In parallel, the concept that all men, whether Greek or barbarian, belonged to the same race was being developed by the Sophists and thus that certain men were slaves although they had the soul of a freeman and vice versa.
Istodobno, sofisti su razvijali gledište po kojem su svi ljudi, i Grci i barbari, pripadali istome ljudskom rodu, pa su stoga neki ljudi robovi, iako imaju dušu slobodnog čovjeka, i obratno.