Stony Brook University

clearly show that their claims cannot be correct. 26 From the beginning Leibniz took quite
seriously the idea that the ground of jurisprudence, or “the science of right” as he later
calls it, 27 is an a priori science based on reason. Reason is the essence of God’s
understanding, which the will is obliged to follow.
Section 3: The “New Method” of jurisprudence and its definitions: jus and obligatio
Now that we have a sense of the general features of the Nova Methodus, let us
turn to its Euclidean “elements.” These are the definitions (or at least, the clarifications of
terms) and propositions or precepts. 28 Leibniz recognizes that works such as Hobbes’
Elementa de Cive et Corpore and Pufendorf’s Elementa Jurisprudentiae were also
modeled after Euclid. But Leibniz considers his unique contribution to be the
systematization of jurisprudence from out of its historical confusion. Before offering any
definitions, he at length identifies several problems with its historical development and
figures. The main problem lies in the history of methodological failure to distinguish
right from fact. 29 For example, Leibniz claims that the Roman Institutes and the Digest
consist of endless divisions of the objects of Right into persons, things, and actions. Each
of these is further divided into kinds of persons, kinds of things, kinds of actions
involving the relations between persons and things, and so on. Leibniz protests that not
only are such divisions uncertain, but that this method of division is largely empirical,
subject to change, and lacking in any universal standard of measure. It is unclear, for
example, how to distinguish a slave owner’s rights over his slave from his rights over his
property (such as a horse), since slaves have some rights as persons, but lack other rights
as property. But the divisions set out in Roman law are incapable of making such
distinctions clear. The “old method” of the Digest, Leibniz says, is “as absurd as if a
geographer were to fix his science, not according to the form, but to the matter, that is,
according to the measure of acres, pastures, and fields.” According to this method, “who
would not laugh at such a new Euclid?” (A.6.1.298). In other words, the science of
jurisprudence must be an a priori deductive science, “established straight from the very
definitions of things,” 30 that is, from the definitions of Right, not from the things that
have been given rights in a wholly non-systematic, historically contingent manner.
Leibniz’s first methodological move, then, is to establish a normative distinction
26 Leibniz’s anti-voluntarism in his later writings, such as Méditation (1703) and On the Principles of
Pufendorf ( 1706) is well-known. Notably, the line in §4 above, “stat pro ratione voluntas,” (which is from
Juvenal’s Saturae) is called in the Méditation, “the motto of a tyrant.” Leibniz then argues for a “formal
reason” of justice to stand as the criterion to which the will of a superior must conform. But some
commentators claim that Leibniz was a voluntarist in his early writings (citing de Arte Combinatoria and
Nova Methodus). Riley (2004) is one; Mulvaney (1968) is another; Busche (p. 430) cites others and
disputes their claims.
27 That is, “la science de droit” as we will see in the Méditation.
28 A.6.1.295.§6: “Jurisprudence Didactica, Elementorum nomine non ineptè appellabitur ad imitationem
Elementorum Euclidis, [...] Elementa duobus absolvuntur: Explicatione terminorum seu Definitionibus,
quibus respondet titulus de verb. sign., et propositionibus seu praeceptis, quo pertinet titulus de reg. jur.” In
a revision note, Leibniz adds to ‘propositionibus seu praeceptis’ “enunciationibus seu praeceptis.”
According to Busche, ‘titulus’ refers to Book 50, chapters 16 and 17 of the Digest.
29 A.6.1.298.§10: “Et ut breviter dicam, est haec Methodus non ex juris sed Facti visceribus sumpta.”
30 A.6.1.300.§14: “. . . ut solidam methodum ex ipsis rerum definitionibus eruamus.”
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