The basic claim in this paper is that segmental primitives have no intrinsic content, contrary to classical distinctive features as well as to unary components such as I A U. Just as the syntagmatic units of the skeleton are now assumed to be homogeneous, unlike the earlier CV positions, so are paradigmatic elements, contrary to irreducible objects such as ‘I A U’, etc. ; just as segments result from operations on ‘pure’ positions (cf. autosegmental ‘associations’), so do symbolic units like ‘I A U’, etc. emerge from operations of some kind on a small set of ‘empty’ (subsymbolic) units. Our claim is supported by four problems involving the naturalness of phonological representations within standard approaches to vowel structure. These problems are resolved here within a model of vowel system morphogenesis where primitives, called ‘particles’, are operations on two arbitrary elements x and y of a Boolean algebra. The vocalic and consonantal primes of current theories follow from such a model, as well as segmental representations through a reformulation of the notion of particle ‘weight’ (cf. Schane 1984, Carvalho 1993, 1994).