Diogenes Laertius (pronounced 'die-OJ-uh-neez ley-UH-shus'; Greek: Διογένης Λαέρτιος, Diogenēs Laertios; lived c. 3rd century CE) was a biographer of the Greek philosophers. Nothing is known about his life, but his surviving Lives and Opinions of Eminent Philosophers is a principal source for the history of Greek philosophy.
“It takes a wise man to discover a wise man.”
“The only way to gall and fret effectively is for yourself to be a good and honest man.”
“The foundation of every state is the education of its youth.”
“Alexander the Great found the philosopher looking attentively at a pile of human bones. Diogenes explained, "I am searching for the bones of your father but cannot distinguish them from those of a slave.”
“To one who asked what was the proper time for lunch, he said, "If a rich man, when you will; if a poor man, when you can.”
“Once he saw the officials of a temple leading away some one who had stolen a bowl belonging to the treasurers, and said, "The great thieves are leading away the little thief.”
“When some one reminded him that the people of Sinope had sentenced him to exile, he said, "And I sentenced them to stay at home.”
“When people laughed at him because he walked backward beneath the portico, he said to them: "Aren't you ashamed, you who walk backward along the whole path of existence, and blame me for walking backward along the path of the promenade?”
“The art of being a slave is to rule one's master.”
“I have nothing to ask but that you would remove to the other side, that you may not, by intercepting the sunshine, take from me what you cannot give.”
“Man is the most intelligent of animals -- and the most silly.”
“Why not whip the teacher when the student misbehaves?”
“Die schönste Sache in der Welt ist die Redefreiheit.”
“Blushing is the color of virtue.”
“Time is the most valuable thing that a man can spend.”