The article introduces a special issue of the journal _Metaphysica_ on vagueness and ontology. The conventional view has it that all vagueness is semantic or representational. Russell, Dummett, Evans and Lewis, inter alia, have argued that the notion of “ontic” or “metaphysical” vagueness is not even intelligible. In recent years, a growing minority of philosophers have tried to make sense of the notion and have spelled it out in various ways. The article gives an overview and relates the idea of (...) ontic vagueness to the unquestioned phenomenon of fuzzy spatiotemporal boundaries and to the associated “problem of the many”. It briefly discusses the question of whether ontic vagueness can be spelled out in terms of “vague identity”, emphasizes the often neglected role of the difference between sortal and non-sortal ontologies and suggests a deflationary answer to the ill-conceived question of whether the “ultimate source” of vagueness lies either in language or in the world. (shrink)

There is a defeasible constraint against double counting. When I count colours, for instance, I can’t freely count both a colour and its shades. Once we properly grasp this constraint, we can solve the problem of the many. Unlike other solutions, this solution requires us to reject neither our counting judgments, nor the metaphysical principles that seemingly conflict with them. The key is recognizing that the judgments and principles are compatible due to the targeted effects of the defeasible constraint.

The problem of the many poses the task of explaining mereological indeterminacy of ordinary objects in a way that sustains our familiar practice of counting these objects. The aim of this essay is to develop a solution to the problem of the many that is based on an account of mereological indeterminacy as having its source in how ordinary objects are, independently of how we represent them. At the center of the account stands a quasi-hylomorphic ontology of ordinary objects as (...) material objects with multiple individual forms. (shrink)

This paper illuminates the explanatory role of vagueness und species membership against the background of scientific developments in recent stem cell research. With the help of the Neo-Aristotelian concept of “life form naturalism” ontologically vague entities such as stem cells, all above induced pluripotent stem cells, could be described as necessary constituents for the correct sorting and naming of natural processes and its bearers. Furthermore this specific assessment allows drawing some important ontological and ethical consequences.