600 GOTTFRIEDLEIBNIZ
the minds of our philosophers from mere material considerations to more noble medita-
tions. It is now time to return from bodies to immaterial natures, to minds in particular,
and to say something of the ways God uses to illumine them and act on them, for we
must not doubt that here too there are laws of nature, a point I could discuss more fully
elsewhere. For now, it is enough to touch a little on ideas, on whether we see all things
in God, and on how God is our light.
Now, it is relevant to note that several errors are occasioned by the misuse of
ideas. For when we reason on something we imagine we have an idea of it, and on that
foundation some recent authors have built a demonstration of God that is, rigorously
speaking, very imperfect. For, they say, I must have an idea of God or of a perfect being,
since I am thinking of Him, and it is impossible to think without an idea. Now the idea
of this Being includes all the perfections and existence is one of these, so that conse-
quently He exists. But as we often think of impossible chimerae, such as the ultimate
degree of speed or the greatest number or the meeting of the conchoid [a plane curve in
geometry] with its base or rule, this reasoning is not enough. Hence in this sense a per-
son can say he has true or false ideas according as the thing in question is possible or
not, and it is only when we are assured of its possibility that we can boast of having an
idea of the thing. Thus the above argument proves at least that God necessarily exists if
He is possible. This is indeed an excellent privilege of the divine nature: to need only its
possibility or essence to exist in fact, just what is called an Ens a se.
- JUST WHATISCLEAR OROBSCURE, DISTINCT ORCONFUSED,
ADEQUATE ANDINTUITIVE ORSUPPOSITIVEKNOWLEDGE,
AND WHATARENOMINAL, REAL, CAUSAL
ANDESSENTIALDEFINITIONS
The better to understand the nature of ideas, we have to touch a little on the varieties of
knowledge. When I know only through experience that something is possible, because
everything that exists is possible, my knowledge is confused. It is in this way that we
know bodies and their qualities. But when I can prove a priorithat something is possi-
ble, this knowledge is distinct. When I can recognise one thing among others without
being able to say in what its differentiaeor properties consist, my knowledge is con-
fused. Thus it is that we sometimes know clearlywithout being in any doubt at all
whether a poem or picture is well or badly made, because there is an I don’t know what
that satisfies or shocks us. But only when I can explain the marks available to me is my
knowledge called distinct. Such is the knowledge of the assayer who discerns the true
and the false by particular tests or marks comprising the definition of gold.
But there are degrees of distinct knowledge, for the notions that enter the defini-
tion would ordinarily themselves need definition and are only confusedly known. But
when every thing that enters a definition or distinct item of knowledge is distinctly
known right back to the primitive notions, I call this knowledge adequate, and when my
mind understands all the primitive ingredients of a notion all at once and distinctly, then
it has an intuitive knowledge of it, something very rare since most human knowledge is
confused or even suppositive.
It is also good to distinguish nominal definitions from real ones. I refer to a nom-
inal definition when it is still possible to doubt that the notion defined is possible. Thus,
for example, when I say that an endless screw is a solid line whose parts are congruent
or can coincide with each other, whoever did not otherwise know what an endless screw