Abstract
Beginning with a research review, the present paper shows that Hans Slugaʼs and esp. Robert Brandomʼs thesis, according to which Frege has adopted the context-principle and the priority of propositional from Kant, can solve problems in current Frege scholarship, on the one hand, but is itself fraught with further problems, on the other hand. In contrast, this paper maintains that the context-principle and the priority of the propositional are implicitly present in Fregeʼs Begriffsschrift since both have not been taken over from Kant, but rather from neo-Aristotelianism: The context-principle and the priority of the propositional were first drawn up in 1834 by O. F. Gruppe. As a consequence, A. F. Trendelenburg has published a re-arranged edition of Aristotleʼs Organon in 1836 which became one of the most influential schoolbooks on logic in the 19th century and of which Frege ought to have been aware. In the beginning of this schoolbook, using the original ancient Greek sentences of Aristotle, the priority of the propositional (De int. I 1) is deduced from the context-principle (De anima III 6).