Stony Brook University

definitions . . . and propositions or precepts.” 163 Leibniz has at least made some effort to
set out the definitions of right and their corresponding precepts, although we are left to
fill in the gaps. His main purpose in doing so, however, is to correct the history of
methodological failure to distinguish right from fact. 164 That is, he aims to establish a
normative distinction between what is a matter of right and what is a matter of fact. In
this sense, the method consists of establishing the a priori foundation of jurisprudence.
Although Leibniz has not used the term “a priori,” this is clearly what he means.
Jurisprudence is a science in the pure sense, established straight from the very definitions
of things. 165 The problem, however, is that at this point Leibniz does not provide any
argument for why these definitions are not merely nominal or arbitrary stipulations.
Hobbes, as we have seen, defines right and obligation quite differently. But which
definitions are “correct”? At this point Leibniz has not yet established a method for
adjudicating among competing definitions. In the next chapter, however, we will see how
he develops and carries out a much more rigorous method of deriving definitions.
Another point relevant to his demonstrative method is that it is not clear that
Leibniz’s definitions are entirely a priori, if by ‘a priori’ is meant ‘independent of any
empirical premises.’ At times Leibniz, like Grotius and Aristotle, depends on the
assumption that humans are naturally inclined to be social rather than egoistic, so that
they will naturally seek a state of convenience and cooperation. But these assumptions
are taken from observations about natural tendencies in humans, not from the definitions
of the terms of right; and it does not appear possible to decide on the true nature of
human beings solely by considering a priori definitions. Moreover, while we might agree
that humans are by definition rational substances, it does not follow with deductive
necessity that we have the moral qualities of right and obligation, since God could have
given humans some other nature and some other qualities. The assumption that we are
rational, social, rights-bearing beings could very easily be based on empirical
observations about our tendencies and what best accords with them. This is however not
a crucial criticism. Aspects of our natural physical constitution are after all part of what
constitutes “natural law,” and Leibniz never denies this. Nor will he give up the search
for a priori principles, nor for a way to make such principles compatible with the laws of
our nature. As we will see, Leibniz often deals with two principles: one based on human
physical nature and the other based on a priori reason. The problem is, however, that
Leibniz has no straightforward way of clearly distinguishing between a posteriori and a
priori in these matters.
A final observation pertains to typical interpretations of Leibniz’s practical
philosophy. A striking feature of the Nova Methodus is that it does not at all discuss the
typical psychological motivations for action, such as happiness and pleasure, frequently
found in Leibniz’s moral theorizing. The only motives discussed here are those connected
with divine reward and punishment. Nor is the science of jurisprudence premised upon
the requirements of metaphysical perfection, i.e., the maximization of reality. This is
significant, since it is often assumed that Leibniz’s practical philosophy consists merely
163 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.”
164 A.6.1.298.§10: “Et ut breviter dicam, est haec Methodus non ex juris sed Facti visceribus sumpta.”
165 A.6.1.300.§14: “Demus igitur operam, ut solidam methodum ex ipsis rerum definitionibus eruamus.”
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