It becomes clear from the preceding investigations about structural definite descriptions that each object name which appears in a scientific statement can in principle (if enough information is available) be replaced by a structural definite description of the object, together with an indication of the object domain to which the description refers. This holds, not only for the names of individual objects, but also for general names, that is, for names of concepts, classes, relations (as we have seen in the example of $ 14, for the relation of road connections and so forth). Thus, each scientific statement can in principle be transformed into a statement which contains only structural properties and the indication of one or more object domains. Now, the fundamental thesis of construction theory (cf. $ 4), which we will attempt to demonstrate in the following investigation, asserts that fundamentally there is only one object domain and that each scientific statement is about the objects in this domain. Thus, it becomes unnecessary to indicate for each statement the object domain, and the result is that each scientific statement can in principle be so transformed that it is nothing but a structure statement. But this transformation is not only possible, it is imperative.
Carnap - Der Logische Aufbau der Welt - 16. All Scientific Statements are Structure Statements
, pp. 28-29.