 Mendelssohn finds linguistic considerations at the very heart of traditional philosophical questions. As noted above (“2. Metaphysics and epistemology”), in the Prize Essay he regards metaphysics’ greater reliance upon arbitrary signs as one reason for its slow progress (relative to that in mathematics) and in Morning Hours he indicates his inclination to regard disputes over idealism as purely verbal. Joining these remarks about the import of language for philosophy are two main treatments of language, one at the beginning, the other at the end of his career. At the outset he critically addresses Rousseau’s views on the origin of language in the context of the Berlin Academy’s essay competitions on language (see Sendschreiben an den Herrn Magister Lessing in Leipzig, the appendix to the translation of Rousseau’s Discours sur les origins de l’inégalité (1756), and Mendelssohn’s review of Michaelis’ prize-winning essay (1759) in Briefe, die neueste Literatur betreffend and “Über die Sprache” (circa 1759)). Michaelis won the Academy’s prize for answering its question: “Quelle est l’influence réciproque des opinions d’un people sur le langage et du langage sur les opinions?”). Mendelssohn takes issue both with Rousseau’s attempt to explain the origin of human language on the basis of a description of the natural condition that human beings share with other animals and with his neglect of any consideration of the providential character of the development of language (Gesammelte Schriften 6/2, p. 27). In these early writings on language, Mendelssohn emphasizes the interdependence of language and its development with the development of innate, divinely-endowed capacities. These capacities include not only reason as the ability to grasp conceptual connections and employ arbitrary signs (Gesammelte Schriften 6/2, pp. 9f), but also — in tandem with the development of rational capacities — the capacity for compassionate interaction in familial and social settings. Thus, on the one hand, the recurrence of auditory, visual, and gesticular phenomena enables reason to signify phenomena bearing no resemblance to them and, indeed, to do so in a way decidedly different from how other animals instinctively employ natural, imitative signs (Gesammelte Schriften 6/2, p. 10). In this manner Mendelssohn underlines the interdependence of reason and language, understood as the use of arbitrary signs. On the other hand, language develops within a process that is social as well as cognitive and the starting point for the investigation of its origins is the family rather than the individual. Borrowing from Condillac and challenging Rousseau’s view of language as primarily a tool for socialization, Mendelssohn writes: “The drive to social life is equally innate in human beings and leads immediately to the occasion for exercising the capacity for language”(Gesammelte Schriften 6/2, p. 8).