This paper examines ‘The Natures of Conceptual Change’, the Notre Dame lectures given by Kuhn in 1980. In particular, I aim to examine the content of these lectures which was not published before. This exegetical task will shed light on the sources of the notion of taxonomy used in these lectures for the first time with the explicit philosophical purposes. It also will shed new light on Kuhn's position regarding the causal theory of reference. Reviewing these archival materials paves the (...) way for intertextual comparisons, as Kuhn included part of these lectures in the texts published later and in the book Plurality of Worlds: an Evolutionary Theory of Scientific Development. In recent years, the publication of Kuhn's archival material and the research on these texts increased in quantity and quality. Faced with this encouraging landscape, a comparative examination of the different unpublished texts is crucial to refining both our research tools on Kuhn's intellectual biography and the philosophical work inspired by his proposal. (shrink)