The Logic of Soku in the Kyoto School

‘A is A, and yet A is not A; therefore A is A’.1 This common inference within the logic of soku is based on the dialectical form ‘A soku not-A’, variously translated as ‘A sive not-A’, ‘A qua not-A’, and ‘A and yet not-A’, and is hereafter referred to as the soku dialectic. Nishida Kitarō, Tanabe Hajime, and Nishitani Keiji, the central philosophers of the Kyoto school, grant the legitimacy of this dialectic without question, and invoke it often. For many (‘Western’) philosophers, however, the conjunction of A and not-A is a contradiction, and the pervasiveness of the soku dialectic in their writings is puzzling, if not absurd and meaningless. Western philosophers insist that ‘A and yet not-A’ is a contradiction, while the Kyoto philosophers acknowledge the fact and maintain that the combination is legitimate: reflection upon reality inevitably reveals antinomies, they argue, so that any logic adequate to such reflection must allow contradictions. Since anything follows from a contradiction,2 Western philosophers can dismiss arguments involving the soku dialectic as unintelligible or meaningless, thereby eschewing any serious confrontation with or appropriation of the Kyoto philosophies.3 Yet disciples of the Kyoto school analyze and critique each others’ work as though it is intelligible and meaningful. Such a situation prompts the suspicion that ‘A soku not-A’ is not a contradiction, despite the insistence of the Kyoto philosophers to the contrary. This essay offers an analysis of ‘A soku not-A’ that removes the appearance of contradiction from the logic of soku (soku hi) through the presentation of a formal system for this logic. Section 1 presents some puzzling features of the soku dialectic, along with attempts to explain these features, the shortcomings of such attempts, and an improved explanation. Section 2 expands the new, informal explanation from section 1 with a formalization of the logic, including a semantics, a natural deduction system, and several important theorems. Finally, section 3 considers the benefits of the system presented in section 2, and suggests how this formal system might be used to criticize or defend the logic of soku. The overarching goals of this essay are to understand better the rhetoric of the Kyoto philosophers and, in the process, defend their approach to philosophy from the usual criticism of unintelligibility.