How Properties Hold Together in Substances
A main aim of chemical research is to understand how the characteristic properties of specific chemical substances relate to the composition and to the structure of those materials. Such investigations assume a broad consensus regarding basic aspects of chemistry. Philosophers generally regard widespread agreement on basic principles as a remote goal, not something already achieved. They do not agree on how properties stay together in ordinary objects. Some follow John Locke [1632–1704] and maintain that properties of entities inhere in substrates. The item that this approach considers to underlie characteristics is often called “a bare particular” (Sider 2006). However, others reject this understanding and hold that substances are bundles of properties—an approach advocated by David Hume [1711–1776]. Some supporters of Hume’s theory hold that entities are collections of “tropes” (property-instances) held together in a “compresence relationship” (Simons 1994). Recently several authors have pointed out the importance of “structures” for the coherence of substances, but serious questions have been raised about those proposals. Philosophers generally use a time-independent (synchronic) approach and do not consider how chemists understand properties of chemical substances and of dynamic networks of chemical reactions. This chapter aims to clarify how current chemical understanding relates to aspects of contemporary philosophy. The first section introduces philosophical debates, the second considers properties of chemical systems, the third part deals with theories of wholes and parts, the fourth segment argues that closure grounds properties of coherences, the fifth section introduces structural realism (SR), the sixth part considers contextual emergence and concludes that dynamic structures of processes may qualify as determinants (“causes”) of specific outcomes, and the final section suggests that ordinary items are based on closure of relationships among constituents additionally determined by selection for integration into more-extensive coherences. Ruth Garrett Millikan discussed the concept of substance in philosophy: . . . Substances . . . are whatever one can learn from given only one or a few encounters, various skills or information that will apply to other encounters. . . . Further, this possibility must be grounded in some kind of natural necessity. . . . The function of a substance concept is to make possible this sort of learning and use of knowledge for a specific substance. . . . (Millikan 2000, 33)