 The pure faculty of understanding, however, is not sufficient for prescribing to appearances a priori, through mere categories, any laws other than those which are involved in a nature in general, as the law-governedness of all appearances in space and time. Particular laws, because they concern empirically determined appearances, can not be completely derived therefrom, although they one and all stand under them. Experience must be added in order to become acquainted with the [particular laws] as such, but only the former laws provide a priori instruction concerning experience in general, and [concerning] that which can be cognized as an object of experience.