Why Mereological Essentialism Applies to Mereological Aggregates

Abstract This article’s purpose is to defend the depiction of ordinary-sized physical objects as mereological aggregates (MAs), to clarify what the ontology of an MA is, and to show why mereological essentialism (ME) applies to MAs that seem to be ubiquitous if we are to adopt what Frank Jackson calls “Serious Metaphysics” and refuse to broaden our ontology beyond what is (allegedly) bequeathed to us by physics and chemistry. To accomplish this goal, first, I clarify certain background issues that inform what follows and I identify certain constraints that relate to the contemporary ambivalence towards ME. Second, I present a primer on Husserlian mereology that provides a superior account of parts and wholes than the inadequate approach identified in the previous section. Third, I will offer a defense of ME as the correct approach to providing an ontological account of MAs. Finally, I will evaluate two defeaters against my thesis.