To say "all that which does not exist" is to introduce,....

“ To say "all that which does not exist" is to introduce, effectively, a new concept, but it does not bring into existence anything more than that very concept which it introduces. That is, a certain entity about which we know nothing except that it bears the name of "all that which does not exist. ”

Pablo Tusset

From : The Best Thing That Can Happen to a Croissant