Stony Brook University

There is then a more general distinction, made in the Digest as well, between private
right—which involves the basic right of individuals to form bonds, families, and other
associations—and public right, which involves the administration of government and
land for public use, and religious matters. 37 Yet both rights, to use a frequent Leibnizian
image, are a kind of mirror or reflection of each other. The right that holds among
individuals is a microcosm of civil right and the right of nations—although the latter two
depend much more on sovereignty and positive law. Leibniz does not comment here on
the potential conflict between public and private right, although in the Codex he does
provide a brief example of how such a conflict is to be resolved, as we shall see.
But the most important and rather striking statement in that passage must not be
missed: “right is the dictate of right reason concerning that which pertains to the
perfection of human society.” It is perhaps the first time, and one of the few times, that
Leibniz explicitly connects the notion of right with the notion of perfection. Thus this
passage shows that the notion of right is the grounding principle of justice as caritas
sapientis and for the principle of perfection. As we can see, “On Justice and Right” began
with the definition of justice as charity of the wise, then showed that justice is a virtue
moderated and directed by right reason. As it turns out, right is the faculty of right
reason; therefore it governs every sphere of right: natural, national, and civil. In sum,
right is the faculty of the perfection of the entire moral and legal sphere.
In view of what comes next it is tempting to understand the structure of “De Justitia et
Jure” as closely parallel to the “science of jurisprudence” developed in the Nova
Methodus. 38 As we saw, Leibniz had defined right as moral power and obligation as
moral necessity. Here, the moral qualities are shown to be the ground of the perfection of
society—that is, the moral principle by which the perfection of the whole of human
society is to be carried out. Following these definitions are the precepts, just as in the
Nova Methodus, as will be seen in a moment. So, the structure of his argument here
parallels the structure of his demonstrative method: definitions of right are to be
established and then precepts are to be derived from them. These precepts are basically
the same as those from the Nova Methodus.
According to the above formulations, we can define an amplified sense of right as the
perfection of society according to right reason. Therefore, the precepts to follow from
this must be precepts of right reason. Included with these precepts are a number of other
descriptive features related to justice that are important to note and to distinguish from
the precepts themselves. This is because in most English translations the distinction
between right and justice has been obscured, and thus the precepts are mistakenly
understood as precepts of justice, rather than as precepts of right. But to understand their
privatum appellatur, quod scilicet ut Ulpianus definit hic spectat ad singulorum utilitatem, etsi enim inter
duas civitates ageretur, tamen quia civitas quaelibet personae instar est, jus privatum locum habet.”
37 Digesta 1.1.1.2: “Huius studii duae sunt positiones, publicum et privatum. Publicum ius est quod ad
statum rei Romanae spectat, privatum quod ad singulorum utilitatem: sunt enim quaedam publice utilia,
quaedam privatim. Publicum ius in sacris, in sacerdotibus, in magistratibus constitit. Privatum ius
tripertitum est: collectum etenim est ex naturalibus praeceptis aut gentium aut civilibus.”
38 We must assume here that faculty in this paper means something very similar to the moral qualities. This
is justified, since Leibniz in the Elementa (p. 465) associates them with Grotius, who in The Rights of War
and Peace says that “this moral Quality when perfect, is called by us a Faculty; when imperfect, an
Aptitude (GR 138). Leibniz also calls ‘faculty’ the right to possession of things (A.6.1.302.§16).
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