(E. guishing it from the mathematical one: that since the latter really has to do only with the combination of parts into a whole, or with the disso lution of a whole into its parts, the conditions of this series always have to be seen as parts of it, hence as being of the same lpnd, and conse quently as appearances, whereas in the former regress, which has to do not with the possibility of an unconditioned whole or an unconditioned part of a given whole but with the derivation of a state from its cause or of the contingent existence of a substance itself from the necessary ex istence of one, the condition need not necessarily constitute one em pirical series along with the conditioned.