Abstract

Consider your right hand and a mirror image duplicate of it. Kant calls such pairs incongruent counterparts. According to him they have the following puzzling features. The relation and situation of the parts of your hand with respect to one another are not sufficient to distinguish it from its mirror duplicate. Nevertheless, there is a spatial difference between the two. Turn and twist them how you will, you cannot make one of them occupy the exact boundaries now occupied by the other. In his 1768 paper, ‘Concerning the Ultimate Foundations of the Differentiation of Regions in Space’, Kant uses these claims to argue against relational accounts of space and goes on to argue that the difference between incongruent counterparts depends on a relation to absolute space as a whole. In his 1770 Inaugural Dissertation he argued that this difference could not be captured by concepts alone but required appeal to intuition. In the Prolegomena (1783) and again in the Metaphysical Foundations of Natural Science (1786) Kant appealed to these puzzling features of incongruent counterparts to support his transcendental idealism about space.