Thomas Aquinas’ doctrine of the unicity of substantial form was the cause of some discussion concerning the mode of being of the elements in the homeomerous mixed body. The very notion of a mixture seems to require that the elements be substantially present, yet the unicity of substantial form seems to make this impossible. Aquinas himself solves the problem with his notion of virtual being. Dietrich von Freiberg argues against Aquinas’ solution and proposes instead a solution that emphasizes the interpenetration and diminished substantiality of the elements in the mixed body. This paper will discuss and evaluate Dietrich’s arguments against Aquinas as well as his arguments in defense of his own distinctive position.
The paper will deal with F. Suárez concept of material substance which is the topic that escapes the attention of Suárez-scholars. The paper will compare Suárez’s concept with Aquinas’ one with the special attention to the different (Suárez´s reified concept) interpretation of matter and form, and the consequent question of the unity of material substance. The study will ‘insert’ Suárez conception into his overal metaphysical structure which is connected mainly wiíth Suárez’s doctrine on the concept of being.