This study focuses on the metaphysics of the great Arabic philosopher Avicenna (or Ibn Sīnā, d. 1037 C.E.). More specifically, it delves into Avicenna's theory of quiddity or essence, a topic which seized the attention of thinkers both during the medieval and modern periods. Building on recent contributions in Avicennian studies, this book proposes a new and comprehensive interpretation of Avicenna's theory of 'the pure quiddity' (also known as 'the quiddity in itself') and of its ontology. The study provides a careful philological analysis of key passages gleaned from the primary sources in Arabic and a close philosophical contextualization of Avicenna's doctrines in light of the legacy of ancient Greek philosophy in Islam and the early development of Arabic philosophy (falsafah) and theology (kalām). The study pays particular attention to how Avicenna's theory of quiddity relates to the ancient Greek philosophical discussion about the universals or common things and Mu'tazilite ontology. Its main thesis is that Avicenna articulated a sophisticated doctrine of the ontology of essence in light of Greek and Bahshamite sources, which decisively shaped subsequent intellectual history in Islam and the Latin West.

• Acknowledgements
• Contents
• Introduction
• Chapter I: Pure Quiddity in Context
• Chapter II: Quiddity in Itself and Mental Existence
• Chapter III: Quiddity in Itself in the Concrete World
• Chapter IV: The Special Ontological Mode of Quiddity in Itself
• Chapter V: The Divine Origin of Pure Quiddity
• Conclusion
• Appendix 1: The Avicennian terminology of pure quiddity
• Appendix 2: The existence of pure quiddity: A list of textual references
• Appendix 3: Quiddity and Avicenna’s matrices of distinctions
• Bibliography
• Index of Names and Places
• Index of Technical Terms