On the basis of a notion of experimentation derived from Hans-Jörg Rheinberger’s concept of ‘experimental system’, which he developed in the context of twentieth-century experimental science, this paper sketches a possible route into a genuine artistic epistemology. While experimental systems are highly conceptual in nature, they are actually meant to produce material, epistemic excess – epistemic things – that enter the world first as unknowns. Given this initial lack of knowledge, the article argues that it is less helpful to decide whether any concrete epistemic thing is fact or fiction; rather, an artistic epistemology is suggested that focuses on the radical individuality of such a thing and the way in which artistic research practice may need to protect its individuality as a site for particular knowledges. This implies a critique of Rheinberger’s emphasis on historicity in experimental systems, a critique which is explained with reference to two works by Marcel Duchamp: Fountain and Three Standard Stoppages. While the former arguably changed the history of art, the latter is said to have had a much greater effect on Duchamp’s practice and understanding.