There is more interest today in the problem of individuation than at any other time in the history of Western philosophy, except perhaps for the period that saw the rise and culmination of scholasticism. Most major philosophers of this century, both in the so-called Analytic tradition and in Continental philosophy, have written extensively about the nature of individuality, its causal explanation and its relation to various other metaphysical and epistemological notions. Moreover, the contemporary preoccupation with this old problem has produced a renewed interest in scholastic doctrines relating to it. The names of Ockham, Scotus and Thomas are frequently found and their theories often mentioned, particularly in recent discussions. Nevertheless, in spite of all this interest, a comprehensive study of the way this problem surfaced and developed in the Middle Ages has not yet appeared. Indeed, even the most rudimentary discussion of the various aspects of the issue is unavailable, leading often to unfortunate misconceptions both about the nature of the problem as faced by scholastics and about the views of individual authors.
The present translation and study of Suárez's Disputation V: On Individual Unity and Its Principle ( 1597) hopefully will help to close this gap in scholarship. Suárez's text provides a careful, knowledgeable analysis of the problem of individuation, and its critical exposition of the main scholastic views on this issue is simply masterful. In addition, the text presents with great clarity Suárez's own view, which, as is well known, played a leading role in the transition between scholastic and modern philosophy, especially through Descartes and Leibniz.