that piety, which warns us to fulfil our duties towards our
country, our parents, or others connected with us by ties of blood,
gratitude is that which retains a recollection of honours and benefits
conferred on one, and acts of friendship done to one, and which shows
itself by a requital of good offices, revenge for injuries is that by
which we repel violence and insult from ourselves and from those who
ought to be dear to us, by defending or avenging ourselves, and by
means of which we punish offences, attention to superiors, they call
the feeling under the influence of which we feel reverence for and pay
respect to those who excel us in wisdom or honour or in any dignity,
truth, they style that habit by which we take care that nothing has
been or shall be done in any other manner than what we state. And the
laws of nature themselves are less inquired into in a controversy of
this sort, because they have no particular connexion with the civil
law of which we are speaking and also, because they are somewhat
remote from ordinary understandings. Still it is often desirable to
introduce them for the purpose of some comparison, or with a view to
add dignity to the discussion.

But the laws of habit are considered to be those which without any
written law, antiquity has sanctioned by the common consent of all
men. And with reference to this habit there are some laws which are
now quite fixed by their antiquity. Of which sort there are many other
laws also, and among them far the greatest part of those laws which
the praetors are in the habit of including in their edicts. But some
kinds of law have already been established by certain custom, such as
those relating to covenants, equity, formal decisions. A covenant
is that which is agreed upon between two parties, because it is
considered to be so just that it is said to be enforced by justice,
equity is that which is equal to all men, a formal decision is that by
which something has been established by the declared opinion of some
person or persons authorized to pronounce one. As for regular laws,
they can only be ascertained from the laws. It is desirable, then, by
trying over every part of the law, to take notice of and to extract
from these portions of the law whatever shall appear to arise out of
the case itself, or out of a similar one, or out of one of greater or
less importance. But since, as has been already said, there are two
kinds of common topics, one of which co