Their opinions are not my concern.
“If any man despises me, that is his problem. My only concern is not doing or saying anything deserving of contempt.”
-Musonius Rufus
Being despised is something Gaius Musonius Rufus knew quite a bit about this was especially notable considering who that contempt came from.
Musonius was a Stoic philosopher in 1st century Rome. He taught during the reign of Nero, an emperor notorious for being thin-skinned and very cruel.
Musonius was an outspoken opponent of the tyranny of Nero and so was sent into exile in AD 65, only returning to Rome only under emperor Galba.
During this time he continued his teaching. He gained such a reputation as a man of morals and integrity that when emperor Vespasian banished all other philosophers from the city he was spared that fate.
It is important to remember that at that time this was the equivalent of exiling every college professor in the nation for the crime of teaching.
Eventually, Vespasians's dislike of philosophers won out and in AD 71 he was banished anyway, not to return until after Vespasian's death.
Musonius spent his life despised by those in power over him. For all appearances, he did nothing to deserve this contempt. Did he let this hatred get to him? Did he return in kind? Did he turn bitter? No, quite the opposite. He saw his time in exile on the barren rocky island of Gyaros as having its advantages.
Instead, he focused on not doing or saying anything deserving of that contempt. The love of his students, both in Rome and the many who travelled to Gyaros just to be with him would show he was successful in this goal.
So in today's easily riled society, the likelihood of earning someone's contempt is quite high. Just do your best not to earn that contempt.
