This post functions as an introduction to a discussion of the Thematic Hierarchy of Semantic Roles.
What the…? What does that mean?
Well, the thematic hierarchy deals with verbs and the kinds of noun phrases that occur in their clauses.. But before I can go on, I need to give some background for those who know little about linguistics. That is what this post is about. So here are some terms I’ll be using in my next post on this topic and how I’ll be using them:
Argument – Necessary Phrases in a clause. A clause would be incomplete ad ungrammatical without these. The dog bit the man has two arguments, the dog and the man. Without these the clause is not grammatical as in: *bit the man.
Adjunct – Extra phrases that are not required by a clause in order to be grammatical. They are typically adverbial in nature. In the clause The dog bit the man with its teeth, the phrase with its teeth an adjunct because the sentence is grammatical without the phrase present.
Core Argument – A core argument is an argument with the grammatical relation subject, object, or object 2 (i.e. indirect object). Core arguments can be described in both semantic and syntactic terms. They are also potential targets of syntactic rules
Oblique Argument – These tend have more semantic significance in a clause rather than syntactic. Oblique arguments tend to be more flexible syntactically. For example, in the clause The hat was given to me by the man, the phrases by the man can be moved between the verb and the phrase to me without making the clause ungrammatical. The phrase the hat must always stay in the same spot.
Semantic Role – This is related to the meaning expressed by the arguments and adjuncts of a clause. Semantic roles are often quite similar to the traditional categories of Greek grammar such as Dative of Recipient. Semantic Roles describe the function of the arguments and adjuncts.
The semantic roles themselves are for the most part self-explanatory:
Agent, Patient, Theme, Recipient, Beneficiary, Experiencer, Stimulus, Goal, Location
Agents cause action. Patients and themes are acted upon, recipients and beneficiaries receive or benefit from the action, experiencers experience a stimulus, stimuli cause experiences, etc. There are more semantic roles than those listed here, but the ones above are probably the ones the most commonly referred to.
Grammatical Relations – These are subject, object, oblique the labels we give to Noun Phrases (and sometimes Prepositional Phrases) depending on their usage in a clause. Thus, in The dog ate the cat, the phrase the dog is the NPsubj and the phrase the cat is the NPobj. Grammatical Relations are different than Semantic roles in that the Agent does not need to be the subject in a clause. For example, in the clause The cat was eaten by the dog, the phrase the cat has now taken the grammatical relation of subject, but still retains the semantic role of patient (i.e. that which receives the action). Likewise, the phrase by the dog is now an oblique prepositional phrase, but continued to be the agent of the action.