PhD defence

Categorial Hylomorphism

• D.R. Pantoja Quiroz

Date

Thursday 19 February 2026

Time

11:30 - 12:30 hour

Address

Academy Building
Rapenburg 73
2311 GJ Leiden

Supervisor(s)

• Prof.dr. J. McAllister
• Prof.dr. M. van der Schaar
• Prof.dr. H. Pringe

Summary

Categories—the most general kinds that structure reality—and hylomorphism—the doctrine that objects are composed of form and matter—are two pivotal subjects in contemporary ontology. However, their systematic connection remains under-explored. This dissertation argues that the categorial architecture of a given ontology is fundamental to any well-formed hylomorphic system. Rather than approaching this abstractly, I employ Aristotle and Kant as methodological touchstones because their theories embody two fundamentally different yet structurally complete ways in which categories organize hylomorphic principles. Aristotle’s formulation is indispensable as it establishes the original categorial framework that still implicitly governs contemporary debates, while Kant’s revision demonstrates how modifying these categorial foundations can overcome systematic limitations. This approach, which I call a categorial approach to hylomorphism—analyzing how the categories operative within a given ontology determine and demarcate hylomorphic composition—finds in these two philosophers not mere historical positions, but exemplars of how categorial structures shape ontological possibilities.

Through this methodological engagement with their systems, this work demonstrates that categories constitutively determine the range of admissible hylomorphic compounds. Consequently, Kant’s categorial innovations provide the conceptual means to ontologically enrich hylomorphism—that is, to systematically expand its explanatory capacity to encompass hylomorphic structures that exceed classical form-matter paradigms while preserving rigorous compositional analysis in the Aristotelian sense. Thus, by using Aristotle and Kant as methodological guides, this categorial approach reveals how hylomorphism’s very possibility as an ontological doctrine depends on its underlying categorial architecture.

PhD dissertations

Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.

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