al
proportion."

_I answer that,_ As stated above (A. 1), in distributive justice
something is given to a private individual, in so far as what belongs
to the whole is due to the part, and in a quantity that is
proportionate to the importance of the position of that part in
respect of the whole. Consequently in distributive justice a person
receives all the more of the common goods, according as he holds a
more prominent position in the community. This prominence in an
aristocratic community is gauged according to virtue, in an oligarchy
according to wealth, in a democracy according to liberty, and in
various ways according to various forms of community. Hence in
distributive justice the mean is observed, not according to equality
between thing and thing, but according to proportion between things
and persons: in such a way that even as one person surpasses another,
so that which is given to one person surpasses that which is allotted
to another. Hence the Philosopher says (Ethic. v, 3, 4) that the mean
in the latter case follows "geometrical proportion," wherein equality
depends not on quantity but on proportion. For example we say that 6
is to 4 as 3 is to 2, because in either case the proportion equals
11/2; since the greater number is the sum of the lesser plus its half:
whereas the equality of excess is not one of quantity, because 6
exceeds 4 by 2, while 3 exceeds 2 by 1.

On the other hand in commutations something is paid to an individual
on account of something of his that has been received, as may be seen
chiefly in selling and buying, where the notion of commutation is
found primarily. Hence it is necessary to equalize thing with thing,
so that the one person should pay back to the other just so much as
he has become richer out of that which belonged to the other. The
result of this will be equality according to the "arithmetical mean"
which is gauged according to equal excess in quantity. Thus 5 is the
mean between 6 and 4, since it exceeds the latter and is exceeded by
the former, by 1. Accordingly if, at the start, both persons have 5,
and one of them receives 1 out of the other's belongings, the one
that is the receiver, will have 6, and the other will be left with 4:
and so there will be justice if both be brought back to the mean, 1
being taken from him that has 6, and given to him that has 4, for
then both will have 5 which is the mean.

Reply Obj. 1: In the other moral virtues the rational, not th