ETRs and Semantic Roles

How far can assignment by default go? When do we need to specify a semantic role in a diathesis, either by diathesis or by prototype rule, and when do we have to make the assignment by direct reference to the schema? Or, in our analyses, can we discard semantic roles and their attribution in diatheses entirely, and reduce them all to the bare syntactic structure? The answer is negative: we cannot do without semantic roles in all cases. But, on the other hand, the delimitation of the situations where semantic role specification is needed is something that will have to be established by detailed research of individual cases. Here the first part of the problem is considered, and it is shown that the postulation of a semantic role is needed for some constituents in the structures of the language. There is a lot of evidence for this, as is shown in this chapter and the subsequent chapters.