Text reuse, encompassing direct citations, paraphrases and allusions, represents a key aspect of intertextuality – a concept central to literary theory since the 1960s. This paper highlights how computational methods, particularly automatic text-reuse detection, can illuminate the complex system of intertextual exchange that informs 18th-century literary culture, focusing on significant works like the Encyclopédie and Voltaire's correspondence. By employing advanced techniques such as sequence alignment and social network analysis, we uncover hidden patterns of influence, citation strategies and the subtle interplay between originality and imitation in Enlightenment literature. The paper also considers the implications of these findings for modern understandings of authorship, originality and textuality, drawing connections to contemporary digital humanities practices. The paper ultimately aims to recontextualise the Enlightenment as a period of intense intertextual productivity, where the reuse of texts was not merely a scholarly exercise but a dynamic and essential component of literary creation.