Monday, June 17, 2013

Semantics



Semantics (from Ancient Greek: σημαντικός sēmantikós)[1][2] is the study of meaning. It focuses on the relation between signifiers, like words, phrases, signs, and symbols, and what they stand for, their denotation. Linguistic semantics is the study of meaning that is used for understanding human expression through language. Other forms of semantics include the semantics of programming languages, formal logics, and semiotics. The word semantics itself denotes a range of ideas, from the popular to the highly technical. It is often used in ordinary language for denoting a problem of understanding that comes down to word selection or connotation. This problem of understanding has been the subject of many formal enquiries, over a long period of time, most notably in the field of formal semantics. In linguistics, it is the study of interpretation of signs or symbols used in agents or communities within particular circumstances and contexts.[3] Within this view, sounds, facial expressions, body language, and proxemics have semantic (meaningful) content, and each comprises several branches of study. In written language, things like paragraph structure and punctuation bear semantic content; other forms of language bear other semantic content.[3]
The formal study of semantics intersects with many other fields of inquiry, including lexicology, syntax, pragmatics, etymology and others, although semantics is a well-defined field in its own right, often with synthetic properties.[4] In philosophy of language, semantics and reference are closely connected. Further related fields include philology, communication, and semiotics. The formal study of semantics is therefore complex. Semantics contrasts with syntax, the study of the combinatorics of units of a language (without reference to their meaning), and pragmatics, the study of the relationships between the symbols of a language, their meaning, and the users of the language.[5]In international scientific vocabulary semantics is also called semasiology.

Linguistics

In linguistics, semantics is the subfield that is devoted to the study of meaning, as inherent at the levels of words, phrases, sentences, and larger units of discourse (termed texts). The basic area of study is the meaning of signs, and the study of relations between different linguistic units and compounds: homonymy, synonymy, antonymy, hypernymy, hyponymy, meronymy, metonymy, holonymy, paronyms. A key concern is how meaning attaches to larger chunks of text, possibly as a result of the composition from smaller units of meaning. Traditionally, semantics has included the study of sense and denotative reference, truth conditions, argument structure, thematic roles[disambiguation needed], discourse analysis, and the linkage of all of these to syntax.

Montague grammar

In the late 1960s, Richard Montague proposed a system for defining semantic entries in the lexicon in terms of the lambda calculus. In these terms, the syntactic parse of the sentence John ate every bagel would consist of a subject (John) and a predicate (ate every bagel); Montague demonstrated that the meaning of the sentence altogether could be decomposed into the meanings of its parts and in relatively few rules of combination. The logical predicate thus obtained would be elaborated further, e.g. using truth theory models, which ultimately relate meanings to a set of Tarskiian universals, which may lie outside the logic. The notion of such meaning atoms or primitives is basic to the language of thought hypothesis from the 1970s.
Despite its elegance, Montague grammar was limited by the context-dependent variability in word sense, and led to several attempts at incorporating context, such as:
In Chomskyan linguistics there was no mechanism for the learning of semantic relations, and the nativist view considered all semantic notions as inborn. Thus, even novel concepts were proposed to have been dormant in some sense. This view was also thought unable to address many issues such as metaphor or associative meanings, and semantic change, where meanings within a linguistic community change over time, and qualia or subjective experience. Another issue not addressed by the nativist model was how perceptual cues are combined in thought, e.g. in mental rotation.[6]
This view of semantics, as an innate finite meaning inherent in a lexical unit that can be composed to generate meanings for larger chunks of discourse, is now being fiercely debated in the emerging domain of cognitive linguistics[7] and also in the non-Fodorian camp in philosophy of language.[8] The challenge is motivated by:
  • factors internal to language, such as the problem of resolving indexical or anaphora (e.g. this x, him, last week). In these situations context serves as the input, but the interpreted utterance also modifies the context, so it is also the output. Thus, the interpretation is necessarily dynamic and the meaning of sentences is viewed as context change potentials instead of propositions.
  • factors external to language, i.e. language is not a set of labels stuck on things, but "a toolbox, the importance of whose elements lie in the way they function rather than their attachments to things."[8] This view reflects the position of the later Wittgenstein and his famous game example, and is related to the positions of Quine, Davidson, and others.
A concrete example of the latter phenomenon is semantic underspecification – meanings are not complete without some elements of context. To take an example of one word, red, its meaning in a phrase such as red book is similar to many other usages, and can be viewed as compositional.[9] However, the colours implied in phrases such as red wine (very dark), and red hair (coppery), or red soil, or red skin are very different. Indeed, these colours by themselves would not be called red by native speakers. These instances are contrastive, so red wine is so called only in comparison with the other kind of wine (which also is not white for the same reasons). This view goes back to de Saussure:
Each of a set of synonyms like redouter ('to dread'), craindre ('to fear'), avoir peur ('to be afraid') has its particular value only because they stand in contrast with one another. No word has a value that can be identified independently of what else is in its vicinity.[10]
and may go back to earlier Indian views on language, especially the Nyaya view of words as indicators and not carriers of meaning.[11]
An attempt to defend a system based on propositional meaning for semantic underspecification can be found in the generative lexicon model of James Pustejovsky, who extends contextual operations (based on type shifting) into the lexicon. Thus meanings are generated "on the fly" (as you go), based on finite context.

Theories in semantics

Originates from Montague's work (see above). A highly formalized theory of natural language semantics in which expressions are assigned denotations (meanings) such as individuals, truth values, or functions from one of these to another. The truth of a sentence, and more interestingly, its logical relation to other sentences, is then evaluated relative to a model.
Pioneered by the philosopher Donald Davidson, another formalized theory, which aims to associate each natural language sentence with a meta-language description of the conditions under which it is true, for example: `Snow is white' is true if and only if snow is white. The challenge is to arrive at the truth conditions for any sentences from fixed meanings assigned to the individual words and fixed rules for how to combine them. In practice, truth-conditional semantics is similar to model-theoretic semantics; conceptually, however, they differ in that truth-conditional semantics seeks to connect language with statements about the real world (in the form of meta-language statements), rather than with abstract models.

Lexical and conceptual semantics

This theory is an effort to explain properties of argument structure. The assumption behind this theory is that syntactic properties of phrases reflect the meanings of the words that head them.[13] With this theory, linguists can better deal with the fact that subtle differences in word meaning correlate with other differences in the syntactic structure that the word appears in.[13] The way this is gone about is by looking at the internal structure of words.[14] These small parts that make up the internal structure of words are termed semantic primitives.[14]

Lexical semantics

A linguistic theory that investigates word meaning. This theory understands that the meaning of a word is fully reflected by its context. Here, the meaning of a word is constituted by its contextual relations.[15] Therefore, a distinction between degrees of participation as well as modes of participation are made.[15] In order to accomplish this distinction any part of a sentence that bears a meaning and combines with the meanings of other constituents is labeled as a semantic constituent. Semantic constituents that cannot be broken down into more elementary constituents are labeled minimal semantic constituents.[15]

Semantic models

Terms such as semantic network and semantic data model are used to describe particular types of data models characterized by the use of directed graphs in which the vertices denote concepts or entities in the world, and the arcs denote relationships between them.
The Semantic Web refers to the extension of the World Wide Web via embedding added semantic metadata, using semantic data modelling techniques such as Resource Description Framework (RDF) and Web Ontology Language (OWL).

Psychology

In psychology, semantic memory is memory for meaning – in other words, the aspect of memory that preserves only the gist, the general significance, of remembered experience – while episodic memory is memory for the ephemeral details – the individual features, or the unique particulars of experience. Word meaning is measured by the company they keep, i.e. the relationships among words themselves in a semantic network. The memories may be transferred intergenerationally or isolated in one generation due to a cultural disruption. Different generations may have different experiences at similar points in their own time-lines. This may then create a vertically heterogeneous semantic net for certain words in an otherwise homogeneous culture.[19] In a network created by people analyzing their understanding of the word (such as Wordnet) the links and decomposition structures of the network are few in number and kind, and include part of, kind of, and similar links. In automated ontologies the links are computed vectors without explicit meaning. Various automated technologies are being developed to compute the meaning of words: latent semantic indexing and support vector machines as well as natural language processing, neural networks and predicate calculus techniques.
Ideasthesia is a rare psychological phenomenon that in certain individuals associates semantic and sensory representations. Activation of a concept (e.g., that of the letter A) evokes sensory-like experiences (e.g., of red color).
What is semantics?
Semantics is a sub discipline of linguistics which focuses on the study of meaning. Semantics tries to understand what meaning is as an element of language and how it is constructed by language as well as interpreted, obscured and negotiated by speakers and listeners of language.[1]
 Semantics is closely linked with another sub discipline of linguistics, pragmatics, which is also, broadly speaking, and the study of meaning. However, unlike pragmatics, semantics is a highly theoretical research perspective, and looks at meaning in language in isolation, in the language itself, whereas pragmatics is a more practical subject and is interested in meaning in language in use.
Semantics is the study of meaning, but what do we mean by 'meaning'?
Meaning has been given different definitions in the past.
 Meaning = Connotation?
Is meaning simply the set of associations that a word evokes, is the meaning of a word defined by the images that its users connect to it?
So 'winter' might mean 'snow', 'sledging' and 'mulled wine'. But what about someone lives in the Amazon? Their 'winter' is still wet and hot, so its original meaning is lost. Because the associations of a word don't always apply, it was decided that this couldn't be the whole story.
Meaning = Denotation?
It has also been suggested that the meaning of a word is simply the entity in the World which that word refers to. This makes perfect sense for proper nouns like 'New York' and 'the Eiffel Tower', but there are lots of words like 'sing' and 'altruism' that don't have a solid thing in the world that they are connected to. So meaning cannot be entirely denotation either.
Meaning = Extension and Intention
So meaning, in semantics, is defined as being Extension: The thing in the world that the word/phrase refers to, plus Intention: The concepts/mental images that the word/phrase evokes.[2] 
Semantics is interested in:
  • How meaning works in language:
The study of semantics looks at how meaning works in language, and because of this it often uses native speaker intuitions about the meaning of words and phrases to base research on. We all understand semantics already on a subconscious level, it's how we all understand each other when we speak.
  • How the way in which words are put together creates meaning:
One of the things that semantics looks at, and is based on, is how the meaning of speech is not just derived from the meanings of the individual words all put together, as you can see from the example below.
The Principle of Compositionality says that the meaning of speech is the sum of the meanings of the individual words plus the way in which they are arranged into a structure.
  • The relationships between words:
Semantics also looks at the ways in which the meanings of words can be related to each other. Here are a few of the ways in which words can be semantically related.
 Semantic relationship
 Definition
 Example
 Synonymy
Words are synonymous/ synonyms when they can be used to mean the same thing (at least in some contexts - words are rarely fully identical in all contexts).
Begin and start,
Big and large,
Youth and adolescent.
 Antonyms
 Words are antonyms of one another when they have opposite meanings (again, at least in some contexts).
Big and small,
Come and go,
Boy and girl.
 Polysemy
 A word is polysemous when it has two or more related meanings. In this case the word takes one form but can be used to mean two different things. In the case of polysemy, these two meanings must be related in some way, and not be two completely unrelated meanings of the word.
Bright- shining and bright- intelligent. Mouse- animal and mouse- on a computer.
 Homophony
 Homophony is similar to polysemy in that it refers to a single form of word with two meanings, however a word is a homophone when the two meanings are entirely unrelated.
Bat- flying mammal and bat- equipment used in cricket.
Pen- writing instrument and pen- small cage.
[2]
  • The relationships between sentences:
  • Ambiguity:
One of the aspects of how meaning works in language which is studied most in semantics is ambiguity. A sentence is ambiguous when it has two or more possible meanings, but how does ambiguity arise in language? A sentence can be ambiguous for either (or both!) of the following reasons:
Lexical Ambiguity: A sentence is lexically ambiguous when it can have two or more possible meanings due to polysemous (words that have two or more related meanings) or homophonous (a single word which has two or more different meanings) words.
Example of lexically ambiguous sentence: 'Prostitutes appeal to the Pope'. This sentence is ambiguous because the word 'appeal' is polysemous and can mean 'ask for help' or 'are attractive to'.
Structural Ambiguity: A sentence is structurally ambiguous if it can have two or more possible meanings due to the words it contains being able to be combined in different ways which create different meanings.
Example of structurally ambiguous sentence: 'Enraged cow injures farmer with axe'. In this sentence the ambiguity arises from the fact that the 'with axe' can either refer to the farmer, or to the act of injuring being carried out (by the cow) 'with axe'.[2]

Semantics in the field of Linguistics

Semantics looks at these relationships in language and looks at how these meanings are created, which is an important part of understanding how language works as a whole. Understanding how meaning occurs in language can inform other sub disciplines such as Language acquisition, to help us to understand how speakers acquire a sense of meaning, and Sociolinguistics, as the achievement of meaning in language is important in language in a social situation.
Semantics is also informed by other sub disciplines of linguistics, such as Morphology, as understanding the words themselves is integral to the study of their meaning, and Syntax, which researchers in semantics use extensively to reveal how meaning is created in language, as how language is structured is central to meaning.

References
[1] http://www.universalteacher.org.uk/lang/semantics.htm [Accessed 3.05.2012]
[2] Wood, G.C., (2011). Lecture on Introduction to Semantics at the University of Sheffield.
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