"Moon-Watcher saw that his father had died in the night. He did not know that the Old One was his father, for such a relationship was utterly beyond his understanding, but as he looked at the emaciated body he felt dim disquiet that was the ancestor of sadness…He never thought of his father again."
January 1, 1970
https://en.wikiquote.org/wiki/2001%3A_A_Space_Odyssey_(novel)