Political Justice is of two kinds, one natural, the other conventional. A rule of justice
is natural that has the same validity everywhere,
and does not depend on our accepting it or not. A rule is conventional that in the first
instance may be settled in one way or the other indifferently, though having once been
settled it is not indifferent: for example, that the ransom for a prisoner shall be a
mina, that a sacrifice shall consist of a goat and not of two sheep; and any regulations
enacted for particular cases, for instance the sacrifice in honor of Brasidas,1
and ordinances in the nature of special decrees.
Some people think that all rules of justice are merely
conventional, because whereas a law of nature is immutable and has the same validity
everywhere, as fire burns both here and in Persia
, rules of justice are seen to vary.
That rules of justice vary is not absolutely true, but only with qualifications. Among
the gods indeed it is perhaps not true at all; but in our world,2
although there is such a thing as Natural Justice, all rules of justice are variable. But
nevertheless there is such a thing as Natural Justice as well as justice not ordained by
and it is easy3
which rules of justice, though not absolute, are natural, and which are not natural but
legal and conventional, both sorts alike being variable. The same distinction will hold
good in all other matters; for instance, the right hand is naturally stronger than the
left, yet it is possible for any man to make himself ambidextrous.
The rules of justice based on convention and expediency are like standard measures.
Corn and wine measures are not equal in all places, but are larger in wholesale and
smaller in retail markets. Similarly the rules of justice ordained not by nature but by
man are not the same in all places, since forms of government are not the same, though in
all places there is only one form of government that is natural, namely, the best
The several rules of justice and of law are related to the actions conforming with them
as universals to particulars, for the actions done are many, while each rule or law is
one, being universal.
There is a difference between ‘that which is unjust’ and
‘unjust conduct,’ and between ‘that which is just’
and ‘just conduct.’ Nature or ordinance pronounces a thing unjust:
when that thing is done, it is ‘unjust conduct’; till it is done, it
is only ‘unjust.’ And similarly with ‘just
conduct,’ a dikaioma （or more
correctly, the general term is dikaiopragema, dikaioma denoting the rectification of an act of
We shall have later4
the several rules of justice and of law, and to enumerate their various kinds and describe
them and the things with which they deal.