Aristotle Contemplating Nature by Jacques Christophe Valmont-Bomare. 1791.
My research focuses on Ancient Greek philosophy, especially on issues in ontology, natural philosophy, biology, and political theory. In exploring these areas, I engage primarily with Aristotle, Plato, and Presocratic philosophers such as Empedocles and Heraclitus. My work examines these thinkers in their intellectual and historical context, illustrating their deep and lasting influence on the history of philosophy, science, and culture.
My current research program explores Aristotle’s ontology of life and the continuing relevance of Aristotle’s thought for issues in contemporary philosophy of biology.
Book Project
Aristotle’s Concept of Life: Essence and Activity
What is life? Aristotle is the first to have seriously engaged with this perennial philosophical question, and his thought has influenced the entire trajectory of scientific inquiry into the phenomena of life to the present day. Yet Aristotle denies that being alive comprises a single essential nature shared by all living things—thus life cannot be defined in the strict sense. For Aristotle, answering the question of life requires understanding a different kind of unity underlying life’s many manifestations, both mortal and divine. In Aristotle’s Concept of Life: Essence and Activity, I show that Aristotle develops a nuanced ontology of life to explain this unity. Against the interpretive orthodoxy, I argue that Aristotle’s theory of the soul cannot answer the question of life. Being alive is not simply equivalent to being ensouled: Aristotle’s gods are paradigms of life, yet they have no souls. Instead, Aristotle understands life as a constitutive relation between the activities which living things perform and their essence. Living things enact their differing essential natures by performing certain life activities characteristic of their kind (such as metabolizing, reproducing, perceiving, discursive reasoning, etc.) While there is no single activity in which all forms of life participate, every living thing achieves its own essential nature in and through the performance of some characteristic activity. Life is not a shared essence, then, but a shared way in which essence is constituted: unlike chairs or piles of sand, living things actively make themselves what they are. This shared ontological structure grounds an analogical unity between mortal and divine life. My interpretation challenges traditional understandings of Aristotle’s essentialism about natural kinds. The essence of each living thing is not a static set of features that it instantiates or conditions that it meets, but rather a set of activities that it performs (or fails to perform). I illustrate some of the important implications of this ontology of life for Aristotle’s metaphysics, biology, and ethics.
Recent Publications
“Aristotle’s Ontology of Death” (PDF)
Epoché: A Journal for the History of Philosophy 30 (1): 73-90. 2025.
Is it natural for living things to die? According to most interpreters Aristotle considers death to be unnatural: it is a failure of the living thing’s form to completely master the inherent tendency of all matter to disintegrate into the elements. On this reading death conflicts with a living thing’s formal nature—it follows from its material nature alone. I argue that this standard story about Aristotle’s ontology of death is incorrect. While it is true that death is inevitable on account of material necessity, an organism’s species-typical life cycle is an expression of its formal nature as well. This life cycle is limited by a natural lifespan and concludes in what he terms “natural death”. Paradoxically, Aristotle considers natural death to be an intrinsic good for living beings, for the completion of its life cycle is a way in which mortal life imitates the immortal life of the heavenly bodies.
“Aristotle’s Causal Definitions of the Soul” (PDF)
Ancient Philosophy 44 (2): 449-467. 2024.
Does Aristotle offer a definition of the soul? In fact, he rejects the possibility of defining the soul univocally. Because “life” is a homonymous concept, so too is “soul”. Given the specific causal role that Aristotle envisages for form and essence, the soul requires multiple different definitions to capture how it functions as a cause in each form of life. Aristotle suggests demonstrations can be given which express these causal definitions; I reconstruct these demonstrations in the paper.
“Aristotle on the Unity of the Nutritive and Reproductive Functions” (PDF)
Phronesis 65 (4): 414–466. 2020.
Co-Authored with James G. Lennox
In De Anima 2.4, Aristotle claims that nutritive soul encompasses two distinct biological functions: nutrition and reproduction. We challenge a pervasive interpretation which posits ‘nutrients’ as the correlative object (antikeimenon) of the nutritive capacity. Instead, the shared object of nutrition and reproduction is that which is nourished and reproduced: the ensouled body, qua ensouled. Both functions aim at preserving this object, and thus at preserving the form, life, and being of the individual organism. In each case, we show how Aristotle’s detailed biological analysis supports this ontological argument.
“Cosmic Democracy or Cosmic Monarchy? Empedocles in Plato’s Statesman” (PDF)
Polis: The Journal for Ancient Greek Political Thought 35 (2): 418-446. 2018.
Plato’s references to Empedocles in the myth of the Statesman perform a crucial role in the overarching political argument of the dialogue. Empedocles conceives of the cosmos as structured like a democracy, where the constituent powers ‘rule in turn’, sharing the offices of rulership equally via a cyclical exchange of power. In a complex act of philosophical appropriation, Plato takes up Empedocles’ cosmic cycles of rule in order to ‘correct’ them: instead of a democracy in which rule is shared cyclically amongst equal constituents, Plato’s cosmos undergoes cycles of the presence and absence of a single cosmic monarch who possesses ‘kingly epistēmē’. By means of a revision of Empedocles’ democratic cosmology, Plato’s richly woven myth is designed precisely to reject the appropriateness of democracy as a form of human political association and legitimate monarchy in its stead.
Pierre Pellegrin: Animals in the World: Five Essays on Aristotle’s Biology. Trans. Anthony Preus. (Albany, NY: SUNY Press, 2023. Pp. vi, 324.) (PDF)
The Review of Politics 87 (2): 296–298. 2025.
