  (1) Kant had tried to establish the possibility of synthetic a priori judgements on the assumption of an object (= x) and of subject (= x) that we ex hypothesi cannot ever know but upon which the system of experience based on the said judgements none the less depends. The two (viz., the subject and object) constitute transcendental conditions of the possibility of the system of experience. Kant’s attempt, however, entails an irresoluble difficulty.  For although the assumed subject and object are factors that ex hypothesi fall outside the system of the a priori judgements to be validated (i.e., they are ‘transcendental’), they can only be defined in terms of the concepts and distinctions that have meaning exclusively inside that system. Kant thus finds himself in the embarrassing situation of negating, while at the same time affirming, the transcendality of the conditions of his system, thereby undermining the stability that the latter should derive from them (Jacobi, 1812–25: vol. 2, 85–91).