In a number of theories of linguistics

Linguistics

Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

, thematic relations is a term used to express the role that a noun phrase

Noun phrase

In grammar, a noun phrase, nominal phrase, or nominal group is a phrase based on a noun, pronoun, or other noun-like word optionally accompanied by modifiers such as adjectives....

 plays with respect to the action or state described by a sentence's verb. For example, in the sentence "Susan ate an apple", Susan is the doer of the eating, so she is an agent

Agent (grammar)

In linguistics, a grammatical agent is the cause or initiator of an event. Agent is the name of the thematic role...

; the apple is the item that is eaten, so it is a patient

Patient (grammar)

In linguistics, a grammatical patient, also called the target or undergoer, is the participant of a situation upon whom an action is carried out. A patient as differentiated from a theme must undergo a change in state. A theme is denoted by a stative verb, where a patient is denoted by a dynamic...

. While most modern linguistic theories make reference to such relations in one form or another, the general term, as well as the terms for specific relations, varies; 'participant role', 'semantic role', and 'deep case' have been used analogously to 'thematic role'.

Major thematic relations

Here is a list of the major thematic relations.

• Agent
  Agent (grammar)
  In linguistics, a grammatical agent is the cause or initiator of an event. Agent is the name of the thematic role...
  
  : deliberately performs the action (e.g., Bill ate his soup quietly.).
• Experiencer: the entity that receives sensory or emotional input (e.g. The smell of lilies filled Jennifer's nostrils. Susan heard the song. I cried.).
• Theme: undergoes the action but does not change its state (e.g., We believe in many gods. I have two children. I put the book on the table. He gave the gun to the police officer.) (Sometimes used interchangeably with patient.)
• Patient
  Patient (grammar)
  In linguistics, a grammatical patient, also called the target or undergoer, is the participant of a situation upon whom an action is carried out. A patient as differentiated from a theme must undergo a change in state. A theme is denoted by a stative verb, where a patient is denoted by a dynamic...
  
  : undergoes the action and changes its state (e.g., The falling rocks crushed the car.). (Sometimes used interchangeably with theme.)
• Instrument: used to carry out the action (e.g., Jamie cut the ribbon with a pair of scissors.).
• Force or Natural Cause: mindlessly performs the action (e.g., An avalanche destroyed the ancient temple.).
• Location: where the action occurs (e.g., Johnny and Linda played carelessly in the park.).
• Direction or Goal: where the action is directed towards (e.g., The caravan continued on toward the distant oasis. He walked to school.).
• Recipient: a special kind of goal associated with verbs expressing a change in ownership, possession. (E.g., I sent John the letter. He gave the book to her.)
• Source or Origin: where the action originated (e.g., The rocket was launched from Central Command. She walked away from him.).
• Time: the time at which the action occurs (e.g., The rocket was launched yesterday.).
• Beneficiary: the entity for whose benefit the action occurs (e.g.. I baked Reggie a cake. He built a car for me. I fight for the king.).
• Manner: the way in which an action is carried out (e.g., With great urgency, Tabitha phoned 911.).
• Purpose: the reason for which an action is performed (e.g., Tabitha phoned 911 right away in order to get some help.).
• Cause: what caused the action to occur in the first place; not for what, rather because of what (e.g., Since Clyde was hungry, he ate the cake.).

There are no clear boundaries between these relations. For example, in "the hammer broke the window", some linguists treat hammer as an agent, some others as instrument, while some others treat it as a special role different from these.

Relationship of case to thematic relations

In many languages, such as Finnish

Finnish language

Finnish is the language spoken by the majority of the population in Finland Primarily for use by restaurant menus and by ethnic Finns outside Finland. It is one of the two official languages of Finland and an official minority language in Sweden. In Sweden, both standard Finnish and Meänkieli, a...

 and Hungarian

Hungarian language

Hungarian is a Uralic language, part of the Ugric group. With some 14 million speakers, it is one of the most widely spoken non-Indo-European languages in Europe....

 and Turkish

Turkish language

Turkish is a language spoken as a native language by over 83 million people worldwide, making it the most commonly spoken of the Turkic languages. Its speakers are located predominantly in Turkey and Northern Cyprus with smaller groups in Iraq, Greece, Bulgaria, the Republic of Macedonia, Kosovo,...

, thematic relations may be reflected in the case

Grammatical case

In grammar, the case of a noun or pronoun is an inflectional form that indicates its grammatical function in a phrase, clause, or sentence. For example, a pronoun may play the role of subject , of direct object , or of possessor...

-marking on the noun. For instance, Hungarian has an instrumental case

Instrumental case

The instrumental case is a grammatical case used to indicate that a noun is the instrument or means by or with which the subject achieves or accomplishes an action...

 ending, (-val/-vel) which explicitly marks the instrument of a sentence. Languages like English often mark such thematic relations with prepositions.

Conflicting terminologies

The term "thematic relation" is frequently confused with theta role

Theta role

In generative grammar , a theta role or θ-role is the formal device for representing syntactic argument structure required syntactically by a particular verb. For example, the verb put requires three arguments...

. Many linguists (particularly generative grammarians

Generative grammar

In theoretical linguistics, generative grammar refers to a particular approach to the study of syntax. A generative grammar of a language attempts to give a set of rules that will correctly predict which combinations of words will form grammatical sentences...

) use the terms interchangeably. This is because theta roles are typically named by the most prominent thematic relation that they are associated with. To make matters more confusing, depending upon which theoretical approach one assumes, the grammatical relations

Grammatical function

In linguistics, grammatical functions refer to functional relationships between participants in a proposition...

 of subject

Subject (grammar)

The subject is one of the two main constituents of a clause, according to a tradition that can be tracked back to Aristotle and that is associated with phrase structure grammars; the other constituent is the predicate. According to another tradition, i.e...

 and object

Object (grammar)

An object in grammar is part of a sentence, and often part of the predicate. It denotes somebody or something involved in the subject's "performance" of the verb. Basically, it is what or whom the verb is acting upon...

, etc., are often closely tied to the semantic relations. For example, in the typological tradition

Morphosyntactic alignment

In linguistics, morphosyntactic alignment is the system used to distinguish between the arguments of transitive verbs and those of intransitive verbs...

 agents/actors are tied closely to the notion of subject (S). Here is a way to distinguish these ideas, when they are used distinctly:

• Thematic relations are purely semantic descriptions of the way in which the entities described by the noun phrase are functioning with respect to the meaning of the action described by the verb. A noun may bear more than one thematic relation. Almost every noun phrase bears at least one thematic relation (the exception are expletives
  Syntactic expletive
  Syntactic expletives are words that perform a syntactic role but contribute nothing to meaning. Expletive subjects are part of the grammar of many non-pro-drop languages such as English, whose clauses normally require overt provision of subject even when the subject can be pragmatically inferred...
  
  ). Thematic relations on a noun are identical in sentences that are paraphrases of one another.
• Theta role
  Theta role
  In generative grammar , a theta role or θ-role is the formal device for representing syntactic argument structure required syntactically by a particular verb. For example, the verb put requires three arguments...
  
  s are syntactic structures reflecting positions in the argument structure
  Verb argument
  In linguistics, a verb argument is a phrase that appears in a syntactic relationship with the verb in a clause. In English, for example, the two most important arguments are the subject and the direct object....
  
   of the verb they are associated with. A noun may only bear one theta role. Only arguments bear theta roles. Adjuncts
  Adjunct (grammar)
  In linguistics, an adjunct is an optional, or structurally dispensable, part of a sentence that, when removed, will not affect the remainder of the sentence except to discard from it some auxiliary information...
  
   do not bear theta roles.
• Grammatical relations
  Grammatical function
  In linguistics, grammatical functions refer to functional relationships between participants in a proposition...
  
  express the surface position (in languages like English) or case (in languages like Latin) that a noun phrase bears in the sentence.

Thematic relations concern the nature of the relationship between the meaning of the verb and the meaning of the noun. Theta roles are about the number of arguments that a verb requires (which is a purely syntactic notion). Theta roles are a syntactic relation that refers to the semantic thematic relations.

For example, take the sentence "Reggie gave the kibble to Fergus on Friday."

• Thematic relations: "Reggie" is doing the action so is the agent, but he is also the source of the kibble (note Reggie bears two thematic relations!); "the kibble" is the entity acted upon so it is the patient; Fergus is the direction/goal or recipient of the giving. Friday represents the time of the action.
• theta roles: The verb "give" requires three arguments (see valency
  Valency (linguistics)
  In linguistics, verb valency or valence refers to the number of arguments controlled by a verbal predicate. It is related, though not identical, to verb transitivity, which counts only object arguments of the verbal predicate...
  
  ). In generative grammar, this is encoded in terms of the number and type of theta roles the verb takes. The theta role is named by the most prominent thematic relation associated with it. So the three required arguments bear the theta roles (confusingly!) named the agent (Reggie) the patient (or theme) (the kibble), and goal/recipient (Fergus). "On Friday" does not receive a theta role from the verb, because it is an adjunct. Note that "Reggie" bears two thematic relations (Agent and Source), but only one theta role (the argument slot associated with these thematic relations).
• grammatical relations: The subject (S) of this sentence is "Reggie", the object (O) is "the kibble", the indirect object is "to Fergus", and "on Friday" is an oblique.

See also

• Morphosyntactic alignment
  Morphosyntactic alignment
  In linguistics, morphosyntactic alignment is the system used to distinguish between the arguments of transitive verbs and those of intransitive verbs...
  
  
• Case grammar
  Case grammar
  Case Grammar is a system of linguistic analysis, focusing on the link between the valence, or number of subjects, objects, etc., of a verb and the grammatical context it requires. The system was created by the American linguist Charles J. Fillmore in , in the context of Transformational Grammar...
  
  
• Theta roles
• Semantic role labeling
  Semantic Role Labeling
  Semantic role labeling is a task in natural language processing consisting of the detection of the semantic arguments associated with the predicate or verb of a sentence and their classification into their specific roles.-References:...
  
  , a natural language processing task to automatically determine thematic roles