Euthymia (philosophy)

Euthymia (Greek: εὐθυμία, "gladness, good mood, serenity", literally "good thumos") is a term used by Democritus to refer to one of the root aspects of human life's goal.

Diogenes Laërtius records Democritus' position as "The chief good he asserts to be cheerfulness (euthymia); which, however, he does not consider the same as pleasure; as some people, who have misunderstood him, have fancied that he meant; but he understands by cheerfulness, a condition according to which the soul lives calmly and steadily, being disturbed by no fear, or superstition, or other passion."[1]

In Seneca’s essay on tranquility, he uses the Greek word euthymia, which he defines as “believing in yourself and trusting that you are on the right path, and not being in doubt by following the myriad footpaths of those wandering in every direction.”[2]