Giacomo Ferrari
Università della Svizzera Italiana (USI)
The so-called “question of fundamental mereology” – “the question of what is the ground of the mereological hierarchy of whole and part” (Schaffer 2010, p. 38) – is among the most vexed issues of contemporary metaphysics. Two rival theses have dominated the debate: Mereological Bottomism (MB) and Mereological Topism (MT). According to MB, all fundamental concrete objects are mereological atoms – objects with no proper parts. MT, by contrast, maintains that all fundamental concrete objects are mereological coatoms – objects with no proper extensions. However, Inman (2017) and Bernstein (2021, p. 1069) have recently suggested that Mereological Middleism (MM), the view that all fundamental concrete objects are mereological intermediates – objects with proper parts and proper extensions – is a valuable even if largely overlooked alternative.
In this paper, I argue against the claim that if MM is true, it is necessarily true (Nec-MM). In particular, I put forward two sets of arguments for such a conclusion: the Arguments from Atoms and Quasi-Atoms and the Arguments from Non-Dependence and Homogeneity. They are both inspired by Steinberg’s (2015) isolation argument against Schaffer’s (2010) Priority Monism, but they are collectively stronger. In fact, I contend that, in the light of these arguments, the MM-ist faces a dilemma. To bring this out, I distinguish between modally thick and modally thin accounts of ontological dependence. The former carry sufficient modal force to support both necessitation and internality principles, while the latter do not. Although it has been argued that Steinberg’s original objection to Priority Monism can be resisted by appealing either to a modally thick (Calosi 2020) or to a modally thin (Costa 2024) conception of ontological dependence, I will demonstrate that neither strategy suffices against my argument targeting MM. If the MM-ist adopts a modally thick notion she can resist the first set of arguments but not the second. If instead she endorses a modally thin notion she can avoid the second but not the first. No matter which horn of the dilemma the MM-ist chooses, Nec-MM turns out to be false. Yet, if any answer to the question of fundamental mereology if “true, [it] is true with metaphysical necessity” (Schaffer 2010, p. 56), this implies that MM is false.
In the final section of the paper, I outline and discuss some possible strategies the MM-ist might adopt in response. (1) Employ a notion of ontological dependence which is neither thick nor thin, in particular a notion that entails necessitation but not internality. (2) Accept a certain measure of contingentism (Schaffer 2010, pp. 62–63; Calosi and Costa forthcoming, p. 20): MM is true at some but not all worlds. (3) Endorse a non-mereological formulation of middleism –e.g. a size- or category-based one (Bernstein 2021, p. 1069). (4) Redefine absolute fundamentality in terms of grounding rather than independence — e.g., Calosi’s notion of Support (2020, pp. 15–19). (5) Embrace a weaker version of MM according to which not all but at least one fundamental concrete object is intermediate.
References
Bernstein, Sara (2021). “Could a Middle Level Be the Most Fundamental?” In: Philosophical Studies 178.4, pp. 1065–1078.
Calosi, Claudio (2020). “Priority Monism, Dependence and Fundamentality”. In: Philosophical Studies 177.1, pp. 1–20.
Costa, Damiano (2024). “What is Priority Monism? Reply to Kovacs”. In: Inquiry: An Interdisciplinary Journal of Philosophy.
Inman, Ross D. (2017). Substance and the Fundamentality of the Familiar: A Neo-Aristotelian Mereology. New York: Routledge.
Schaffer, Jonathan (2010). “Monism: The Priority of the Whole”. In: Philosophical Review 119.1, pp. 31–76.
Steinberg, Alex (2015). “Priority Monism and Part/Whole Dependence”. In: Philosophical Studies 172.8, pp. 2025–2031.
Chair: Peihong Xie
Time: 05 September, 10:40-11:10
Location: HS E.002
SOPhiA 2026 