Mentalism and objectivism have enjoyed strikingly interlocking parallels in the history of psychology and linguistics. Nineteenth century historical, comparative language studies culminated with the neogrammarians at Leipzig in the 1880s, who established the regularity of sound change as the cornerstone of linguistic science. This focus on linguistic form, together with Ferdinand de Saussure's (1916) priority of synchronic linguistics, which takes language as a 'social fact," over diachronic, and Leonard Bloomfield's (1933) declaration of an autonomous linguistics based on postulates borrowed from the mechanistic psychology of Max Meyer and his student Albert Weiss and from John Watson's behavioristic psychology gave rise to American structuralist linguistics (Blumenthal, 1970; Esper, 1968). This objectivist science of phonetic, morphological, and syntactic speech forms eschewed language meaning as the mere expression of mentalism.