Stony Brook University

The passage is potentially confusing, but it can be best understood this way: There are
basically two kinds of innate truths and two ways to know them. The most general kind is
instinctive truths. This category includes speculative principles and practical principles.
These principles are known by illumination or by instinct. Speculative principles are
known by illumination. This means to use the “light of reason” to analyze an idea or
demonstrate a proposition. Practical principles are known by instinct, or more
specifically, as he has said, by the instinct of sense or feeling (p. 89). However, the
interesting point here is that practical principles are known by both instinct and
illumination. Thus we know, by pleasure and by reason, how to “act humanely.” To know
by pleasure presumably means this: When we act humanely, that is, for the good of
another, we experience a feeling of pleasure. This of course indicates that the act is good
for us, and then we are further inclined to perform such acts. But we can also discover by
reason or by proof that the act itself is humane. That is, reason can explain what it means
to act justly. It can tell us what our duties are, and so forth. Reason can also explain that
the instinct to act justly is a just instinct. But when we are lacking in knowledge by
illumination of what is just, the instinct of pleasure inclines us in the just direction. Thus
by instinct and illumination we may know what is morally required, i.e., what is just. As
we will soon see, there is more to say in this context about how to determine by reason
‘what is just’.
The division Leibniz makes between types of innate truth, illumination and
instinct, is also expressed further down.
Every feeling is the perception of a truth, and that natural feeling [le
sentiment naturel] is the perception of an innate truth, though very often a
confused one, as are the experiences of the outer senses. Thus innate
truths can be distinguished from the natural light (which contains only
what is distinctly knowable) as a genus should be distinguished from its
species, since innate truths comprise instincts as well as the natural light.
(NE 1.2.9.94) 47
In other words, there are two species of truth under the genus innate truth: (1) truths
which are known confusedly, e.g., “the natural feeling” 48 and (2) truths which may be
known distinctly, i.e., known by the natural light of reason. The natural feeling is
“confused,” in the sense that while we have conscious awareness of the feeling, we do
conclusions de la lumiere naturelle, qui sont des principes par rapport à l’instinct. C’est ainsi que nous
sommes portés aux actes d’humanité, par instinct parce que cela nous plaist, et par raison parce que cela est
juste. Il y a donc en nous des verités d’instinct qui sont des principes innés, qu’on sent et qu’on approuve,
quand même on n’en a point la preuve, qu’on obtient pourtant lors qu’on rend raison de cet instinct.”
47 A.6.6.94: “Tout sentiment est la perception d’une verité, et que le sentiment naturel l’est d’une verité
innée, mais bien souvent confuse, comme sont les experiences des sens externes: ainsi on peut distinguer
les verités innées d’avec la lumiere naturelle (qui ne contient que de distinctement connoissables) comme le
genre doit estre distingué de son espece, puisque les verités innées comprennent tant les instincts que las
lumiere naturelle.”
48 By ‘natural feeling’ (le sentiment naturel) Leibniz is referring to a group of instincts mentioned prior to
this passage (which I will discuss below) i.e., a “sense of justice”, a “feeling for humanity,”, “a general
social instinct” or “philanthropy.”
184