The chief aim of this thesis is mobilizing parts of the work of Wilfrid Sellars in order to reconsider the notion of medium in relation to the ones of language and thought and, per extension, conception and mind. Indeed, the account of the notion of medium is constructed as a generalization of the case of language, as described in its rapport with thought, in Sellarsian philosophy. The thesis tries to position the medium as a pivot point of articulation between epistemology (...) and ontology, mostly by using as a blue-print the Sellarsian articulation of the two through the Manifest and Scientific Images. We consider Sellars’ project of accounting for the normative character of language independently from conception, with his dismissal of the instrumentalist-dualist reading of the relation between language and thought as well as the purely materialist reading of the same. We then introduce the notion of thought as inner mental episodes with a treatment of the methods of postulation and observation. This finally leads us to zeroing in on the notion of medium qua an extension of the notion of language as presented up to this point, taking move from the thesis that Johanna Seibt draws out of Sellars’ work that language is the medium of conception rather than its expression. Finally, we articulate three chief characteristics of the notion of medium: synthetic function, actuality and observational capacity, each referring to terminology introduced in the course of the thesis. In the process of introducing the three features, we also face three preoccupations underlying the research from the beginning: the question of translatability or specificity of a medium, the problem of communication and the notion of empirical truth. Especially this latter point will lead us to the sketching of a natural-history of mediums based on the notion of medium-series. (shrink)