What is a theta role? Is it the same as a thematic role?
And what does it mean for a theta role to be undischarged/unsaturated? I came across these terms in a syntax paper. It seems like both undischarged/unsaturated were referring to the same effect. It might help to know what it means for a theta role to discharge/become saturated, and how it happens to discharge/become saturated.
There is a syntactic notion and a very closely related semantic notion of "thematic role" that are more or less meant to map onto one another. Essentially, a theta role is the label for how the referent of an NP acts in the event the sentence describes. So, in "John ate an apple", John is the eater, and the apple is the eatee. In linguistic theory we think we've come up with "general" theta roles that are what the syntax care about -- the eater in "John ate an apple", the kicker in "John kicked the ball" etc are "agents", the eaten thing and the kicked thing are the "patients". Mark Baker has proposed -- and it has been pretty standardly assumed to be true in Chomskyan syntax -- that these theta roles are tied to particular positions in the syntax (which is why "John loves Mary" and "Mary loves John" mean different things!). Theta theory says that each verb comes predetermined with a certain number of theta roles, and each theta role must be assigned to one and only one NP. That's why "John loves" doesn't mean the same thing as "John loves himself", and why "*John arrived Mary" isn't acceptable ("arrived" doesn't have an object theta role).Tweet