LAUSR

The eighteen papers in this special issue scrutinise the multifarious roles that identity plays in mereology. In this introduction, we present an overview of the topics at stake. Specifically, in Sect. 2we characterize in general themain points of contact between mereology and the philosophical problems raised by identity. InSect. 3wedealwith the problem of whether mereology enjoys a status of topic neutrality and overall logicality analogous to that usually attributed to identity. We also discuss the connected epistemological problem of the alleged analyticity of some mereological principles. This section presents the papers by Aaron Cotnoir, Jean-Baptiste Guillon, Paolo Maffezioli & Achille Varzi, Lorenzo Azzano and Meg Wallace. In Sect. 4 we focus on mereological extensionality, discussing in particular the paper by Jeroen Smid. In Sect. 5 we ask whether mereological principles can explain or ground other principles, or are in turn in need of an explanation or ground, and we show that similar problems can arise about identity. The papers by Joshua Spencer and Phillip Bricker are presented in this section. In Sect. 6 we compare the modal status of identity with the seemingly different modal status of mereological relations, and we present in particular Manuel Lechthaler’s paper and our own paper. In the last two Sects. 7, 8, we cover the papers that more directly concern the so-called thesis of Composition as Identity. In Sect. 7 we show that some papers raise new issues for Composition as Identity and other related philosophical theses. The contributions by Martin Lipman, Byeong-uk Yi and Claudio Calosi belong to this group. Finally, in Sect. 8, we introduce the new varieties of Composition as Identity and some new reflections on its methodological aspects,