The metaphysical exposition, it would therefore seem, is so entitled because it professes to prove that space is _a priori_, not empirical, and to do so by analysis of its concept.[452] Now by Kant’s own definition of the term transcendental, as the theory of the _a priori_, this exposition might equally well have been named the transcendental exposition. In any case it is an essential and chief part of the _Transcendental Aesthetic_. Such division of the _Transcendental Aesthetic_ into a metaphysical and a transcendental part involves a twofold use, wider and narrower, of one and the same term. Only as descriptive of the whole _Aesthetic_ is transcendental employed in the sense defined. Exposition (_Erörterung_, Lat. _expositio_) is Kant’s substitute for the more ordinary term definition. Definition is the term which we should naturally have expected; but as Kant holds that no =given= concept, whether _a priori_ or empirical, can be defined in the strict sense,[453] the substitutes the term exposition, using it to signify such definition of the nature of space as is possible to us. To complete the parallelism Kant speaks of the transcendental enquiry as also an exposition. It is, however, in no sense a definition. Kant’s terms here, as so often elsewhere, are employed in a more or less arbitrary and extremely inexact manner. The distinction between the two expositions is taken by Kant as follows. The metaphysical exposition determines the nature of the concept of space, and shows it to be a given _a priori_ intuition. The transcendental exposition shows how space, when viewed in this manner, renders comprehensible the possibility of synthetic _a priori_ knowledge. The omission of the third argument on space from the second edition, and its incorporation into the new transcendental exposition, is certainly an improvement. In its location in the first edition, it breaks in upon the continuity of Kant’s argument without in any way contributing to the further definition of the concept of space. Also, in emphasising that mathematical knowledge depends upon the _construction_ of concepts,[454] Kant presupposes that space is intuitional; and that has not yet been established.