Abstract : Most Proustian critics consider the theoretical pages in Le Temps retrouvé, especially "L'adoration perpétuelle", as sequences contrasting sharply with the narrative; but they indiscriminately use different terms to designate them (essay or philosophy, in particular), and simply view such sequences as nonfictional, preferring to examine the effect produced by the presence of such pages, their relation to the Proustian theories expressed in the Contre Sainte-Beuve papers or the thoughts of philosophers. They skip any analysis of the status and nature of such sequences, which are, implicitly, taken for granted. This paper addresses those neglected questions and focuses the assimilation of the theoretical pages with an essay: first, it examines the logical implications of the common idea that the theoretical sequences do not belong to fiction but are close to essay (which is nonfictional): can they possibly belong to another genre, while they are inside a novel? Then it examines the obstacles to this assimilation: the status of the I, the insertion of the sequences in a fictional frame (the novel), the semantic convergence between them and the narrative, but also the importance of general laws (lois), which appear as a link between the two. Ultimately, what are we to call these sequences evoking the essay form, inside a novel, and producing the impression that we are reading a specific form of theory?