Abstract

The dissertation is concerned with a classic problem in metaphysics, namely, the nature of the unity of composite substances. The dissertation argues that such substances must have a very strong sort of unity that is greater than that of even the tightest arrangement of a plurality of substances acting in concert. ;Four theories of substance are examined in an attempt to show that the oldest of them, that of the scholastic Francis Suarez, is still a very viable option. In the introduction these theories are briefly described and assessed. In addition to Suarez's, they are, the structural theory of Baruch Brody, the monadistic theory of Gottfried Leibniz, and the dynamic theory of Ivor Leclerc. ;In the course of the dissertation it is shown that Suarez's scholastic theory is best equipped to solve the problem of substantial unity, because only it sees substances as consisting of principles which can come together to form a single substantial being; all other theories end up making composite substances consist of a number of substances which are fully substantial in themselves. It is concluded, therefore, that these other theories do not ascribe a great enough unity to composite substances. Thus, by elimination, the scholastic theory of substances propounded by Suarez, is shown to be preferable to the other theories, when the problem of substantial unity is addressed