Aristotle identified such an optimum activity (the virtuous mean, between the accompanying vices of excess or deficiency) of the soul as the aim of all human deliberate action, eudaimonia, generally translated as "happiness" or sometimes "well-being".
ˈæɹɪstˌɑːɾəl aɪdˈɛntᵻfˌaɪd sˈʌtʃ ɐn ˈɑːptɪməm æktˈɪvᵻɾi ðə vˈɜːtʃuːəs mˈiːn, bᵻtwˌiːn ðɪ ɐkˈʌmpəniɪŋ vˈaɪsᵻz ʌv ɛksˈɛs ɔːɹ dᵻfˈɪʃənsi ʌvðə sˈoʊl æz ðɪ ˈeɪm ʌv ˈɔːl hjˈuːmən dᵻlˈɪbɚɹət ˈækʃən, jˌuːdeɪmˈoʊniə, dʒˈɛnɚɹəli tɹænslˈeɪɾᵻd æz "hˈæpɪnəs" ɔːɹ sˈʌmtaɪmz "wˈɛlbˈiːɪŋ".