How similar is similar?

ion on which similarity between musical entities can be measured. Then, each of these concepts is examined in more detail with respect to a number of research studies presented in the recent special issue of Musicæ Scientiæ on musical similarity (Discussion Forum 4A, 2007). Views claiming that a geometric piano-roll-like representation is the most appropriate choice for polyphonic pattern matching, or that musical repetition is structurally significant if at least fifty percent of a pattern is equivalent (i.e. if it is more similar than dissimilar), or that “dramatic disparities” between musical similarities and corresponding categories can be found in empirical studies, are critically re-examined with a view to clarifying the fundamental concept of similarity.