This book examines Plotinus’ concept of number, one of the most difficult and obscure topics in Neoplatonism. The book argues that Plotinus is the first philosopher who explains the Platonic “true number” and the quantitative mathematical numbers in a conceptually informed relationship as between an intelligible paradigm and its sense-perceptible image. Throughout the Enneads and especially in Ennead VI.6, the treatise On Numbers, Plotinus systematically peels off the layers of mathematical and quantitative perception from the concept of number to reveal that real number is the primary activit ... More

This book examines Plotinus’ concept of number, one of the most difficult and obscure topics in Neoplatonism. The book argues that Plotinus is the first philosopher who explains the Platonic “true number” and the quantitative mathematical numbers in a conceptually informed relationship as between an intelligible paradigm and its sense-perceptible image. Throughout the Enneads and especially in Ennead VI.6, the treatise On Numbers, Plotinus systematically peels off the layers of mathematical and quantitative perception from the concept of number to reveal that real number is the primary activity of substance (ousia), which orders the unfolding of the universe from its absolute source into a finite multiplicity. The book traces the development of Plotinus’ concepts of number and multiplicity in Plato’s Timaeus, Aristotle’s criticism of Plato’s view of number, and Neopythagoreanism. This analysis establishes number to be the building block of the intelligible realm and the architecture of the universe in Plotinus. For him, as for his Platonic and Neopythagorean predecessors, the universe has a meaning, enciphered by number. In this light, Plotinus’ concept of number is the fundamental link between the number theories of the Neopythagoreans and the later Neoplatonists.