Full Idea
Mastership in the abstract is mastership of slavery in the abstract.
Gist of Idea
The concept of a master includes the concept of a slave
Source
Plato (Parmenides [c.366 BCE], 133e)
Book Reference
Plato: 'Plato IV (Cratylus,Parmenides,Hippias Maj, Min)', ed/tr. Fowler,H.N. [Harvard Loeb 1926], p.225