Stony Brook University

our passions and our present concerns as much as [moral doctrine] does,
we would dispute it and transgress it almost as much. (NE 1.2.12.95) 72
Leibniz does not think that the lack of universal use, effectiveness, or agreement on moral
principles is any proof that they are not innate nor universally valid. Interestingly, he says
that nature, not God, as engraved the characters. Likely he is alluding to the natural law
of the Gospel; and whatever it prescribes, it is likely similar to the universal love that is
characteristic of the virtue of justice. Yet we are not given a demonstration of this.
Section 4: Moral doctrine, pure reason, and the science of right
At the beginning of the chapter on innate practical principles, Leibniz agrees with
Locke that moral doctrine is a demonstrable science. What was not established in the
dialogue was any sense of method. However, at the end of the chapter on innate practical
principles, Leibniz provides some methodological pointers about demonstration in
general.
We agree about this; for, far from approving acceptance of doubtful
principles, I want to see an attempt to demonstrate even Euclid’s axioms,
as some of the ancients tried to do. If it be asked how one can know and
investigate innate principles, I reply in conformity with what I have said
above: apart from the instincts the reason for which is unknown, we must
try to reduce them to first principles (i.e. to identical or immediate axioms)
by means of definitions, which are nothing but a distinct setting out of
ideas. (NE 1.2.24-7) 73
Leibniz’s requirements for demonstration are so strict that he even requires, and carries
out elsewhere, demonstrations of Euclid’s axioms. Some of this “distinct setting out of
ideas” we have seen in his analysis of definitions of right, just, and justice. Along these
lines there are several additional positions to examine in the Nouveaux Essais. These
positions do not involve any sensual instincts, but rely solely on the analysis of ideas, and
suggest ways that moral doctrine might still be considered demonstrative. Although no
demonstrations are carried out, these ideas show that some principle of right,
jurisprudence, or even “pure reason” lies at the foundation of morals. Once again we
begin with Locke.
72 NE 1.2.12: “Cette violation supposée, il s’ensuit seulement qu’on n’a pas bien lû ces characteres de la
nature gravés dans nos ames, mais quelques fois assez enveloppés par nos desordres. Outre que pour voir la
necessité des devoirs d’une maniere invincible, il en faut envisager la demonstration, ce qui n’est pas fort
ordinaire. Si la Geometrie s’opposoit autant à nos passions et à nos interests présens que la morale, nous ne
la contesterions et ne la violerions gueres moins...”
73 NE 1.2.24-7: “Nous sommes d’accord sur ce point, car bien loin que j’approuve qu’on se fasse des
principes douteux, je voudrois moi qu’on cherchât jusqu’à la démonstration des Axiomes d’Euclide . . . Et
lors qu’on demande le moyen de connoitre et d’examiner les principes innés, je réponds, suivant ce que j’ay
dit ci dessus, qu’excepté les instincts dont la raison est inconnue, il faut tâcher de les reduire aux premiers
principes, c’est à dire, aux Axiomes identiques ou immediats par le moyen des definitions, qui ne sont autre
chose qu’une exposition distincte des idées.”
193