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Danse Macabre

The Danse Macabre, also called the Dance of Death, is an artistic genre of allegory from the Late Middle Ages on the universality of death.

The Danse Macabre consists of the dead, or a personification of death, summoning representatives from all walks of life to dance along to the grave, typically with a pope, emperor, king, child, and labourer. The effect is both frivolous and terrifying, beseeching its audience to react emotionally. It was produced as memento mori, to remind people of the fragility of their lives and how vain are the glories of earthly life. Its origins are postulated from illustrated sermon texts; the earliest recorded visual scheme (apart from 14th century Triumph of Death paintings) was a now-lost mural at Holy Innocents' Cemetery in Paris dating from 1424 to 1425.

Background
In his 1998 study on medieval religious practices, historian Francis Rapp wrote that"Christians were moved by the sight of the Infant Jesus playing on his mother's knee; their hearts were touched by the Pietà; and patron saints reassured them by their presence. But, all the while, the danse macabre urged them not to forget the end of all earthly things."This Danse Macabre was enacted at village pageants and at court masques, with people "dressing up as corpses from various strata of society", and may have been the origin of costumes worn during Allhallowtide.

In her thesis, The Black Death and its Effect on 14th and 15th Century Art, Anna Louise Des Ormeaux describes the effect of the Black Death on art, mentioning the Danse Macabre as she does so:"Some plague art contains gruesome imagery that was directly influenced by the mortality of the plague or by the medieval fascination with the macabre and awareness of death that were augmented by the plague. Some plague art documents psychosocial responses to the fear that plague aroused in its victims. Other plague art is of a subject that directly responds to people's reliance on religion to give them hope." The cultural impact of mass outbreaks of disease are not fleeting or temporary. The effect can endure past the initial stages of outbreak, in its deep etching upon the culture and society. This can be seen in the artworks and motifs of Danse Macabre as people attempted to cope with the death surrounding them.

Paintings

What is often considered to be the earliest recorded visual example is the lost mural on the south wall of the Cemetery of the Holy Innocents in Paris. It was painted in 1424–25 during the regency of John, Duke of Bedford. It features an emphatic inclusion of a dead crowned king at a time when France did not have a crowned king. The mural may well have had a political subtext. However, some have argued that 14th century Triumph of Death paintings such as the fresco by Francesco Traini are also examples of danse macabre.

There were also painted schemes in Basel (the earliest dating from c. 1440); a series of paintings on canvas by Bernt Notke (1440–1509) in Lübeck (1463); the initial fragment of the original Bernt Notke painting Danse Macabre (accomplished at the end of the 15th century) in the St Nicholas' Church, Tallinn, Estonia; the painting at the back wall of the chapel of Sv. Marija na Škrilinama in the Istrian town of Beram (1474), painted by Vincent of Kastav; the painting in the Holy Trinity Church of Hrastovlje, Istria by John of Kastav (1490).

A notable example was painted on the cemetery walls of the Dominican Abbey, in Bern, by Niklaus Manuel Deutsch (1484–1530) in 1516/7. This work of art was destroyed when the wall was torn down in 1660, but a 1649 copy by Albrecht Kauw (1621–1681) is extant. There was also a Dance of Death painted around 1430 and displayed on the walls of Pardon Churchyard at Old St Paul's Cathedral, London, with texts by John Lydgate (1370–1451) known as the 'Dance of (St) Poulys', which was destroyed in 1549.

The deathly horrors of the 14th century such as recurring famines, the Hundred Years' War in France, and, most of all, the Black Death, were culturally assimilated throughout Europe. The omnipresent possibility of sudden and painful death increased the religious desire for penance, but it also evoked a hysterical desire for amusement while still possible; a last dance as cold comfort. The Danse Macabre combines both desires: in many ways similar to the medieval mystery plays, the dance-with-death allegory was originally a didactic dialogue poem to remind people of the inevitability of death and to advise them strongly to be prepared at all times for death (see memento mori and Ars moriendi).

Short verse dialogues between Death and each of its victims, which could have been performed as plays, can be found in the direct aftermath of the Black Death in Germany and in Spain (where it was known as the Totentanz and la Danza de la Muerte, respectively).

The French term Danse Macabre may derive from the Latin Chorea Machabæorum, literally "dance of the Maccabees." In 2 Maccabees, a deuterocanonical book of the Bible, the grim martyrdom of a mother and her seven sons is described and was a well-known medieval subject. It is possible that the Maccabean Martyrs were commemorated in some early French plays, or that people just associated the book's vivid descriptions of the martyrdom with the interaction between Death and its prey.

An alternative explanation is that the term entered France via Spain, the مقابر, maqabir (pl., "cemeteries") being the root of the word. Both the dialogues and the evolving paintings were ostensive penitential lessons that even illiterate people (who were the overwhelming majority) could understand.

Mural paintings
Frescoes and murals dealing with death had a long tradition, and were widespread. For example, the legend of the Three Living and the Three Dead. On a ride or hunt, three young gentlemen meet three cadavers (sometimes described as their ancestors) who warn them, Quod fuimus, estis; quod sumus, vos eritis ("What we were, you are; what we are, you will be"). Numerous mural versions of that legend from the 13th century onwards have survived (for instance, in the Hospital Church of Wismar or the residential Longthorpe Tower outside Peterborough). Since they showed pictorial sequences of men and corpses covered with shrouds, those paintings are sometimes regarded as cultural precursors of the new genre.

A Danse Macabre painting may show a round dance headed by Death or, more usually, a chain of alternating dead and live dancers. From the highest ranks of the mediaeval hierarchy (usually pope and emperor) descending to its lowest (beggar, peasant, and child), each mortal's hand is taken by an animated skeleton or cadaver. The famous Totentanz by Bernt Notke in St. Mary's Church, Lübeck (destroyed during the Allied bombing of Lübeck in World War II), presented the dead dancers as very lively and agile, making the impression that they were actually dancing, whereas their living dancing partners looked clumsy and passive. The apparent class distinction in almost all of these paintings is completely neutralized by Death as the ultimate equalizer, so that a sociocritical element is subtly inherent to the whole genre. The Totentanz of Metnitz, for example, shows how a pope crowned with his tiara is being led into Hell by Death.

Usually, a short dialogue is attached to each pair of dancers, in which Death is summoning him (or, more rarely, her) to dance and the summoned is moaning about impending death. In the first printed Totentanz textbook (Anon.: Vierzeiliger oberdeutscher Totentanz, Heidelberger Blockbuch, c. 1455/58), Death addresses, for example, the emperor:

"Emperor, your sword won't help you out Sceptre and crown are worthless here I've taken you by the hand For you must come to my dance"

At the lower end of the Totentanz, Death calls, for example, the peasant to dance, who answers:

"I had to work very much and very hard The sweat was running down my skin I'd like to escape death nonetheless But here I won't have any luck" Various examples of Danse Macabre in Slovenia and Croatia below:

Hans Holbein's woodcuts
Renowned for his Dance of Death series, the famous designs by Hans Holbein the Younger (1497–1543) were drawn in 1526 while he was in Basel. They were cut in wood by the accomplished Formschneider (block cutter) Hans Lützelburger.

William Ivins (quoting W. J. Linton) writes of Lützelburger's work wrote:

"`Nothing indeed, by knife or by graver, is of higher quality than this man's doing.' For by common acclaim the originals are technically the most marvelous woodcuts ever made."

These woodcuts soon appeared in proofs with titles in German. The first book edition, containing forty-one woodcuts, was published at Lyons by the Treschsel brothers in 1538. The popularity of the work, and the currency of its message, are underscored by the fact that there were eleven editions before 1562, and over the sixteenth century perhaps as many as a hundred unauthorized editions and imitations. Ten further designs were added in later editions.

The Dance of Death (1523–26) refashions the late-medieval allegory of the Danse Macabre as a reformist satire, and one can see the beginnings of a gradual shift from traditional to reformed Christianity. That shift had many permutations however, and in a study Natalie Zemon Davis has shown that the contemporary reception and afterlife of Holbein's designs lent themselves to neither purely Catholic or Protestant doctrine, but could be outfitted with different surrounding prefaces and sermons as printers and writers of different political and religious leanings took them up. Most importantly, "The pictures and the Bible quotations above them were the main attractions […] Both Catholics and Protestants wished, through the pictures, to turn men's thoughts to a Christian preparation for death.".

The 1538 edition which contained Latin quotations from the Bible above Holbein's designs, and a French quatrain below composed by Gilles Corrozet (1510–1568) actually did not credit Holbein as the artist. It bore the title: Les simulachres & / HISTORIEES FACES / DE LA MORT, AUTANT ELE/gammēt pourtraictes, que artifi/ciellement imaginées. / A Lyon. / Soubz l'escu de COLOIGNE. / M.D. XXXVIII. ("Images and Illustrated facets of Death, as elegantly depicted as they are artfully conceived.") These images and workings of death as captured in the phrase "histories faces" of the title "are the particular exemplification of the way death works, the individual scenes in which the lessons of mortality are brought home to people of every station."

In his preface to the work Jean de Vauzèle, the Prior of Montrosier, addresses Jehanne de Tourzelle, the Abbess of the Convent at St. Peter at Lyons, and names Holbein's attempts to capture the ever-present, but never directly seen, abstract images of death "simulachres." He writes: "[…] simulachres les dis ie vrayement, pour ce que simulachre vient de simuler, & faindre ce que n'est point." ("Simulachres they are most correctly called, for simulachre derives from the verb to simulate and to feign that which is not really there.") He next employs a trope from the memento mori (remember we all must die) tradition and a metaphor from printing which well captures the undertakings of Death, the artist, and the printed book before us in which these simulachres of death barge in on the living: "Et pourtant qu'on n'a peu trouver chose plus approchante a la similitude de Mort, que la personne morte, on d'icelle effigie simulachres, & faces de Mort, pour en nos pensees imprimer la memoire de Mort plus au vis, que ne pourroient toutes les rhetoriques descriptiones de orateurs." ("And yet we cannot discover any one thing more near the likeness of Death than the dead themselves, whence come these simulated effigies and images of Death's affairs, which imprint the memory of Death with more force than all the rhetorical descriptions of the orators ever could.").

Holbein's series shows the figure of "Death" in many disguises, confronting individuals from all walks of life. None escape Death's skeletal clutches, not even the pious. As Davis writes, "Holbein's pictures are independent dramas in which Death comes upon his victim in the midst of the latter's own surroundings and activities. This is perhaps nowhere more strikingly captured than in the wonderful blocks showing the plowman earning his bread by the sweat of his brow only to have his horses speed him to his end by Death. The Latin from the 1549 Italian edition pictured here reads: "In sudore vultus tui, vesceris pane tuo." ("Through the sweat of thy brow you shall eat your bread"), quoting Genesis 3.19. The Italian verses below translate: ("Miserable in the sweat of your brow,/ It is necessary that you acquire the bread you need eat,/ But, may it not displease you to come with me,/ If you are desirous of rest."). Or there is the nice balance in composition Holbein achieves between the heavy-laden traveling salesman insisting that he must still go to market while Death tugs at his sleeve to put down his wares once and for all: "Venite ad me, qui onerati estis." ("Come to me, all ye who [labour and] are heavy laden"), quoting Matthew 11.28. The Italian here translates: "Come with me, wretch, who are weighed down / Since I am the dame who rules the whole world:/ Come and hear my advice / Because I wish to lighten you of this load."

Musical settings
Musical settings of the motif include:
 * Mattasin oder Toden Tanz, 1598, by August Nörmiger
 * Totentanz. Paraphrase on "Dies irae." by Franz Liszt, 1849, a set of variations based on the plainsong melody "Dies Irae".
 * Danse Macabre by Camille Saint-Saëns, 1874
 * Songs and Dances of Death, 1875–77, by Modest Mussorgsky
 * Symphony No. 4, 2nd Movement, 1901, by Gustav Mahler
 * Totentanz der Prinzipien, 1914, by Arnold Schönberg
 * The Green Table, 1932, ballet by Kurt Jooss
 * Totentanz, 1934, by Hugo Distler, inspired by the Lübecker Totentanz
 * "Scherzo (Dance of Death)," in Op. 14 Ballad of Heroes, 1939, by Benjamin Britten
 * Piano Trio No. 2 in E minor, Op. 67, 4th movement, "Dance of Death," 1944, by Dmitri Shostakovich
 * Der Kaiser von Atlantis, oder Die Tod-Verweigerung, 1944, by Viktor Ullmann and Peter Kien
 * Le Grand Macabre, opera written by György Ligeti (Stockholm 1978)
 * Danse Macabre, song, 1984, by Celtic Frost, Swiss extreme metal band
 * Dance of Death, 2003, an album and a song by Iron Maiden, heavy metal band
 * Cortège & Danse Macabre from the symphonic suite Cantabile, 2009, by Frederik Magle
 * Totentanz (Adès) by Thomas Adès, 2013, a piece for voices and orchestra based on the 15th century text.
 * La Danse Macabre, song on the Shovel Knight soundtrack, 2014, by Jake Kaufman
 * Danse Macabre, song by Purson, 2014
 * Danse Macabre, song by The Oh Hellos, 2015
 * Dance Macabre, 2018, by Ghost (Swedish band), Swedish heavy metal band
 * La danse macabre, song, 2019, by Clément Belio, French multi-instrumentalist
 * Danse Macabre by Jörg Widmann, 2022
 * Danse Macabre, song and album, 2023, by Duran Duran, English new wave band
 * Danse Macabre by Prach Boondiskulchok, 2023
 * Danse Macabre by Heaven Pierce Her, 2023

Textual examples of the Danse Macabre
The Danse Macabre was a frequent motif in poetry, drama and other written literature in the Middle Ages in several areas of western Europe. There is a Spanish Danza de la Muerte, a French Danse Macabre, and a German Totentanz with various Latin manuscripts written during the 14th century. Printed editions of books began appearing in the 15th century, such as the ones produced by Guy Marchant of Paris. Similarly to the musical or artistic representations, the texts describe living and dead persons being called to dance or form a procession with Death.

Danse Macabre texts were often, though not always, illustrated with illuminations and woodcuts.

There is one danse macabre text devoted entirely to women: The Danse Macabre of Women. This work survives in five manuscripts, and two printed editions. In it, 36 women of various ages, in Paris, are called from their daily lives and occupations to join the Dance with Death. An English translation of the French manuscript was published by Ann Tukey Harrison in 1994.

John Lydgate's Dance of Death is a Middle English poem written in the early 15th century. It is a translation of a French poem of the same name, and it is one of the most popular examples of the Danse Macabre genre.

The poem is a moral allegory in which Death leads a procession of people from all walks of life to their graves. The poem includes a variety of characters, including the emperor, the pope, the cardinal, the bishop, the abbot, the prioress, the monk, the nun, the doctor, the lawyer, the merchant, the knight, the plowman, the beggar, and the child. The poem is written in rhyme royal, a seven-line stanzaic form that was popular in the Middle Ages.

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title: Danse Macabre


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David Abercromby

David Abercromby was a 17th-century Scottish physician and writer, thought to have died in 1702. Brought up at Douai as a Roman Catholic by Jesuit priests, he was converted to Protestantism in 1682 and came to abjure popery, and published Protestancy proved Safer than Popery (1686).

Works
His medical reputation was based on his Tuta ac efficax luis venereae saepe absque mercurio ac semper absque salivatione mercuriali curando methodus (1684) which was translated into French, Dutch and German. Two other works by him were De Pulsus Variatione (1685), and Ars explorandi medicas facultates plantarum ex solo sapore (1688); his Opuscula were collected in 1687. These professional writings gave him a place and memorial in Albrecht von Haller, Bibliotheca Medicinae Practicae (1779). According to Haller he was alive early in the 18th century.

He also wrote some books in theology and philosophy, controversial in their time but little remembered today. But the most noticeable of his productions is A Discourse of Wit (1685), which contains some of the most characteristic metaphysical opinions of the Scottish philosophy of common sense. It was followed by Academia Scientiarum (1687), and by A Moral Discourse of the Power of Interest (1690), dedicated to Robert Boyle, Abercromby's patron in the 1680s. He later wrote Reasons Why A Protestant Should not Turn Papist (1687), which has often wrongly been attributed to Boyle. A Short Account of Scots Divines, by him, was printed at Edinburgh in 1833, edited by James Maidment.

title: David Abercromby


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Deconstruction

Deconstruction is a loosely-defined set of approaches to understanding the relationship between text and meaning. The concept of deconstruction was introduced by the philosopher Jacques Derrida, who described it as a turn away from Platonism's ideas of "true" forms and essences which are valued above appearances.

Since the 1980s, these proposals of language's fluidity instead of being ideally static and discernible have inspired a range of studies in the humanities, including the disciplines of law, anthropology, historiography, linguistics, sociolinguistics, psychoanalysis, LGBT studies, and feminism. Deconstruction also inspired deconstructivism in architecture and remains important within art, music, and literary criticism.

Overview
Jacques Derrida's 1967 book Of Grammatology introduced the majority of ideas influential within deconstruction. Derrida published a number of other works directly relevant to the concept of deconstruction, such as Différance, Speech and Phenomena, and Writing and Difference.

To Derrida, "That is what deconstruction is made of: not the mixture but the tension between memory, fidelity, the preservation of something that has been given to us, and, at the same time, heterogeneity, something absolutely new, and a break."

According to Derrida, and taking inspiration from the work of Ferdinand de Saussure, language as a system of signs and words only has meaning because of the contrast between these signs. As Richard Rorty contends, "words have meaning only because of contrast-effects with other words ... no word can acquire meaning in the way in which philosophers from Aristotle to Bertrand Russell have hoped it might—by being the unmediated expression of something non-linguistic (e.g., an emotion, a sensed observation, a physical object, an idea, a Platonic Form)". As a consequence, meaning is never present, but rather is deferred to other signs. Derrida refers to the—in his view, mistaken—belief that there is a self-sufficient, non-deferred meaning as metaphysics of presence. Rather, according to Derrida, a concept must be understood in the context of its opposite: for example, the word being does not have meaning without contrast with the word nothing.

Further, Derrida contends that "in a classical philosophical opposition we are not dealing with the peaceful coexistence of a vis-a-vis, but rather with a violent hierarchy. One of the two terms governs the other (axiologically, logically, etc.), or has the upper hand": signified over signifier; intelligible over sensible; speech over writing; activity over passivity, etc. The first task of deconstruction is, according to Derrida, to find and overturn these oppositions inside text(s); but the final objective of deconstruction is not to surpass all oppositions, because it is assumed they are structurally necessary to produce sense: the oppositions simply cannot be suspended once and for all, as the hierarchy of dual oppositions always reestablishes itself (because it is necessary for meaning). Deconstruction, Derrida says, only points to the necessity of an unending analysis that can make explicit the decisions and hierarchies intrinsic to all texts.

Derrida further argues that it is not enough to expose and deconstruct the way oppositions work and then stop there in a nihilistic or cynical position, "thereby preventing any means of intervening in the field effectively". To be effective, deconstruction needs to create new terms, not to synthesize the concepts in opposition, but to mark their difference and eternal interplay. This explains why Derrida always proposes new terms in his deconstruction, not as a free play but from the necessity of analysis. Derrida called these undecidables—that is, unities of simulacrum—"false" verbal properties (nominal or semantic) that can no longer be included within philosophical (binary) opposition. Instead, they inhabit philosophical oppositions—resisting and organizing them—without ever constituting a third term or leaving room for a solution in the form of a Hegelian dialectic (e.g., différance, archi-writing, pharmakon, supplement, hymen, gram, spacing).

Influences
Derrida's theories on deconstruction were themselves influenced by the work of linguists such as Ferdinand de Saussure (whose writings on semiotics also became a cornerstone of structuralism in the mid-20th century) and literary theorists such as Roland Barthes (whose works were an investigation of the logical ends of structuralist thought). Derrida's views on deconstruction stood in opposition to the theories of structuralists such as psychoanalytic theorist Jacques Lacan, and anthropologist Claude Lévi-Strauss. However, Derrida resisted attempts to label his work as "post-structuralist".

Influence of Nietzsche
Derrida's motivation for developing deconstructive criticism, suggesting the fluidity of language over static forms, was largely inspired by Friedrich Nietzsche's philosophy, beginning with his interpretation of Trophonius. In Daybreak, Nietzsche announces that "All things that live long are gradually so saturated with reason that their origin in unreason thereby becomes improbable. Does not almost every precise history of an origination impress our feelings as paradoxical and wantonly offensive? Does the good historian not, at bottom, constantly contradict?".

Nietzsche's point in Daybreak is that standing at the end of modern history, modern thinkers know too much to continue to be deceived by an illusory grasp of satisfactorily complete reason. Mere proposals of heightened reasoning, logic, philosophizing and science are no longer solely sufficient as the royal roads to truth. Nietzsche disregards Platonism to revisualize the history of the West as the self-perpetuating history of a series of political moves, that is, a manifestation of the will to power, that at bottom have no greater or lesser claim to truth in any noumenal (absolute) sense. By calling attention to the fact that he has assumed the role of a subterranean Trophonius, in dialectical opposition to Plato, Nietzsche hopes to sensitize readers to the political and cultural context, and the political influences that impact authorship.

Where Nietzsche did not achieve deconstruction, as Derrida sees it, is that he missed the opportunity to further explore the will to power as more than a manifestation of the sociopolitically effective operation of writing that Plato characterized, stepping beyond Nietzsche's penultimate revaluation of all Western values, to the ultimate, which is the emphasis on "the role of writing in the production of knowledge".

Influence of Saussure
Derrida approaches all texts as constructed around elemental oppositions which all discourse has to articulate if it intends to make any sense whatsoever. This is so because identity is viewed in non-essentialist terms as a construct, and because constructs only produce meaning through the interplay of difference inside a "system of distinct signs". This approach to text is influenced by the semiology of Ferdinand de Saussure.

Saussure is considered one of the fathers of structuralism when he explained that terms get their meaning in reciprocal determination with other terms inside language:

"In language there are only differences. Even more important: a difference generally implies positive terms between which the difference is set up; but in language there are only differences without positive terms. Whether we take the signified or the signifier, language has neither ideas nor sounds that existed before the linguistic system, but only conceptual and phonic differences that have issued from the system. The idea or phonic substance that a sign contains is of less importance than the other signs that surround it. [...] A linguistic system is a series of differences of sound combined with a series of differences of ideas; but the pairing of a certain number of acoustical signs with as many cuts made from the mass thought engenders a system of values."

Saussure explicitly suggested that linguistics was only a branch of a more general semiology, a science of signs in general, human codes being only one part. Nevertheless, in the end, as Derrida pointed out, Saussure made linguistics "the regulatory model", and "for essential, and essentially metaphysical, reasons had to privilege speech, and everything that links the sign to phone". Derrida will prefer to follow the more "fruitful paths (formalization)" of a general semiotics without falling into what he considered "a hierarchizing teleology" privileging linguistics, and to speak of "mark" rather than of language, not as something restricted to mankind, but as prelinguistic, as the pure possibility of language, working everywhere there is a relation to something else.

Etymology
Derrida's original use of the word deconstruction was a translation of Destruktion, a concept from the work of Martin Heidegger that Derrida sought to apply to textual reading. Heidegger's term referred to a process of exploring the categories and concepts that tradition has imposed on a word, and the history behind them.

Basic philosophical concerns
Derrida's concerns flow from a consideration of several issues:

 * A desire to contribute to the re-evaluation of all Western values, a re-evaluation built on the 18th-century Kantian critique of pure reason, and carried forward to the 19th century, in its more radical implications, by Kierkegaard and Nietzsche.
 * An assertion that texts outlive their authors, and become part of a set of cultural habits equal to, if not surpassing, the importance of authorial intent.
 * A re-valuation of certain classic western dialectics: poetry vs. philosophy, reason vs. revelation, structure vs. creativity, episteme vs. techne, etc.

To this end, Derrida follows a long line of modern philosophers, who look backwards to Plato and his influence on the Western metaphysical tradition. Like Nietzsche, Derrida suspects Plato of dissimulation in the service of a political project, namely the education, through critical reflections, of a class of citizens more strategically positioned to influence the polis. However, unlike Nietzsche, Derrida is not satisfied with such a merely political interpretation of Plato, because of the particular dilemma in which modern humans find themselves. His Platonic reflections are inseparably part of his critique of modernity, hence his attempt to be something beyond the modern, because of his Nietzschean sense that the modern has lost its way and become mired in nihilism.

Différance
Différance is the observation that the meanings of words come from their synchrony with other words within the language and their diachrony between contemporary and historical definitions of a word. Understanding language, according to Derrida, requires an understanding of both viewpoints of linguistic analysis. The focus on diachrony has led to accusations against Derrida of engaging in the etymological fallacy.

There is one statement by Derrida—in an essay on Rousseau in Of Grammatology—which has been of great interest to his opponents. It is the assertion that "there is no outside-text" (il n'y a pas de hors-texte), which is often mistranslated as "there is nothing outside of the text". The mistranslation is often used to suggest Derrida believes that nothing exists but words. Michel Foucault, for instance, famously misattributed to Derrida the very different phrase Il n'y a rien en dehors du texte for this purpose. According to Derrida, his statement simply refers to the unavoidability of context that is at the heart of différance.

For example, the word house derives its meaning more as a function of how it differs from shed, mansion, hotel, building, etc. (form of content, which Louis Hjelmslev distinguished from form of expression) than how the word house may be tied to a certain image of a traditional house (i.e., the relationship between signified and signifier), with each term being established in reciprocal determination with the other terms than by an ostensive description or definition: when can one talk about a house or a mansion or a shed? The same can be said about verbs in all languages: when should one stop saying walk and start saying run? The same happens, of course, with adjectives: when must one stop saying yellow and start saying orange, or exchange past for present? Not only are the topological differences between the words relevant here, but the differentials between what is signified is also covered by différance.

Thus, complete meaning is always "differential" and postponed in language; there is never a moment when meaning is complete and total. A simple example would consist of looking up a given word in a dictionary, then proceeding to look up the words found in that word's definition, etc., also comparing with older dictionaries. Such a process would never end.

Metaphysics of presence
Derrida describes the task of deconstruction as the identification of metaphysics of presence, or logocentrism in western philosophy. Metaphysics of presence is the desire for immediate access to meaning, the privileging of presence over absence. This means that there is an assumed bias in certain binary oppositions where one side is placed in a position over another, such as good over bad, speech over the written word, male over female. Derrida writes, "Without a doubt, Aristotle thinks of time on the basis of ousia as parousia, on the basis of the now, the point, etc. And yet an entire reading could be organized that would repeat in Aristotle's text both this limitation and its opposite."

To Derrida, the central bias of logocentrism was the now being placed as more important than the future or past. This argument is largely based on the earlier work of Heidegger, who, in Being and Time, claimed that the theoretical attitude of pure presence is parasitical upon a more originary involvement with the world in concepts such as ready-to-hand and being-with.

Deconstruction and dialectics
In the deconstruction procedure, one of the main concerns of Derrida is to not collapse into Hegel's dialectic, where these oppositions would be reduced to contradictions in a dialectic that has the purpose of resolving it into a synthesis. The presence of Hegelian dialectics was enormous in the intellectual life of France during the second half of the 20th century, with the influence of Kojève and Hyppolite, but also with the impact of dialectics based on contradiction developed by Marxists, and including the existentialism of Sartre, etc. This explains Derrida's concern to always distinguish his procedure from Hegel's, since Hegelianism believes binary oppositions would produce a synthesis, while Derrida saw binary oppositions as incapable of collapsing into a synthesis free from the original contradiction.

Difficulty of definition
There have been problems defining deconstruction. Derrida claimed that all of his essays were attempts to define what deconstruction is, and that deconstruction is necessarily complicated and difficult to explain since it actively criticises the very language needed to explain it.

Derrida's "negative" descriptions
Derrida has been more forthcoming with negative (apophatic) than with positive descriptions of deconstruction. When asked by Toshihiko Izutsu some preliminary considerations on how to translate deconstruction in Japanese, in order to at least prevent using a Japanese term contrary to deconstruction 's actual meaning, Derrida began his response by saying that such a question amounts to "what deconstruction is not, or rather ought not to be".

Derrida states that deconstruction is not an analysis, a critique, or a method in the traditional sense that philosophy understands these terms. In these negative descriptions of deconstruction, Derrida is seeking to "multiply the cautionary indicators and put aside all the traditional philosophical concepts". This does not mean that deconstruction has absolutely nothing in common with an analysis, a critique, or a method, because while Derrida distances deconstruction from these terms, he reaffirms "the necessity of returning to them, at least under erasure". Derrida's necessity of returning to a term under erasure means that even though these terms are problematic, they must be used until they can be effectively reformulated or replaced. The relevance of the tradition of negative theology to Derrida's preference for negative descriptions of deconstruction is the notion that a positive description of deconstruction would over-determine the idea of deconstruction and would close off the openness that Derrida wishes to preserve for deconstruction. If Derrida were to positively define deconstruction—as, for example, a critique—then this would make the concept of critique immune to itself being deconstructed. Some new philosophy beyond deconstruction would then be required in order to encompass the notion of critique.

Not a method
Derrida states that "Deconstruction is not a method, and cannot be transformed into one". This is because deconstruction is not a mechanical operation. Derrida warns against considering deconstruction as a mechanical operation, when he states that "It is true that in certain circles (university or cultural, especially in the United States) the technical and methodological "metaphor" that seems necessarily attached to the very word 'deconstruction' has been able to seduce or lead astray". Commentator Richard Beardsworth explains that:

"Derrida is careful to avoid this term [method] because it carries connotations of a procedural form of judgement. A thinker with a method has already decided how to proceed, is unable to give him or herself up to the matter of thought in hand, is a functionary of the criteria which structure his or her conceptual gestures. For Derrida [...] this is irresponsibility itself. Thus, to talk of a method in relation to deconstruction, especially regarding its ethico-political implications, would appear to go directly against the current of Derrida's philosophical adventure."

Beardsworth here explains that it would be irresponsible to undertake a deconstruction with a complete set of rules that need only be applied as a method to the object of deconstruction, because this understanding would reduce deconstruction to a thesis of the reader that the text is then made to fit. This would be an irresponsible act of reading, because it becomes a prejudicial procedure that only finds what it sets out to find.

Not a critique
Derrida states that deconstruction is not a critique in the Kantian sense. This is because Kant defines the term critique as the opposite of dogmatism. For Derrida, it is not possible to escape the dogmatic baggage of the language used in order to perform a pure critique in the Kantian sense. Language is dogmatic because it is inescapably metaphysical. Derrida argues that language is inescapably metaphysical because it is made up of signifiers that only refer to that which transcends them—the signified. In addition, Derrida asks rhetorically "Is not the idea of knowledge and of the acquisition of knowledge in itself metaphysical?" By this, Derrida means that all claims to know something necessarily involve an assertion of the metaphysical type that something is the case somewhere. For Derrida the concept of neutrality is suspect and dogmatism is therefore involved in everything to a certain degree. Deconstruction can challenge a particular dogmatism and hence de-sediment dogmatism in general, but it cannot escape all dogmatism all at once.

Not an analysis
Derrida states that deconstruction is not an analysis in the traditional sense. This is because the possibility of analysis is predicated on the possibility of breaking up the text being analysed into elemental component parts. Derrida argues that there are no self-sufficient units of meaning in a text, because individual words or sentences in a text can only be properly understood in terms of how they fit into the larger structure of the text and language itself. For more on Derrida's theory of meaning see the article on différance.

Not post-structuralist
Derrida states that his use of the word deconstruction first took place in a context in which "structuralism was dominant" and deconstruction's meaning is within this context. Derrida states that deconstruction is an "antistructuralist gesture" because "[s]tructures were to be undone, decomposed, desedimented". At the same time, deconstruction is also a "structuralist gesture" because it is concerned with the structure of texts. So, deconstruction involves "a certain attention to structures" and tries to "understand how an 'ensemble' was constituted". As both a structuralist and an antistructuralist gesture, deconstruction is tied up with what Derrida calls the "structural problematic". The structural problematic for Derrida is the tension between genesis, that which is "in the essential mode of creation or movement", and structure: "systems, or complexes, or static configurations". An example of genesis would be the sensory ideas from which knowledge is then derived in the empirical epistemology. An example of structure would be a binary opposition such as good and evil where the meaning of each element is established, at least partly, through its relationship to the other element.

It is for this reason that Derrida distances his use of the term deconstruction from post-structuralism, a term that would suggest that philosophy could simply go beyond structuralism. Derrida states that "the motif of deconstruction has been associated with 'post-structuralism, but that this term was "a word unknown in France until its 'return' from the United States". In his deconstruction of Edmund Husserl, Derrida actually argues  the contamination of pure origins by the structures of language and temporality. Manfred Frank has even referred to Derrida's work as "neostructuralism", identifying a "distaste for the metaphysical concepts of domination and system".

Alternative definitions
The popularity of the term deconstruction, combined with the technical difficulty of Derrida's primary material on deconstruction and his reluctance to elaborate his understanding of the term, has meant that many secondary sources have attempted to give a more straightforward explanation than Derrida himself ever attempted. Secondary definitions are therefore an interpretation of deconstruction by the person offering them rather than a summary of Derrida's actual position.
 * Paul de Man was a member of the Yale School and a prominent practitioner of deconstruction as he understood it. His definition of deconstruction is that, "[i]t's possible, within text, to frame a question or undo assertions made in the text, by means of elements which are in the text, which frequently would be precisely structures that play off the rhetorical against grammatical elements."
 * Richard Rorty was a prominent interpreter of Derrida's philosophy. His definition of deconstruction is that, "the term 'deconstruction' refers in the first instance to the way in which the 'accidental' features of a text can be seen as betraying, subverting, its purportedly 'essential' message."
 * According to John D. Caputo, the very meaning and mission of deconstruction is:"'to show that things - texts, institutions, traditions, societies, beliefs, and practices of whatever size and sort you need - do not have definable meanings and determinable missions, that they are always more than any mission would impose, that they exceed the boundaries they currently occupy'"
 * Niall Lucy points to the impossibility of defining the term at all, stating: "'While in a sense it is impossibly difficult to define, the impossibility has less to do with the adoption of a position or the assertion of a choice on deconstruction's part than with the impossibility of every 'is' as such. Deconstruction begins, as it were, from a refusal of the authority or determining power of every 'is', or simply from a refusal of authority in general. While such refusal may indeed count as a position, it is not the case that deconstruction holds this as a sort of 'preference' '."
 * David B. Allison, an early translator of Derrida, states in the introduction to his translation of Speech and Phenomena: "[Deconstruction] signifies a project of critical thought whose task is to locate and 'take apart' those concepts which serve as the axioms or rules for a period of thought, those concepts which command the unfolding of an entire epoch of metaphysics. 'Deconstruction' is somewhat less negative than the Heideggerian or Nietzschean terms 'destruction' or 'reversal'; it suggests that certain foundational concepts of metaphysics will never be entirely eliminated...There is no simple 'overcoming' of metaphysics or the language of metaphysics."
 * Paul Ricœur defines deconstruction as a way of uncovering the questions behind the answers of a text or tradition.

Popular definitions
A survey of the secondary literature reveals a wide range of heterogeneous arguments. Particularly problematic are the attempts to give neat introductions to deconstruction by people trained in literary criticism who sometimes have little or no expertise in the relevant areas of philosophy in which Derrida is working. These secondary works (e.g. Deconstruction for Beginners and Deconstructions: A User's Guide)  have attempted to explain deconstruction while being academically criticized for being too far removed from the original texts and Derrida's actual position.

Cambridge Dictionary states that deconstruction is "the act of breaking something down into its separate parts in order to understand its meaning, especially when this is different from how it was previously understood". The Merriam-Webster dictionary states that deconstruction is "the analytic examination of something (such as a theory) often in order to reveal its inadequacy".

Application
Derrida's observations have greatly influenced literary criticism and post-structuralism.

Literary criticism
Derrida's method consisted of demonstrating all the forms and varieties of the originary complexity of semiotics, and their multiple consequences in many fields. His way of achieving this was by conducting readings of philosophical and literary texts, with the goal to understand what in those texts runs counter to their apparent systematicity (structural unity) or intended sense (authorial genesis). By demonstrating the aporias and ellipses of thought, Derrida hoped to show the infinitely subtle ways that this originary complexity, which by definition cannot ever be completely known, works its structuring and destructuring effects.

Deconstruction denotes the pursuing of the meaning of a text to the point of exposing the supposed contradictions and internal oppositions upon which it is founded—supposedly showing that those foundations are irreducibly complex, unstable, or impossible. It is an approach that may be deployed in philosophy, in literary analysis, and even in the analysis of scientific writings. Deconstruction generally tries to demonstrate that any text is not a discrete whole but contains several irreconcilable and contradictory meanings; that any text therefore has more than one interpretation; that the text itself links these interpretations inextricably; that the incompatibility of these interpretations is irreducible; and thus that an interpretative reading cannot go beyond a certain point. Derrida refers to this point as an "aporia" in the text; thus, deconstructive reading is termed "aporetic". He insists that meaning is made possible by the relations of a word to other words within the network of structures that language is.

Derrida initially resisted granting to his approach the overarching name deconstruction, on the grounds that it was a precise technical term that could not be used to characterize his work generally. Nevertheless, he eventually accepted that the term had come into common use to refer to his textual approach, and Derrida himself increasingly began to use the term in this more general way.

Derrida's deconstruction strategy is also used by postmodernists to locate meaning in a text rather than discover meaning due to the position that it has multiple readings. There is a focus on the deconstruction that denotes the tearing apart of a text to find arbitrary hierarchies and presuppositions for the purpose of tracing contradictions that shadow a text's coherence. Here, the meaning of a text does not reside with the author or the author's intentions because it is dependent on the interaction between reader and text. Even the process of translation is also seen as transformative since it "modifies the original even as it modifies the translating language".

Critique of structuralism
Derrida's lecture at Johns Hopkins University, "Structure, Sign, and Play in the Human Sciences", often appears in collections as a manifesto against structuralism. Derrida's essay was one of the earliest to propose some theoretical limitations to structuralism, and to attempt to theorize on terms that were clearly no longer structuralist. Structuralism viewed language as a number of signs, composed of a signified (the meaning) and a signifier (the word itself). Derrida proposed that signs always referred to other signs, existing only in relation to each other, and there was therefore no ultimate foundation or centre. This is the basis of différance.

The Yale School
Between the late 1960s and the early 1980s, many thinkers were influenced by deconstruction, including Paul de Man, Geoffrey Hartman, and J. Hillis Miller. This group came to be known as the Yale school and was especially influential in literary criticism. Derrida and Hillis Miller were subsequently affiliated with the University of California, Irvine.

Miller has described deconstruction this way: "Deconstruction is not a dismantling of the structure of a text, but a demonstration that it has already dismantled itself. Its apparently solid ground is no rock, but thin air."

Critical legal studies movement
Arguing that law and politics cannot be separated, the founders of the Critical Legal Studies movement found it necessary to criticize the absence of the recognition of this inseparability at the level of theory. To demonstrate the indeterminacy of legal doctrine, these scholars often adopt a method, such as structuralism in linguistics, or deconstruction in Continental philosophy, to make explicit the deep structure of categories and tensions at work in legal texts and talk. The aim was to deconstruct the tensions and procedures by which they are constructed, expressed, and deployed.

For example, Duncan Kennedy, in explicit reference to semiotics and deconstruction procedures, maintains that various legal doctrines are constructed around the binary pairs of opposed concepts, each of which has a claim upon intuitive and formal forms of reasoning that must be made explicit in their meaning and relative value, and criticized. Self and other, private and public, subjective and objective, freedom and control are examples of such pairs demonstrating the influence of opposing concepts on the development of legal doctrines throughout history.

Deconstructing History
Deconstructive readings of history and sources have changed the entire discipline of history. In Deconstructing History, Alun Munslow examines history in what he argues is a postmodern age. He provides an introduction to the debates and issues of postmodernist history. He also surveys the latest research into the relationship between the past, history, and historical practice, as well as articulating his own theoretical challenges.

The Inoperative Community
Jean-Luc Nancy argues, in his 1982 book The Inoperative Community, for an understanding of community and society that is undeconstructable because it is prior to conceptualisation. Nancy's work is an important development of deconstruction because it takes the challenge of deconstruction seriously and attempts to develop an understanding of political terms that is undeconstructable and therefore suitable for a philosophy after Derrida. Nancy’s work produced a critique of deconstruction by making the possibility for a relation to the other. This relation to the other is called “anastasis” in Nancy’s work.

The Ethics of Deconstruction
Simon Critchley argues, in his 1992 book The Ethics of Deconstruction, that Derrida's deconstruction is an intrinsically ethical practice. Critchley argues that deconstruction involves an openness to the Other that makes it ethical in the Levinasian understanding of the term.

Derrida and the Political
Jacques Derrida has had a great influence on contemporary political theory and political philosophy. Derrida's thinking has inspired Slavoj Zizek, Richard Rorty, Ernesto Laclau, Judith Butler and many more contemporary theorists who have developed a deconstructive approach to politics. Because deconstruction examines the internal logic of any given text or discourse it has helped many authors to analyse the contradictions inherent in all schools of thought; and, as such, it has proved revolutionary in political analysis, particularly ideology critiques.

Richard Beardsworth, developing from Critchley's Ethics of Deconstruction, argues, in his 1996 Derrida and the Political, that deconstruction is an intrinsically political practice. He further argues that the future of deconstruction faces a perhaps undecidable choice between a theological approach and a technological approach, represented first of all by the work of Bernard Stiegler.

American Evangelical Christianity
In American Evangelical Christianity in the 2020s, the term "deconstructing faith" came to designate a process of critically examining one's own religious beliefs with the possibility of rejecting them. Author David Hayward said he "co-opted the term" deconstruction because he was reading the work of Derrida at the time his religious beliefs came into question.

Cuisine
Leading Spanish chef Ferran Adrià coined "deconstruction" as a style of cuisine, which he described as drawing from the creative principles of Spanish modernists like Salvador Dalí and Antoni Gaudí to deconstruct conventional cooking techniques in the modern era. Deconstructed recipes typically preserve the core ingredients and techniques of an established dish, but prepare components of a dish separately while experimenting radically with its flavor, texture, ratios, and assembly to culminate in a stark, minimalist style of presentation with similarly minimal portion sizes.

Criticisms
Derrida was involved in a number of high-profile disagreements with prominent philosophers, including Michel Foucault, John Searle, Willard Van Orman Quine, Peter Kreeft, and Jürgen Habermas. Most of the criticism of deconstruction were first articulated by these philosophers then repeated elsewhere.

John Searle
In the early 1970s, Searle had a brief exchange with Jacques Derrida regarding speech-act theory. The exchange was characterized by a degree of mutual hostility between the philosophers, each of whom accused the other of having misunderstood his basic points. Searle was particularly hostile to Derrida's deconstructionist framework and much later refused to let his response to Derrida be printed along with Derrida's papers in the 1988 collection Limited Inc. Searle did not consider Derrida's approach to be legitimate philosophy, or even intelligible writing, and argued that he did not want to legitimize the deconstructionist point of view by paying any attention to it. Consequently, some critics have considered the exchange to be a series of elaborate misunderstandings rather than a debate, while others have seen either Derrida or Searle gaining the upper hand.

The debate began in 1972, when, in his paper "Signature Event Context", Derrida analyzed J. L. Austin's theory of the illocutionary act. While sympathetic to Austin's departure from a purely denotational account of language to one that includes "force", Derrida was sceptical of the framework of normativity employed by Austin. Derrida argued that Austin had missed the fact that any speech event is framed by a "structure of absence" (the words that are left unsaid due to contextual constraints) and by "iterability" (the constraints on what can be said, imposed by what has been said in the past). Derrida argued that the focus on intentionality in speech-act theory was misguided because intentionality is restricted to that which is already established as a possible intention. He also took issue with the way Austin had excluded the study of fiction, non-serious, or "parasitic" speech, wondering whether this exclusion was because Austin had considered these speech genres as governed by different structures of meaning, or had not considered them due to a lack of interest. In his brief reply to Derrida, "Reiterating the Differences: A Reply to Derrida", Searle argued that Derrida's critique was unwarranted because it assumed that Austin's theory attempted to give a full account of language and meaning when its aim was much narrower. Searle considered the omission of parasitic discourse forms to be justified by the narrow scope of Austin's inquiry. Searle agreed with Derrida's proposal that intentionality presupposes iterability, but did not apply the same concept of intentionality used by Derrida, being unable or unwilling to engage with the continental conceptual apparatus. This, in turn, caused Derrida to criticize Searle for not being sufficiently familiar with phenomenological perspectives on intentionality. Some critics have suggested that Searle, by being so grounded in the analytical tradition that he was unable to engage with Derrida's continental phenomenological tradition, was at fault for the unsuccessful nature of the exchange, however Searle also argued that Derrida's disagreement with Austin turned on Derrida's having misunderstood Austin's type–token distinction and having failed to understand Austin's concept of failure in relation to performativity.

Derrida, in his response to Searle ("a b c ..." in Limited Inc), ridiculed Searle's positions. Claiming that a clear sender of Searle's message could not be established, Derrida suggested that Searle had formed with Austin a société à responsabilité limitée (a "limited liability company") due to the ways in which the ambiguities of authorship within Searle's reply circumvented the very speech act of his reply. Searle did not reply. Later in 1988, Derrida tried to review his position and his critiques of Austin and Searle, reiterating that he found the constant appeal to "normality" in the analytical tradition to be problematic.

Jürgen Habermas
In The Philosophical Discourse of Modernity, Jürgen Habermas criticized what he considered Derrida's opposition to rational discourse. Further, in an essay on religion and religious language, Habermas criticized what he saw as Derrida's emphasis on etymology and philology (see Etymological fallacy).

Walter A. Davis
The American philosopher Walter A. Davis, in Inwardness and Existence: Subjectivity in/and Hegel, Heidegger, Marx and Freud, argues that both deconstruction and structuralism are prematurely arrested moments of a dialectical movement that issues from Hegelian "unhappy consciousness".

In popular media
Popular criticism of deconstruction intensified following the Sokal affair, which many people took as an indicator of the quality of deconstruction as a whole, despite the absence of Derrida from Sokal's follow-up book Impostures intellectuelles.

Chip Morningstar holds a view critical of deconstruction, believing it to be "epistemologically challenged". He claims the humanities are subject to isolation and genetic drift due to their unaccountability to the world outside academia. During the Second International Conference on Cyberspace (Santa Cruz, California, 1991), he reportedly heckled deconstructionists off the stage. He subsequently presented his views in the article "How to Deconstruct Almost Anything", where he stated, "Contrary to the report given in the 'Hype List' column of issue #1 of Wired ('Po-Mo Gets Tek-No', page 87), we did not shout down the postmodernists. We made fun of them."

title: Deconstruction


text:
Direct product

In mathematics, one can often define a direct product of objects already known, giving a new one. This induces a structure on the Cartesian product of the underlying sets from that of the contributing objects. More abstractly, one talks about the product in category theory, which formalizes these notions.

Examples are the product of sets, groups (described below), rings, and other algebraic structures. The product of topological spaces is another instance.

There is also the direct sum – in some areas this is used interchangeably, while in others it is a different concept.

Examples

 * If we think of $$\R$$ as the set of real numbers without further structure, then the direct product $$\R \times \R$$ is just the Cartesian product $$\{(x,y) : x,y \in \R\}.$$
 * If we think of $$\R$$ as the group of real numbers under addition, then the direct product $$\R\times \R$$ still has $$\{(x,y) : x,y \in \R\}$$ as its underlying set. The difference between this and the preceding example is that $$\R \times \R$$ is now a group, and so we have to also say how to add their elements. This is done by defining $$(a,b) + (c,d) = (a+c, b+d).$$
 * If we think of $$\R$$ as the ring of real numbers, then the direct product $$\R\times \R$$ again has $$\{(x,y) : x,y \in \R\}$$ as its underlying set. The ring structure consists of addition defined by $$(a,b) + (c,d) = (a+c, b+d)$$ and multiplication defined by $$(a,b) (c,d) = (ac, bd).$$
 * Although the ring $$\R$$ is a field, $$\R \times \R$$ is not, because the nonzero element $$(1,0)$$ does not have a multiplicative inverse.

In a similar manner, we can talk about the direct product of finitely many algebraic structures, for example, $$\R \times \R \times \R \times \R.$$ This relies on the direct product being associative up to isomorphism. That is, $$(A \times B) \times C \cong A \times (B \times C)$$ for any algebraic structures $$A,$$ $$B,$$ and $$C$$ of the same kind. The direct product is also commutative up to isomorphism, that is, $$A \times B \cong B \times A$$ for any algebraic structures $$A$$ and $$B$$ of the same kind. We can even talk about the direct product of infinitely many algebraic structures; for example we can take the direct product of countably many copies of $$\mathbb R,$$ which we write as $$\R \times \R \times \R \times \dotsb.$$

Direct product of groups
In group theory one can define the direct product of two groups $$(G, \circ)$$ and $$(H, \cdot),$$ denoted by $$G \times H.$$ For abelian groups that are written additively, it may also be called the direct sum of two groups, denoted by $$G \oplus H.$$

It is defined as follows: Note that $$(G, \circ)$$ may be the same as $$(H, \cdot).$$
 * the set of the elements of the new group is the Cartesian product of the sets of elements of $$G \text{ and } H,$$ that is $$\{(g, h) : g \in G, h \in H\};$$
 * on these elements put an operation, defined element-wise: $$(g, h) \times \left(g', h'\right) = \left(g \circ g', h \cdot h'\right)$$

This construction gives a new group. It has a normal subgroup isomorphic to $$G$$ (given by the elements of the form $$(g, 1)$$), and one isomorphic to $$H$$ (comprising the elements $$(1, h)$$).

The reverse also holds. There is the following recognition theorem: If a group $$K$$ contains two normal subgroups $$G \text{ and } H,$$ such that $$K = GH$$ and the intersection of $$G \text{ and } H$$ contains only the identity, then $$K$$ is isomorphic to $$G \times H.$$ A relaxation of these conditions, requiring only one subgroup to be normal, gives the semidirect product.

As an example, take as $$G \text{ and } H$$ two copies of the unique (up to isomorphisms) group of order 2, $$C^2:$$ say $$\{1, a\} \text{ and } \{1, b\}.$$ Then $$C_2 \times C_2 = \{(1,1), (1,b), (a,1), (a,b)\},$$ with the operation element by element. For instance, $$(1,b)^* (a,1) = \left(1^* a, b^* 1\right) = (a, b),$$ and$$(1,b)^* (1, b) = \left(1, b^2\right) = (1, 1).$$

With a direct product, we get some natural group homomorphisms for free: the projection maps defined by $$\begin{align} \pi_1: G \times H \to G, \ \ \pi_1(g, h) &= g \\ \pi_2: G \times H \to H, \ \ \pi_2(g, h) &= h \end{align}$$ are called the coordinate functions.

Also, every homomorphism $$f$$ to the direct product is totally determined by its component functions $$f_i = \pi_i \circ f.$$

For any group $$(G, \circ)$$ and any integer $$n \geq 0,$$ repeated application of the direct product gives the group of all $$n$$-tuples $$G^n$$ (for $$n = 0,$$ this is the trivial group), for example $$\Z^n$$ and $$\R^n.$$

Direct product of modules
The direct product for modules (not to be confused with the tensor product) is very similar to the one defined for groups above, using the Cartesian product with the operation of addition being componentwise, and the scalar multiplication just distributing over all the components. Starting from $$\R$$ we get Euclidean space $$\R^n,$$ the prototypical example of a real $$n$$-dimensional vector space. The direct product of $$\R^m$$ and $$\R^n$$ is $$\R^{m+n}.$$

Note that a direct product for a finite index $\prod_{i=1}^n X_i$ is canonically isomorphic to the direct sum $\bigoplus_{i=1}^n X_i.$  The direct sum and direct product are not isomorphic for infinite indices, where the elements of a direct sum are zero for all but for a finite number of entries. They are dual in the sense of category theory: the direct sum is the coproduct, while the direct product is the product.

For example, consider $X = \prod_{i=1}^\infty \R$ and $Y = \bigoplus_{i=1}^\infty \R,$  the infinite direct product and direct sum of the real numbers. Only sequences with a finite number of non-zero elements are in $$Y.$$ For example, $$(1, 0, 0, 0, \ldots)$$ is in $$Y$$ but $$(1, 1, 1, 1, \ldots)$$ is not. Both of these sequences are in the direct product $$X;$$ in fact, $$Y$$ is a proper subset of $$X$$ (that is, $$Y \subset X$$).

Topological space direct product
The direct product for a collection of topological spaces $$X_i$$ for $$i$$ in $$I,$$ some index set, once again makes use of the Cartesian product $$\prod_{i \in I} X_i.$$

Defining the topology is a little tricky. For finitely many factors, this is the obvious and natural thing to do: simply take as a basis of open sets to be the collection of all Cartesian products of open subsets from each factor: $$\mathcal B = \left\{U_1 \times \cdots \times U_n\ : \ U_i\ \mathrm{open\ in}\ X_i\right\}.$$

This topology is called the product topology. For example, directly defining the product topology on $$\R^2$$ by the open sets of $$\R$$ (disjoint unions of open intervals), the basis for this topology would consist of all disjoint unions of open rectangles in the plane (as it turns out, it coincides with the usual metric topology).

The product topology for infinite products has a twist, and this has to do with being able to make all the projection maps continuous and to make all functions into the product continuous if and only if all its component functions are continuous (that is, to satisfy the categorical definition of product: the morphisms here are continuous functions): we take as a basis of open sets to be the collection of all Cartesian products of open subsets from each factor, as before, with the proviso that all but finitely many of the open subsets are the entire factor: $$\mathcal B = \left\{ \prod_{i \in I} U_i\ : \ (\exists j_1,\ldots,j_n)(U_{j_i}\ \mathrm{open\ in}\ X_{j_i})\ \mathrm{and}\ (\forall i \neq j_1,\ldots,j_n)(U_i = X_i) \right\}.$$

The more natural-sounding topology would be, in this case, to take products of infinitely many open subsets as before, and this does yield a somewhat interesting topology, the box topology. However it is not too difficult to find an example of bunch of continuous component functions whose product function is not continuous (see the separate entry box topology for an example and more). The problem that makes the twist necessary is ultimately rooted in the fact that the intersection of open sets is only guaranteed to be open for finitely many sets in the definition of topology.

Products (with the product topology) are nice with respect to preserving properties of their factors; for example, the product of Hausdorff spaces is Hausdorff; the product of connected spaces is connected, and the product of compact spaces is compact. That last one, called Tychonoff's theorem, is yet another equivalence to the axiom of choice.

For more properties and equivalent formulations, see the separate entry product topology.

Direct product of binary relations
On the Cartesian product of two sets with binary relations $$R \text{ and } S,$$ define $$(a, b) T (c, d)$$ as $$a R c \text{ and } b S d.$$ If $$R \text{ and } S$$ are both reflexive, irreflexive, transitive, symmetric, or antisymmetric, then $$T$$ will be also. Similarly, totality of $$T$$ is inherited from $$R \text{ and } S.$$ Combining properties it follows that this also applies for being a preorder and being an equivalence relation. However, if $$R \text{ and } S$$ are connected relations, $$T$$ need not be connected; for example, the direct product of $$\,\leq\,$$ on $$\N$$ with itself does not relate $$(1, 2) \text{ and } (2, 1).$$

Direct product in universal algebra
If $$\Sigma$$ is a fixed signature, $$I$$ is an arbitrary (possibly infinite) index set, and $$\left(\mathbf{A}_i\right)_{i \in I}$$ is an indexed family of $$\Sigma$$ algebras, the direct product $\mathbf{A} = \prod_{i \in I} \mathbf{A}_i$ is a $$\Sigma$$ algebra defined as follows: For each $$i \in I,$$ the $$i$$th projection $$\pi_i : A \to A_i$$ is defined by $$\pi_i(a) = a(i).$$ It is a surjective homomorphism between the $$\Sigma$$ algebras $$\mathbf{A} \text{ and } \mathbf{A}_i.$$
 * The universe set $$A$$ of $$\mathbf{A}$$ is the Cartesian product of the universe sets $$A_i$$ of $$\mathbf{A}_i,$$ formally: $A = \prod_{i \in I} A_i.$
 * For each $$n$$ and each $$n$$-ary operation symbol $$f \in \Sigma,$$ its interpretation $$f^{\mathbf{A}}$$ in $$\mathbf{A}$$ is defined componentwise, formally: for all $$a_1, \dotsc, a_n \in A$$ and each $$i \in I,$$ the $$i$$th component of $$f^{\mathbf{A}}\!\left(a_1, \dotsc, a_n\right)$$ is defined as $$f^{\mathbf{A}_i}\!\left(a_1(i), \dotsc, a_n(i)\right).$$

As a special case, if the index set $$I = \{1, 2\},$$ the direct product of two $$\Sigma$$ algebras $$\mathbf{A}_1 \text{ and } \mathbf{A}_2$$ is obtained, written as $$\mathbf{A} = \mathbf{A}_1 \times \mathbf{A}_2.$$ If $$\Sigma$$ just contains one binary operation $$f,$$ the above definition of the direct product of groups is obtained, using the notation $$A_1 = G, A_2 = H,$$ $$f^{A_1} = \circ, \ f^{A_2} = \cdot, \ \text{ and } f^A = \times.$$ Similarly, the definition of the direct product of modules is subsumed here.

Categorical product
The direct product can be abstracted to an arbitrary category. In a category, given a collection of objects $$(A_i)_{i \in I}$$ indexed by a set $$I$$, a product of these objects is an object $$A$$ together with morphisms $$p_i \colon A \to A_i$$ for all $$i \in I$$, such that if $$B$$ is any other object with morphisms $$f_i \colon B \to A_i$$ for all $$i \in I$$, there exists a unique morphism $$B \to A$$ whose composition with $$p_i$$ equals $$f_i$$ for every $$i$$.

Such $$A$$ and $$(p_i)_{i \in I}$$ do not always exist. If they do exist, then $$(A,(p_i)_{i \in I})$$ is unique up to isomorphism, and $$A$$ is denoted $$\prod_{i \in I} A_i$$.

In the special case of the category of groups, a product always exists: the underlying set of $$\prod_{i \in I} A_i$$ is the Cartesian product of the underlying sets of the $$A_i$$, the group operation is componentwise multiplication, and the (homo)morphism $$p_i \colon A \to A_i$$ is the projection sending each tuple to its $$i$$th coordinate.

Internal and external direct product
Some authors draw a distinction between an internal direct product and an external direct product. For example, if $$A$$ and $$B$$ are subgroups of an additive abelian group $$G$$, such that $$A + B = G$$ and $$A \cap B = \{0\}$$, then $$A \times B \cong G,$$ and we say that $$G$$ is the internal direct product of $$A$$ and $$B$$. To avoid ambiguity, we can refer to the set $$\{\, (a,b) \mid a \in A, \, b \in B \,\}$$ as the external direct product of $$A$$ and $$B$$.

title: Direct product


text:
Déjà vu

Déjà vu (, ; "already seen") is the phenomenon of feeling as though one has lived through the present situation before. It is an illusion of memory whereby—despite a strong sense of recollection—the time, place, and context of the "previous" experience are uncertain or impossible. Approximately two-thirds of surveyed populations report experiencing déjà vu at least one time in their lives. The phenomenon manifests occasionally as a symptom of seizure auras, and some researchers have associated chronic/frequent "pathological" déjà vu with neurological or psychiatric illness. Experiencing déjà vu has been correlated with higher socioeconomic status, better educational attainment, and lower ages. People who travel often, frequently watch films, or frequently remember their dreams are also more likely to experience déjà vu than others.

History
The phrase "déjà vu" is borrowed from French and means "already seen". Déjà vu occurs when someone perceives they have already experienced a situation before, and their body experiences familiarity with the experience and confusion. This term was first used by Émile Boirac in the year 1876. Boirac was a French philosopher who wrote a book that included the sensation of déjà vu in his writings, titled "The Psychology of the Future" (LiveScience, Ede). Déjà vu has been presented as a reminiscence of memories, "These experiments have led scientists to suspect that déjà vu is a memory phenomenon. We encounter a situation that is similar to an actual memory but we can’t fully recall that memory". This evidence, found by Émile Boirac, helps the public understand what déjà vu can entail on the average brain. It was also stated, ". . . Our brain recognizes the similarities between our current experience and one in the past . . . left with a feeling of familiarity that we can’t quite place" (Scientific American, Stierwalt). Throughout history, there have been many theories on what causes déjà vu. This phenomenon has displayed its difficulty to be tested due to its random occurrence in people.

Medical disorders
Déjà vu is associated with temporal lobe epilepsy. This experience is a neurological anomaly related to epileptic electrical discharge in the brain, creating a strong sensation that an event or experience currently being experienced has already been experienced in the past.

Migraines with aura are also associated with déjà vu. Early researchers tried to establish a link between déjà vu and mental disorders such as anxiety, dissociative identity disorder and schizophrenia but failed to find correlations of any diagnostic value. No special association has been found between déjà vu and schizophrenia. A 2008 study found that déjà vu experiences are unlikely to be pathological dissociative experiences.

Some research has looked into genetics when considering déjà vu. Although there is not currently a gene associated with déjà vu, the LGI1 gene on chromosome 10 is being studied for a possible link. Certain forms of the gene are associated with a mild form of epilepsy, and, though by no means a certainty, déjà vu, along with jamais vu, occurs often enough during seizures (such as simple partial seizures) that researchers have reason to suspect a link.

Pharmacology
Certain combinations of medical drugs have been reported to increase the chances of déjà vu occurring in the user. Taiminen and Jääskeläinen (2001) explored the case of an otherwise healthy person who started experiencing intense and recurrent sensations of déjà vu upon taking the drugs amantadine and phenylpropanolamine together to relieve flu symptoms. Because of the dopaminergic action of the drugs and previous findings from electrode stimulation of the brain (e.g. Bancaud, Brunet-Bourgin, Chauvel, & Halgren, 1994), Tamminen and Jääskeläinen speculated that déjà vu occurs as a result of hyperdopaminergic action in the medial temporal areas of the brain. A similar case study by Karla, Chancellor, and Zeman (2007) suggests a link between déjà vu and the serotonergic system, after an otherwise healthy woman began experiencing similar symptoms while taking a combination of 5-hydroxytryptophan and carbidopa.

Split perception explanation
Déjà vu may happen if a person experienced the current sensory experience twice successively. The first input experience is brief, degraded, occluded, or distracted. Immediately following that, the second perception might be familiar because the person naturally related it to the first input. One possibility behind this mechanism is that the first input experience involves shallow processing, which means that only some superficial physical attributes are extracted from the stimulus.

Implicit memory
Research has associated déjà vu experiences with good memory functions, particularly long-term implicit memory. Recognition memory enables people to realize the event or activity that they are experiencing has happened before. When people experience déjà vu, they may have their recognition memory triggered by certain situations which they have never encountered.

The similarity between a déjà-vu-eliciting stimulus and an existing, or non-existing but different, memory trace may lead to the sensation that an event or experience currently being experienced has already been experienced in the past. Thus, encountering something that evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to reproduce the sensation experimentally, Banister and Zangwill (1941) used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the 10 participants reporting what the authors termed "paramnesias".

Two approaches are used by researchers to study feelings of previous experience, with the process of recollection and familiarity. Recollection-based recognition refers to an ostensible realization that the current situation has occurred before. Familiarity-based recognition refers to the feeling of familiarity with the current situation without being able to identify any specific memory or previous event that could be associated with the sensation.

In 2010, O'Connor, Moulin, and Conway developed another laboratory analog of déjà vu based on two contrast groups of carefully selected participants, a group under posthypnotic amnesia condition (PHA) and a group under posthypnotic familiarity condition (PHF). The idea of PHA group was based on the work done by Banister and Zangwill (1941), and the PHF group was built on the research results of O'Connor, Moulin, and Conway (2007). They applied the same puzzle game for both groups, "Railroad Rush Hour", a game in which one aims to slide a red car through the exit by rearranging and shifting other blocking trucks and cars on the road. After completing the puzzle, each participant in the PHA group received a posthypnotic amnesia suggestion to forget the game in the hypnosis. Then, each participant in the PHF group was not given the puzzle but received a posthypnotic familiarity suggestion that they would feel familiar with this game during the hypnosis. After the hypnosis, all participants were asked to play the puzzle (the second time for PHA group) and reported the feelings of playing.

In the PHA condition, if a participant reported no memory of completing the puzzle game during hypnosis, researchers scored the participant as passing the suggestion. In the PHF condition, if participants reported that the puzzle game felt familiar, researchers scored the participant as passing the suggestion. It turned out that, both in the PHA and PHF conditions, five participants passed the suggestion and one did not, which is 83.33% of the total sample. More participants in PHF group felt a strong sense of familiarity, for instance, comments like "I think I have done this several years ago." Furthermore, more participants in PHF group experienced a strong déjà vu, for example, "I think I have done the exact puzzle before." Three out of six participants in the PHA group felt a sense of déjà vu, and none of them experienced a strong sense of it. These figures are consistent with Banister and Zangwill's findings. Some participants in PHA group related the familiarity when completing the puzzle with an exact event that happened before, which is more likely to be a phenomenon of source amnesia. Other participants started to realize that they may have completed the puzzle game during hypnosis, which is more akin to the phenomenon of breaching. In contrast, participants in the PHF group reported that they felt confused about the strong familiarity of this puzzle, with the feeling of playing it just sliding across their minds. Overall, the experiences of participants in the PHF group is more likely to be the déjà vu in life, while the experiences of participants in the PHA group is unlikely to be real déjà vu.

A 2012 study in the journal Consciousness and Cognition, that used virtual reality technology to study reported déjà vu experiences, supported this idea. This virtual reality investigation suggested that similarity between a new scene's spatial layout and the layout of a previously experienced scene in memory (but which fails to be recalled) may contribute to the déjà vu experience. When the previously experienced scene fails to come to mind in response to viewing the new scene, that previously experienced scene in memory can still exert an effect—that effect may be a feeling of familiarity with the new scene that is subjectively experienced as a feeling that an event or experience currently being experienced has already been experienced in the past, or of having been there before despite knowing otherwise. In 2018 a study examined volunteers' brains under experimentally induced déjà vu through the use of fMRI brain scans. The induced "deja vu" state was created by getting them to look at a series of logically related and unrelated words. The researchers would then ask the participants how many words starting with a specific letter they saw. With related words such as "door, shutter, screen, breeze", the participants would be asked if they saw any words that started with "W" (i.e. Window, a term that was not presented to the participants). If they did note that they thought they saw a word that wasn't presented to them, then déjà vu was induced. The researchers would then examine the volunteers' brains at the moment of induced déjà vu. From these scans, they noticed that there was visible activity in regions of the brain associated with mnemonic conflict. This finding suggests that more research regarding memory conflict may be important in better understanding déjà vu.

Cryptomnesia
Another possible explanation for the phenomenon of déjà vu is the occurrence of cryptomnesia, which is where information learned is forgotten but nevertheless stored in the brain, and similar occurrences invoke the contained knowledge, leading to a feeling of familiarity because the event or experience being experienced has already been experienced in the past, known as "déjà vu". Some experts suggest that memory is a process of reconstruction, rather than a recollection of fixed, established events. This reconstruction comes from stored components, involving emotions, distortions, and omissions. Each successive recall of an event is merely a recall of the last reconstruction. The proposed sense of recognition (déjà vu) involves achieving a good match between the present experience and the stored data. This reconstruction, however, may now differ so much from the original event it is as though it had never been experienced before, even though it seems similar.

Dual neurological processing
In 1965, Robert Efron of Boston's Veterans Hospital proposed that déjà vu is caused by dual neurological processing caused by delayed signals. Efron found that the brain's sorting of incoming signals is done in the temporal lobe of the brain's left hemisphere. However, signals enter the temporal lobe twice before processing, once from each hemisphere of the brain, normally with a slight delay of milliseconds between them. Efron proposed that if the two signals were occasionally not synchronized properly, then they would be processed as two separate experiences, with the second seeming to be a re-living of the first.

Dream-based explanation
Dreams can also be used to explain the experience of déjà vu, and they are related in three different aspects. Firstly, some déjà vu experiences duplicate the situation in dreams instead of waking conditions, according to the survey done by Brown (2004). Twenty percent of the respondents reported their déjà vu experiences were from dreams and 40% of the respondents reported from both reality and dreams. Secondly, people may experience déjà vu because some elements in their remembered dreams were shown. Research done by Zuger (1966) supported this idea by investigating the relationship between remembered dreams and déjà vu experiences, and suggested that there is a strong correlation. Thirdly, people may experience déjà vu during a dream state, which links déjà vu with dream frequency.

Collective unconscious
Collective Unconscious is a controversial theory created by Carl Jung that has been used to explain the phenomenon of déjà vu. His theory was that all people have a shared pool of knowledge that has been passed down through generations and we can unconsciously access this knowledge. Some of said knowledge would be about certain archetypes like mother, father and hero or possibly about basic situations, emotions or other patterns. If we can access shared knowledge deja vu could potentially be an effect of recognizing one of the collectively stored patterns.

Jamais vu
Jamais vu (from French, meaning "never seen") is any familiar situation which is not recognized by the observer.

Often described as the opposite of déjà vu, jamais vu involves a sense of eeriness and the observer's impression of seeing the situation for the first time, despite rationally knowing that they have been in the situation before. Jamais vu is most commonly experienced when a person momentarily does not recognize a word, person or place that they already know. Jamais vu is sometimes associated with certain types of aphasia, amnesia, and epilepsy.

Theoretically, a jamais vu feeling in someone with a delirious disorder or intoxication could result in a delirious explanation of it, such as in the Capgras delusion, in which the patient takes a known person for a false double or impostor. If the impostor is himself, the clinical setting would be the same as the one described as depersonalization, hence jamais vus of oneself or of the "reality of reality", are termed depersonalization (or surreality) feelings.

The feeling has been evoked through semantic satiation. Chris Moulin of the University of Leeds asked 95 volunteers to write the word "door" 30 times in 60 seconds. Sixty-eight percent of the subjects reported symptoms of jamais vu, with some beginning to doubt that "door" was a real word.

Déjà vécu
Déjà vécu (from French, meaning "already lived") is an intense, but false, feeling of having already lived through the present situation. Recently, it has been considered a pathological form of déjà vu. However, unlike déjà vu, déjà vécu has behavioral consequences. Patients with déjà vécu often cannot tell that this feeling of familiarity is not real. Because of the intense feeling of familiarity, patients experiencing déjà vécu may withdraw from their current events or activities. Patients may justify their feelings of familiarity with beliefs bordering on delusion.

Presque vu
Presque vu (, from French, meaning "almost seen") is the intense feeling of being on the very brink of a powerful epiphany, insight, or revelation, without actually achieving the revelation. The feeling is often therefore associated with a frustrating, tantalizing sense of incompleteness or near-completeness.

Déjà rêvé
Déjà rêvé (from French, meaning "already dreamed") is the feeling of having already dreamed something that is currently being experienced.

Déjà entendu
Déjà entendu (literally "already heard") is the experience of feeling sure about having already heard something, even though the exact details are uncertain or were perhaps imagined.

title: Déjà vu


text:
Talk:Déjà vu

Deja Vu
Carl Sagan supported the idea that deja vu is precognition. Susanj96 (talk) 17:12, 11 July 2019 (UTC)

Deja vu is fake Iamferian (talk) 10:36, 1 February 2020 (UTC)

 * No its not trust me ... 2400:ADCC:11D:5400:8517:5FE0:D970:DD3D (talk) 20:42, 31 October 2023 (UTC)
 * it'not fake it's damn true i generally face it every month 2409:40D4:1A:5EFA:8000:0:0:0 (talk) 17:22, 30 November 2023 (UTC)

"in fragile conditions"?
In the introductory section, I am stopped by the expression "in fragile conditions". What is that supposed to mean?

Identifying paramnesia
It is sometimes said that Déjà vu is also known as identifying paramnesia.. Brian Inglis (Science and Parascience, Hodder, 1984, p.230, sorry about the unreliable source) suggested rather that identifying paramnesia was a psychological hypothesis put forward to explain the experience of déjà vu. Herman N. Sno (1991. "The deja vu experience: Remembrance of things past?", American Journal of Psychiatry 147(12):1587-95. DOI:10.1176/ajp.147.12.1587) makes a clear distinction between the two, noting that there are two forms of deja vu and that one author has associated the stronger form with reduplicative paramnesia. Can anybody clarify the current understanding, and might Sno's paper be worth citing in the article? — Cheers, Steelpillow (Talk) 11:54, 17 February 2022 (UTC)

What is the opposite of deja Vu
What is it 94.69.100.80 (talk) 21:11, 28 May 2022 (UTC)
 * Are you thinking of jamais vu? Schazjmd   (talk)  21:13, 28 May 2022 (UTC)

Casual déjà vu
This article doesn't address the vague feeling of "déjà vu" in cases where one remembers actual people, places and/or situations that one has experienced before while not being able to recall the extract details, time or other circumstances. -- T71024 (talk) 10:56, 5 June 2022 (UTC)
 * Do you have any reliable sources describing such events, which we could cite? I agree that the term is also used to describe the same feeling, whether it accompanies a false or genuine half-memory. But Wikipedia policy demands sources for what we add, and I know of none that are sufficiently reliable. — Cheers, Steelpillow (Talk) 12:33, 5 June 2022 (UTC)

Déjà vu
Why déjà vu occurs? 106.0.54.219 (talk) 20:00, 27 August 2022 (UTC)

Improving this page
As mentioned by @Box73 above, this article has a lot of issues in terms of sources, neutrality, and bias. I'm not an expert on déjà vu (I've only really started looking into the phenomenon relatively recently), but I think it's worth trying to shape this page up, especially since the phenomenon has a decent body of literature on it outside of pure speculation.

I'm fairly new to Wikipedia, so please forgive me if I am going about this wrong, but I think the following sections of the article need attention:

• The etymology section is extremely short, and may not be accurate. According to Alan Brown in his 2003 paper A Review of the Déjà Vu Experience, the exact origin of the term is ambiguous and contested. The history of déjà vu research and records of its existence throughout history are also not mentioned, nor prior definitions of the term. I believe this section could be significantly improved by changing it from "Etymology" to "History".

• As mentioned by @Box73, the pharmacology section is based entirely on a single case study, and cites only the case study itself directly. (I added a second case study prior to learning about Wikipedia's policy on primary sources, whoops). It also treats the case study as proving a pharmacological link between déjà vu and a combination of amantadine and phenylpropanolamine, which isn't really accurate. I believe this section should be removed.

• The explanations section of the article gives significantly more attention to the implicit memory explanation than others, which is likely due to bias. There are also some explanations that have not been mentioned, such as the theory that déjà vu is caused by seizure activity in the section of the brain responsible for the feeling of familiarity (which appears to only be mentioned as an implication in the "Mental disorders" section of the article). I believe adding additional detail in the other explanations (and possibly reducing the immense detail of the implicit memory section) may be necessary to present all the main theories behind the phenomenon and provide unbiased views.

I intend to try improving on the article in logical increments, but as I'm still new to editing on Wikipedia and not an expert on the subject matter, I felt it necessary to solicit further discussion about the topic rather than trying to immediately edit the article radically. If more experienced Wikipedians see this and are willing to comment, discussion would be appreciated.

Yossipossi (talk) 03:46, 19 December 2022 (UTC)

Why people fall in deja vu
Why people fall in deja vu? 103.248.94.31 (talk) 11:15, 18 January 2023 (UTC)

Wiki Education assignment: Introduction to Psychology Honors
— Assignment last updated by TheOneCheese (talk) 19:26, 7 November 2023 (UTC)

Does this still count as Déjà vu?
For some reason whenever i go in a car like my moms friends car that ive never been in before or seen before i feel like ive been in THAT specific car. Which i dont see any like visions or memories from it like the wiki says but i just get a weird Tingly feeling. 97.73.80.137 (talk) 12:26, 16 December 2023 (UTC)

 * -IP
 * (I forgot to add my inishials to the thing like i usally do.)
 * (also you would think now that im in 7th grade that i would be able to spell inishals right but NOPE lol) 97.73.80.137 (talk) 12:29, 16 December 2023 (UTC)

title: Talk:Déjà vu


text:
Talk:Deuterium

Deuterium
Hello, Are there any other ways of producing/extracting deuterium besides electrolytis? The product should be of high concentration because it is meant for fusion energy. Thank you for your help Maurice Herp. (talk) 20:21, 11 December 2022 (UTC)

Hyperfine transition
The article could make mention of the 327-MHz deuterium hyperfine transition, particularly in an astronomy context (Cf. hydrogen line). Thanks. Praemonitus (talk) 22:24, 2 May 2023 (UTC)

Standard Model Instability
It seems that in the standard model, the deuteron is not completely stable, but rather very long lived. t'Hooft writes at the bottom of page 3 "Thus, because of the Cabibbo rotation, a proton and a neutron (two baryons equal six quarks) may annihilate to form two antileptons, one of electron and one of muon type. The factors exp(- 16pi /g^2) = exp(- 4pi * 137 * sin theta_W)" This calculation is elaborated here: https://physics.stackexchange.com/a/288913/10991 to conclude a lifetime of 10^180 seconds.

Should Deuterium glow tube be used for lede image?
Would it make more sense for File:Deuterium discharage tube.jpg to be used as the lead image instead, or maybe along with, the isotope highlighted on the table of nuclides? After all, we don't just put images of elements highlighted on the periodic table for their lede sections. ✨ΩmegaMantis✨blather 18:30, 14 December 2023 (UTC)
 * Infobox isotope does not seem to prescribe any standard for the image. Might be useful to ask WikiProject Elements to coordinate this across the many such articles. DMacks (talk) 19:35, 14 December 2023 (UTC)
 * Added the gas discharge tube photo for now, since the project seems to favor actual photos of elements, and someone else has already suggested it. Mrfoogles (talk) 17:47, 30 June 2024 (UTC)
 * If there's any opposition this can go on the WikiProject talk page Mrfoogles (talk) 17:49, 30 June 2024 (UTC)

Symbol
IUPAC recommends that the chemical symbol for deuterium should be $2$H, rather than D. I strongly agree with that recommendation, for multiple reasons. This article should follow IUPAC's recommendation; for instance, writing $2$H$2$O rather than D$2$O (see "Heavy water"). Solomonfromfinland (talk) 22:02, 12 March 2024 (UTC)

Section "Data for molecular deuterium"
That section contains also data concerning atomic deuterium, and deuterium combined with other elements, such as HDO. This seems to contradict the heading of the section. Ekisbares (talk) 08:59, 17 July 2024 (UTC)

title: Talk:Deuterium