Does Isidore appropriately describe
the characteristics of positive law?
It seems that Isidore does not appropriately
describe the characteristics (qualitatem) of
positive law when he says, “The law will be (a) morally
upright (honesta), (b) just (justa), (c)
possible according to nature, (d) in keeping with the
customs of the country, (e) appropriate for the time
and place, (f) necessary, (g) useful, (h) clear as well,
lest it contain anything deceptive because of its obscurity,
(I) written for no one’s private advantage, but for
the common advantage of the citizens.”
Objection 1: He had
previously explained the characteristics of law by listing
[just] three conditions: “The law will be everything
that builds upon reason, as long as it (a) agrees with
religion, (b) contributes to discipline, and (c) promotes
welfare (salus).” Therefore, it was unnecessary
for him to multiply the conditions later on.
As Tully explains in De Officiis, justice (iustitia)
is a part of moral uprightness (honestas).
Therefore, once Isidore had said “morally upright,” it was
unnecessary to add “just.”
According to Isidore, the written law is opposed to
custom. Therefore, he should not have put
“in keeping with the customs of the
country” in the definition of law.
There are two types of necessary things. The first is
what is necessary absolutely speaking, i.e., such that it
is impossible for it to be otherwise; this type of
necessary thing is not subject to human judgment and so
this sort of necessity is irrelevant to human law.
Something can also be necessary for the sake of an end,
and this sort of necessity is the same as usefulness.
Therefore, it is superfluous to posit both “necessary” and
But contrary to this
is the authority of Isidore himself.
As Physics 2 makes clear, everything that exists
for the sake of an end must be such that its form is
proportioned to that end—in the way that the form of
a saw is such that is appropriate for cutting.
In addition, everything that is rectified and measured
must have a form proportioned to its rule and measure.
Now human law has both these features, since (a) it
is something ordered toward an end and (b) it is a rule
or measure that is itself ruled or measured by a higher
measure—where, as is clear from what was said above
(q. 93, a. 3), this higher measure is twofold, viz.,
divine law and the law of nature. Moreover, the
end of human law is its usefulness for men, as the Legal
Expert likewise points out.
And this is why, in giving the conditions for law, Isidore
first lays down these three: that (a) law agrees
with religion, viz., insofar as it is proportioned to
the divine law, that (b) it contributes to discipline,
insofar as it is proportioned to the law of nature,
and that (c) it promotes welfare, insofar as it is proportioned
to human usefulness. All the other characteristics
that he posits later on are traced back to these three.
For the law’s being morally upright is traced back to
its being agreement with religion.
And what he then adds—viz., “just, possible according
to nature, in keeping with the customs of the country,
appropriate for the time and place”—is added because
it contributes to discipline. For human discipline
is concerned in the first place with the order of reason,
which is implied by is saying “just.” Second,
it has to do with the ability of the agents, since discipline
should be appropriate for each one in accord with what
is possible for him, likewise keeping in mind what is
possible for nature (for the same discipline imposed
on grown men should not be imposed on children), and
in accord with human custom, since a man cannot live
by himself in society and fail to defer to others.
Third, as far as fitting circumstances are concerned,
he says, “appropriate to the time and place.”
Now what he then adds, viz., “necessary, useful, etc.,”
is traced back to the fact that law expedites human
welfare, so that “necessity” refers to the removal of
evils, “usefulness” to the pursuit of goods, and “clear”
to the prevention of the harm that could come from the
And since, as was
explained above (q. 90, a. 2), law is ordered toward
the common good, this point itself is made clear in
the last part of the definition.
Reply to objection 1 and objection 2
and objection 3 and objection 4:
The replies to the objections are clear from what has been