swer it for
ourselves by seeing that a group of three straight lines or
directions, no two of which are parallel, must, as such, enclose a
space, this insight presupposing the apprehension of an actual group
of three straight lines. It may be said, therefore, that we can only
determine the possibility of the object of a complex conception in
the proper sense, through an act in which we apprehend its necessity
and its actuality at once. It is only where conceptions are
'fictitious', and so not properly conceptions, that appeal to
experience is necessary. The question 'Is an object corresponding to
the conception of a man with six toes possible?' presupposes the
reality of man and asks whether any man can have six toes. If we
understood the nature of man and could thereby apprehend either that
the possession of six toes was, or that it was not, involved in one of
the possible differentiations of man, we could decide the question of
possibility _a priori_, i. e. through our conceiving alone without an
appeal to experience; but we could do so only because we apprehended
either that a certain kind of man with six toes was necessary and
actual, or that such a man was impossible and not actual. If, however,
as is the case, we do not understand the nature of man, we can only
decide the question of possibility by an appeal to experience, i. e.
to the experience of a corresponding object, or of an object from
which the existence of such an object could be inferred. Here,
therefore--assuming the required experience to be forthcoming--we
can appeal to Kant's formula and say that we know that such a man,
i. e. an object corresponding to the conception, is actual, as
being connected with the material conditions of experience. But the
perception which constitutes the material conditions of experience
in the case in question is only of use because it carries us beyond
possibility to actuality, and appeal to it is only necessary because
the object is not really conceived or, in other words, because the
so-called conception is not really a conception.

[12] For instance, it might at least be _argued_ that we know
space to be actual without knowing it to be necessary.

[13] _Not_ 'together with the apprehension _that_ the
elements are connected'. Cf. p. 311.

Kant really treats his 'objectively real' conceptions as if they were
'fictitious', even though he speaks of them as complete. Consequently,
his conceptions not b