Reification in
natural language processing
Natural language processing (NLP) is an interdisciplinary subfield of linguistics, computer science, and artificial intelligence concerned with the interactions between computers and human language, in particular how to program computers to pro ...
refers to where a natural language statement is transformed so actions and events in it become
quantifiable
Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a uni ...
variables. For example "John chased the duck furiously" can be transformed into something like
:(Exists e)(chasing(e) & past_tense(e) & actor(e,John) & furiously(e) & patient(e,duck)).
Another example would be "Sally said John is mean", which could be expressed as something like
:(Exists u,v)(saying(u) & past_tense(u) & actor(u,Sally) & that(u,v) & is(v) & actor(v,John) & mean(v)).
Such representations allow one to use the tools of classical
first-order predicate calculus
First-order logic—also known as predicate logic, quantificational logic, and first-order predicate calculus—is a collection of formal systems used in mathematics, philosophy, linguistics, and computer science. First-order logic uses quan ...
even for statements which, due to their use of tense, modality, adverbial constructions, propositional arguments (''e.g.'' "Sally said that X"), etc., would have seemed intractable. This is an advantage because predicate calculus is better understood and simpler than the more complex alternatives (higher-order logics, modal logics, temporal logics, etc.), and there exist better automated tools (''e.g.''
automated theorem prover
Automated theorem proving (also known as ATP or automated deduction) is a subfield of automated reasoning and mathematical logic dealing with proving mathematical theorems by computer programs. Automated reasoning over mathematical proof was a maj ...
s and
model checker
In computer science, model checking or property checking is a method for checking whether a finite-state model of a system meets a given specification (also known as correctness). This is typically associated with hardware or software system ...
s) for manipulating it.
Reified forms can be used for other purposes besides the application of first-order logic; one example is the automatic discovery of synonymous phrases.
[Dekang Lin and Patrick Pantel, "DIRT – Discovery of Inference Rules from Text", (2001) KDD01-Proceedings of the seventh ACM SIGKDD international conference on Knowledge discovery and data mining][Hoifung Poon and Pedro Domingos "Unsupervised Semantic Parsing" (2009) EMNLP09: Proceedings of the 2009 Conference on Empirical Methods in Natural Language Processing]
The reified forms are sometimes called quasi-logical forms, and the existential variables are sometimes treated as
Skolem constants.
Not all natural language constructs admit a uniform translation to first order logic. See
donkey sentence
Donkey sentences are sentences that contain a pronoun with clear meaning (it is bound semantically) but whose syntactical role in the sentence poses challenges to grammarians. Such sentences defy straightforward attempts to generate their formal ...
for examples and a discussion.
See also
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Drinker paradox
The drinker paradox (also known as the drinker's theorem, the drinker's principle, or the drinking principle) is a theorem of classical predicate logic that can be stated as "There is someone in the pub such that, if he or she is drinking, then e ...
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Nonfirstorderizability In formal logic, nonfirstorderizability is the inability of a natural-language statement to be adequately captured by a formula of first-order logic. Specifically, a statement is nonfirstorderizable if there is no formula of first-order logic whic ...
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Reification (computer science)
Reification is the process by which an abstract idea about a computer program is turned into an explicit data model or other object created in a programming language. A computable/addressable object—a resource—is created in a system as a prox ...
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Reification (fallacy)
Reification (also known as concretism, hypostatization, or the fallacy of misplaced concreteness) is a fallacy of ambiguity, when an abstraction (abstract belief or hypothetical construct) is treated as if it were a concrete real event or physical ...
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Reification (knowledge representation)
Reification in knowledge representation is the process of turning a predicate or statement into an addressable object. Reification allows the representation of assertions so that they can be referred to or qualified by ''other'' assertions, i.e., ...
References
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Computational linguistics