It is argued here that most phonological theory is not theoretical, but based on primitives and axioms (the so-called`constraints') which derive directly from the data they are supposed to explain. This article attempts to show what a non-circular conception of phonological theory may look like. The number of segmental primes, their markedness value, phonological content, and combinatory properties, as well as currently assumed constraints on syllable structure are shown to follow from a Boolean algebra, and, thus, to be independently motivated theory-grounded theorems. Hence, for example, neither the onset nor the no-coda constraints posited by OT are required. Another issue of the present theory is that segmental content and syllable structure and interdependent aspects, which emerge from the determination of skeletal units.* I wish to thank Marc Klein, Jean-Elie Boltanski, Tobias Scheer, Philippe Se Âge Âral and an anonymous reviewer for Studia linguistica for helpful comments on earlier drafts of this paper. I am also indebted to Helen Dochney-Le Âpine for crucial help in the preparation of the present version. 228 Joaquim Branda Äo de Carvalho # The Editorial Board of Studia Linguistica 2002.