They're such supreme egos. It's disgusting. I've never seen anything worse than an artist as a mind. It is very low, uninteresting as far as the rela… - Marcel Duchamp

You [ Katherine Sophie Dreier; director of the Art Center in New York City; she co-founded with Duchamp and Man Ray the 'Sociéte Anonyme' in Manhattan in 1920] must understand:
My attitude toward the book is based upon my attitude towards 'Art' since 1918 – so I am furious myself that you will accept only partly that attitude [in a new publication by Katherine Dreier]. It can be no more question of my life as an artist’s life: [because] I gave it up ten years ago; this period is long enough to prove that my intention to remain outside of any art manifestation is permanent.. .The third question is that I want to be alone as much as possible.
This abrupt way to speak of my 'hardening process' is not meant to be mean, but is the result of '42 years of age'.. ..10 000 apologies for this rough letter and affectueusement
Dee -

Since a three-dimensional object casts a two-dimensional shadow, we should be able to imagine the unknown four-dimensional object whose shadow we are.

I have been wanting to write to you for some time, but never have time, so absorbed I am in playing chess. I play night and day and nothing in the whole world interests me more than finding the right move.. .Nothing transcendental going on here – strikes [in Buenos Aires, where chess competitions were organized that year for not professionals] a lot of strikes, the people are on the move. Painting interests me less and less.