The first volume of Diderot's epoch-making Encyclopédie (1751) opens with a diagram of the “Detailed System of Human Knowledge,” which depicts visually the tree of knowledge described in Francis Bacon's Advancement of Learning (1605). The diagram was subsequently copied and translated back into English in the first volume of T.H. Croker's Complete Dictionary of Arts and Sciences (1764). This epistemological tree reduces the realm of the imagination, which takes in poetry and its sister arts, to a conspicuously small compass – barely a sixth of the space allotted to the “reasoning” disciplines of theology, ethics, mathematics, medicine, botany, chemistry, and the like (see Figure 2). The image is striking: poetry is nearly crowded off the edge of the intellectual map.

On Bacon's or the Encyclopédie's account, the difference between the respective contributions of the beaux arts and the philosophic disciplines to learning ran deeper than their associations with separate mental faculties. The several branches of philosophy and their attendant professors each contributed to the advancement of knowledge by cultivating a narrow plot of intellectual territory. In the eighteenth-century division of intellectual labor, disciplines such as physics, botany, chemistry, and moral philosophy had delimited themselves by each identifying with a particular object of knowledge. The philosophers and scientists in these fields could be recognized as experts in large part because they used and understood particular, expert languages designed to describe their respective objects.