It is commonly assumed that Aristotle thinks that his claim that being exhibits a category-based pros hen structure, which he introduces to obviate the problem of categorial heterogeneity, is sufficient to defend the possibility of a science of being qua being. We, on the contrary, argue that Aristotle thinks that the pros hen structure is necessary only, but not sufficient, for this task. The central thesis of our paper is that Aristotle, in what follows 1003b19, raises a second problem for (...) the possibility of the science of being qua being; and that he does not think that the resolution of the first, the category-based problem, is either necessary or sufficient for resolving this problem. This is the problem: how can a plurality of apparently primary kinds and their opposites (they include to hen, to on, to auto, to homoion, to heteron and to anhomoion) be the subject-matter of the science of being qua being? It has been argued that these kinds are per se attributes of ousia and that, therefore, this problem is not different from the first problem. This, we argue, is mistaken; for nowhere in Gamma 2 does Aristotle claim that unity is a per se attribute of ousia. Rather, he says that identity, similarity, etc. are per se attributes of being qua being and unity qua unity. Aristotle’s resolution of the second problem, we argue, is that most of these kinds are reducible to a single compound principle: being-and-unity. Being and unity, moreover, are themselves related to each other as primary ousia and consequent ousia; but, we argue, Aristotle leaves it open, in Gamma 2, which of the two is primary, and which is consequent ousia. (shrink)

The article examines some aspects of Brentano's ontology, starting with his 1862 dissertation "On the ambiguity of Being according to Aristotle", as well as its influence on the philosophy of M. Heidegger. The author shows that the ontology of the early Brentano is not limited to ousiology, since it includes a discussion of the field of mental being (ens rationis, ὂν ὡς ἀληθές) and it is in this aspect that he influences the young Heidegger. Following Aristotle, Brentano assigns a central (...) role to the ontology of essence, which in the late period leads him to the position of reism, but in the lectures of the middle period Brentano discusses the problems of intentional inexistence, thanks to which projects of "new types of ontology" by Husserl and Mainong appear. The author believes that Heidegger was also influenced by these ideas. Of course, there are fundamental differences between the positions of Brentano and Heidegger, but the similarities are quite large. In particular, if Brentano, highlighting the real and true areas, gives preference in favor of the former, then Heidegger's ontology is built on the second member of this opposition. In particular, everything that can be given is called being by Heidegger, because we are talking about intentional being, about ens rationis, or ὂν ὡς ἀληθές. (shrink)

This doctoral thesis addresses a group of conceptual instruments that are central to Aristotle's philosophy, namely, the concepts of pros hen, homonymy, synonymy and multivocity. These instruments are crucial to many of Aristotle's works as he devotes himself to analysing the key notions in each of his investigations using these instruments. Despite the undisputable importance of these instruments, they display severe interpretative problems, which this thesis critically evaluates. The currently established view on the relationship between homonymy and multivocity is discussed (...) and then reassessed in order to approach the definition of the so-called pros hen structure. This approach takes into account a so-far undescribed distinction of types of examples Aristotle uses and sheds new light on the assessments of the role of the pros hen structure in Aristotle’s philosophy and the theories on development in Aristotle’s thought. Niels Tolkiehn studied Philosophy and Systematic Musicology at the University of Hamburg. He continued his studies as a doctoral student at the Munich School of Ancient Philosophy, a graduate school of the Ludwig-Maximilians-Universität München. Supervised by Prof. Dr. Christof Rapp, he was awarded his doctoral degree in 2019 with this dissertation. (shrink)