"We imagine that hardness, violence, slavery, peril in the street and in the heart, concealment, Stoicism, temptation, and deviltry of every sort, everything evil, frightful, tyrannical, raptor- and snake-like in man, serves as well for the advancement of the species "man" as their opposite."
January 1, 1970
https://en.wikiquote.org/wiki/Friedrich_Nietzsche