Philosophical problems about the part-whole relation have been discussed throughout the history of philosophy, at least since Plato and Aristotle. In contemporary philosophy, the understanding of these issues has benefited from the formal tools of Classical Extensional Mereology. This paper aims is to defend mereological restrictivism against some constraints imposed by the vagueness argument. To achieve this, the paper is divided into three parts. In the first, I introduce the special composition question (hereafter SCQ) as formulated by [Van Inwagen, 1990] (...) and briefly present the three sets of theories that proffer answers to it. In the second part, I focus on the vagueness argument, that was presented by [Lewis, 1986, ] and [Sider, 2007, ] to defend mereological universalism. In the third section, I introduce the theory of natural properties by David Lewis. From this theory, I propose a new mereological operation labeled as natural fusion. The purpose of this operation is to falsify one of the premises of the vagueness argument. Then, I discuss some examples and counter-examples to natural fusion. (shrink)

I present in this note an alternative answer to the princesses' earring problem, found in the first chapter of Cezar Augusto Mortari's book "Introdução à Lógica”.

I argue in this dissertation that natural properties play a central role in David Lewis' modal realism. To argue in favor of this thesis I present: a bottom-up explanation of a top-down possible world metaphysics; a new definition of natural properties and natural fusion, a new mereological operation. To achieve these aims, in the first chapter, I contextualize the discussion, in the second I resume the discussion about universals in contemporary philosophy and argue that, considering the distinct formulations of the (...) problem, class nominalism combined with modal realism might be the best solution. Furthermore, I discuss Devitt's solution in which he defends that the problem about universals is, in fact, a pseudo problem. In the third chapter, I introduce a minimal ontology of properties, regarding natural properties, I discuss the existing definitions, present a new one and discuss some theories of similarity, a notion that is in the core of the definition I propose. Besides, I present how natural properties benefit the definition of terms of nomological package, linked to its fundamentality role. I also present some applications related to the rationality role that encompass some well-known philosophical problems of the second half of 20th century. In the fourth chapter, I present some varieties of philosophical realism, I consider the theoretical advantages of taking scientific realism as background and I discuss one more utility of natural properties, the solution to the problem of eligibility of reference or, the Putnam's paradox. In the fifth chapter, I discuss how mereology is important to link several aspects of Lewis' modal realism. For such, I discuss the relation between composition as identity and ontological innocence of mereology and I present the natural fusion mereology, a new mereological operation that aims to minimize the problems of unrestricted composition. (shrink)

Essa comunicação possui dois objetivos. Em primeiro lugar, pretendo esboçar as diferentes alternativas teóricas contemporâneas que procuram responder ao conhecido “ problema dos universais”. Para isso, apresentamos os nominalismos de predicados, classes, semelhanças e a teoria de tropos. Em segundo lugar, pretendo mostrar, inspirado no trabalho de David Lewis, como o nominalismo de classes, a noção de propriedade natural e uma teoria de mundos possíveis prometem resolver o problema em questão.

Resenha de MUMFORD, Stephen. Metaphysics: a very short introduction. Oxford: Oxford University Press, 2012. Principios, v. 21, p. 319-326, 2015.