Composition

This chapter explores the philosophical and formal issues surrounding mereological composition. It carefully examines the difference between three main types of fusion: algebraic joins, Leśniewski sums, and Goodman fusions. It also examines different views about their conditions of existence (the so-called ‘special composition question’), including the controversial doctrines of mereological universalism, nihilism, and restricted theories of composition. Next it considers whether fusions are unique and how this impacts extensionality, including presenting a detailed analysis of the thesis known as ‘composition as identity’. A number of ‘structural’ conceptions of composition (and related algebraic principles) are then examined. Finally, parallel to questions about a null object, atomism, and ‘atomless gunk’, the existence of a universal object and the ideas of ‘worldless junk’, and coatomism are considered.

Intensional Composition as Identity

Composition as Identity claims that a composite object is identical to its parts taken collectively. This is often understood as reducing the identity of composite objects to the identity of their parts. The author argues that Composition as Identity is not such a reduction. His central claim is that an intensional notion of composition, which is sensitive to the arrangement of the composing objects, avoids criticisms based on an extensional understanding of composition. The key is to understand composition as an intensional kind of identity relation, many-one identity. Eventually, the author suggests an arrangement condition for many-one identity that allows him to distinguish between composite objects, even if they have the same parts.

Grief and Composition as Identity

‘It feels like I have lost a part of myself’ is frequently uttered by those grieving the death of a loved one. Despite the ubiquity of such utterances, and the palpable sense that they express something true, few philosophers have considered what, if anything, accounts for their truth. Here, I develop a suggestion from Donald Baxter according to which Composition as Identity provides us a means to understand the grief utterances literally. In doing so, I identify and develop a version of Leibniz's Law required for Composition as Identity to account for the truth of the grief utterances. In turn, this principle helps shed light on Composition as Identity's central claim: that the parts are identical to the whole. By considering objections to the resulting view, I construct a list of desiderata for other philosophers interested in accounting for the grief utterances.