402 Cohen Hall
‘Is everything entirely made up of atoms? … Or is everything made up of atomless “gunk”—as Lewis (1991: 20) calls it—that divides forever into smaller and smaller parts?’ (Varzi 2014)
The thought that matter is divisible has both intuitive appeal and empirical justification, and is a widespread position amongst ancient and modern metaphysicians. The thought that matter is unlimitedly divisible on the other hand has intuitive appeal, but not empirical justification, which is why there are only few metaphysicians upholding this view; for instance, Aristotle. But the thought that matter is unlimitedly divided is neither intuitive nor empirically justifiable, and has been very rarely endorsed in the history of metaphysics; Leibniz is one of the few exceptions. Yet, unlimited division is the keystone of two ancient metaphysical systems that in many other respects are different from one another: Anaxagoras’ and the Stoics’. I submit that both Anaxagoras and the Stoics posited an unlimitedly divided bedrock of reality, and that they took this stance for metaphysical reasons, i.e. because this assumption does explanatory work that would have otherwise been left undone in their systems.
Since Plato and particularly Aristotle, all the way to our times, metaphysicians overcome the restrictions imposed on explanation by physical laws governing material objects (such as the explanation of resemblance; of change; of generation; of being an object of thought, etc.) by introducing non-physical entities that ‘permeate’ the constitution of substances. Such non-physical entities are for instance universal forms, properties, underlying substrata, etc., all of which can be individuated only by abstraction. The resulting abstract entities can overlap in the constitution of objects because they are abstract, not subject to physical law. So abstraction is the operation that supports most of the ancients’ as well as our explanatory practice in metaphysics. Anaxagoras and the Stoics are two exceptions; they developed an alternative (and formidable) way to account for the constitution of objects, which enables them to give metaphysical explanations free of abstract entities: this is unlimited physical division.
In this paper I will concentrate on the Stoics, and in particular on the following challenge that arises from their physicalist assumptions: how is matter en-formed by properties, if this is not by the (mysterious) instantiation of (Aristotelian) universals? I present a causal model I find developed in the Stoics, by which they could give an account of how a propertiless soma can be en-formed by the powers of pneuma. Key to this model is the unlimited division of matter into material gunk. Such division allows matter to be collocated. In this connection, I discuss critically Daniel Nolan (2006)’s account of the collocation of Stoic gunk, and show that the model the Stoics developed introduces a sui generis conception of collocation of gunk, which gives rise to what I call the Stoic Empowerment Model.