Stony Brook University

denominated either impossible or necessary (or unjust and owed). 176
Moral freedom corresponds with what is morally contingent or possible to do, while duty
corresponds to the restrictions on freedom. These formulations correspond to the juridical
modes as shown in the square of opposition, and once again emphasize that right and
obligation (formulated here as freedom and duty) form the a priori basis of Leibniz’s
practical philosophy.
Following these remarks, Leibniz derives a long and complex list of “theoremata”
and “corollaria” that derive from the demonstration. 177 These derivations are mainly a
logical exercise intended to show how the concepts of necessity, possibility, and the
definition of the good person are logically inferable and may be read off the square of
opposition. I briefly mention some examples. The first set of theorems includes: “Nothing
just is unjust, since nothing possible is impossible, that is, for a good person.” And then,
“Nothing omissible is owed” since nothing contingent is necessary, and so forth. “This is
a species of Logic part simple, part modal, applied to Jurisprudence” (469). Recognizing
that these theorems may be obvious, Leibniz nevertheless insists that all axioms can and
must be demonstrated. 178 Seeing how the theorems are logically related is part of
Leibniz’s effort to make their demonstrability as transparent as possible. The second set
of theorems, eight of them, show the logic of possibility in the mode of right.
Everything just is possible. Because, by definition ‘just’ is what is possible
for a good person. Therefore, everything just is possible “for someone.”
Someone possible is simply: possible, since possible is what is posited in
some case. Therefore, everything impossible is unjust, through
contraposition of the first theorem. 179
A third set of theorems shows that Leibniz “conceives of natural law from the
primacy of the possible or Permitted, rather than from the Forbidden:” 180 An act is
generally just rather than unjust. That is, an act will first be assumed to be just.” 181
And, “an action is more easily not owed than owed.” Leibniz appears to be
working toward a probability calculus based on the fact that according to
classification, just acts are more likely to occur than unjust acts. That is because
just acts include the necessary, the possible, and the omissible, while unjust acts
include only the impossible. He offers a probability calculus based on the
176 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.”
177 A.6.1.467: “Definitiones, qvas qvidem ipsa Juris definitio a nobis exegit, perpetua Analysi seqvuntur
Theoremata, seu Terminorum combinationes.”
178 This requirement is reasserted in the Nouveaux Essais (1.2) in response to Locke and in his criticism of
Descartes’ proof for God’s existence.
179 A.6.1.470: “Omne justum possibile est. Qvia justum est possibile viro bono, per def. Ergo alicui. Alicui
possibile est simpliciter: possibile, qvia possibile est, qvod aliqvo casu posito est. Ergo, omne justum
possibile est. Ergo qvicqvid est impossibile, id injustum est, conversione per contrapositionem theorematis
praecedentis.”
180 Busche, fn. 184 p. 476. Busche claims this relates to St. Paul’s thought in Romans 2 and 7 that through
Christ we are released from the obsolete letter of the law, but given to the spirit of the law; that is, “true
circumcision is of the heart” (2:29). But I see no reason to think that is what Leibniz is trying to show here.
181 A.6.1.471: “Actus facilius est justus qvam injustus. Actus praesumitur justus.”
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