Ataraxia

Ataraxia [ἀταραξία] is the essence of Epicurean happiness: a state freed of pain and anxiety [ταραχή]. Attaining ataraxia requires only modest means, judicious limitation of one's desires, and conscious resistance to any and all forms of superstition, such as aspirations of immortality.

According to Epicurus, ataraxia is the goal of philosophy, when correctly understood and practiced, just as health is the goal of medicine.