Abstract
The popular metaphysical view that concrete objects are grounded in their ultimate parts is often motivated by appeals to realist interpretations of contemporary physics. This paper argues that an examination of mainstream interpretations of quantum mechanics undercuts such atomist claims. First, mereological atomism is only plausible in conjunction with Bohmian mechanics. Second, on either an endurantist or perdurantist theory of time, atomism exacerbates Bohmianism’s existing tensions with serious Lorentz invariance in a way that undermines the realist appeal of both views. Bohmians should therefore resist atomism, leaving atomists somewhat physically homeless.