Om man ska tro wikiquote så är det Kazantzakis:
Citat:
By believing passionately in something which still does not exist, we create it. The nonexistent is whatever we have not sufficiently desired.
Attributed to Kafka in Ambiguous Spaces (2008) by NaJa & deOstos (Nannette Jackowski and Ricardo de Ostos), p. 7, and a couple other publications since, this is actually from Report to Greco (1965) by Nikos Kazantzakis, p. 434