Abstract
Based on archival material from the Carnap and FeiglArchives, this paper re-examines Carnap's approach tothe issue of scientific realism in the 1950s and theearly 1960s. It focuses on Carnap's re-invention ofthe Ramsey-sentence approach to scientific theoriesand argues that Carnap wanted to entertain a genuineneutral stance in the realism-instrumentalism debate.Following Grover Maxwell, it claims that Carnap'sposition may be best understood as a version of`structural realism'. However, thus understood,Carnap's position faces the challenge that Newmanraised against Russell's structuralism: the claim thatthe knowledge of the unobservable is limited to itspurely structural characteristics is eitheruninformative or unsustainable.