Material Composition

Abstract

A material composite object is an object composed of two or more material parts. The world, it seems, is simply awash with such things. The Eiffel Tower, for instance, is composed of iron girders, nuts and bolts, and so on. You and I, as human beings, are composed of flesh and bone, and various organs. Moreover, these parts themselves are composed of further parts, such as molecules, which themselves are composed of atoms, which are composed of sub-atomic particles. Material composite objects are, it seems, ubiquitous. However, despite their ubiquity, a little philosophical reflection on the matter, as is so often the case, reveals that they are also deeply puzzling.

The question which has received most attention from philosophers interested in material composition is: under what circumstances do two or more material objects compose a further object? Why is it, for instance, that a collection of iron girders that are bolted together in the centre of Paris do compose an object (i.e. the Eiffel Tower), but that there is no object composed of the Eiffel Tower and the Moon? What conditions are satisfied by the first set of objects, and not by the second set of objects, which make this the case? In short, what are the necessary and sufficient conditions for composition to occur?
Over the last thirty years or so, philosophers have devoted a lot of attention to this question, and it has proved much more difficult to answer than one may have initially thought. This entry will provide a survey of the various answers that have been given to this question, and the arguments that have been offered in their defence.