Stony Brook University

which something is suitable to it. And even men ought to pay more
attention to these instincts: they occur in humans as well, though our
artificial way of life has almost wiped out most of them. . . . And although
we do not understand the causes of these inclinations or endeavours as
well as might be wished, still we have a notion of them which is sufficient
for intelligible discourse about them. (NE 3.11.8.351) 26
An instinct is defined as an inclination or endeavor for something suitable to an animal or
person. Leibniz will use these terms often. We can also further understand what is
indemonstrable about the principle of joy and sorrow. Instincts are primitive features of
us. We have them, we are born with them, and in this sense instincts are innate. They
incline us to things for no discernible reason other than their own power. Of course, we
can certainly conceive that we are drawn to things for the pleasure they give and we are
repelled by other things for the pain they give; but we do not need an explanation in order
to be drawn or repelled. Perhaps Leibniz also means that we have no conception,
certainly no complete conception, of the causal processes involved that draw and repel
us. In any case, instincts are simply natural innate sensual inclinations, and they are clear
to us in the immediacy of experience.
We should also clarify in what sense joy and sorrow are principles. Leibniz is
implying that they are moral principles. But in what sense are they moral? There are
several possibilities: (1) they are descriptive principles of motivation. They describe the
kinds of things we tend to be drawn to and repelled from. (2) They are prescriptive
principles of moral justification. They determine the sorts of actions that we ought to
perform. As we will see, Leibniz maintains that (1) is true rather than (2). But there is a
third possibility that best describes his position: (3) joy and sorrow are initial indications
of the normative good and provide primary motives for following and apprehending the
normative good. But they are not sufficient for knowing or fulfilling the normative good.
Let us see how this works out. In any case, the principle is not known by the light of
reason (i.e., in a “luminous way”) but by an instinct that we sense. And from this
principle, he says, “scientific conclusions” may be drawn. This implies that on the basis
of the principle of joy and sorrow moral doctrine is a demonstrative science.
We must now ask in what sense is the principle of pleasure and pain (joy and
sorrow) demonstrable? I will deal with this issue in detail in section 4. But here a few
points should be mentioned. First, what type of demonstration would result? As we saw
in my Chapter Four, demonstrations may involve truths of reason or truths of fact. Since
the principle in question here is not known by reason, but rather by “inner experience,”
and since it is after all a feeling, this implies that it is a truth of fact, and not a truth of
reason. Therefore, the demonstration would not be a demonstration of a necessary truth,
but rather of a contingent truth. Secondly, what is to be demonstrated? That we do follow
the principle? That we should follow it? That from it one can derive additional moral
rules and truths? The answer seems to be suggested by a brief remark that immediately
26 A.6.6.351: “Il semble que tout le monde entend par l’instinct, une inclination d’un animal à ce qui lui est
convenable, sans qu’il en conçoive pour cela la raison. Et les hommes mêmes devroient moins negliger ces
instincts, qui se decouvrent encour en eux, quoique leur maniere de vivre artificielle les ait presque effacés
dans la plupart. . . . Et quoiqu’on n’ait point l’intelligence de la cause de ces inclinations, ou tendances qui
seroit à souhaiter; on en a pourtant une notion suffisante, pour en discourir intelligiblement.”
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