 One final note on indirect interpretation is in order. Both Carnap (1961) and Lewis (1970) interpret theoretical terms indirectly simply because any definition is an instance of an indirect interpretation. For this reason, Sneed’s problem of theoretical terms  (Section 3.2)  does not arise. Yet, the pattern of Carnap’s and Lewis’s proposals conforms to the pattern of a definition in the narrow sense and not to the peculiar pattern of indirect interpretation that Carnap (1939) envisioned for the interpretation of theoretical terms. This is why the indirect interpretation semantics has been separated from the present discussion of defining theoretical terms.