry of Ghent, John Duns Scotus and Peter Auriol.  In addition to contemporary appeal, Aquinas’s perspective on causal powers is significant for understanding his broader thought, as well as the background to discussions of powers and causation in the early modern period.

Preliminary Table of Contents:

Part 1: Background:

1. Hylomorphism as a metaphysics of material substance and change

2. Causation in general and its species

Part 2: Efficient causation:

3. Reality’s second layer of potentiality: Active power

4. Reality’s second layer of actuality: The actions of active powers

5. Types of efficient causes and cooperation relationships between powers

Part 3: The powers of material substances:

6. Elemental powers

7. The powers of living organisms

8. Habits and dispositions

Duns Scotus on Causal Powers (Invited chapter for Interpreting Scotus, ed. G. Pini, Cambridge Press)

Abstract: In ordinary discourse about the world people often explain the occurrence of physical events in terms of the exercise of an object’s powers. For instance, the doctor claims that the cure happened through the medicine’s power to neutralize acid and the mechanic identifies the cause of the rust as the salt’s power to corrode. Since the time of Hume a majority of Anglophone philosophers have denied that causal powers are real features of the world. Yet, recently in contemporary analytic philosophy there has been a revival of neo-Aristotelian theories which postulate real causal powers. In light of its contemporary relevance, this chapter recovers Duns Scotus’s intriguing arguments and positions on what causal powers are and how they operate. Like other late scholastic thinkers, Scotus understands causal powers and their activity through the lens of the Aristotelian distinction between potency and act. Yet, Scotus adopts a number of distinctive positions about precisely what powers are ontologically, the different types of causal powers, and the kinds cooperative relationships which obtain between agents with different powers. This chapter reconstructs Scotus’s fascinating arguments and positions on these topics and related issues.

Congenital Disabilities (Invited chapter for Disabilities in Medieval Philosophy, ed. S. Williams)

This chapter explores how medieval Aristotelians typically understood the causes which accounted for what we today refer to as “congenital disabilities.” A congenital disability is defined as a medical condition which is present at birth. The contemporary category includes medical conditions which are the result of genetic inheritance or mutation, as well as environmental factors during pregnancy. This chapter will show that although medieval thinkers lacked knowledge of genetics, they nevertheless recognized that some disabilities present at birth arose through the causality of the parent organisms, while others arose from external interferences in the process of generation. In order to elucidate the medieval conception of congenital disabilities and their causes, the chapter will go into the details of how medieval thinkers understood the metaphysics and physics of living organisms, their causal powers and sexual reproduction. I will rely primarily on Aquinas’s texts to present the general Aristotelian theories on these topics, yet I will note where other thinkers such as Avicenna, Bonaventure, Scotus and Buridan disagreed with the details of Aquinas’s positions.

The chapter will conclude with a discussion of the broader historical and philosophical significance of medieval Aristotelian discussions of congenital disabilities. I will show that early modern mechanists raised the case of congenital disabilities as a powerful objection against the Aristotelian-scholastic hylomorphic metaphysics of substance. Locke, among others, argued that if substantial forms were immutable and did indeed account for the essential properties of an organism, then it would not be possible for a substance to both be informed by the substantial form proper to its kind and lack one of the essential powers proper to its kind. He was aware that Aristotelians tried to causally explain the lack of essential powers through impediments in matter and deficiencies in the efficient causes of the organism. According to him, this account fails because it gives material and efficient causes priority over formal causes—i.e. matter and efficient causes determine how the form exercises its causality. I use this objection which contributed to the downfall of Aristotelian metaphysics as a springboard for gaining further conceptual clarity on the metaphysics and physics of congenital disability in the medieval Aristotelian tradition.