Welcome to Potestas Essendi

Welcome to Potestas Essendi. If you want to know more about philosophical intricacies concerning nature and its fading hylomorphic roots as they were envisioned by medieval thinkers, I guess this is the right place. You can find here materials of different nature and scope, following the development of my research interests over time. Much of it is related to the tension between ontology and natural philosophy in the Middle Ages and, specifically, the concepts of matter, prime matter, and materiality.

However, Potestas Essendi offers more than just specialised stuff for people with strange interests. One of the main questions I have been asking myself during the past few years is how medieval philosophy can be “communicated” in the sense of “shared” and made “common” as per the original sense of the Latin verb“communicare”. For this reason, Potestas Essendi also hosts some projects directed to a wider audience of people who might be interested in knowing more about medieval stuff.

About Nicola Polloni

I’m Nicola Polloni, the editor of Potestas Essendi: you will find here much information about my work and research so a short introduction is necessary.

I grew up in Tuscany, surrounded by medieval buildings and centuries-long traditions. Although I travelled much during my career, I still believe that my Tuscan roots have brought about much of my passion for how history shapes our lives. My philosophical training refined this vision of a world that is fashioned by complexity and needs to be carefully analysed in all its constitutive aspects to finally appreciate its constitutive patterns of simplicity.

In academia, my work is centred on medieval philosophy, more specifically on the ontological constitution of the natural world. What is that? Well, basically why a thing is what it is according to the way it is naturally made. Before the European scientific revolution, the answer to this question was given by a theory called “hylomorphism”, which claimed that all bodies are made of matter and form. As you will see, I am particularly passionate about the philosophical puzzles arising from the notions of matter and prime matter.

Browsing around

Here is a short outline of what Potestas Essendi has to offer to any fellow web-wanderer with interests in philosophy and its long history.

My research projects

My updated CV

All my publications

Past and future events

Useful materials

Memorable moments

Outreach initiatives

The latest updates

In the spotlight


Fostering a new approach to the study of the history of natural philosophy this series aims to expand the discussion on natural philosophy cross-culturally and comparatively by focusing on the philosophical reasoning about nature developed particularly, but not exclusively, in three main cultural settings: Europe, the Middle East, and China. One of the main focal points of Global Perspectives on the History of Natural Philosophy is the interplay between philosophical and scientific concepts, stances, and problems arising from the premodern consideration of nature, broadly considered. Accordingly, the series provides a cutting-edge framework in which natural philosophy can be considered from new philosophically meaningful angles. Acknowledging the historical interweaving of philosophy and science of nature, the series publishes monographs and edited volumes dealing with the history of natural philosophy from three methodological perspectives: philosophical analysis, historical reconstruction, and comparative studies. Submitted manuscripts may either examine authors and issues from a specific philosophical tradition or engage comparatively with patterns and problems shared by different cultural settings.

Read more


One of the most important thinkers of the Middle Ages, the Jewish philosopher Solomon Ibn Gabirol (known in the Latin Middle Ages as ‘Avicebron’) greatly contributed to the history of metaphysics. His most famous work, the Fons vitae, was the source of sophisticated, radical doctrines (like universal hylomorphism and the plurality of substantial forms) that were rigorously debated in the Latin world for centuries. Breaking a long period of scholarly neglect of his thought, this volume scrutinises Ibn Gabirol’s philosophical contributions by disentangling his original theories from the misconceptions originated by his medieval readers and critics, like Thomas Aquinas and Albert the Great. Authored by some of the most renowned worldwide experts on Hebrew and Latin philosophy, the cutting-edge contributions included in the volume give a lively picture of a complex yet fascinating medieval philosopher and his unique interpretation of the universe.

Read more


Grégory Clesse, Antonella Sciancalepore, Paula Silva, João Rebalde, and I have organised a series of panels and round tables at the 2023 International Medieval Congress in Leeds. Over two days, we are going to delve into the intricacies and entanglements of medieval philosophy and science, with a specific focus on metaphysics and natural philosophy, on the one hand, and philosophy and literature, on the other. This is the first of a series of events that we are planning to strengthen the presence of medieval philosophy at IMC Leeds. Download the programme (see the link below) for more information about the panels, round table, sponsoring institutions, and participants.



Stemming from the 2022 Common Seminar of the Institute of Philosophy at KU Leuven, the workshop Project Design for Philosophical Research will delve into the specificities of research proposals and their most mysterious, troublesome sections. All students from the Common Seminar are free to join the workshop, which will expand on many features of philosophical academic publishing, research proposals, and persuasive communication that we have discussed in the classroom. The workshop will be take place in Room N (HIW, Kardinaal Mercierplein 2) at 4 pm on 4 February 2023. Being a hands-on workshop, much time will be dedicated to discuss real research proposals and, most importantly, your drafts

Read more


A very common narrative in the history of both philosophy and science reconstructs the dawn of early-modern thought as a clean break from the dusk of Scholasticism and its Aristotelian roots. The workshop Divergent Scholasticism: Philosophical Thought and Scholastic Tradition between Europe and the Americas, 1500-1700 focuses on a different story. It is a story made of continuities and ruptures within late Scholasticism and nourished by refined theoretical elaboration and wide transmission of knowledge between the two shores of the Atlantic Ocean. Expanding from Europe (Leuven, Salamanca, and Coimbra) to Latin America and Asia, Second Scholasticism has received growing attention from scholarship only in recent decades. Organised by Abel Aravena Zamora, Christophe Geudens, and Nicola Polloni, the aim of Divergent Scholasticism is to foster a collaborative global network of interested scholars to better understand the specificities of such long-neglected debate.

More info


Organised by Nicola Polloni, The Elusive Substrate: Prime Matter and Hylomorphism from Ancient Rome to Early Qing China aims at disentangling the richness of metaphysical theories of original/prime matter that have been produced in the centuries-long philosophical debate about this concept. Focussing on the Latin tradition, the congress reconstructs the main tenets of the history of prime matter by considering how philosophers envisioned the basic ontological constitution of the universe. Such examination will be centred on nine historical phases. These are sections of the Latin debate that are characterised by doctrinal peculiarities, authoritative references, and specificities of problems to be addressed. Each phase will be engaged through the examination of three case-studies. Through their insights, the congress will examine the history of prime matter from a unitary perspective enriched by a plurality of philosophical doctrines and methodological approaches.

More info


In their historical course, philosophy and science have looked at nature to find meaningful patterns, causes, and links able to explain the behaviour of natural phenomena: why they work the way they do and how they can be turned to human advance. A specific aspect of such historical query has been the study of the ontological structure of the natural world. Most philosophical traditions have postulated the existence of a physical or metaphysical substrate of the natural world: a subject over or into which physical change happens. Organised by Nicola Polloni (濮若一) and Shixiang Jin (晋世翔), Materia, 气/Qì, and Their Epistemes focuses on such obscure substrate and the historical constructions aimed at unveiling it in the European and Chinese traditions. In both traditions, the “material” principle – materia and 气 – underwent an epistemic fragmentation into a plurality of disciplinary epistemes following the effort to grasp how such principle was supposed to work in theoretical and practical contexts (from metaphysics to alchemy, pharmacy, weather forecast, and so on).

More info


A better academia is nurtured by constant effort. Let’s level the playing field together leaving no room for intolerance, exclusion, racism, and elitism. It is our responsibility – to our students, ourselves, and our society.