Carnap on empirical significance

Carnap's search for a criterion of empirical significance is usually considered a failure. I argue that the results from two out of his three different approaches are at the very least problematic, but that one approach led to success. Carnap's criterion of translatability into logical syntax is too vague to allow for definite results. His criteria for terms-introducibility by chains of reduction sentences and his criterion from The Methodological Character of Theoretical Concepts-are almost trivial and have no clear relation to the empirical significance of sentences. However, his criteria for sentences-translatability, verifiability, falsifiability, confirmability-are usable, and under the assumptions needed for the Carnap sentence approach, verifiability, falsifiability, and translatability become equivalent. As a result of the Carnap sentence approach, metaphysics is rendered analytic.