"To Peter Wessel Zapffe ... the only dignified exit for man is to die out, not through a messy, unsavory and unworthy suicide, but by deciding to abstain from propagating and to leave the earth deserted behind him. Not in despair, but in triumph over finally having realized “what it is all about,” and saying his final "no more.”"
January 1, 1970
https://en.wikiquote.org/wiki/Philosophical_pessimism