DE MONARCHIA OF DANTE ALIGHIERI
CHAPTER VI: He who purposes Right proceeds according to Right.
1. We have then demonstrated two things: one, that whoever purposes the good of the commonwealth purposes the end of Right; the other, that the Roman people in subduing the world purposed the public good. We may now further our argument in this wise: Whoever has in view the end of Right proceeds according to Right; the Roman people in subjecting the world to itself had in view the end of Right, as we plainly proved in the chapter above;  therefore the Roman people in subjecting the world to itself acted with Right, and consequently appropriated with Right the dignity of Empire.
2. That this conclusion may be reached by
all manifest premises, it must be reached by
the one that affirms that whoever purposes the
end of Right proceeds according to Right. For
clearness in this matter, notice that everything
exists because of some end, otherwise it would
be useless, which we have said before is not
possible.  And just as every object exists for
its proper end, so every end has its proper
object whereof it is the end. Hence it cannot
be that any two objects, in as far as they are
two, each expressing its individuality, should
have in view the same end, for the same untenable
conclusion would follow that one or the
other exists in vain. Since, as we have proved,
there is a certain end of Right, to postulate that
end is to postulate the Right, seeing it is the
proper and intrinsic effect of Right. And since,
as is clear by construction and destruction,  in
any sequence an antecedent is impossible without
its consequent (as "man" without "animal"),
so it is impossible to attain a good condition
of one's members without health; and so it is
impossible to seek the end of Right without
Right as a means, for each thing has toward its
end the relation of consequent to antecedent. Wherefore it is very obvious that he who has
in view the end of Right must proceed by the
right means. Nor is that objection valid which is generally drawn
from the Philosopher's words concerning "good counsel." He says indeed,
"There is a kind of false syllogism in which a true conclusion may be
drawn by means of a false middle."  Now if a true conclusion is
sometimes reached through false premises, it is by accident, because the
true conclusion is conveyed in the words of the inference. Of itself
the true never follows from the false, though
symbols of truth may follow from symbols of
falsehood.  And so it is in actions. Should a
thief aid a poor man with stolen goods, he yet
could not be said to be giving alms; rather is
his action one which would have the form  of
alms had it been performed with the man's own
substance. Likewise with the end of Right.
For if anything calling itself the end of Right
be reached other than by means of Right, it
would be the end of Right, that is, the common
good, only as the offering made from ill-gotten
gains is an alms. Since in this proposition
we are considering the existent, not the
apparent ends of Right, the objection is invalid.
The point we are seeking is therefore
1. See chapter 5.
2. De Mon. 1. 3, note 3.
3. "Construendo et destruendo." The first of these logical terms designates a refutation which proceeds from the antecedent to the consequent; the second, one that proceeds from the consequent to the antecedent.
5. "Signa tamen veri bene sequuntur ex signis, quae sunt signa falsi." "Signa" I take to mean "words;" Dante would say that words may be ambiguous, but not the ideas that they stand for.
6. No line in the De Mon. shows better the change in usage that has been undergone by this word "form," and how, from meaning the vitalizing, internal principle of a thing, it has come to be the symbol of externality.
Conv. 4. 27. 7 makes use of the thief again for demonstrative purposes.
Par. 5. 33: "Thou art desiring to make a good work of a bad gain."