Stony Brook University

[determine] the truth of propositions or the use of words in speech, even
when we do not know we are doing so. (LL 133) 59
So, the doctrine of right, since it is an a priori science, must begin by investigating its
“clear” ideas (which presumably are not yet distinct), in order to make them distinct. In
effect, we start, as Aristotle would say, from what we already know. The method is
described further.
The method of our investigation is to gather the more important and
distinctive examples of the use of these terms and to set up some meaning
consistent with these and other examples. For just as we construct a
hypothesis by induction from observations, so we construct a definition by
comparing propositions; in both cases we make a compendium of all other
instances, as yet untried, out of the most important given cases. This
method is necessary whenever it is not desirable to determine the use of
terms arbitrarily for oneself. (LL 133) 60
The method Leibniz is describing here is likely what Aristotle called in the Posterior
Analytics, “epagoge,” or induction. 61 This is not, however, induction from empirical
observations, but from propositions and definitions. As he employs it here, it means
setting out a large number of typical or accepted definitions of the terms (right, just, and
justice), rejecting those definitions that meet with some objection, and retaining those that
do not. This, however, is not quite what happens; Leibniz’s investigation is much less
rigorous than it is significant, not the least for his claim to have arrived at the “true and
perfect definition of justice.”
Now let us turn to the investigation itself, beginning with the rather brief and
compact paragraph on right. Two preliminary points must be made. First, Leibniz does
not explicitly state the definitions of right and obligation that he had established in the
Nova Methodus (right is a moral power; obligation a moral necessity). But to understand
what Leibniz is doing in this paragraph, and indeed in the investigation in Draft 4 as a
whole, it is crucial to keep these definitions in mind. Moreover, this will help to explain
why the very last sentence of the entire Draft 4 simply ends, seemingly inexplicably, with
“Right (ius) is the power (potentia) of doing what is just (iustum).” 62 Second point:
within this paragraph, Leibniz briefly opens a window onto the most pervasive themes of
59 A.6.1.461: “Cum igitur doctrina juris scientia sit, et scientiae causa sit demonstratio, demonstrationis
principium definitio, conseqvens est vocabulorum Iuris, Iusti, Iustitiae, definitiones, id est ideas qvasdam
claras, ad qvas ipsi cum loqvimur exigere propositionum, id est usus vocabulorum, veritatem etiam
nescientes solemus, debere ante omnia investigari.”
60 A.6.1.461: “Investigationis haec methodus est, ut insigniora et maximè dissita ex usa loqvendi exempla
conferentes, comminiscamur aliqvid qvod et his et caeteris congruat. Qvemadmodum enim inductione
experimentorum struimus hypothesin, ita propositionum collatione definitionem utrobiqve ex potissimis
praetentatis compendium facimus caeterorum intentatorum. Hâc methodo opus est qvoties inconsultum est
formare sibi pro arbitrio usum vocum.”
61 Post. An 1.18.81.a39-40; 81b5; Post An 2.19.100a5,6.
62 Two reasons why this appears inexplicable: one is that it comes after a long discussion of love and
justice, not directly after the earlier investigation of right; secondly, by focusing on love and justice most
commentators have neglected to recognize the significance of the earlier paragraph, and/or have completely
neglected the Nova Methodus.
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