is
altogether necessary that we should be _convinced_ of the existence of God,
but not so necessary that his existence should be _demonstrated_" are more
noteworthy than the argument itself. This runs: All possibility presupposes
something actual wherein and whereby all that is conceivable is given as
a determination or a consequence. That actuality the destruction of which
would destroy all possibility is absolutely necessary. Therefore there
exists an absolutely necessary Being as the ultimate real ground of all
possibility; this Being is one, simple, unchangeable, eternal, the _ens
realissimum_ and a spirit. The _Attempt to introduce the Notion of
Negative Quantities into Philosophy_, 1763, distinguishes--contrary to
Crusius--between logical opposition, contradiction or mere negation (_a_
and _not-a_, pleasure and the absence of pleasure, power and lack of
power), and real opposition, which cannot be explained by logic (+_a_ and
-_a_, pleasure and pain, capital and debts, attraction and repulsion;
in real opposition both determinations are positive, but in opposite
directions). Parallel with this it distinguishes, also, between logical
ground and real ground. The prize essay, _Inquiry concerning the Clearness_
(Evidence) _of the Principles of Natural Theology and Ethics_, 1764, draws
a sharp distinction between mathematical and metaphysical knowledge, and
warns philosophy against the hurtful imitation of the geometrical method,
in place of which it should rather take as an example the method which
Newton introduced into natural science. Quantity constitutes the object of
mathematics, qualities, the object of philosophy; the former is easy and
simple, the latter difficult and complicated--how much more comprehensible
the conception of a trillion is than the philosophical idea of freedom,
which the philosophers thus far have been unable to make intelligible.
In mathematics the general is considered under symbols _in concrete_, in
philosophy, by means of symbols _in abstracto_; the former constructs its
object in sensuous intuition, while the object of the latter is given
to it, and that as a confused concept to be decomposed. Mathematics,
therefore, may well begin with definitions, since the conception which is
to be explained is first brought into being through the definition, while
philosophy must begin by seeking her conceptions. In the former the
definition is first in order, and in the latter almost always last; in