identity, in philosophy, problem of distinguishing sameness from change, or unity from diversity; primarily examined in connection with personal identity, universals, and the law of identity in logic. In personal identity the concern has been to determine whether anything in the body or mind remains constant; philosophers have reached no general agreement on this point. The term identity has also become increasingly important in modern psychology, largely through the work of Erik Erikson. He has used the term to designate a sense of self that develops in the course of a man's life and that both relates him to and sets him apart from his social milieu. The terms "identity crisis" and "identity confusion," introduced by Erikson, have gained a wide usage, which often varies from their intended technical sense.

In the philosophy of mind, the doctrine that mental events are identical to physico-chemical events in the brain. So-called “type” identity theory asserts that each type of mental event, such as pain, is identical to some type of event in the brain, such as the firing of c-fibres. In response to objections based on the assumed “multiple realizability” of mental states, “token” identity theory makes the weaker claim that each token of a mental event, such as a particular pain, is identical to some token of a brain event of some type. Seealso mind-body problem.

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formerly multiple personality disorder

Rare condition indicated by the absence of a clear and comprehensive identity. In most cases two or more independent and distinct personality systems develop in the same individual. Each personality may alternately inhabit the person's conscious awareness to the exclusion of the others, but one is usually dominant. The various personalities typically differ from one another in outlook, temperament, and body language and might assume different first names. The condition is generally viewed as resulting from dissociative mental processes—that is, the splitting off from conscious awareness and control of thoughts, feelings, memories, and other mental components in response to situations that are painful, disturbing, or somehow unacceptable to the person experiencing them. Treatment is aimed at integrating the disparate personalities back into a single and unified personality.

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Identity may refer to:

Philosophy

• Identity (philosophy), the sameness of two things
• Identity theory of mind, in the philosophy of mind, holds that the mind is identical to the brain
• Personal identity (philosophy)
• Identity (social science)
• Identity formation
• Law of identity, a principle of logic

Mathematics

• Identity (mathematics), an equality that holds regardless of the values of its variables
• Identity function, a function that does not alter its argument
• Identity element, a special element in a set or structure with respect to an operator
• Identity matrix, a square matrix I with ones on the diagonal, zeros elsewhere

Social science and psychology

• Identity (social science), stemming from cognitive theory, sociology, politics, and psychology.
• Cultural identity, a person's self-affiliation (or categorization by others) as a member of a cultural group
• Gender identity, the gender with which a person identifies (or is identified by others)
• Psychological identity, an individual's unique identity that develops relatively late in his life. (see Identity formation)
• Identity In Organizational Communication, organizational communication scholars look at how our membership in different organizations shapes our “selves,” both in our workplace and in our group affiliations.
• Online identity, established and used by computer network users (see also Digital identity in Computer Science)
• National identity, belief in membership of a nation.

In some countries where there is more than one "nation" in the state or identity is otherwise confused, there may be a debate over what the nation's real identity is, see:

*Britishness, Scottish national identity

*Canadian identity, Québécois nation motion

Business

• Accounting identity, a basic accounting relation that must hold by definition
• Corporate identity, the physical manifestation of a business brand
• Identity theft, the deliberate appropriation of someone else's identity (without that person's permission) for criminal purposes

Computer science

• Digital identity, the representation of identity in terms of digital information (see also online identity in social science)
• Federated identity, identity management with defined trust relations between independent principals
• Laws of identity , laws that define a unifying identity metasystem
• Identity (object-oriented programming), a property of objects that allows those objects to be distinguished from each other.
• Identity column in SQL Server, a database field whose values uniquely identify a row in the table

Religion

• Christian Identity, a Christian religious movement

Television, film, music and literature

• Identity (novel), by Milan Kundera
• Identity (film), directed by James Mangold and starring John Cusack
• Identity (album), by Zee with Richard Wright and Dave Harris
• Identity (music), a transformation of pitches in music
• Identity (game show), a short lived game show
• "Identity" (Law & Order: Special Victims Unit), an episode of Law & Order: Special Victims Unit
• Identity, an episode of the USA Network television show Burn Notice.
• Identify (song), a Natalie Imbruglia song
• iD_eNTITY, a manhwa
• the name of the BNP magazine

See also

• Secret identity (disambiguation)
• Identity theft
• Identity document
• Identification (disambiguation)
• Biometrics
• Entity