Ken Lodge investigates the basic concepts of phonological theory. He especially focuses on sameness and difference, each a sine qua non of classification. It is assumed that all academic disciplines utilize these two basic concepts in classification. Since phonology deals with the interface between the abstract system of native speaker knowledge and physical entities, the linguistic classification of those physical entities needs a clear and rigorously applied criteria for deciding what constitutes the same sound and what does not. For the past hundred years, linguists have generally assumed that the criteria for classification are found in a segmentalized version of the phonetic continuum of spoken language. This is still largely the case today, even though the system of native speaker knowledge of language is considered to be a highly abstract mental representation of that knowledge. This book questions the basis of such assumptions, in particular segmentation, abstractness, monosystemicity, and derivation.