Stony Brook University

Section 2: Early formulations
To properly understand the relationship between early and late uses of ‘moral
necessity,’ we must first review Leibniz’s earliest formulations of it. We have just above
recalled the relevant passages in Nova Methodus and Elementa, where right and
obligation are the moral qualities of the good person (vir bonus). These passages
represent the “deontic” context to which Murray refers. However, Murray seems not to
have taken into account that the moral qualities of right and obligation correspond quite
precisely with the notions of freedom and necessity. Right is a moral power, which in the
Elementa becomes moral possibility. Moral possibility means the freedom to act within
moral constraints. Thus right is a moral power because it analytically entails duties (or
obligations). This is well-expressed in the following passage.
Freedom is the moral power or answerability in a good person congruent
with natural power. Duty is the reduction of the natural power to the moral
power. 9
Therefore, the moral qualities of right and obligation quite readily transfer to the
idea of freedom, and furthermore, the idea of freedom contains the
“answerability” of a good person, that is, the moral capacity of a person to restrict
her natural power. Such restriction is called duty, obligation, and moral necessity.
Freedom is also connected with the concepts of contingency and necessity, and
duty is connected with necessity.
Therefore freedom is the mode by which acts are denominated either
possible or contingent (or just and indifferent) for a good person. Duty is
denominated either impossible or necessary (or unjust and owed). 10
This necessity is nothing other than moral necessity. These formulations are indeed
connected with jurisprudence, or the science of right, as the following concluding
passage to the Elementa will show. But this does not mean that they are to be understood
only within that context (as both Murray and Adams claim). Jurisprudence, or the science
of right, is absolutely fundamental, since it is the science that defines the sorts of actions
that are morally possible and morally impossible, that is, that are morally necessary.
Jurisprudence is the science of the just, or the science of freedom and
duties, or the science of right, in relation to some case or fact. A science I
call practical, since all of its propositions can be demonstrated from the
definition of a good person, and do not depend on induction and examples.
And yet [the propositions] may be confirmed by the harmony of various
laws, by the written and unwritten consensus of the prudent, as well as
eminently enlightened by the popular voice of the public, and before men
9
A.6.1.467: “Libertas est potentiae moralis seu cadentis in virum bonum congruitas cum naturali. Officium
est defectus potentiae moralis à naturali.”
10
A.6.1.467: “Ergo libertas est modus à qvo actus denominatur possibilis aut contingens viro bono, seu
justus et indifferens. Officium, à qvo denominatur impossibilis aut necessarius seu injustus debitusqve.”
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