Categorization is fundamental to all higher cognitive activities. Yet two different approaches to categorization raises deep philosophical and linguistic problems: one is discrete category (e.g. binary features), the other is continuous category (e.g. prototape categories).
In this paper, I will propose a integrated concept called ` phonon', which is a basic unit of phonological representations on Head-driven Phrase Structure Grammar (HPSG). Furthermore, Phonon has both qualitative inner structures which achieve the same effects as the underspecification theories and quantitative inner structures including the interaction systems between articulatory and perceptual cost-functions. This idea can also combine phonology with phonetics.