en:I know that I know nothing
el:ἓν οἶδα ὅτι οὐδὲν οἶδα
es:Solo sé que no sé nada
de:Ich weiß, dass ich nichts weiß
lat:Scio me nihil scire— Σωκράτης
Conflict between the men who possess more than they have earned and the men who have earned more than they possess is the central condition of progress.