Full Idea
Some say the distinction between slave and free is one of convention only, and in nature there is no difference, so that this form of rule is based on force and is therefore not just.
Clarification
'Convention' is the Greek word 'nomos', which also translates as 'law'
Gist of Idea
Some say slavery is unnatural and created by convention, and is therefore forced, and unjust
Source
Aristotle (Politics [c.332 BCE], 1253b20)
Book Reference
Aristotle: 'Politics', ed/tr. Sinclair,T.A. /Saunders,T. [Penguin 1992], p.63
A Reaction
Note that Aristotle gives good expression to the main view opposed to his own. History has clearly proved Aristotle wrong, and the present idea to be correct. Ditto the subjugation of women.