Lesson 1

8 September 2025

Hylomorphism and Scholasticism  
The first session of the course aims to provide students with an introduction to the main features of scholastic philosophy – its chronology, historical and speculative contexts, and the main characteristics of its debates – as well as to scholastic hylomorphism. With regard to the latter, the session will explore the structure of the Scholastic Hylomorphic Framework, distinguishing between its different models and examining their interconnections. The entire lesson will be dedicated to this introductory discussion.

Lesson 2

10 September 2025

Act and Potency, Matter and Form
The second session delves into Aristotelian ontology. Its main focus is the medieval reception of Aristotle’s theory of substance and the distinction between substances and accidents. This distinction introduces two fundamental sets of concepts: the modal pair act/potency and the hylomorphic principles matter/form. In the first part of the session, we will examine how the scholastic approach to ontology profoundly interweaves act and potency, on the one hand, with matter and form, on the other, in order to explain the metaphysical constitution of physical substances. The second part of the session will consist of a classroom reading and commentary on a passage from Aquinas’s On the Principles of Nature, which addresses these core themes of scholastic philosophy.

Lesson 3

12 September 2025

Accidental and Substantial Change
The session will be dedicated to the philosophical examination of change. The natural world is characterised by constant change: leaves fall from trees, people age, apples ripen. However, not all change appears to be the same. Sometimes, an object seems to persist despite undergoing modifications, while in other cases we say that something has become entirely different. The first part of this session will explore how the distinction between these two types of change – accidental and substantial – is directly connected to hylomorphism. The second part will focus on a close analytical reading of Question 12 from Francisco de Toledo’s commentary on Book I of Aristotle’s Physics, which explores these issues in detail.

Lesson 4

15 September 2025

Arguments for the Existence of Prime Matter
The previous session demonstrated that hylomorphism is essential to explaining how change occurs in nature. In both accidental and substantial change, a new form – either accidental or substantial – is introduced, since change involves the replacement of one form with another. For this process to be possible, however, a persisting subject or substrate is required. This session focuses on the substrate involved in substantial change, which is typically identified with prime matter. After introducing what Robert Pasnau has termed the “Substratum Thesis” and the “Conservation Thesis”, the session will examine the main arguments used to demonstrate the existence of this principle, with a particular emphasis on later scholastic thought. In the second part of the session, students will apply this theoretical framework to an analytical reading of an excerpt from Francisco Suárez’s thirteenth metaphysical disputation, focusing on his epistemic strategy to prove the existence of prime matter.

Lesson 5

17 September 2025

Arguments for the Existence of Substantial Forms
After examining the main demonstrative strategies employed by scholastic philosophers to prove the existence of prime matter, the fifth session will pose similar questions concerning the existence of substantial forms. Adopting a hands-on approach, the session will engage with natural phenomena – such as the cooling of boiling water – which were traditionally considered as evidence for the existence of a substantial form, upon which all accidental characteristics of a substance depend. The second part of the session will be devoted to reading and commenting on excerpts from Suárez’s fifteenth metaphysical disputation, focusing on his arguments in support of the existence of substantial forms.

Lesson 6

19 September 2025

Prime matter as Pure Potency
Prime matter appears to be a rather peculiar principle. By definition, it is entirely devoid of any substantial form – otherwise, it would not be capable of receiving all of them. Yet a substantial form is precisely what makes a thing that thing: it is a principle of actualisation, given that everything existing in act has a substantial form. These considerations led to the formulation of a radical thesis, famously advanced by Thomas Aquinas: prime matter is nothing other than pure potency. This thesis, however, raises several implications and challenges – including how God might know such a purely potential being, and how it could be created in this ontological condition. The first part of the session will explore these issues in depth. The second part will focus on the reading of two texts: one from Aquinas’s Quodlibet III, and the other from the Summa theologiae I.15

Lesson 7

22 September 2025

Prime Matter as Entitative Act
The thesis of prime matter as pure potency provoked considerable criticism among scholastic philosophers. Among its most notable critics was John Duns Scotus. According to Scotus, prime matter cannot be a pure potency; rather, it possesses a form of actuality of its own, later termed by his followers as entitative actuality. This session will be devoted to examining Scotus’s discussion of objective and subjective potency, and the types of distinction that may be applied to the hylomorphic principles. The second part will focus on the reading and commentary of a passage from the Lectura, where Scotus articulates his criticism of Aquinas’s thesis and presents his own solution to the problem of prime matter’s potency.

Lesson 8

24 September 2025

Universal vs Physical Hylomorphism
From a contemporary perspective, matter appears to be a feature proper only to physical substances. Many of the theses and arguments discussed in previous sessions seem to reinforce this commonsensical assumption. However, numerous scholastic philosophers proposed a more radical interpretation of hylomorphism. On the one hand, they held that substance as such is structured as a hylomorphic compound; on the other, this conviction led them to claim that spiritual beings – such as angels and human souls – are also composed of form and matter. This is the so-called “universal hylomorphism”, defended by what we may call the Universal Hylomorphic Model. This session will examine the main reasons behind this model and the key implications it entails. The second part will engage with the reading of an exemplary text illustrating this view: Dominicus Gundissalinus’s On Unity and the One.

Lesson 9

26 September 2025

Formal Pluralism
The Universal Hylomorphic Model is often associated with another curious thesis concerning the hylomorphic constitution of substances: the claim that each substance is composed of a plurality of substantial forms. This “formal pluralism” stands in contrast to the formal unity thesis maintained by authors such as Thomas Aquinas, and stems from a rigorous application of the Porphyrian Tree – a logical tool – to the ontology of substances. In this session, we will explore various types of formal pluralism and their speculative foundations, focusing on theories proposed by Avicenna, Roger Bacon, and John Duns Scotus. The session will also consider alternative interpretations of more obscure formal configurations, and weigh the theoretical advantages and disadvantages of the pluralist thesis. The second part will be devoted to reading and commenting on a passage from Suárez’s Disputationes Metaphysicae rejecting formal pluralism.

Lesson 10

29 September 2025

Prime Matter: One or Many?
Just as scholasticism debated the multiplicity of substantial forms, it also questioned whether prime matter is one or many. This issue is even more complex. Devoid of any distinguishing features, how could prime matter be multiple? Yet if prime matter is numerically one, how can it be individually present in and compose a multitude of substances – that is, all physical substances? This session will investigate these challenges by examining the opposing theses of numerical identity and numerical plurality of prime matter. It will explore the implications and advantages of both views and introduce Roger Bacon’s radical alternative: the specific plurality of prime matter. The second part of the session will analyse a key text on this topic: William of Ockham’s discussion of the unity of matter in his Summulae of natural philosophy.

Lesson 11

10 October 2025

Heavenly Issues with Hylomorphism
Physical hylomorphism affirms that the fundamental role of prime matter is to serve as the enduring substrate of substantial change. This function has a crucial implication: must we assume that prime matter also composes those substances that are (1) corporeal and yet (2) do not undergo processes of substantial change? This issue is especially relevant to heavenly bodies – stars and planets – which exhibit only local motion (a form of accidental change) and are traditionally thought to be impervious to generation and corruption. Scholastic debates offered three main positions affirming respectively that (a) heavenly bodies lack matter entirely, (b) they are composed of a genus of formless matter distinct from the prime matter of sublunary substances, (c) they partake of the same kind of prime matter found in terrestrial bodies. The first part of the session will present these options and their underlying arguments. The second part will be devoted to analysing how the Coimbra commentary on Aristotle’s De caelo approaches this issue, and to discussing the solution proposed by the Coimbrans.

Lesson 12

13 October 2025

The Emergence of Quantity
Bodies are substances extended in space. According to scholasticism, this extension results from their parts being placed “one after another”. Hence, it seems that a body, in order to be such, must have quantitative parts properly ordered. An issue arises from this consideration: where does this quantity come from? On the one hand, it appears that substantial forms require this extension into parts to be already present – otherwise, how could a substantial form join a chunk of matter and structure its parts? On the other hand, how can formless matter possess quantity without being joined to a substantial form? Aristotelianism is built on a radical distinction between accidents and substances, and an accident like quantity does not seem to apply directly to formless matter. The scholastic debate surrounding these questions gave rise to at least four main alternatives, which will be examined in the first part of this session. The second part will be dedicated to commenting on Francisco de Toledo’s discussion of the emergence of quantity in his Commentary on the Physics.

Lesson 13

15 October 2025

Can the Hylomorphic Principles Be Conceived?
According to scholasticism, human knowledge begins with the senses and is then processed by the intellectual faculties. The fundamental role of the senses has a direct and important implication for hylomorphism. Indeed, we perceive accidents such as colours, tastes, and shapes, but we do not perceive substances directly. Their ontological core – composed of matter and form – lies entirely beyond our perception. This means that neither prime matter nor the substantial form can be known directly by our minds. In response, scholastic philosophers developed various justifications and epistemic strategies to demonstrate that it is still possible to grasp the principles of natural bodies. This session will explore several of these strategies, with special attention to the peculiar case of prime matter, which – being entirely devoid of epistemic content – appears to lack anything that could be known. The second part will analyse the treatment of this problem by Alonso de la Veracruz, a scholastic philosopher active in Mexico at the dawn of early modernity.

Lesson 14

17 October 2025

The Conundrum of Mixtures
Up to this point, the course has treated physical bodies from a metaphysical perspective. However, if we examine bodies from a more physical standpoint, we must introduce two additional types of entities upheld by scholastic philosophers: the elements and the elemental mixtures. The elements – fire, air, water, and earth – are the simplest bodies, each characterised by two elemental qualities (hot or cold, dry or moist). Yet complex bodies are not composed of elements directly, but of their mixtures, such as blood, bones, and flesh. These elemental mixtures are uniform bodies: the smallest fragment ground from a bone remains bone, not one of the elements. Aristotle’s difficult discussion of mixtures in De generatione et corruptione I.10 gave rise to a series of pivotal questions about how elemental qualities are present in mixtures even though the elements themselves are not present in act. This session will delve into this rich and complex problem – one of the clearest examples of the tension between metaphysics and natural philosophy in the scholastic hylomorphic framework. The second part of the session will be devoted to selected readings from Thomas Aquinas’s treatise on elemental mixtures

Lesson 15

20 October 2025

Global Hylomorphism
When Jesuit missionaries arrived in China at the dawn of the modern age, they encountered for the first time an ancient and entirely different philosophical tradition. Matteo Ricci and his successors engaged with Chinese philosophers, texts, and concepts from the 宋明理学, interpreting them through the lens of later scholasticism. This session will explore how Ricci and Longobardo engaged with the concepts of 氣and 理in their European-language writings, attempting to align these ideas with the scholastic hylomorphic framework. This first encounter between European and Chinese philosophy stands as one of the most significant – yet still underrated – moments in the history of global philosophy. Although these European thinkers were not comparative philosophers in the modern sense and often misunderstood the theses proposed by 張載and 朱熹, their creative attempts to make sense of Chinese metaphysics offer rich interpretative insights, both historically and philosophically. The second part of the session will examine Longobardo’s interpretation of Chinese metaphysics in his Brief Response.