This article critically examines the literary history–history of thought relationship, focusing on the methodology of Arthur Lovejoy and the theory of the history of ideas. The central question is whether Lovejoy’s approach is a valid method in literary history and how well it illuminates literary works as cultural documents. Relying on “unit-ideas,” Lovejoy decomposes intellectual systems into their stable elements to trace their continuity and transformation across historical contexts. He places literature alongside philosophy and other fields of thought and stresses an interdisciplinary and transnational approach. On the one hand, this approach moves literary history beyond mere cataloguing and pure aesthetics, linking it to grand intellectual narratives; on the other hand, it has been the target of fundamental criticisms. Critics regard the reduction of literariness to philosophical content, the imposition of an illusory continuity on a history full of ruptures, the reification of ideas, and the neglect of the role of form, audience, and socio-economic contexts as its most significant shortcomings. In conclusion, the article evaluates Lovejoy’s approach as a necessary condition for dynamism in literary research but insufficient for a comprehensive explanation of the literary work. The proposed solution is a critical juxtaposition of the history of ideas with formal analysis, cultural history, and methodological self-awareness, so that through a self-conscious dialectic, unit-ideas are employed not as historical truths but as analytical tools for organizing data, thereby opening a horizon for enduring questions in the intersection of literature and the history of thought.