Neurath’s Protocol Sentences and Schlick’s “Konstatierungen” Versus Quine’s Observation Sentences

The relation between theory and reality is an important problem for phüosophy of science. Positivists or logical empkicists of the Vienna Circle have tried to solve it by postulating several types of so-called basic statements induced by immediate experience or observation. According to Neurath protocol sentences are distinguished from other synthetic sentences only m virtue of their syntactical form. Since consistency is a relation concerning sentences only, not a sentence and any immediate experience,he contends that there remains an unbridgeable gap between observationstatements and observation itself and consequently he adopts a coherentist strategy of corroboration, which Schlick, as a thorough empiricist, wants to avoid. For that purpose he introduces the notion of "Konstatierung". Such ascertainments play a decisive role as endpoints in the corroboration of theories insofar as they serve to verify predictions which express expected ascertainments. In spite of the fact that they are synthetic wc recognize their truth when grasping their meaning and, therefore, error is precluded in their case, while protocol sentences remain mere hypotheses. Quine attempts to overcome the weaknesses of all prior positions by proposing a purely behavioristic definition of 'observation sentence' which avoids the pitfalls of former sense-data theories as well as the ones of cultural relativism or irrationalism. Considering science to be a bridge linking together our sensory stimuli he comes to the view that empirical support of a theory is a consequence of the logical relation between the theory formulation and the observation categoricals derivable from it. He considers the ideological and epistemological neutrality of his conception as one of its main merits. Its feasibility depends, however, on the question whether, by his behavioristic method, he effectively can explain how linguistic expressions acquire their meanings