portion.107 And these terms loss and gain are derived from voluntary exchange: that is to say, the having more than what was one’s own is called gaining, and the having less than one’s original stock is called losing; for instance, in buying or selling, or any other transactions which are guaranteed by law: but when the result is neither more nor less, but exactly the same as there was originally,108 people say they have their own, and neither lose nor gain.
So then the Just we have been speaking of is a mean between loss and gain arising in involuntary transactions; that is, it is the having the same after the transaction as one had before it took place.
Chapter VIII.
There are people who have a notion that Reciprocation is simply just, as the Pythagoreans said: for they defined the Just simply and without qualification as “That which reciprocates with another.” But this simple Reciprocation will not fit on either to the Distributive Just, or the Corrective (and yet this is the interpretation they put on the Rhadamanthian rule of Just,