have their origin within the
mind; with the other, that they are not the earliest knowledge, but are
conditioned by sensations. This synthesis, however, was possible only
because Leibnitz looked on sensation differently from both the others. If
sensation is to be the mother of thought, and the latter at the same time
to preserve its character as original, _i.e._, as something not obtained
from without, sensation must, first, include an unconscious thinking in
itself, and, secondly, must itself receive a title to originality and
spontaneity. As the Catholic dogma added the immaculate conception of the
mother to that of the Son, so Leibnitz transfers the (virginal) origin of
rational concepts, independent of external influence, to sensations. The
monad has no windows. It bears germinally in itself all that it is to
experience, and nothing is impressed on it from without. The intellect
should not be compared to a blank tablet, but to a block of marble in whose
veins the outlines of the statue are prefigured. Ideas can only arise from
ideas, never from external impressions or movements of corporeal parts.
Thus _all_ ideas are innate in the sense that they grow from inner germs;
we possess them from the beginning, not developed (_explicite_), but
potentially, that is, we have the capacity to produce them. The old
Scholastic principle that "there is nothing in the understanding which was
not previously in sense" is entirely correct, only one must add, except the
understanding itself, that is, the faculty of developing our knowledge
out of ourselves. Thought lies already dormant in perception. With the
mechanical position (sensuous representation precedes and conditions
rational thought) is joined the teleological position (sensuous
representations exist, in order to render the origin of thoughts possible),
and with this purposive determination, sensation attains a higher dignity:
it is more than has been seen in it before, for it includes in itself the
future concept of the understanding in an unconscious form, nay, it is
itself an imperfect thought, a thought in process of becoming. Sensation
and thought are not different in kind, and if the former is called a
passive state, still passivity is nothing other than diminished activity.
Both are spontaneous; thought is merely spontaneous in a higher degree.

[Footnote 1: A careful comparison of Locke's theory of knowledge with
that of Leibnitz is given by G. Hartenstein, _Abhandlu