Abstract
The rejection of metaphysical questions is a constant in Carnap’s thought. The first part of the paper delves into the question of the basic tenets of Carnap’s anti-metaphysics. Tying up to the accounts of authors like Michael Friedman and Werner Sauer, the author examines the relation between verificationism and so-called logical criteria, arguing not only that verificationism is secondary, but that the integration of both instruments in Carnap’s early philosophy faces difficulties. The second part focuses on the application of these instruments to the realism/idealism dispute. The author tries to show that Carnap’s position in the Aufbau is neither neutral in regard to traditional aspects of this dispute nor stable in itself, but involves concessions to both realism and idealism. In historical perspective, it is shown that almost all of the issues of the famous protocol-sentence debate are already present in unfolding young Carnap’s treatment of the problem of realism.