In “A Tale of Two Simples,” I presented an argument against the possibility of extended heterogeneous simples that relied on the possibility of extended atomic regions of space. Andrew Jaeger has presented a parody of one part of my argument for a clearly absurd conclusion. In this short paper, I defend my argument by showing that there is a significant disanalogy between my support for a key premise in my argument and Jaeger’s support for the corresponding premise in his parody (...) argument. Also, in opposition to my previous position, I present a case against the possibility of extended atomic regions of space. (shrink)

There is broad consensus (both scientific and philosophical) as to what a rigid body is in classical mechanics. The idea is that a rigid body is an undeformable body (in such a way that all undeformable bodies are rigid bodies). In this paper I show that, if this identification is accepted, there are therefore rigid bodies which are unstable. Instability here means that the evolution of certain rigid bodies, even when isolated from all external influence, may be such that their (...) identity is not preserved over time. The result is followed by analyzing supertasks that are possible in infinite systems of rigid bodies. I propose that, if we wish to preserve our original intuitions regarding the necessary stability of rigid bodies, then the concept of rigid body must be clearly distinguished from that of undeformable body. I therefore put forward a new definition of rigid body. Only the concept of undeformable body is holistic (every connected part of an undeformable body is not always an undeformable body) and every connected part of a rigid body in this new sense is always a rigid body in this new sense. Finally, I briefly discuss the connection between this conceptual distinction and the dimensionality of space, thereby enabling it to be supported from a new and interesting perspective. (shrink)