Ataraxia

Ataraxia (ἀταραξία, "tranquility") is a Greek term used by Pyrrho and Epicurus for a lucid state of robust tranquility, characterized by ongoing freedom from distress and worry.

Quotes

 * Aristo the Bald, a native of Chios and nicknamed the Siren, said that the chief good was to live in perfect indifference to all those things that are of an intermediate character between virtue and vice; making not the slightest difference between them, but regarding them all on a footing of equality. For that the wise man resembles a good actor; who, whether he is filling the part of Agamemnon or Thersites, will perform them both equally well.
 * Aristo of Chios, quoted by Diogenes Laërtius, vii. 160


 * Ὁ δίκαιος ἀταρακτότατος, ὁ δ᾽ ἄδικος πλείστης ταραχῆς γέμων.
 * The just man is most free from disturbance, while the unjust is full of the utmost disturbance.
 * Epicurus, The 40 "Sovran Maxims" (or "Sovereign Maxims), or "Principal Doctrines" as translated by Robert Drew Hicks p.17