While Rosalind Krauss has argued that Marcel Duchamp’s so-called Precision Optics is concerned with what she called an “erotic theatre”, this paper attempts to demonstrate that it was primarily artistic questions, or rather art historical ones, which were the motivation behind Duchamp’s series of works collated by the term Optique de précision. The argument is that in the title, Precision Optics, which was to be understood as ironic, Duchamp was seeking to address the theoretical foundations of one of the history of painting’s most fundamental means of representation, so-called linear perspective. The question that concerned Duchamp may well have been something like this: how is an actual impression of spatial depth achievable by means of a blocked, monocular gaze? Or, in other words: how is the ‘promise of linear perspective’, that is the creation of ‘illusionary’ spatial depth frontal, perceived with a blocked, monocular viewpoint, to be resolved in the form of a sketch drawn in linear perspective? It is an ‘illogical’ basis for enquiry, since it is based on a-rational premises and yet it is an original, artistic one. This paper shows that in his precision optical works Duchamp was involved with playing with the cardinal problems of the history of painting.