Duchamp: “the passage from one to the other takes place in the infrathin”
PhMuseum: "the infrathin [is] a notion with no conceptual definition that –as [Duchamp] said in an interview in 1945– can only be explained by examples of it, like ‘the warmth of a seat which has just been left’, ‘the difference between two forms cast from the same mold’, or ‘when the tobacco smoke smells also of the mouth which exhales it’. Ideas that, alongside other examples from his notes, reveal a sensibility towards the subtle differences that movement, the passage of time, dimension and state shifts, repetitions, or non-visible physical sensations create."