Thematic role is the semantic relationship between a predicate (e.g. a verb) and an argument (e.g. the noun phrases) of a sentence. Thematic roles include:

• Agent: deliberately performs the action

eg. Bill ate his soup quietly.

• Experiencer: receives sensory or emotional input

eg. The smell of lillies filled Jennifer's nostrils.

• Theme/Patient: undergoes the action

eg. The falling rocks crushed the car.

• Instrument: used to carry out the action

eg. Jamie cut the ribbon with a pair of scissors.

• Cause: mindlessly performs the action

eg. An avalanche destroyed the ancient temple.

• Location: where the action occurs

eg. Johnny and Linda played carelessly in the park.

• Goal: what the action is directed towards

eg. The caravan continued on toward the distant oasis.

• Source: where the action originated

eg. The rocket was launched from Central Command.

Thematic roles are the same in sentences that are paraphrases. Thematic roles may remain the same in sentences that are not paraphrases.

Thematic roles have sometimes been associated with a theory known as Case theory, as in many languages thematic roles are reflected in the case which the noun assumes. However, nowadays most linguists deny the grammatical visibility (i.e. the morpho-syntactic marking) of thematic roles, as most languages do not mark thematic roles homomorphically: For example, in German Nominative can realize Agent, Experiencer, or THEME. In contrast, other languages (like Thai) have no such markings at all and others (like English) employ word regularities to express the thematic constellations of a sentence.

Theta-criterion: A particular thematic role may only occur once in a sentence. This is a proposed universal principle. (See also Universal grammar.)

See also: theta role