It is not always easy to find an entry point through Marcel Duchamp's

separative phenomenon. In its most simplistic form, infra-thin

is a kind of immeasurable difference or separation between

two things; according to Duchamp, this partition is invisible and

intangible, but otherwise manifestly present. It was within his

concept of infra-thin that many of his most significant works were

framed. According to Duchamp, infra-thin is present in the

transparency of the Large Glass; it can be found when pondering

the difference between a common bottle rack and Duchamp's

readymade art work Bottle Rack; and infra-thin is illustrated in

the microscopic discrepancies in casts from identical molds.

Duchamp used infra-thin to define the infinitesimal breadth of

something without thickness. It gave him the means to characterize

and identify subtle, unseen — but imagined — phenomenological

occurrences. In his Notes, he illustrated infra-thin as the way one

knows the presence of an absent person through the warmth

of the chair seat from which they've just risen. With infra-thin,

Duchamp found a perfect apparatus through which to measure