I now want to turn to the specifically linguistic aspect of sameness and difference by looking first at a topic that all phonologists should agree with: the notion of meaningful contrast as the centre of phonological analysis. However, I would like to scrutinize it in a little more detail than is perhaps usual by considering how we, as phonologists, determine what constitutes sameness in phonology and what the consequences of that identification are. I will then elaborate on the topic in the later chapters of the book. As I have tried to show in the first chapter, one of the fascinating things about human beings is the way in which they classify: for the most part, sameness does not mean absolute identity, and sameness in one set of circumstances may be difference in others. To take a simple phonological example, native speakers of English typically identify regular plurality as being the same in all instances, despite the fact that phonetically we have [s], [z] and [iz] as predictable realizations; yet when distinguishing mace and maze native speakers have no difficulty in recognizing the same phonetic difference as marking a meaningful contrast. (Students of phonetics, even those who are quite competent in discrimination and transcription, typically transcribe regular plural forms with [s] even after voiced sounds, for example, [ctogs], and the regular past tense as [d], even after voiceless sounds, for example, [wokd].) The significance of the reinforcement of such classifications by the system of English spelling will be discussed in Chapter 4.