"In the wake of modernity we once again find ourselves in the abyss of the infra-thin, a concept that permeates Marcel Duchamp’s entire oeuvre, a shorthand label for his life-long desire to overcome the distance between Signifier and signified, thing and meaning, love and knowledge, inner and outer, up and down, appearance and apparition, mold and molded, of and in. To be precise, the word “infra-thin” was to him “not a noun but an adjective, although the sign of the accordance might be the perfect exemplification of the infra thin made into a noun. Even as an adjective, ‘infra-thin’ never qualifies a thing or an experience, but rather the difference between two things or experiences. This difference is at its thinnest when those two things are the same."
--Gunnar Olsson, Abysmal: A Critique of Cartographical Reason
"Fire without smoke, the warmth of a seat which has just been left, reflection from a mirror or glass, watered silk , iridescents, the people who go through (subway gates) at the very last moment, velvet trousers their whistling sound is an infra-thin separation signaled"- Marcel Duchamp, Notes, (Translated by Paul Matisse)