Giacomo Ferrari

Mereological Middleism (MM) is the view that fundamental objects are mereologically intermediate. Together with Mereological Bottomism (MB), the view that fundamental objects are mereologically atomic, and Mereological Topism (MT), the view that fundamental objects are mereologically coatomic, MM constitutes one of the three standard answers to Schaffer’s Question of Fundamental Mereology (QFM). In this paper, I present a novel argument against the claim that MM is necessarily true (Nec-MM). If one assumes that any answer to the QFM, if true, is necessarily true (QFM Necessitarianism), then MM itself is under threat. To support this conclusion, I develop two sets of arguments: the Arguments from Atoms and Quasi-Atoms, and the Arguments from Dependence and Non-Dependence. I further show that the middleist faces a dilemma, since the most promising strategy for resisting the first set of arguments undermines the most promising strategy for resisting the second, and vice versa. After considering and rejecting several responses, I argue that Nec-MM should be abandoned as a naïve formulation of the necessity of middleism and replaced with a more sophisticated formulation that preserves the core commitments of MM. This provides the middleist with a principled reason to reject QFM Necessitarianism, thereby avoiding the argument. Finally, I suggest that analogous reformulations are available to proponents of MB and MT, and that this has important implications for how the QFM itself ought to be understood.