326 MARY WHITON CALKINS : as two separate existences . . . only when we leave the causal relation out of sight ". Important as it is, this argument never receives detailed consideration, doubtless because it substantially repeats Kant's causal theory, which was common property of metaphysicians when Hegel wrote the Logic. Hegel therefore devotes his main effort to the demonstration of the seeming paradox : self-identity implies the existence of others. The argument from causal connexion is barely suggested in book i., in the treatment of infinity as an indefinite series of temporally connected finites, 1 and in book iii., under the section on "Mechanism". It is distinctly, but very briefly, considered in book ii., in the discussion of Cause and Effect. These categories and their parallels Condition and Conditioned, and Possibility and Actuality (in one use of these last two terms) 2 are categories of connexion. Like Identity, Difference and the others they do not characterise either Essence Unknowable Reality or Appearance regarded as illusory manifestation of Essence, but are applicable, rather, to things in their relation to each other. No single, exclusive entity or reality this is Hegel's teaching can be in itself ultimate or absolute reality, because it is in necessary connexion with other realities, and thus is dependent upon them instead of being self- sufficient. The force of this argument is weakened, in Hegel's statement of it, in several ways. In the first place, he sometimes seems to use the ex- pression ' cause and effect ' as mere synonym for ' substance and accident,' that is, for ' essence and appearance '. 3 In the second place, Hegel, like Kant, does not realise the partial identity of the conceptions of time and causality. 4 Finally, because of this incomplete analysis, he confuses mutual causality with reciprocity (in the narrower sense). Both Kant and Hegel, it is true, make use of the term ' reciprocity,' but mean by it merely a reciprocal causality in which, as Hegel says, "there is only one and the same thing, viz., one cause and another and their connexion with one another". 5 Kant illustrates this mutual relation from the influence of heavenly bodies on each other; 6 Hegel exemplifies it by the reciprocal relation of the " character and manners of a nation " and its "nature and laws," 7 observing that either side may be regarded either as cause or as effect, that is, that the manners affect the laws but are also affected by them. This reciprocal influence is, however, a mere involved and doubled form of causality. Neither Kant nor Hegel dis- cusses the necessary but non-temporal form of dependence Schopen- hauer's Grund des Seins which is best named reciprocity. The relation, for example, of mathematical quantities to each other is reciprocity, in this more definite sense. Like causality (the temporal form of necessary 1 Werke, iii., S. 146 seq. ; EncycL, 92 seq. 2 EncycL, 146, note; Werke, iv., 221 1 . Hegel sometimes, however, uses ' possibility ' and ' actuality' as mere equivalents for ' essence ' and ' appearance ' (cf. EncycL, 145, note ; Werke, iv., 202 4 ). In other con- texts, the opposition seems to be that of the purely imaginary to the real (cf. EncycL, 143, note). 3 Cf. EncycL, 152 ; Werke, iv., 216 2 . 4 Cf. an article, by the writer, on " Time as Related to Causality and to Space," in MIND, N.S., April, 1899. 5 EncycL, 154 2 . 6 Critique of Pure Reason, Third Analogy. 7 EncycL, 156, note.
