text:
Cognitive science

Cognitive science is the interdisciplinary, scientific study of the mind and its processes. It examines the nature, the tasks, and the functions of cognition (in a broad sense). Mental faculties of concern to cognitive scientists include language, perception, memory, attention, reasoning, and emotion; to understand these faculties, cognitive scientists borrow from fields such as linguistics, psychology, artificial intelligence, philosophy, neuroscience, and anthropology. The typical analysis of cognitive science spans many levels of organization, from learning and decision to logic and planning; from neural circuitry to modular brain organization. One of the fundamental concepts of cognitive science is that "thinking can best be understood in terms of representational structures in the mind and computational procedures that operate on those structures."

History
The cognitive sciences began as an intellectual movement in the 1950s, called the cognitive revolution. Cognitive science has a prehistory traceable back to ancient Greek philosophical texts (see Plato's Meno and Aristotle's De Anima); Modern philosophers such as Descartes, David Hume, Immanuel Kant, Benedict de Spinoza, Nicolas Malebranche, Pierre Cabanis, Leibniz and John Locke, rejected scholasticism while mostly having never read Aristotle, and they were working with an entirely different set of tools and core concepts than those of the cognitive scientist.

The modern culture of cognitive science can be traced back to the early cyberneticists in the 1930s and 1940s, such as Warren McCulloch and Walter Pitts, who sought to understand the organizing principles of the mind. McCulloch and Pitts developed the first variants of what are now known as artificial neural networks, models of computation inspired by the structure of biological neural networks.

Another precursor was the early development of the theory of computation and the digital computer in the 1940s and 1950s. Kurt Gödel, Alonzo Church, Alan Turing, and John von Neumann were instrumental in these developments. The modern computer, or Von Neumann machine, would play a central role in cognitive science, both as a metaphor for the mind, and as a tool for investigation.

The first instance of cognitive science experiments being done at an academic institution took place at MIT Sloan School of Management, established by J.C.R. Licklider working within the psychology department and conducting experiments using computer memory as models for human cognition. In 1959, Noam Chomsky published a scathing review of B. F. Skinner's book Verbal Behavior. At the time, Skinner's behaviorist paradigm dominated the field of psychology within the United States. Most psychologists focused on functional relations between stimulus and response, without positing internal representations. Chomsky argued that in order to explain language, we needed a theory like generative grammar, which not only attributed internal representations but characterized their underlying order.

The term cognitive science was coined by Christopher Longuet-Higgins in his 1973 commentary on the Lighthill report, which concerned the then-current state of artificial intelligence research. In the same decade, the journal Cognitive Science and the Cognitive Science Society were founded. The founding meeting of the Cognitive Science Society was held at the University of California, San Diego in 1979, which resulted in cognitive science becoming an internationally visible enterprise. In 1972, Hampshire College started the first undergraduate education program in Cognitive Science, led by Neil Stillings. In 1982, with assistance from Professor Stillings, Vassar College became the first institution in the world to grant an undergraduate degree in Cognitive Science. In 1986, the first Cognitive Science Department in the world was founded at the University of California, San Diego.

In the 1970s and early 1980s, as access to computers increased, artificial intelligence research expanded. Researchers such as Marvin Minsky would write computer programs in languages such as LISP to attempt to formally characterize the steps that human beings went through, for instance, in making decisions and solving problems, in the hope of better understanding human thought, and also in the hope of creating artificial minds. This approach is known as "symbolic AI".

Eventually the limits of the symbolic AI research program became apparent. For instance, it seemed to be unrealistic to comprehensively list human knowledge in a form usable by a symbolic computer program. The late 80s and 90s saw the rise of neural networks and connectionism as a research paradigm. Under this point of view, often attributed to James McClelland and David Rumelhart, the mind could be characterized as a set of complex associations, represented as a layered network. Critics argue that there are some phenomena which are better captured by symbolic models, and that connectionist models are often so complex as to have little explanatory power. Recently symbolic and connectionist models have been combined, making it possible to take advantage of both forms of explanation. While both connectionism and symbolic approaches have proven useful for testing various hypotheses and exploring approaches to understanding aspects of cognition and lower level brain functions, neither are biologically realistic and therefore, both suffer from a lack of neuroscientific plausibility. Connectionism has proven useful for exploring computationally how cognition emerges in development and occurs in the human brain, and has provided alternatives to strictly domain-specific / domain general approaches. For example, scientists such as Jeff Elman, Liz Bates, and Annette Karmiloff-Smith have posited that networks in the brain emerge from the dynamic interaction between them and environmental input.

Recent developments in quantum computation, including the ability to run quantum circuits on quantum computers such as IBM Quantum Platform, has accelerated work using elements from quantum mechanics in cognitive models.

Levels of analysis
A central tenet of cognitive science is that a complete understanding of the mind/brain cannot be attained by studying only a single level. An example would be the problem of remembering a phone number and recalling it later. One approach to understanding this process would be to study behavior through direct observation, or naturalistic observation. A person could be presented with a phone number and be asked to recall it after some delay of time; then the accuracy of the response could be measured. Another approach to measure cognitive ability would be to study the firings of individual neurons while a person is trying to remember the phone number. Neither of these experiments on its own would fully explain how the process of remembering a phone number works. Even if the technology to map out every neuron in the brain in real-time were available and it were known when each neuron fired it would still be impossible to know how a particular firing of neurons translates into the observed behavior. Thus an understanding of how these two levels relate to each other is imperative. Francisco Varela, in The Embodied Mind: Cognitive Science and Human Experience, argues that "the new sciences of the mind need to enlarge their horizon to encompass both lived human experience and the possibilities for transformation inherent in human experience". On the classic cognitivist view, this can be provided by a functional level account of the process. Studying a particular phenomenon from multiple levels creates a better understanding of the processes that occur in the brain to give rise to a particular behavior. Marr gave a famous description of three levels of analysis:

 * 1) The computational theory, specifying the goals of the computation;
 * 2) Representation and algorithms, giving a representation of the inputs and outputs and the algorithms which transform one into the other; and
 * 3) The hardware implementation, or how algorithm and representation may be physically realized.

Interdisciplinary nature
Cognitive science is an interdisciplinary field with contributors from various fields, including psychology, neuroscience, linguistics, philosophy of mind, computer science, anthropology and biology. Cognitive scientists work collectively in hope of understanding the mind and its interactions with the surrounding world much like other sciences do. The field regards itself as compatible with the physical sciences and uses the scientific method as well as simulation or modeling, often comparing the output of models with aspects of human cognition. Similarly to the field of psychology, there is some doubt whether there is a unified cognitive science, which have led some researchers to prefer 'cognitive sciences' in plural.

Many, but not all, who consider themselves cognitive scientists hold a functionalist view of the mind—the view that mental states and processes should be explained by their function – what they do. According to the multiple realizability account of functionalism, even non-human systems such as robots and computers can be ascribed as having cognition.

Cognitive science: the term
The term "cognitive" in "cognitive science" is used for "any kind of mental operation or structure that can be studied in precise terms" (Lakoff and Johnson, 1999). This conceptualization is very broad, and should not be confused with how "cognitive" is used in some traditions of analytic philosophy, where "cognitive" has to do only with formal rules and truth-conditional semantics.

The earliest entries for the word "cognitive" in the OED take it to mean roughly "pertaining to the action or process of knowing". The first entry, from 1586, shows the word was at one time used in the context of discussions of Platonic theories of knowledge. Most in cognitive science, however, presumably do not believe their field is the study of anything as certain as the knowledge sought by Plato.

Scope
Cognitive science is a large field, and covers a wide array of topics on cognition. However, it should be recognized that cognitive science has not always been equally concerned with every topic that might bear relevance to the nature and operation of minds. Classical cognitivists have largely de-emphasized or avoided social and cultural factors, embodiment, emotion, consciousness, animal cognition, and comparative and evolutionary psychologies. However, with the decline of behaviorism, internal states such as affects and emotions, as well as awareness and covert attention became approachable again. For example, situated and embodied cognition theories take into account the current state of the environment as well as the role of the body in cognition. With the newfound emphasis on information processing, observable behavior was no longer the hallmark of psychological theory, but the modeling or recording of mental states.

Below are some of the main topics that cognitive science is concerned with. This is not an exhaustive list. See List of cognitive science topics for a list of various aspects of the field.

Artificial intelligence
Artificial intelligence (AI) involves the study of cognitive phenomena in machines. One of the practical goals of AI is to implement aspects of human intelligence in computers. Computers are also widely used as a tool with which to study cognitive phenomena. Computational modeling uses simulations to study how human intelligence may be structured. (See .)

There is some debate in the field as to whether the mind is best viewed as a huge array of small but individually feeble elements (i.e. neurons), or as a collection of higher-level structures such as symbols, schemes, plans, and rules. The former view uses connectionism to study the mind, whereas the latter emphasizes symbolic artificial intelligence. One way to view the issue is whether it is possible to accurately simulate a human brain on a computer without accurately simulating the neurons that make up the human brain.

Attention
Attention is the selection of important information. The human mind is bombarded with millions of stimuli and it must have a way of deciding which of this information to process. Attention is sometimes seen as a spotlight, meaning one can only shine the light on a particular set of information. Experiments that support this metaphor include the dichotic listening task (Cherry, 1957) and studies of inattentional blindness (Mack and Rock, 1998). In the dichotic listening task, subjects are bombarded with two different messages, one in each ear, and told to focus on only one of the messages. At the end of the experiment, when asked about the content of the unattended message, subjects cannot report it.

The psychological construct of Attention is sometimes confused with the concept of Intentionality due to some degree of semantic ambiguity in their definitions. At the beginning of experimental research on Attention, Wilhelm Wundt defined this term as "that psychical process, which is operative in the clear perception of the narrow region of the content of consciousness." His experiments showed the limits of Attention in space and time, which were 3-6 letters during an exposition of 1/10 s. Because this notion develops within the framework of the original meaning during a hundred years of research, the definition of Attention would reflect the sense when it accounts for the main features initially attributed to this term – it is a process of controlling thought that continues over time. While Intentionality is the power of minds to be about something, Attention is the concentration of awareness on some phenomenon during a period of time, which is necessary to elevate the clear perception of the narrow region of the content of consciousness and which is feasible to control this focus in mind.

The significance of knowledge about the scope of attention for studying cognition is that it defines the intellectual functions of cognition such as apprehension, judgment, reasoning, and working memory. The development of attention scope increases the set of faculties responsible for the mind relies on how it perceives, remembers, considers, and evaluates in making decisions. The ground of this statement is that the more details (associated with an event) the mind may grasp for their comparison, association, and categorization, the closer apprehension, judgment, and reasoning of the event are in accord with reality. According to Latvian professor Sandra Mihailova and professor Igor Val Danilov, the more elements of the phenomenon (or phenomena ) the mind can keep in the scope of attention simultaneously, the more significant number of reasonable combinations within that event it can achieve, enhancing the probability of better understanding features and particularity of the phenomenon (phenomena). For example, three items in the focal point of consciousness yield six possible combinations (3 factorial) and four items – 24 (4 factorial) combinations. The number of reasonable combinations becomes significant in the case of a focal point with six items with 720 possible combinations (6 factorial).

Bodily processes related to cognition
Embodied cognition approaches to cognitive science emphasize the role of body and environment in cognition. This includes both neural and extra-neural bodily processes, and factors that range from affective and emotional processes, to posture, motor control, proprioception, and kinaesthesis, to autonomic processes that involve heartbeat and respiration, to the role of the enteric gut microbiome. It also includes accounts of how the body engages with or is coupled to social and physical environments. 4E (embodied, embedded, extended and enactive) cognition includes a broad range of views about brain-body-environment interaction, from causal embeddedness to stronger claims about how the mind extends to include tools and instruments, as well as the role of social interactions, action-oriented processes, and affordances. 4E theories range from those closer to classic cognitivism (so-called "weak" embodied cognition ) to stronger extended and enactive versions that are sometimes referred to as radical embodied cognitive science.

Knowledge and processing of language

The ability to learn and understand language is an extremely complex process. Language is acquired within the first few years of life, and all humans under normal circumstances are able to acquire language proficiently. A major driving force in the theoretical linguistic field is discovering the nature that language must have in the abstract in order to be learned in such a fashion. Some of the driving research questions in studying how the brain itself processes language include: (1) To what extent is linguistic knowledge innate or learned?, (2) Why is it more difficult for adults to acquire a second-language than it is for infants to acquire their first-language?, and (3) How are humans able to understand novel sentences?

The study of language processing ranges from the investigation of the sound patterns of speech to the meaning of words and whole sentences. Linguistics often divides language processing into orthography, phonetics, phonology, morphology, syntax, semantics, and pragmatics. Many aspects of language can be studied from each of these components and from their interaction.

The study of language processing in cognitive science is closely tied to the field of linguistics. Linguistics was traditionally studied as a part of the humanities, including studies of history, art and literature. In the last fifty years or so, more and more researchers have studied knowledge and use of language as a cognitive phenomenon, the main problems being how knowledge of language can be acquired and used, and what precisely it consists of. Linguists have found that, while humans form sentences in ways apparently governed by very complex systems, they are remarkably unaware of the rules that govern their own speech. Thus linguists must resort to indirect methods to determine what those rules might be, if indeed rules as such exist. In any event, if speech is indeed governed by rules, they appear to be opaque to any conscious consideration.

Learning and development
Learning and development are the processes by which we acquire knowledge and information over time. Infants are born with little or no knowledge (depending on how knowledge is defined), yet they rapidly acquire the ability to use language, walk, and recognize people and objects. Research in learning and development aims to explain the mechanisms by which these processes might take place.

A major question in the study of cognitive development is the extent to which certain abilities are innate or learned. This is often framed in terms of the nature and nurture debate. The nativist view emphasizes that certain features are innate to an organism and are determined by its genetic endowment. The empiricist view, on the other hand, emphasizes that certain abilities are learned from the environment. Although clearly both genetic and environmental input is needed for a child to develop normally, considerable debate remains about how genetic information might guide cognitive development. In the area of language acquisition, for example, some (such as Steven Pinker) have argued that specific information containing universal grammatical rules must be contained in the genes, whereas others (such as Jeffrey Elman and colleagues in Rethinking Innateness) have argued that Pinker's claims are biologically unrealistic. They argue that genes determine the architecture of a learning system, but that specific "facts" about how grammar works can only be learned as a result of experience.

Memory
Memory allows us to store information for later retrieval. Memory is often thought of as consisting of both a long-term and short-term store. Long-term memory allows us to store information over prolonged periods (days, weeks, years). We do not yet know the practical limit of long-term memory capacity. Short-term memory allows us to store information over short time scales (seconds or minutes).

Memory is also often grouped into declarative and procedural forms. Declarative memory—grouped into subsets of semantic and episodic forms of memory—refers to our memory for facts and specific knowledge, specific meanings, and specific experiences (e.g. "Are apples food?", or "What did I eat for breakfast four days ago?"). Procedural memory allows us to remember actions and motor sequences (e.g. how to ride a bicycle) and is often dubbed implicit knowledge or memory.

Cognitive scientists study memory just as psychologists do, but tend to focus more on how memory bears on cognitive processes, and the interrelationship between cognition and memory. One example of this could be, what mental processes does a person go through to retrieve a long-lost memory? Or, what differentiates between the cognitive process of recognition (seeing hints of something before remembering it, or memory in context) and recall (retrieving a memory, as in "fill-in-the-blank")?

Perception and action

Perception is the ability to take in information via the senses, and process it in some way. Vision and hearing are two dominant senses that allow us to perceive the environment. Some questions in the study of visual perception, for example, include: (1) How are we able to recognize objects?, (2) Why do we perceive a continuous visual environment, even though we only see small bits of it at any one time? One tool for studying visual perception is by looking at how people process optical illusions. The image on the right of a Necker cube is an example of a bistable percept, that is, the cube can be interpreted as being oriented in two different directions.

The study of haptic (tactile), olfactory, and gustatory stimuli also fall into the domain of perception.

Action is taken to refer to the output of a system. In humans, this is accomplished through motor responses. Spatial planning and movement, speech production, and complex motor movements are all aspects of action.

Consciousness
Consciousness is the awareness of experiences within oneself. This helps the mind with having the ability to experience or feel a sense of self.

Research methods
Many different methodologies are used to study cognitive science. As the field is highly interdisciplinary, research often cuts across multiple areas of study, drawing on research methods from psychology, neuroscience, computer science and systems theory.

Behavioral experiments
In order to have a description of what constitutes intelligent behavior, one must study behavior itself. This type of research is closely tied to that in cognitive psychology and psychophysics. By measuring behavioral responses to different stimuli, one can understand something about how those stimuli are processed. Lewandowski & Strohmetz (2009) reviewed a collection of innovative uses of behavioral measurement in psychology including behavioral traces, behavioral observations, and behavioral choice. Behavioral traces are pieces of evidence that indicate behavior occurred, but the actor is not present (e.g., litter in a parking lot or readings on an electric meter). Behavioral observations involve the direct witnessing of the actor engaging in the behavior (e.g., watching how close a person sits next to another person). Behavioral choices are when a person selects between two or more options (e.g., voting behavior, choice of a punishment for another participant).
 * Reaction time. The time between the presentation of a stimulus and an appropriate response can indicate differences between two cognitive processes, and can indicate some things about their nature. For example, if in a search task the reaction times vary proportionally with the number of elements, then it is evident that this cognitive process of searching involves serial instead of parallel processing.
 * Psychophysical responses. Psychophysical experiments are an old psychological technique, which has been adopted by cognitive psychology. They typically involve making judgments of some physical property, e.g. the loudness of a sound. Correlation of subjective scales between individuals can show cognitive or sensory biases as compared to actual physical measurements. Some examples include:
 * sameness judgments for colors, tones, textures, etc.
 * threshold differences for colors, tones, textures, etc.
 * Eye tracking. This methodology is used to study a variety of cognitive processes, most notably visual perception and language processing. The fixation point of the eyes is linked to an individual's focus of attention. Thus, by monitoring eye movements, we can study what information is being processed at a given time. Eye tracking allows us to study cognitive processes on extremely short time scales. Eye movements reflect online decision making during a task, and they provide us with some insight into the ways in which those decisions may be processed.

Brain imaging

Brain imaging involves analyzing activity within the brain while performing various tasks. This allows us to link behavior and brain function to help understand how information is processed. Different types of imaging techniques vary in their temporal (time-based) and spatial (location-based) resolution. Brain imaging is often used in cognitive neuroscience.
 * Single-photon emission computed tomography and positron emission tomography. SPECT and PET use radioactive isotopes, which are injected into the subject's bloodstream and taken up by the brain. By observing which areas of the brain take up the radioactive isotope, we can see which areas of the brain are more active than other areas. PET has similar spatial resolution to fMRI, but it has extremely poor temporal resolution.
 * Electroencephalography. EEG measures the electrical fields generated by large populations of neurons in the cortex by placing a series of electrodes on the scalp of the subject. This technique has an extremely high temporal resolution, but a relatively poor spatial resolution.
 * Functional magnetic resonance imaging. fMRI measures the relative amount of oxygenated blood flowing to different parts of the brain. More oxygenated blood in a particular region is assumed to correlate with an increase in neural activity in that part of the brain. This allows us to localize particular functions within different brain regions. fMRI has moderate spatial and temporal resolution.
 * Optical imaging. This technique uses infrared transmitters and receivers to measure the amount of light reflectance by blood near different areas of the brain. Since oxygenated and deoxygenated blood reflects light by different amounts, we can study which areas are more active (i.e., those that have more oxygenated blood). Optical imaging has moderate temporal resolution, but poor spatial resolution. It also has the advantage that it is extremely safe and can be used to study infants' brains.
 * Magnetoencephalography. MEG measures magnetic fields resulting from cortical activity. It is similar to EEG, except that it has improved spatial resolution since the magnetic fields it measures are not as blurred or attenuated by the scalp, meninges and so forth as the electrical activity measured in EEG is. MEG uses SQUID sensors to detect tiny magnetic fields.

Computational modeling

Computational models require a mathematically and logically formal representation of a problem. Computer models are used in the simulation and experimental verification of different specific and general properties of intelligence. Computational modeling can help us understand the functional organization of a particular cognitive phenomenon. Approaches to cognitive modeling can be categorized as: (1) symbolic, on abstract mental functions of an intelligent mind by means of symbols; (2) subsymbolic, on the neural and associative properties of the human brain; and (3) across the symbolic–subsymbolic border, including hybrid.
 * Symbolic modeling evolved from the computer science paradigms using the technologies of knowledge-based systems, as well as a philosophical perspective (e.g. "Good Old-Fashioned Artificial Intelligence" (GOFAI)). They were developed by the first cognitive researchers and later used in information engineering for expert systems. Since the early 1990s it was generalized in systemics for the investigation of functional human-like intelligence models, such as personoids, and, in parallel, developed as the SOAR environment. Recently, especially in the context of cognitive decision-making, symbolic cognitive modeling has been extended to the socio-cognitive approach, including social and organizational cognition, interrelated with a sub-symbolic non-conscious layer.
 * Subsymbolic modeling includes connectionist/neural network models. Connectionism relies on the idea that the mind/brain is composed of simple nodes and its problem-solving capacity derives from the connections between them. Neural nets are textbook implementations of this approach. Some critics of this approach feel that while these models approach biological reality as a representation of how the system works, these models lack explanatory powers because, even in systems endowed with simple connection rules, the emerging high complexity makes them less interpretable at the connection-level than they apparently are at the macroscopic level.
 * Other approaches gaining in popularity include (1) dynamical systems theory, (2) mapping symbolic models onto connectionist models (Neural-symbolic integration or hybrid intelligent systems), and (3) and Bayesian models, which are often drawn from machine learning.

All the above approaches tend either to be generalized to the form of integrated computational models of a synthetic/abstract intelligence (i.e. cognitive architecture) in order to be applied to the explanation and improvement of individual and social/organizational decision-making and reasoning or to focus on single simulative programs (or microtheories/"middle-range" theories) modelling specific cognitive faculties (e.g. vision, language, categorization etc.).

Neurobiological methods
Research methods borrowed directly from neuroscience and neuropsychology can also help us to understand aspects of intelligence. These methods allow us to understand how intelligent behavior is implemented in a physical system.
 * Single-unit recording
 * Direct brain stimulation
 * Animal models
 * Postmortem studies

Key findings
Cognitive science has given rise to models of human cognitive bias and risk perception, and has been influential in the development of behavioral finance, part of economics. It has also given rise to a new theory of the philosophy of mathematics (related to denotational mathematics), and many theories of artificial intelligence, persuasion and coercion. It has made its presence known in the philosophy of language and epistemology as well as constituting a substantial wing of modern linguistics. Fields of cognitive science have been influential in understanding the brain's particular functional systems (and functional deficits) ranging from speech production to auditory processing and visual perception. It has made progress in understanding how damage to particular areas of the brain affect cognition, and it has helped to uncover the root causes and results of specific dysfunction, such as dyslexia, anopsia, and hemispatial neglect.

Notable researchers
Some of the more recognized names in cognitive science are usually either the most controversial or the most cited. Within philosophy, some familiar names include Daniel Dennett, who writes from a computational systems perspective, John Searle, known for his controversial Chinese room argument, and Jerry Fodor, who advocates functionalism.

Others include David Chalmers, who advocates Dualism and is also known for articulating the hard problem of consciousness, and Douglas Hofstadter, famous for writing Gödel, Escher, Bach, which questions the nature of words and thought.

In the realm of linguistics, Noam Chomsky and George Lakoff have been influential (both have also become notable as political commentators). In artificial intelligence, Marvin Minsky, Herbert A. Simon, and Allen Newell are prominent.

Popular names in the discipline of psychology include George A. Miller, James McClelland, Philip Johnson-Laird, Lawrence Barsalou, Vittorio Guidano, Howard Gardner and Steven Pinker. Anthropologists Dan Sperber, Edwin Hutchins, Bradd Shore, James Wertsch and Scott Atran, have been involved in collaborative projects with cognitive and social psychologists, political scientists and evolutionary biologists in attempts to develop general theories of culture formation, religion, and political association.

Computational theories (with models and simulations) have also been developed, by David Rumelhart, James McClelland and Philip Johnson-Laird.

Epistemics
Epistemics is a term coined in 1969 by the University of Edinburgh with the foundation of its School of Epistemics. Epistemics is to be distinguished from epistemology in that epistemology is the philosophical theory of knowledge, whereas epistemics signifies the scientific study of knowledge.

Christopher Longuet-Higgins has defined it as "the construction of formal models of the processes (perceptual, intellectual, and linguistic) by which knowledge and understanding are achieved and communicated." In his 1978 essay "Epistemics: The Regulative Theory of Cognition", Alvin I. Goldman claims to have coined the term "epistemics" to describe a reorientation of epistemology. Goldman maintains that his epistemics is continuous with traditional epistemology and the new term is only to avoid opposition. Epistemics, in Goldman's version, differs only slightly from traditional epistemology in its alliance with the psychology of cognition; epistemics stresses the detailed study of mental processes and information-processing mechanisms that lead to knowledge or beliefs.

In the mid-1980s, the School of Epistemics was renamed as The Centre for Cognitive Science (CCS). In 1998, CCS was incorporated into the University of Edinburgh's School of Informatics.

Binding problem in cognitive science
One of the core aims of cognitive science is to achieve an integrated theory of cognition. This requires integrative mechanisms explaining how the information processing that occurs simultaneously in spatially segregated (sub-)cortical areas in the brain is coordinated and bound together to give rise to coherent perceptual and symbolic representations. One approach is to solve this "Binding problem"  (that is, the problem of dynamically representing conjunctions of informational elements, from the most basic perceptual representations ("feature binding") to the most complex cognitive representations, like symbol structures ("variable binding")), by means of integrative synchronization mechanisms. In other words, one of the coordinating mechanisms appears to be the temporal (phase) synchronization of neural activity based on dynamical self-organizing processes in neural networks, described by the Binding-by-synchrony (BBS) Hypothesis from neurophysiology. Connectionist cognitive neuroarchitectures have been developed that use integrative synchronization mechanisms to solve this binding problem in perceptual cognition and in language cognition. In perceptual cognition the problem is to explain how elementary object properties and object relations, like the object color or the object form, can be dynamically bound together or can be integrated to a representation of this perceptual object by means of a synchronization mechanism ("feature binding", "feature linking"). In language cognition the problem is to explain how semantic concepts and syntactic roles can be dynamically bound together or can be integrated to complex cognitive representations like systematic and compositional symbol structures and propositions by means of a synchronization mechanism ("variable binding") (see also the "Symbolism vs. connectionism debate" in connectionism).

However, despite significant advances in understanding the integrated theory of cognition (specifically the Binding problem), the debate on this issue of beginning cognition is still in progress. From the different perspectives noted above, this problem can be reduced to the issue of how organisms at the simple reflexes stage of development overcome the threshold of the environmental chaos of sensory stimuli: electromagnetic waves, chemical interactions, and pressure fluctuations. The so-called Primary Data Entry (PDE) thesis poses doubts about the ability of such an organism to overcome this cue threshold on its own. In terms of mathematical tools, the PDE thesis underlines the insuperable high threshold of the cacophony of environmental stimuli (the stimuli noise) for young organisms at the onset of life. It argues that the temporal (phase) synchronization of neural activity based on dynamical self-organizing processes in neural networks, any dynamical bound together or integration to a representation of the perceptual object by means of a synchronization mechanism can not help organisms in distinguishing relevant cue (informative stimulus) for overcome this noise threshold.

title: Cognitive science


text:
Copula (linguistics)

In linguistics, a copula (: copulas or copulae; abbreviated ) is a word or phrase that links the subject of a sentence to a subject complement, such as the word is in the sentence "The sky is blue" or the phrase was not being in the sentence "It was not being cooperative." The word copula derives from the Latin noun for a "link" or "tie" that connects two different things.

A copula is often a verb or a verb-like word, though this is not universally the case. A verb that is a copula is sometimes called a copulative or copular verb. In English primary education grammar courses, a copula is often called a linking verb. In other languages, copulas show more resemblances to pronouns, as in Classical Chinese and Guarani, or may take the form of suffixes attached to a noun, as in Korean, Beja, and Inuit languages.

Most languages have one main copula (in English, the verb "to be"), although some (like Spanish, Portuguese and Thai) have more than one, while others have none. While the term copula is generally used to refer to such principal verbs, it may also be used for a wider group of verbs with similar potential functions (like become, get, feel and seem in English); alternatively, these might be distinguished as "semi-copulas" or "pseudo-copulas".

Grammatical function
The principal use of a copula is to link the subject of a clause to a subject complement. A copular verb is often considered to be part of the predicate, the remainder being called a predicative expression. A simple clause containing a copula is illustrated below:

"The book is on the table."

In that sentence, the noun phrase the book is the subject, the verb is serves as the copula, and the prepositional phrase on the table is the predicative expression. The whole expression is on the table may (in some theories of grammar) be called a predicate or a verb phrase.

The predicative expression accompanying the copula, also known as the complement of the copula, may take any of several possible forms: it may be a noun or noun phrase, an adjective or adjective phrase, a prepositional phrase (as above) or an adverb or another adverbial phrase expressing time or location. Examples are given below (with the copula in bold and the predicative expression in italics):

Mary and John are my friends. The sky was blue. I am taller than most people. The birds and the beasts were there.

The three components (subject, copula and predicative expression) do not necessarily appear in that order: their positioning depends on the rules for word order applicable to the language in question. In English (an SVO language), the ordering given above is the normal one, but certain variation is possible:
 * In many questions and other clauses with subject–auxiliary inversion, the copula moves in front of the subject: Are you happy?
 * In inverse copular constructions (see below) the predicative expression precedes the copula, but the subject follows it: In the room were three men.

It is also possible, in certain circumstances, for one (or even two) of the three components to be absent:
 * In null-subject (pro-drop) languages, the subject may be omitted, as it may from other types of sentence. In Italian, sono stanco means I am tired, literally am tired.
 * In non-finite clauses in languages like English, the subject is often absent, as in the participial phrase being tired or the infinitive phrase to be tired. The same applies to most imperative sentences like Be good!
 * For cases in which no copula appears, see below.
 * Any of the three components may be omitted as a result of various general types of ellipsis. In particular, in English, the predicative expression may be elided in a construction similar to verb phrase ellipsis, as in short sentences like I am; Are they? (where the predicative expression is understood from the previous context).

Inverse copular constructions, in which the positions of the predicative expression and the subject are reversed, are found in various languages. They have been the subject of much theoretical analysis, particularly in regard to the difficulty of maintaining, in the case of such sentences, the usual division into a subject noun phrase and a predicate verb phrase.

Another issue is verb agreement when both subject and predicative expression are noun phrases (and differ in number or person): in English, the copula typically agrees with the syntactical subject even if it is not logically (i.e. semantically) the subject, as in the cause of the riot is (not are) these pictures of the wall. Compare Italian la causa della rivolta sono queste foto del muro; notice the use of the plural sono to agree with plural queste foto these photos rather than with singular la causa the cause. In instances where an English syntactical subject comprises a prepositional object that is pluralized, however, the prepositional object agrees with the predicative expression, e.g. "What kind of birds are those?"

The definition and scope of the concept of a copula is not necessarily precise in any language. As noted above, though the concept of the copula in English is most strongly associated with the verb to be, there are many other verbs that can be used in a copular sense as well.
 * The boy became a man.
 * The girl grew more excited as the holiday preparations intensified.
 * The dog felt tired from the activity.

And more tenuously
 * The milk turned sour.
 * The food smells good.
 * You seem upset.

Other functions
A copular verb may also have other uses supplementary to or distinct from its uses as a copula. Some co-occurrences are common.

Auxiliary verb
The English verb to be is also used as an auxiliary verb, especially for expressing passive voice (together with the past participle) or expressing progressive aspect (together with the present participle):

The man was killed. (passive) It is raining. (progressive)

Other languages' copulas have additional uses as auxiliaries. For example, French être can be used to express passive voice similarly to English be; both French être and German sein are used to express the perfect forms of certain verbs (formerly English be was also):

Je suis arrivé(e) French for I have arrived, literally I am arrived.

The auxiliary functions of these verbs derived from their copular function, and could be interpreted as special cases of the copular function (with the verbal forms it precedes being considered adjectival).

Another auxiliary usage in English is to denote an obligatory action or expected occurrence: "I am to serve you". "The manager is to resign". This can be put also into past tense: "We were to leave at 9". For forms like "if I was/were to come", see English conditional sentences. (By certain criteria, the English copula be may always be considered an auxiliary verb; see Diagnostics for identifying auxiliary verbs in English.)

Existential verb
The English to be and its equivalents in certain other languages also have a non-copular use as an existential verb, meaning "to exist". This use is illustrated in the following sentences: I want only to be, and that is enough; I think therefore I am; To be or not to be, that is the question. In these cases, the verb itself expresses a predicate (that of existence), rather than linking to a predicative expression as it does when used as a copula. In ontology it is sometimes suggested that the "is" of existence is reducible to the "is" of property attribution or class membership; to be, Aristotle held, is to be something. However, Abelard in his Dialectica made a reductio ad absurdum argument against the idea that the copula can express existence.

Similar examples can be found in many other languages; for example, the French and Latin equivalents of I think therefore I am are Je pense, donc je suis and Cogito ergo sum, where suis and sum are the equivalents of English "am", normally used as copulas. However, other languages prefer a different verb for existential use, as in the Spanish version Pienso, luego existo (where the verb existir to exist is used rather than the copula ser or estar to be).

Another type of existential usage is in clauses of the there is... or there are... type. Languages differ in the way they express such meanings; some of them use the copular verb, possibly with an expletive pronoun like the English there, while other languages use different verbs and constructions, like the French il y a (which uses parts of the verb avoir to have, not the copula) or the Swedish finns (the passive voice of the verb for "to find"). For details, see existential clause.

Relying on a unified theory of copular sentences, it has been proposed that the English there-sentences are subtypes of inverse copular constructions.

Meanings
Predicates formed using a copula may express identity: that the two noun phrases (subject and complement) have the same referent or express an identical concept:

I want only to be myself. The Morning Star is the Evening Star.

They may also express membership of a class or a subset relationship:

She was a nurse. Cats are carnivorous mammals.

Similarly they may express some property, relation or position, permanent or temporary:

The trees are green. I am your boss. The hen is next to the cockerel. The children are confused.

Essence versus state
Some languages use different copulas, or different syntax, to denote a permanent, essential characteristic of something versus a temporary state. For examples, see the sections on the Romance languages, Slavic languages and Irish.

Forms
In many languages the principal copula is a verb, like English (to) be, German sein, Mixtec kuu, Touareg emous, etc. It may inflect for grammatical categories like tense, aspect and mood, like other verbs in the language. Being a very commonly used verb, it is likely that the copula has irregular inflected forms; in English, the verb be has a number of highly irregular (suppletive) forms and has more different inflected forms than any other English verb (am, is, are, was, were, etc.; see English verbs for details).

Other copulas show more resemblances to pronouns. That is the case for Classical Chinese and Guarani, for instance. In highly synthetic languages, copulas are often suffixes, attached to a noun, but they may still behave otherwise like ordinary verbs: -u- in Inuit languages.

In some other languages, like Beja and Ket, the copula takes the form of suffixes that attach to a noun but are distinct from the person agreement markers used on predicative verbs. This phenomenon is known as nonverbal person agreement (or nonverbal subject agreement), and the relevant markers are always established as deriving from cliticized independent pronouns.

Zero copula
In some languages, copula omission occurs within a particular grammatical context. For example, speakers of Russian, Indonesian, Turkish, Hungarian, Arabic, Hebrew, Geʽez and Quechuan languages consistently drop the copula in present tense: Russian: я человек, I (am a) human; Indonesian: saya seorang manusia I (am) a human; Turkish: o insan s/he (is a) human; Hungarian: ő ember s/he (is) a human; Arabic: أنا إنسان,  I (am a) human; Hebrew: אני אדם,  I (am a) human; Geʽez: አነ ብእሲ/ብእሲ አነ,  /  I (am a) man / (a) man I (am); Southern Quechua: payqa runam s/he (is) a human. The usage is known generically as the zero copula. In other tenses (sometimes in forms other than third person singular), the copula usually reappears.

Some languages drop the copula in poetic or aphoristic contexts. Examples in English include Such poetic copula dropping is more pronounced in some languages other than English, like the Romance languages.
 * The more, the better.
 * Out of many, one.
 * True that.

In informal speech of English, the copula may also be dropped in general sentences, as in "She a nurse." It is a feature of African-American Vernacular English, but is also used by a variety of other English speakers. An example is the sentence "I saw twelve men, each a soldier."

Examples in specific languages
In Ancient Greek, when an adjective precedes a noun with an article, the copula is understood: ὁ οἴκος ἐστὶ μακρός, "the house is large", can be written μακρός ὁ οἴκος, "large the house (is)."

In Quechua (Southern Quechua used for the examples), zero copula is restricted to present tense in third person singular (kan): Payqa runam (s)he is a human; but: (paykuna) runakunam kanku (they) are human.

In Māori, the zero copula can be used in predicative expressions and with continuous verbs (many of which take a copulative verb in many Indo-European languages) — He nui te whare, literally a big the house, the house (is) big; I te tēpu te pukapuka, literally at (past locative particle) the table the book, the book (was) on the table; Nō Ingarangi ia, literally from England (s)he, (s)he (is) from England, Kei te kai au, literally at the (act of) eating I, I (am) eating.

Alternatively, in many cases, the particle ko can be used as a copulative (though not all instances of ko are used as thus, like all other Māori particles, ko has multiple purposes): Ko nui te whare The house is big; Ko te pukapuka kei te tēpu It is the book (that is) on the table; Ko au kei te kai It is me eating.

However, when expressing identity or class membership, ko must be used: Ko tēnei tāku pukapuka This is my book; Ko Ōtautahi he tāone i Te Waipounamu Christchurch is a city in the South Island (of New Zealand); Ko koe tōku hoa You are my friend.

When expressing identity, ko can be placed on either object in the clause without changing the meaning (ko tēnei tāku pukapuka is the same as ko tāku pukapuka tēnei) but not on both (ko tēnei ko tāku pukapuka would be equivalent to saying "it is this, it is my book" in English).

In Hungarian, zero copula is restricted to present tense in third person singular and plural: Ő ember/Ők emberek — s/he is a human / they are humans; but: (én) ember vagyok I am a human, (te) ember vagy you are a human, mi emberek vagyunk we are humans, (ti) emberek vagytok you (all) are humans. The copula also reappears for stating locations: az emberek a házban vannak the people are in the house, and for stating time: hat óra van it is six o'clock. However, the copula may be omitted in colloquial language: hat óra (van) it is six o'clock.

Hungarian uses copula lenni for expressing location: Itt van Róbert Bob is here, but it is omitted in the third person present tense for attribution or identity statements: Róbert öreg Bob is old; ők éhesek they are hungry; Kati nyelvtudós Cathy is a linguist (but Róbert öreg volt Bob was old, éhesek voltak they were hungry, Kati nyelvtudós volt Cathy was a linguist).

In Turkish, both the third person singular and the third person plural copulas are omittable. Ali burada and Ali buradadır both mean Ali is here, and Onlar aç and Onlar açlar both mean They are hungry. Both of the sentences are acceptable and grammatically correct, but sentences with the copula are more formal.

The Turkish first person singular copula suffix is omitted when introducing oneself. Bora ben I am Bora is grammatically correct, but Bora benim (same sentence with the copula) is not for an introduction (but is grammatically correct in other cases).

Further restrictions may apply before omission is permitted. For example, in the Irish language, is, the present tense of the copula, may be omitted when the predicate is a noun. Ba, the past/conditional, cannot be deleted. If the present copula is omitted, the pronoun (e.g., é, í, iad) preceding the noun is omitted as well.

Copula-like words
Sometimes, the term copula is taken to include not only a language's equivalent(s) to the verb be but also other verbs or forms that serve to link a subject to a predicative expression (while adding semantic content of their own). For example, English verbs like become, get, feel, look, taste, smell, and seem can have this function, as in the following sentences (the predicative expression, the complement of the verb, is in italics):

She became a student. They look tired. The milk tastes bad. That bread smells good. I feel bad that she can't come with us. London stands (is) on the river Thames. How is Mary? ; She seems (is) well (fine).

(This usage should be distinguished from the use of some of these verbs as "action" verbs, as in They look at the wall, in which look denotes an action and cannot be replaced by the basic copula are.)

Some verbs have rarer, secondary uses as copular verbs, like the verb fall in sentences like The zebra fell victim to the lion.

These extra copulas are sometimes called "semi-copulas" or "pseudo-copulas." For a list of common verbs of this type in English, see List of English copulae.

Indo-European
In Indo-European languages, the words meaning to be are sometimes similar to each other. Due to the high frequency of their use, their inflection retains a considerable degree of similarity in some cases. Thus, for example, the English form is is a cognate of German ist, Latin est, Persian and Russian, even though the Germanic, Italic, Iranian and Slavic language groups split at least 3000 years ago. The origins of the copulas of most Indo-European languages can be traced back to four Proto-Indo-European stems: ' ('), ' ('), ' and ' ().

English
The English copular verb be has eight basic forms (be, am, is, are, being, was, were, been) and five negative forms (ain't (in some dialects), isn't, aren't, wasn't, weren't). No other English verb has more than five forms. Additional archaic forms include art, wast, wert, and occasionally beest (as a subjunctive). For more details see English verbs. For the etymology of the various forms, see Indo-European copula.

The main uses of the copula in English are described in the above sections. The possibility of copula omission is mentioned under.

A particular construction found in English (particularly in speech) is the use of two successive copulas when only one appears necessary, as in My point is, is that.... The acceptability of this construction is a disputed matter in English prescriptive grammar.

The simple English copula "be" may on occasion be substituted by other verbs with near identical meanings.

Persian
In Persian, the verb to be can take the form of either (cognate to English is) or  (cognate to be).

 * {| border="0" cellspacing="2" cellpadding="1"

 * آسمان آبی است
 * The sky is blue.
 * آسمان آبی خواهد بود
 * The sky will be blue.
 * آسمان آبی بود
 * The sky was blue.
 * آسمان آبی خواهد بود
 * The sky will be blue.
 * آسمان آبی بود
 * The sky was blue.
 * آسمان آبی بود
 * The sky was blue.

 * }

Hindustani
In Hindustani (Hindi and Urdu), the copula होना  can be put into four grammatical aspects (simple, habitual, perfective, and progressive) and each of those four aspects can be put into five grammatical moods (indicative, presumptive, subjunctive, contrafactual, and imperative). Some example sentences using the simple aspect are shown below:

Besides the verb होना  to be, there are three other verbs which can also be used as the copula: रहना   to stay, जाना   to go, and आना   to come. The following table shows the conjugations of the copula होना  in the five grammatical moods in the simple aspect. The transliteration scheme used is ISO 15919.

Romance
Copulas in the Romance languages usually consist of two different verbs that can be translated as "to be", the main one from the Latin esse (via Vulgar Latin essere; esse deriving from *es-), often referenced as sum (another of the Latin verb's principal parts) and a secondary one from stare (from *sta-), often referenced as stō. The resulting distinction in the modern forms is found in all the Iberian Romance languages, and to a lesser extent Italian, but not in French or Romanian. The difference is that the first usually refers to essential characteristics, while the second refers to states and situations, e.g., "Bob is old" versus "Bob is well." A similar division is found in the non-Romance Basque language (viz. egon and izan). (The English words just used, "essential" and "state", are also cognate with the Latin infinitives esse and stare. The word "stay" also comes from Latin stare, through Middle French estai, stem of Old French ester.) In Spanish and Portuguese, the high degree of verbal inflection, plus the existence of two copulas (ser and estar), means that there are 105 (Spanish) and 110 (Portuguese) separate forms to express the copula, compared to eight in English and one in Chinese.

In some cases, the verb itself changes the meaning of the adjective/sentence. The following examples are from Portuguese:

Slavic
Some Slavic languages make a distinction between essence and state (similar to that discussed in the above section on the Romance languages), by putting a predicative expression denoting a state into the instrumental case, and essential characteristics are in the nominative. This can apply with other copula verbs as well: the verbs for "become" are normally used with the instrumental case.

As noted above under, Russian and other North Slavic languages generally or often omit the copula in the present tense.

Irish
In Irish and Scottish Gaelic, there are two copulas, and the syntax is also changed when one is distinguishing between states or situations and essential characteristics.

Describing the subject's state or situation typically uses the normal VSO ordering with the verb bí. The copula is is used to state essential characteristics or equivalences.

 * {| border="0" cellspacing="2" cellpadding="1" valign="top"

 * align=left valign=top| || align=right valign=top |  || align=left valign=top |
 * Is fear é Liam. || Liam is a man. || (lit. Is man Liam.)
 * Is leabhar é sin. || That is a book. || (lit. Is book it that.)
 * }
 * Is leabhar é sin. || That is a book. || (lit. Is book it that.)
 * }

The word is is the copula (rhymes with the English word "miss").

The pronoun used with the copula is different from the normal pronoun. For a masculine singular noun, é is used (for "he" or "it"), as opposed to the normal pronoun sé; for a feminine singular noun, í is used (for "she" or "it"), as opposed to normal pronoun sí; for plural nouns, iad is used (for "they" or "those"), as opposed to the normal pronoun siad.

To describe being in a state, condition, place, or act, the verb "to be" is used: Tá mé ag rith. I am running.

North Levantine Arabic
The North Levantine Arabic dialect, spoken in Syria and Lebanon, has a negative copula formed by  and a suffixed pronoun.

Chichewa
In Chichewa, a Bantu language spoken mainly in Malawi, a very similar distinction exists between permanent and temporary states as in Spanish and Portuguese, but only in the present tense. For a permanent state, in the 3rd person, the copula used in the present tense is ndi (negative sí):
 * iyé ndi mphunzitsi he is a teacher
 * iyé sí mphunzitsi he is not a teacher

For the 1st and 2nd persons the particle ndi is combined with pronouns, e.g., ine I:
 * ine ndine mphunzitsi I am a teacher
 * iwe ndiwe mphunzitsi you (sg.) are a teacher
 * ine síndine mphunzitsi I am not a teacher

For temporary states and location, the copula is the appropriate form of the defective verb -li:
 * iyé ali bwino he is well
 * iyé sáli bwino he is not well
 * iyé ali ku nyumbá he is in the house

For the 1st and 2nd persons the person is shown, as normally with Chichewa verbs, by the appropriate pronominal prefix:
 * ine ndili bwino I am well
 * iwe uli bwino you (sg.) are well
 * kunyumbá kuli bwino at home (everything) is fine

In the past tenses, -li is used for both types of copula:
 * iyé analí bwino he was well (this morning)
 * iyé ánaalí mphunzitsi he was a teacher (at that time)

In the future, subjunctive, or conditional tenses, a form of the verb khala sit/dwell is used as a copula:
 * máwa ákhala bwino he'll be fine tomorrow

Muylaq' Aymaran
Uniquely, the existence of the copulative verbalizer suffix in the Southern Peruvian Aymaran language variety, Muylaq' Aymara, is evident only in the surfacing of a vowel that would otherwise have been deleted because of the presence of a following suffix, lexically prespecified to suppress it. As the copulative verbalizer has no independent phonetic structure, it is represented by the Greek letter ʋ in the examples used in this entry.

Accordingly, unlike in most other Aymaran variants, whose copulative verbalizer is expressed with a vowel-lengthening component, -:, the presence of the copulative verbalizer in Muylaq' Aymara is often not apparent on the surface at all and is analyzed as existing only meta-linguistically. However, in a verb phrase like "It is old", the noun thantha old does not require the copulative verbalizer: thantha-wa It is old.

It is now pertinent to make some observations about the distribution of the copulative verbalizer. The best place to start is with words in which its presence or absence is obvious. When the vowel-suppressing first person simple tense suffix attaches to a verb, the vowel of the immediately preceding suffix is suppressed (in the examples in this subsection, the subscript "c" appears prior to vowel-suppressing suffixes in the interlinear gloss to better distinguish instances of deletion that arise from the presence of a lexically pre-specified suffix from those that arise from other (e.g. phonotactic) motivations). Consider the verb sara-, which is inflected for the first person simple tense and so, predictably, loses its final root vowel: sar(a)-ct-wa I go.

However, prior to the suffixation of the first person simple suffix -ct to the same root nominalized with the agentive nominalizer -iri, the word must be verbalized. The fact that the final vowel of -iri below is not suppressed indicates the presence of an intervening segment, the copulative verbalizer: sar(a)-iri-ʋ-t-wa I usually go.

It is worthwhile to compare of the copulative verbalizer in Muylaq' Aymara as compared to La Paz Aymara, a variant which represents this suffix with vowel lengthening. Consider the near-identical sentences below, both translations of "I have a small house" in which the nominal root uta-ni house-attributive is verbalized with the copulative verbalizer, but the correspondence between the copulative verbalizer in these two variants is not always a strict one-to-one relation.

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * La Paz Aymara:
 * ma: jisk'a uta-ni-:-ct(a)-wa
 * Muylaq' Aymara:
 * ma isk'a uta-ni-ʋ-ct-wa
 * }
 * ma isk'a uta-ni-ʋ-ct-wa
 * }

Georgian
As in English, the verb "to be" is irregular in Georgian (a Kartvelian language); different verb roots are employed in different tenses. The roots, , , and (past participle) are used in the present tense, future tense, past tense and the perfective tenses respectively. Examples:

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * I am a teacher.
 * I will be a teacher.
 * I was a teacher.
 * I have been a teacher.
 * I had been a teacher.
 * }
 * I was a teacher.
 * I have been a teacher.
 * I had been a teacher.
 * }
 * I have been a teacher.
 * I had been a teacher.
 * }
 * I had been a teacher.
 * }
 * }

In the last two examples (perfective and pluperfect), two roots are used in one verb compound. In the perfective tense, the root qop (which is the expected root for the perfective tense) is followed by the root ar, which is the root for the present tense. In the pluperfective tense, again, the root qop is followed by the past tense root qav. This formation is very similar to German (an Indo-European language), where the perfect and the pluperfect are expressed in the following way:

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * Ich bin Lehrer gewesen.
 * I have been a teacher, literally I am teacher been.
 * Ich war Lehrer gewesen.
 * I had been a teacher, literally I was teacher been.
 * }
 * I had been a teacher, literally I was teacher been.
 * }

Here, gewesen is the past participle of sein to be in German. In both examples, as in Georgian, this participle is used together with the present and the past forms of the verb in order to conjugate for the perfect and the pluperfect aspects.

Haitian Creole
Haitian Creole, a French-based creole language, has three forms of the copula: se, ye, and the zero copula, no word at all (the position of which will be indicated with Ø, just for purposes of illustration).

Although no textual record exists of Haitian-Creole at its earliest stages of development from French, se is derived from French (written c'est), which is the normal French contraction of  (that, written ce) and the copula  (is, written est) (a form of the verb être).

The derivation of ye is less obvious; but we can assume that the French source was ("he/it is", written il est), which, in rapidly spoken French, is very commonly pronounced as  (typically written y est).

The use of a zero copula is unknown in French, and it is thought to be an innovation from the early days when Haitian-Creole was first developing as a Romance-based pidgin. Latin also sometimes used a zero copula.

Which of se/ye/Ø is used in any given copula clause depends on complex syntactic factors that we can superficially summarize in the following four rules:

1. Use Ø (i.e., no word at all) in declarative sentences where the complement is an adjective phrase, prepositional phrase, or adverb phrase:

Li te Ø an Ayiti.

she PAST COP in Haiti.

"She was in Haiti."

Liv-la Ø jon.

book-the COP yellow.

"The book is yellow." Timoun-yo Ø lakay.

Kids-the COP home.

"The kids are [at] home."

2. Use se when the complement is a noun phrase. But, whereas other verbs come after any tense/mood/aspect particles (like pa to mark negation, or te to explicitly mark past tense, or ap to mark progressive aspect), se comes before any such particles:

Chal se ekriven.

Charles is writer.

"Charles is a writer."

Chal, ki se ekriven, pa vini.

Charles, who is writer, not come.

3. Use se where French and English have a dummy "it" subject:

Se mwen!

C'est moi!

"It's me!"

Se pa fasil.

C'est pas facile.

"It's not easy"

4. Finally, use the other copula form ye in situations where the sentence's syntax leaves the copula at the end of a phrase:

Kijan ou ye?

how 2SG be?

"How you are?"

Pou kimoun liv-la te ye?

Of who book-the PAST be?

"Whose book was it?"

M pa konnen kimoun li ye.

I not know who he is.

"I don't know who he is."

Se yon ekriven Chal ye.

C'est un écrivain Charles est.

Be a writer Charles be.

"Charles is a writer!"

The above is, however, only a simplified analysis.

Japanese
The Japanese copula (most often translated into English as an inflected form of "to be") is unique among verbs in Japanese. It is highly irregular, and in several ways behaves in ways other verbs do not; such as requiring a separate relativised form in some circumstances, and acting simply as a marker of formality/politeness with no predication force in some circumstances. In the most basic case, it behaves like a normal verb with irregular forms, which (like most copulas crosslinguistically) takes a non-case-marked complement instead of an object.

As with all verbs in Japanese, it is necessary to mark the speaker's implied social relationship to the addressee by the choice of verb form. The following two sentences differ only in the fact that the first is appropriate only between decently close friends or family, or said by someone of significantly higher social status than the listener, and the second is only appropriate outside of such circumstances.

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * あれはホテルだ.
 * || That's a hotel. ||
 * あれはホテルです.
 * || That is a hotel. ||
 * }
 * || That is a hotel. ||
 * }

Japanese has two classes of words which correspond to adjectives in English, one of which requires a copula to become a predicate and one of which does not.

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * このビールはおいしい.
 * || This beer is delicious.
 * このビールは豪華だ.
 * || This beer is extravagant.
 * *このビールはおいしいだ.
 * * || colspan=2 | Invalid, as is its own predicate and does not need a copula to make it a predicate
 * }
 * *このビールはおいしいだ.
 * * || colspan=2 | Invalid, as is its own predicate and does not need a copula to make it a predicate
 * }

However, the polite copula is used as a means to mark the self-predicating class of adjectives as grammatically formal, and thus the formal equivalent of  is. In these situations, the copula is not serving as an actual predication device; it is only a means to supply formality marking.

The non-self-predicating class of adjectives is the one place in modern Japanese where a separate relativiser form appears; these require the form in order to modify nouns.

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * このビールはおいしい.
 * || This beer is delicious.
 * おいしいビール
 * || delicious beer
 * このビールは豪華だ.
 * || This beer is extravagant.
 * 豪華なビール
 * || extravagant beer
 * *豪華ビール
 * * || colspan=2 | Invalid, as this class of adjectives cannot just be placed next to a noun to modify it
 * *豪華だビール
 * * || colspan=2 | Invalid, as the copula form requires a specially marked form when it heads a relative clause, unlike all other verbs in modern Japanese
 * }
 * *豪華ビール
 * * || colspan=2 | Invalid, as this class of adjectives cannot just be placed next to a noun to modify it
 * *豪華だビール
 * * || colspan=2 | Invalid, as the copula form requires a specially marked form when it heads a relative clause, unlike all other verbs in modern Japanese
 * }
 * }

Etymologically the copula is a reduced form of, which effectively means 'exists as'; in formal situations or its formal form  can appear in place of  or , and in certain situations other forms of  may be appropriate (such as /). Nonstandard forms such as や in Kansai and じゃ  in much of the rest of western Japan (see map above) are due to various dialects reducing  differently than the Kantō-based standard form did.

The negative form of the copula is generally or its reduced form  (or in formal situations, substitute  for ). This includes the topic marker, due to negative copula sentences typically implying some kind of contrastive topic-like force on the complement. can occur in relative clauses, where information structure marking might be odd, but is also a general negative copula and would be sensible still in any situation  might be used.

Many sentences in Japanese are structurally a headless relative clause nominalised by (or its reduced form ) and then predicated with a copula; the structure is analogous to something like English it's that.... This structure is used to indicate that the statement is intended to answer a question or explain confusion a listener may have had (though the question it answers may not have ever been overtly spoken). This has largely been incorporated into Japanese's sentence-final particle system, and is far more common than the equivalent English structure.

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * そこにある.
 * || It's over there.
 * そこにあるんだ.
 * || (What's going on is that) it's over there.
 * }
 * || (What's going on is that) it's over there.
 * }

Similarly, has also been recruited into the sentence-final particle system, and is used to mark a sentence that the speaker should have been decently obvious to the listener, or to indicate that the speaker is surprised to find that the sentence is true. In this role it can cooccur with an actual predicative, but not with the positive ; is omitted in such sentences.

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * 明日じゃない！
 * || Why, it's tomorrow! (differs from "It's not tomorrow" only by intonation; as a sentence-final particle is not a separate phonological unit while as a negative copula it is)
 * 明日じゃないじゃない！
 * || Why, it isn't tomorrow!
 * }
 * || Why, it isn't tomorrow!
 * }

Korean
For sentences with predicate nominatives, the copula 이 is added to the predicate nominative (with no space in between).

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * 바나나는 과일이다.
 * || Bananas are a fruit.
 * }
 * }

Some adjectives (usually colour adjectives) are nominalized and used with the copula 이.

1. Without the copula 이 :

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * 장미는 빨개요.
 * || Roses are red.
 * }
 * }

2. With the copula 이 :

 * {| border="0" cellspacing="2" cellpadding="1"

 * align=left | || align=right |  || align=left |
 * 장미는 빨간색이다.
 * || Roses are red-coloured.
 * }
 * }

Some Korean adjectives are derived using the copula. Separating these articles and nominalizing the former part will often result in a sentence with a related, but different meaning. Using the separated sentence in a situation where the un-separated sentence is appropriate is usually acceptable as the listener can decide what the speaker is trying to say using the context.

Chinese
In Chinese, both states and qualities are, in general, expressed with stative verbs (SV) with no need for a copula, e.g., in Chinese, "to be tired" (累 ), "to be hungry" (饿 ), "to be located at" (在 ), "to be stupid" (笨 ) and so forth. A sentence can consist simply of a pronoun and such a verb: for example, 我饿 (I am hungry). Usually, however, verbs expressing qualities are qualified by an adverb (meaning "very", "not", "quite", etc.); when not otherwise qualified, they are often preceded by 很, which in other contexts means "very", but in this use often has no particular meaning.

Only sentences with a noun as the complement (e.g., "This is my sister") use the copular verb "to be":. This is used frequently; for example, instead of having a verb meaning "to be Chinese", the usual expression is "to be a Chinese person" (lit. I am a Chinese person; I am Chinese). This is sometimes called an equative verb. Another possibility is for the complement to be just a noun modifier (ending in ), the noun being omitted:

Before the Han dynasty, the character served as a demonstrative pronoun meaning "this" (this usage survives in some idioms and proverbs.) Some linguists believe that  developed into a copula because it often appeared, as a repetitive subject, after the subject of a sentence (in classical Chinese we can say, for example: "George W. Bush, this president of the United States" meaning "George W. Bush is the president of the United States). The character  appears to be formed as a compound of characters with the meanings of "early" and "straight."

Another use of in modern Chinese is in combination with the modifier   to mean "yes" or to show agreement. For example:

"Question: 你的汽车是不是红色的？ Is your car red or not?Response: 是的 Is, meaning 'Yes', or 不是  Not is, meaning 'No.'"

(A more common way of showing that the person asking the question is correct is by simply saying "right" or "correct", 对 ; the corresponding negative answer is 不对 not right.)

Yet another use of is in the shì...(de) construction, which is used to emphasize a particular element of the sentence; see.

In Hokkien  acts as the copula, and   is the equivalent in Wu Chinese. Cantonese uses  instead of ; similarly, Hakka uses.

Siouan languages
In Siouan languages like Lakota, in principle almost all words—according to their structure—are verbs. So not only (transitive, intransitive and so-called "stative") verbs but even nouns often behave like verbs and do not need to have copulas.

For example, the word wičháša refers to a man, and the verb to be a man is expressed as wimáčhaša/winíčhaša/wičháša I am/you are/he is a man. Yet there also is a copula héčha to be a ... that in most cases is used: wičháša hemáčha/heníčha/héčha I am/you are/he is a man.

In order to express the statement I am a doctor of profession, one has to say pezuta wičháša hemáčha. But, in order to express that that person is THE doctor (say, that had been phoned to help), one must use another copula iyé to be the one:

pežúta wičháša (kiŋ) miyé yeló

medicine-man DEF ART I-am-the-one MALE ASSERT

I am the doctor

In order to refer to space (e.g., Robert is in the house), various verbs are used, e.g., yaŋkÁ (lit., to sit) for humans, or háŋ/hé to stand upright for inanimate objects of a certain shape. "Robert is in the house" could be translated as Robert thimáhel yaŋké (yeló), whereas "There's one restaurant next to the gas station" translates as Owótethipi wígli-oínažiŋ kiŋ hél isákhib waŋ hé.

Constructed languages
The constructed language Lojban has two words that act similar to a copula in natural languages. The clause me ... me'u turns whatever follows it into a predicate that means to be (among) what it follows. For example, me la .bob. (me'u) means "to be Bob", and me le ci mensi (me'u) means "to be one of the three sisters". Another one is du, which is itself a predicate that means all its arguments are the same thing (equal). One word which is often confused for a copula in Lojban, but is not one, is cu. It merely indicates that the word which follows is the main predicate of the sentence. For example, lo pendo be mi cu zgipre means "my friend is a musician", but the word cu does not correspond to English is; instead, the word zgipre, which is a predicate, corresponds to the entire phrase "is a musician". The word cu is used to prevent lo pendo be mi zgipre, which would mean "the friend-of-me type of musician".

General references

 * (See "copular sentences" and "existential sentences and expletive there" in Volume II.)
 * Moro, A. (1997) The Raising of Predicates. Cambridge University Press, Cambridge, England.
 * Tüting, A. W. (December 2003). Essay on Lakota syntax..
 * Moro, A. (1997) The Raising of Predicates. Cambridge University Press, Cambridge, England.
 * Tüting, A. W. (December 2003). Essay on Lakota syntax..
 * Moro, A. (1997) The Raising of Predicates. Cambridge University Press, Cambridge, England.
 * Tüting, A. W. (December 2003). Essay on Lakota syntax..
 * Tüting, A. W. (December 2003). Essay on Lakota syntax..

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Copula (linguistics)