There are two competing notions of the predicate in theories of grammar. Traditional grammar tends to view a predicate as one of two main parts of a sentence, the other part being the subject. The purpose of the predicate is to modify the subject. The other understanding of predicates is inspired from work in predicate calculus (predicate logic, first order logic) and is prominent in modern theories of syntax and grammar. On this approach, the predicate of a sentence corresponds mainly to the main verb and any auxiliaries that accompany the main verb, whereby the arguments of that predicate (e.g. the subject and object noun phrases) are outside of the predicate. The competition between these two concepts has generated confusion concerning the use of the term predicate in theories of grammar. This article considers both of these notions.
Predicates in traditional grammar 
The predicate in traditional grammar is inspired by propositional logic of antiquity (as opposed to the more modern predicate logic). A predicate is seen as a property that a subject has or is characterized by. A predicate is therefore an expression that can be true of something. Thus, the expression "is moving" is true of those things that are moving. This classical understanding of predicates was adopted more or less directly into Latin and Greek grammars and from there it made its way into English grammars, where it is applied directly to the analysis of sentence structure. It is also the understanding of predicates in English-language dictionaries. The predicate is one of the two main parts of a sentence (the other being the subject, which the predicate modifies). The predicate must contain a verb, and the verb requires, permits, or precludes other sentence elements to complete the predicate. These elements are: objects (direct, indirect, prepositional), predicatives, and adjuncts:
- She dances. - verb-only predicate
- Ben reads the book. - verb + direct object predicate
- Ben's mother, Felicity, gave me a present. - verb + indirect object + direct object predicate
- She listened to the radio. - verb + prepositional object predicate
- They elected him president. - verb + object + predicative noun predicate
- She met him in the park. - verb + object + adjunct predicate
- She is in the park. - verb + predicative prepositional phrase predicate
The predicate provides information about the subject, such as what the subject is, what the subject is doing, or what the subject is like. The relation between a subject and its predicate is sometimes called a nexus. A predicative nominal is a noun phrase that functions as the main predicate of a sentence, such as George III is the king of England, the king of England being the predicative nominal. The subject and predicative nominal must be connected by a linking verb, also called a copula. A predicative adjective is an adjective that functions as a predicate, such as Ivano is attractive, attractive being the predicative adjective. The subject and predicative adjective must also be connected by a copula.
This traditional understanding of predicates has a concrete reflex in all phrase structure theories of syntax. These theories divide the generic declarative sentence (S) into a noun phrase (NP) and verb phrase (VP), e.g.
The subject NP is shown in green, and the predicate VP in blue. This concept of sentence structure stands in stark contrast to dependency structure theories of grammar, which place the finite verb (= conjugated verb) as the root of all sentence structure and thus reject this binary NP-VP division.
Predicates in modern theories of syntax and grammar 
Most modern theories of syntax and grammar take their inspiration for the theory of predicates from predicate calculus as associated with Gottlob Frege. This understanding sees predicates as relations or functions over arguments. The predicate serves either to assign a property to a single argument or to relate two or more arguments to each other. Sentences consist of predicates and their arguments (and adjuncts) and are thus predicate-argument structures, whereby a given predicate is seen as linking its arguments into a greater structure. This understanding of predicates sometimes renders a predicate and its arguments in the following manner:
- Bob laughed. → laughed (Bob) or, laughed = ƒ(Bob)
- Sam helped you. → helped (Sam, you)
- Jim gave Jill his dog. → gave (Jim, Jill, his dog)
Predicates are placed on the left outside of brackets, whereas the predicate's arguments are placed inside the brackets. One acknowledges the valency of predicates, whereby a given predicate can be avalent (not shown), monovalent (laughed in the first sentence), divalent (helped in the second sentence), or trivalent (gave in the third sentence). These types of representations are analogous to formal semantic analyses, where one is concerned with the proper account of scope facts of quantifiers and logical operators. Concerning basic sentence structure however, these representations suggest above all that verbs are predicates and the noun phrases that they appear with are their arguments. On this understanding of the sentence, the binary division of the clause into a subject NP and a predicate VP is hardly possible. Instead, the verb is the predicate, and the noun phrases are its arguments.
Other function words - e.g. auxiliary verbs, certain prepositions, phrasal particles, etc. - are viewed as part of the predicate. The matrix predicates are in bold in the following examples:
- Bill will have laughed.
- Will Bill have laughed?
- That is funny.
- Has that been funny?
- They had been satisfied.
- Had they been satisfied, ...
- The butter is in the drawer.
- Fred took a picture of Sue.
- Susan is pulling your leg.
- Who did Jim give his dog to?
- You should give it up.
Note that not just verbs can be part of the matrix predicate, but also adjectives, nouns, prepositions, etc. The understanding of predicates suggested by these examples sees the main predicate of a clause consisting of at least one verb and a variety of other possible words. The words of the predicate need not form a string nor a constituent, but rather they can be interrupted by their arguments (and/or adjuncts). The approach to predicates illustrated with these sentences is widespread in Europe, particularly in Germany, where the understanding predicates from traditional grammar discussed above seems to hardly exist (for those who know German, see the Wikipedia article in German on the predicate).
The matrix predicate is (again) marked in blue and its two arguments are in green. While the predicate cannot be construed as a constituent in the formal sense, it is a catena. Barring a discontinuity, predicates and their arguments are always catenae in dependency structures.
Some theories of grammar seek to avoid the confusion generated by the competition between the two predicate notions by acknowledging predicators. The term predicate is employed in the traditional sense of the binary division of the clause, whereas the term predicator is used to denote the more modern understanding of matrix predicates. On this approach, the periphrastic verb catenae briefly illustrated in the previous section are predicators. Further illustrations are provided next:
The predicators are in blue. These verb catenae generally contain a main verb and potentially one or more auxiliary verbs. The auxiliary verbs help express functional meaning of aspect and voice. Since the auxiliary verbs contribute functional information only, they do not qualify as separate predicators, but rather each time they form the matrix predicator with the main verb.
Carlson classes 
The seminal work of Greg Carlson distinguishes between types of predicates. Based on Carlson's work, predicates have been divided into the following sub-classes, which roughly pertain to how a predicate relates to its subject.
Stage-level predicates 
A stage-level predicate is true of a temporal stage of its subject. For example, if John is "hungry", then he typically will eat some food, which lasts a certain amount of time, and not his entire lifespan. Stage-level predicates can occur in a wide range of grammatical constructions and are probably the most versatile kind of predicate.
Individual-level predicates 
An individual-level predicate is true throughout the existence of an individual. For example, if John is "smart", this is a property that he has, regardless of which particular point in time we consider. Individual-level predicates are more restricted than stage-level ones. Individual-level predicates cannot occur in presentational "there" sentences (a star in front of a sentence indicates that it is odd or ill-formed):
- There are police available. - available is stage-level predicate
- *There are firemen altruistic. - altruistic is an individual-level predicate
Stage-level predicates allow modification by manner adverbs and other adverbial modifiers. Individual-level predicates do not, e.g.
- Tyrone spoke French loudly in the corridor. - speak French can be interpreted as a stage-level predicate
- *Tyrone knew French silently in the corridor. - know French cannot be interpreted as a stage-level predicate
When an individual-level predicate occurs in past tense, it gives rise to what is called a lifetime effect: The subject must be assumed to be dead or otherwise out of existence.
- John was available. - Stage-level predicate does NOT evoke the lifetime effect.
- John was altruistic. - Individual-level predicate does evoke the lifetime effect.
Kind-level predicates 
A kind-level predicate is true of a kind of thing, but cannot be applied to individual members of the kind. An example of this is the predicate are widespread. One cannot meaningfully say of a particular individual John that he is widespread. One may only say this of kinds, as in
- Humans are widespread.
- *A cat is widespread. - Compare: Nightmares are widespread.
Collective vs. distributive predicates 
Predicates may also be collective or distributive. Collective predicates require their subjects to be somehow plural, while distributive ones do not. An example of a collective predicate is "formed a line". This predicate can only stand in a nexus with a plural subject:
- The students formed a line. - Collective predicate appears with plural subject.
- *The student formed a line. - Collective predicate cannot appear with singular subject.
Other examples of collective predicates include meet in the woods, surround the house, gather in the hallway and carry the piano together. Note that the last one (carry the piano together) can be made non-collective by removing the word together. Quantifiers differ with respect to whether or not they can be the subject of a collective predicate. For example, quantifiers formed with all the can, while ones formed with every or each cannot.
- All the students formed a line. - Collective predicate possible with all the.
- All the students gathered in the hallway. - Collective predicate possible with all the.
- All the students carried a piano together. - Collective predicate possible with all the.
- *Every student formed a line. - Collective predicate IMpossible with every.
- *Each student gathered in the hallway. - Collective predicate IMpossible with each.
See also 
- See Carnie (2007:51).
- Concerning Aristotlean logic as the source for the binary subject-predicate division of the sentence, see Matthews (1981:102).
- See Kroeger (2005:53).
- See for instance The American Heritage College Dictionary (1993:1077) and The Miriam Webster's Dictionary (2004:566).
- Constituency trees like the one here, which divides the sentence into a subject NP and a predicate VP, can be found in most textbooks on syntax and grammar, e.g. Carnie (2007), although the trees of these textbooks will vary in important details.
- There are exceptions to this statement. For instance, Matthews (1981:85), Burton-Roberts (1986:28ff.), Thomas (1993:15) and van Riemsdijk and Williams (1986:326) continue to pursue the tranditional stance whereby a predicates corresponds to the finite VP constituent.
- For examples of theories that pursue this understanding of predicates, see Langendoen (1970:96ff.), Cattell (1984), Harrocks (1987:49f.), McCawley (1988:187), Napoli (1989), Cowper (1992:54), Haegeman (1994:43ff.), Ackerman and Webelhuth (1998:39), Fromkin et al. (2000:117), Carnie (2007:51).
- For examples of this use of notation, see Allerton (1979:259), van Riemsdijk and Williams (1987:241), Bennet (1995:21f.).
- See for example Parisi and Antinucci (1976:17ff.), Brown and Miller (1992:63f.), Napoli (1989:14ff, 1993:98), Ackerman and Webelhuth (1998:39f.). While the analyses of these linguists vary, they agree insofar various types of function words are grouped together as part of the predicate, which means complex predicates are very possible.
- For examples of theories that extend the predicate to other word classes (beyond verbs), see Cattell (1984), Parisi and Antinucci (1976:34), Napoli (1986:30f.), Haegeman (1994:44ff.).
- That many predicates are not constituents is acknowledged by many, e.g. Cattell (1984:50), Napoli (1986:14f.).
- Dependency trees like the one here can be found in, for instance, Osborne et al. (2012).
- For examples of grammars that employ the term predicator, see for instance Matthews (1981:101), Huddleston (1988:9f.), Downing and Locke (1992:48), and Lockwood (2002:4f.).
- See Carlson (1977a, 1977b).
- Allerton, D. 1979. Essentials of grammatical theory. London: Routledge & Kegan Paul.
- Ackerman, F. and G. Webelhuth. 1998. A theory of predicates. Stanford, CA: CSLI Publications.
- Burton-Roberts, N. 1997. Analysing sentences: An introduction to English grammar. London: Longman.
- The American Heritage College Dictionary, third edition. 1993 Boston: Houghton Mifflin Company.
- Bennet, P. 1995. A course in Generalized Phrase Structure Grammar. London: UCL Press Limited.
- Carlson, G. 1977a. A unified analysis of the English bare plural. Linguistics and Philosophy 1, 3, 413–58.
- Carlson, G. 1977b. Reference to Kinds in English. New York: Garland. (Also distributed by Indiana University Linguistics Club and GLSA UMass/Amherst.)
- Carnie, A. 2007. Syntax: A generative introduction, 2nd edition. Malden, MA: Blackwell Publishing.
- Cattell, R. 1984. Composite predicates in English. Syntax and Semantics 17. Sydney: Academic Press.
- Chomsky, N. 1965. Aspects of the thoery of syntax. Cambridge, MA: MIT Press.
- Cowper, E. 1992. A concise introduction to syntactic theory: The government-binding approach. Chicago: The University of Chicago Press.
- Culicover, P. 1997. Principles and Parameters: An introduction to syntactic theory. Oxford University Press.
- Downing, A. and P. Locke. 1992. English grammar: A university course, second edition. London: Routledge.
- Fromkin, V. et al. 2000. Linguistics: An introduction to linguistic theory. Malden, MA: Blackwell Publishers.
- Haegeman, L. 1994. Introduction to government and binding theory, 2nd edition. Oxford, UK: Blackwell.
- Harrocks, G. 1987. Generative Grammar. London: Longman.
- Huddleston, R. 1988. English grammar: An outline. Cambridge, UK: Cambridge University Press.
- Kroeger, P. 2005. Analyzing Grammar: An Introduction. Cambridge: Cambridge University Press.
- Langendoen, T. 1970. the study of syntax: The generative-transformational approach to the study of English. New York: Holt, Rinehart and Winston, Inc.
- Lockwood, D. 2002. Syntactic analysis and description: A constructional approach. London: continuum.
- Matthews, P. 1981. Syntax. Cambridge, UK: Cambridge University Press.
- McCawley, T. 1988. The syntactic phenomena of English, Vol. 1. Chicago: The University of Chicago Press.
- The Merriam Webster Dictionary. 2004. Springfield, Massachusetts: Merriam-Webster.
- Napoli, D. 1989. Predication theory: A case study for indexing theory. Cambridge, UK: Cambridge University Press.
- Napoli, D. 1993. Syntax: Theory and problems. New York: Oxford University Press.
- Osborne, T., M. Putnam, and T. Groß 2012. Catenae: Introducing a novel unit of syntactic analysis. Syntax 15, 4, 354-396.
- Parisi, D. and F. Antinucci. 1976. Essentials of grammar. Translated by E. Bates. New York: Academic Press.
- van Riemsdijk, H. and E. Williams. 1986. Introduction to the theory of grammar. Cambridge, MA: The MIT Press.
- Thomas, L. 1993. Beginning syntax. Oxford, UK: Blackwell.