Arguments and grammatical functions

In generative grammar, a structural distinction is made between two types of syntactic positions: argument positions and grammatical function positions (e.g. Chomsky 1981). Argument positions are those in which arguments selected by a verb (such as agent, theme, patient) are syntactically realized. Grammatical function positions are those in which grammatical functions (such as subject, object, indirect object) are syntactically realized. Assuming a bottom- up derivational model, noun phrases are first realized in an argument position, and then moved up to a grammatical function position.

On this approach, different argument roles are distinguished configurationally, in that the structural relation between a verb and an element expressing a patient or theme role is different from the structural relation between a verb and an element expressing an agent role. Typically, the patient/theme element would be a sister of the verb, and the agent would not.