125 H.M. Lloyd (ed.), The Discourse of Sensibility: The Knowing Body in the Enlightenment, Studies in History and Philosophy of Science 35, DOI 10.1007/978-3-319-02702-9_7, © Springer International Publishing Switzerland 2013 Abstract The best-known intellectual persona of the French Enlightenment, the philosophe, is typically associated not with the vicissitudes of sensory, corporeal exis- tence, but with reason, truth-telling, and the pursuit of social and political reform. However, like many other aspects of eighteenth-century culture, the figure of the thinker was deeply inflected by sensibility’s rise as a concept that bridged body, mind, and milieu. This chapter focuses on the absorbed thinker as a type to reconstruct what sensibility was held to do in the mind and body during the act of intense cerebration. It examines the ambiguous affective and sensory state which various moralists and physi- cians ascribed to thinkers observed or imagined in the state of absorption. It then con- siders some of the purposes to which Denis Diderot put the figure, focusing particularly on the absentminded geometer characters that appeared in his fictional dialogue Le Rêve de d’Alembert (1769) and in the Eléments de physiologie (1778). Finally, it considers what those depictions imply, both for Diderot’s views on the thinking process and for existing historiographical accounts of sensibility in the Enlightenment era. There are no deep thinkers, no ardent imaginations that are not subject to momentary catalepsies. A singular idea comes to mind, a strange connection distracts us, and our heads are lost. We come back from that state as from a dream, asking those around us, ‘where was I? What was I saying?’ 1 Denis Diderot’s bemused fascination for ‘deep thinkers’ and ‘ardent imagina- tions’ reflected both his own, occasionally idiosyncratic, views on human nature 1 ‘Point de penseurs profonds, point d’imaginations ardentes qui ne soient sujets à des catalepsies momentanées. Une idée singulière se présente, un rapport bizarre distrait, et voila la tête perdue on revient de là comme d ’un rêve : on demande à ses auditeurs , où en étais-je? Que disais-je? ’. Diderot 1778/1975–, 328–329. All translations are my own, unless otherwise noted. Chapter 7 Penseurs Profonds: Sensibility and the Knowledge-Seeker in Eighteenth-Century France Anne C. Vila A.C. Vila (*) Department of French and Italian, University of Wisconsin-Madison, 618 Van Hise Hall, 53706 Madison, WI, USA e-mail: acvila@wisc.edu © Lloyd, Henry Martyn, Dec 12, 2013, The Discourse of Sensibility : The Knowing Body in the Enlightenment Springer, Dordrecht, ISBN: 9783319027029