Scope.

Pseudonyms include stage names and user names, ring names, pen names, nicknames, aliases, superhero or villain identities and code names, gamer identifications, and regnal names of emperors, popes, and other monarchs. Historically, they have sometimes taken the form of anagrams, Graecisms, and Latinisations, although there are many other methods of choosing a pseudonym.  Pseudonyms should not be confused with new names that replace old ones and become the individual's full-time name. Pseudonyms are "part-time" names, used only in certain contexts – to provide a more clear-cut separation between one's private and professional lives, to showcase or enhance a particular persona, or to hide an individual's real identity, as with writers' pen names, graffiti artists' tags, resistance fighters' or terrorists' "noms de guerre", and computer hackers' handles. Actors, voice-over artists, musicians, and other performers sometimes use stage names, for example, to better channel a relevant energy, gain a greater sense of security and comfort via privacy, more easily avoid troublesome fans/"stalkers", or to mask their ethnic backgrounds.  In some cases, pseudonyms are adopted because they are part of a cultural or organisational tradition: for example devotional names used by members of some religious institutes, and "cadre names" used by Communist party leaders such as Trotsky and Lenin.  A pseudonym may also be used for personal reasons: for example, an individual may prefer to be called or known by a name that differs from their given or legal name, but is not ready to take the numerous steps to get their name legally changed; or an individual may simply feel that the context and content of an exchange offer no reason, legal or otherwise, to provide their given or legal name.  A "collective name" or "collective pseudonym" is one shared by two or more persons, for example the co-authors of a work, such as Carolyn Keene, Ellery Queen, Nicolas Bourbaki, or James S. A. Corey.

Etymology.

The term "pseudonym" is derived from the Greek ("pseudṓnymon"), literally "false name", from ("pseûdos"), "lie, falsehood" and ("ónoma"), "name". The term "alias" is a Latin adverb meaning "at another time, elsewhere".

Distinction from allonyms, ghost writers and pseudepigrapha.

A pseudonym is distinct from an "allonym", which is the (real) name of another person, assumed by the author of a work of art. This may occur when someone is ghostwriting a book or play, or in parody, or when using a "front" name, such as by screenwriters blacklisted in Hollywood in the 1950s and 1960s. See also pseudepigraph, for "falsely" attributed authorship.

Usage.

Legal name change.

Sometimes people change their name in such a manner that the new name becomes permanent and is used by all who know the person. This is not an alias or pseudonym, but in fact a new name. In many countries, including common law countries, a name change can be ratified by a court and become a person's new legal name.  For example, in the 1960s, black civil rights campaigner Malcolm Little changed his surname to "X", to represent his unknown African ancestral name that had been lost when his ancestors were brought to North America as slaves. He then changed his name again to Malik El-Shabazz when he converted to Islam. Likewise some Jews adopted Hebrew family names upon immigrating to Israel, dropping surnames that had been in their families for generations. The politician David Ben-Gurion, for example, was born David Grün in Poland. He adopted his Hebrew name in 1910, when he published his first article in a Zionist journal in Jerusalem. Many transgender people also choose to adopt a new name, typically around the time of their social transitioning, to match their desired gender better than their birth name.

Concealing identity.

Business.

Businesspersons of ethnic minorities in some parts of the world are sometimes advised by an employer to use a pseudonym that is common or acceptable in that area when conducting business, to overcome racial or religious bias.

Criminal activity.

Criminals may use aliases, fictitious business names, and dummy corporations (corporate shells) to hide their identity, or to impersonate other persons or entities in order to commit fraud. Aliases and fictitious business names used for dummy corporations may become so complex that, in the words of the "Washington Post", "getting to the truth requires a walk down a bizarre labyrinth" and multiple government agencies may become involved to uncover the truth.

Literature.

A pen name, or ""nom de plume"" (French for "pen name"), is a pseudonym (sometimes a particular form of the real name) adopted by an author (or on the author's behalf by their publishers).  Some female authors used male pen names, in particular in the 19th century, when writing was a male-dominated profession. The Brontë sisters used pen names for their early work, so as not to reveal their gender (see below) and so that local residents would not know that the books related to people of the neighbourhood. The Brontës used their neighbours as inspiration for characters in many of their books. Anne Brontë's "The Tenant of Wildfell Hall" (1848) was published under the name Acton Bell, while Charlotte Brontë used the name Currer Bell for "Jane Eyre" (1847) and "Shirley" (1849), and Emily Brontë adopted Ellis Bell as cover for "Wuthering Heights" (1847). Other examples from the nineteenth-century are the novelist Mary Ann Evans (George Eliot) and the French writer Amandine Aurore Lucile Dupin (George Sand). Pseudonyms may also be used due to cultural or organization or political prejudices.  On the other hand, some 20th and 21st-century male romance novelists have used female pen names. A few examples are Brindle Chase, Peter O'Donnell (as Madeline Brent), Christopher Wood (as Penny Sutton and Rosie Dixon), and Hugh C. Rae (as Jessica Sterling).  A pen name may be used if a writer's real name is likely to be confused with the name of another writer or notable individual, or if the real name is deemed unsuitable.  Authors who write both fiction and non-fiction, or in different genres, may use different pen names to avoid confusing their readers. For example, the romance writer Nora Roberts writes mystery novels under the name J.D. Robb.  In some cases, an author may become better known by his pen name than his real name. A famous example is Samuel Clemens, writing as Mark Twain. The British mathematician Charles Dodgson wrote fantasy novels as Lewis Carroll and mathematical treatises under his own name.  Some authors, such as Harold Robbins, use several literary pseudonyms.  Some pen names have been used for long periods, even decades, without the author's true identity being discovered, as with Elena Ferrante and Torsten Krol.  Some pen names are not strictly pseudonyms, as they are simply variants of the authors' actual names. The authors C.L. Moore and S.E. Hinton were female authors who used the initialled forms of their full names, Moore being Catherine Lucille Moore, writing in the 1930s male-dominated science fiction genre, and Hinton, (author of "The Outsiders") Susan Eloise Hinton. "Star Trek" writer D.C. Fontana (Dorothy Catherine) wrote using her own abbreviated name and under the pen names Michael Richards and J. Michael Bingham. Author V.C. Andrews intended to publish under her given name, Virginia Andrews, but was told that, due to a production error, her first novel was being released under the name of "V.C. Andrews"; later she learned that her publisher had in fact done this deliberately. Joanne Kathleen Rowling published the "Harry Potter" series as J.K. Rowling. Rowling also published the Cormoran Strike series, a series of detective novels including "The Cuckoo's Calling" under the pseudonym "Robert Galbraith".  Winston Churchill wrote as Winston S. Churchill (from his full surname "Spencer-Churchill" which he did not otherwise use) in an attempt to avoid confusion with an American novelist of the same name. The attempt was not wholly successful – the two are still sometimes confused by booksellers.  A pen name may be used specifically to hide the identity of the author, as with exposé books about espionage or crime, or explicit erotic fiction. Some prolific authors adopt a pseudonym to disguise the extent of their published output, e. g. Stephen King writing as Richard Bachman. Co-authors may choose to publish under a collective pseudonym, e. g., P. J. Tracy and Perri O'Shaughnessy. Frederic Dannay and Manfred Lee used the name Ellery Queen as a pen name for their collaborative works and as the name of their main character. Asa Earl Carter, a Southern white segregationist affiliated with the KKK, wrote Western books under a fictional Cherokee persona to imply legitimacy and conceal his history.  "Why do authors choose pseudonyms? It is rarely because they actually hope to stay anonymous forever," mused writer and columnist Russell Smith in his review of the Canadian novel "Into That Fire" by the pseudonymous M.J. Cates.  A famous case in French literature was Romain Gary. Already a well-known writer, he started publishing books as Émile Ajar to test whether his new books would be well received on their own merits, without the aid of his established reputation. They were: Émile Ajar, like Romain Gary before him, was awarded the prestigious Prix Goncourt by a jury unaware that they were the same person. Similarly, TV actor Ronnie Barker submitted comedy material under the name Gerald Wiley.  A collective pseudonym may represent an entire publishing house, or any contributor to a long-running series, especially with juvenile literature. Examples include Watty Piper, Victor Appleton, Erin Hunter, and Kamiru M. Xhan.  Another use of a pseudonym in literature is to present a story as being written by the fictional characters in the story. The series of novels known as "A Series Of Unfortunate Events" are written by Daniel Handler under the pen name of Lemony Snicket, a character in the series. This applies also to some of the several 18th-century English and American writers who used the name Fidelia.  An anonymity pseudonym or multiple-use name is a name used by many different people to protect anonymity. It is a strategy that has been adopted by many unconnected radical groups and by cultural groups, where the construct of personal identity has been criticised. This has led to the idea of the "open pop star".

Medicine.

Pseudonyms and acronyms are often employed in medical research to protect subjects' identities through a process known as de-identification.

Science.

Nicolaus Copernicus put forward his theory of heliocentrism in the manuscript Commentariolus anonymously. Sophie Germain and William Sealy Gosset used pseudonyms to publish their work in the field of mathematics. Satoshi Nakamoto is a pseudonym of a still unknown author or authors' group behind a white paper about bitcoin. In the field of physics, one case of usage of pseudonyms is denounced. Ignazio Ciufolini is accused of publishing two papers on the scientific preprint archive arXiv.org under pseudonyms, each criticizing one of the rivals to LAGEOS, what is argued to be a form of ventriloquism. Such conduct is a violation of arXiv terms of use.

Military and paramilitary organizations.

In Ancien Régime France, a "nom de guerre" ("war name") would be adopted by each new recruit (or assigned to them by the captain of their company) as they enlisted in the French army. These pseudonyms had an official character and were the predecessor of identification numbers: soldiers were identified by their first names, their family names, and their "noms de guerre" (e. g. "Jean Amarault dit Lafidélité"). These pseudonyms were usually related to the soldier's place of origin (e. g. "Jean Deslandes dit Champigny", for a soldier coming from a town named Champigny), or to a particular physical or personal trait (e. g. "Antoine Bonnet dit Prettaboire", for a soldier "prêt à boire", ready to drink). In 1716, a "nom de guerre" was mandatory for every soldier; officers did not adopt "noms de guerre" as they considered them derogatory. In daily life, these aliases could replace the real family name.  "Noms de guerre" were adopted for security reasons by members of the World War II French resistance and Polish resistance. Such pseudonyms are often adopted by military special-forces soldiers, such as members of the SAS and similar units of resistance fighters, terrorists, and guerrillas. This practice hides their identities and may protect their families from reprisals; it may also be a form of dissociation from domestic life. Some well-known men who adopted "noms de guerre" include Carlos, for Ilich Ramírez Sánchez; Willy Brandt, Chancellor of West Germany; and Subcomandante Marcos, spokesman of the Zapatista Army of National Liberation (EZLN). During Lehi's underground fight against the British in Mandatory Palestine, the organization's commander Yitzchak Shamir (later Prime Minister of Israel) adopted the "nom de guerre" "Michael", in honour of Ireland's Michael Collins.  Revolutionaries and resistance leaders, such as Lenin, Trotsky, Golda Meir, Philippe Leclerc de Hauteclocque, and Josip Broz Tito, often adopted their "noms de guerre" as their proper names after the struggle. George Grivas, the Greek-Cypriot EOKA militant, adopted the "nom de guerre" Digenis (Διγενής). In the French Foreign Legion, recruits can adopt a pseudonym to break with their past lives. Mercenaries have long used "noms de guerre", sometimes even multiple identities, depending on country, conflict and circumstance. Some of the most familiar noms de guerre today are the kunya used by Islamic mujahideen. These take the form of a teknonym, either literal or figurative.

Online activity.

Individuals using a computer online may adopt or be required to use a form of pseudonym known as a "handle" (a term deriving from CB slang), "user name", "login name", "avatar", or, sometimes, "screen name", "gamertag" "IGN (In Game (Nick)Name)" or "nickname". On the Internet, pseudonymous remailers use cryptography that achieves persistent pseudonymity, so that two-way communication can be achieved, and reputations can be established, without linking physical identities to their respective pseudonyms. Aliasing is the use of multiple names for the same data location.  More sophisticated cryptographic systems, such as anonymous digital credentials, enable users to communicate pseudonymously (i. e., by identifying themselves by means of pseudonyms). In well-defined abuse cases, a designated authority may be able to revoke the pseudonyms and reveal the individuals' real identity.  Use of pseudonyms is common among professional eSports players, despite the fact that many professional games are played on LAN.

Privacy.

People seeking privacy often use pseudonyms to make appointments and reservations. Those writing to advice columns in newspapers and magazines may use pseudonyms. Steve Wozniak used a pseudonym when attending the University of California, Berkeley after co-founding Apple Computer, because "I knew I wouldn't have time enough to be an A+ student."

Stage names.

When used by an actor, musician, radio disc jockey, model, or other performer or "show business" personality a pseudonym is called a "stage name", or, occasionally, a "professional name", or "screen name".

Film, theatre, and related activities.

Members of a marginalized ethnic or religious group have often adopted stage names, typically changing their surname or entire name to mask their original background.  Stage names are also used to create a more marketable name, as in the case of Creighton Tull Chaney, who adopted the pseudonym Lon Chaney, Jr., a reference to his famous father Lon Chaney, Sr.  Chris Curtis of Deep Purple fame was christened as Christopher Crummey ("crumby" is UK slang for poor quality). In this and similar cases a stage name is adopted simply to avoid an unfortunate pun.  Pseudonyms are also used to comply with the rules of performing arts guilds (Screen Actors Guild (SAG), Writers Guild of America, East (WGA), AFTRA, etc.), which do not allow performers to use an existing name, in order to avoid confusion. For example, these rules required film and television actor Michael Fox to add a middle initial and become Michael J. Fox, to avoid being confused with another actor named Michael Fox. This was also true of author and actress Fannie Flagg, who chose this pseudonym; her real name, Patricia Neal, being the name of another well-known actress; and British actor Stewart Granger, whose real name was James Stewart. The film-making team of Joel and Ethan Coen, for instance, share credit for editing under the alias Roderick Jaynes.  Some stage names are used to conceal a person's identity, such as the pseudonym Alan Smithee, which was used by directors in the Directors Guild of America (DGA) to remove their name from a film they feel was edited or modified beyond their artistic satisfaction. In theatre, the pseudonyms George or Georgina Spelvin, and Walter Plinge are used to hide the identity of a performer, usually when he or she is "doubling" (playing more than one role in the same play).  David Agnew was a name used by the BBC to conceal the identity of a scriptwriter, such as for the Doctor Who serial City of Death, which had three writers, including Douglas Adams, who was at the time of writing the show's Script Editor. In another Doctor Who serial, The Brain of Morbius, writer Terrance Dicks demanded the removal of his name from the credits saying it could go out under a "bland pseudonym". This ended up as "Robin Bland".

Music.

Musicians and singers can use pseudonyms to allow artists to collaborate with artists on other labels while avoiding the need to gain permission from their own labels, such as the artist Jerry Samuels, who made songs under Napoleon XIV. Rock singer-guitarist George Harrison, for example, played guitar on Cream's song "Badge" using a pseudonym. In classical music, some record companies issued recordings under a "nom de disque" in the 1950s and 1960s to avoid paying royalties. A number of popular budget LPs of piano music were released under the pseudonym Paul Procopolis. Another example is that Paul McCartney used his fictional name "Bernerd Webb" for Peter and Gordon's song Woman.  Pseudonyms are used as stage names in heavy metal bands, such as Tracii Guns in LA Guns, Axl Rose and Slash in Guns N' Roses, Mick Mars in Mötley Crüe, Dimebag Darrell in Pantera, or C.C. Deville in Poison. Some such names have additional meanings, like that of Brian Hugh Warner, more commonly known as Marilyn Manson: Marilyn coming from Marilyn Monroe and Manson from convicted serial killer Charles Manson. Jacoby Shaddix of Papa Roach went under the name "Coby Dick" during the "Infest" era. He changed back to his birth name when "lovehatetragedy" was released.  David Johansen, front man for the hard rock band New York Dolls, recorded and performed pop and lounge music under the pseudonym Buster Poindexter in the late 1980s and early 1990s. The music video for Poindexter's debt single, Hot Hot Hot, opens with a monologue from Johansen where he notes his time with the New York Dolls and explains his desire to create more sophisticated music.  Ross Bagdasarian, Sr., creator of Alvin and the Chipmunks, wrote original songs, arranged, and produced the records under his real name, but performed on them as David Seville. He also wrote songs as Skipper Adams. Danish pop pianist Bent Fabric, whose full name is Bent Fabricius-Bjerre, wrote his biggest instrumental hit "Alley Cat" as Frank Bjorn.  For a time, the musician Prince used an unpronounceable "Love Symbol" as a pseudonym ("Prince" is his actual first name rather than a stage name). He wrote the song "Sugar Walls" for Sheena Easton as "Alexander Nevermind" and "Manic Monday" for The Bangles as "Christopher Tracy". (He also produced albums early in his career as "Jamie Starr").  Many Italian-American singers have used stage names, as their birth names were difficult to pronounce or considered too ethnic for American tastes. Singers changing their names included Dean Martin (born Dino Paul Crocetti), Connie Francis (born Concetta Franconero), Frankie Valli (born Francesco Castelluccio), Tony Bennett (born Anthony Benedetto), and Lady Gaga (born Stefani Germanotta)  In 2009, the British rock band Feeder briefly changed its name to Renegades so it could play a whole show featuring a set list in which 95 per cent of the songs played were from their forthcoming new album of the same name, with none of their singles included. Front man Grant Nicholas felt that if they played as Feeder, there would be uproar over him not playing any of the singles, so used the pseudonym as a hint. A series of small shows were played in 2010, at 250- to 1,000-capacity venues with the plan not to say who the band really are and just announce the shows as if they were a new band.  In many cases, hip-hop and rap artists prefer to use pseudonyms that represents some variation of their name, personality, or interests. Examples include Iggy Azalea (her stage name is a combination of her dog's name, Iggy, and her home street in Mullumbimby, Azalea Street), Ol' Dirty Bastard (known under at least six aliases), Diddy (previously known at various times as Puffy, P. Diddy, and Puff Daddy), Ludacris, Flo Rida (whose stage name is a tribute to his home state, Florida), British-Jamaican hip-hop artist Stefflon Don (real name Stephanie Victoria Allen), LL Cool J, and Chingy. Black metal artists also adopt pseudonyms, usually symbolizing dark values, such as Nocturno Culto, Gaahl, Abbath, and Silenoz. In punk and hardcore punk, singers and band members often replace real names with tougher-sounding stage names such as Sid Vicious (real name John Simon Ritchie) of the late 1970s band Sex Pistols and "Rat" of the early 1980s band The Varukers and the 2000s re-formation of Discharge. The punk rock band The Ramones had every member take the last name of Ramone.  Henry John Deutschendorf Jr., an American singer-songwriter, used the stage name John Denver. The Australian country musician born Robert Lane changed his name to Tex Morton. Reginald Kenneth Dwight legally changed his name in 1972 to Elton John.

A pseudonym () or alias () is a name that a person or group assumes for a particular purpose, which can differ from their first or true name (orthonym). The term is not used when a new name entirely replaces an individual's own.

化名,指某人在本名之外使用的虚拟姓名,很多时候,目的在于掩饰自己的真实身份。笔名、网名、艺名、假名、佛教僧人的法号、教宗就职后的教名都是化名的一种。需要注意的是,字、号、谱名、学名、斋名与小名等别名于某些情况内是相当于本名,不应与化名相混。


Life and career.

Family and early life.

Beethoven was the grandson of Ludwig van Beethoven (1712–1773), a musician from the town of Mechelen in the Austrian Duchy of Brabant (in what is now the Flemish region of Belgium) who had moved to Bonn at the age of 21. Ludwig was employed as a bass singer at the court of Clemens August, Archbishop-Elector of Cologne, eventually rising to become, in 1761, Kapellmeister (music director) and hence a pre-eminent musician in Bonn. The portrait he commissioned of himself towards the end of his life remained displayed in his grandson's rooms as a talisman of his musical heritage. Ludwig had one son, Johann (1740–1792), who worked as a tenor in the same musical establishment and gave keyboard and violin lessons to supplement his income.  Johann married Maria Magdalena Keverich in 1767; she was the daughter of Heinrich Keverich (1701–1751), who had been the head chef at the court of the Archbishopric of Trier. Beethoven was born of this marriage in Bonn at what is now the Beethoven House Museum, Bonnstrasse 20.

1780–1792: Bonn.

In 1780 or 1781, Beethoven began his studies with his most important teacher in Bonn, Christian Gottlob Neefe. Neefe taught him composition; in March 1783 appeared Beethoven's first published work, a set of keyboard variations (WoO 63). Beethoven soon began working with Neefe as assistant organist, at first unpaid (1782), and then as a paid employee (1784) of the court chapel. His first three piano sonatas, WoO 47, sometimes known as "" ("Elector") for their dedication to the Elector Maximilian Friedrich (1708–1784), were published in 1783. In the same year the first printed reference to Beethoven appeared in the "Magazin der Musik" – "Louis van Beethoven [sic]... a boy of 11 years and most promising talent. He

1792–1802: Vienna – the early years.

Beethoven left Bonn for Vienna in November 1792, amid rumours of war spilling out of France; he learned shortly after his arrival that his father had died. Over the next few years, Beethoven responded to the widespread feeling that he was a successor to the recently deceased Mozart by studying that master's work and writing works with a distinctly Mozartian flavour.  He did not immediately set out to establish himself as a composer, but rather devoted himself to study and performance. Working under Haydn's direction, he sought to master counterpoint. He also studied violin under Ignaz Schuppanzigh. Early in this period, he also began receiving occasional instruction from Antonio Salieri, primarily in Italian vocal composition style; this relationship persisted until at least 1802, and possibly as late as 1809.  With Haydn's departure for England in 1794, Beethoven was expected by the Elector to return home to Bonn. He chose instead to remain in Vienna, continuing his instruction in counterpoint with Johann Albrechtsberger and other teachers.

1802–1812: The 'heroic' period.

Deafness.

Beethoven told the English pianist Charles Neate (in 1815) that he dated his hearing loss from a fit he suffered in 1798 induced by a quarrel with a singer. During its gradual decline, his hearing was further impeded by a severe form of tinnitus. As early as 1801, he wrote to Wegeler and another friend Karl Amenda, describing his symptoms and the difficulties they caused in both professional and social settings (although it is likely some of his close friends were already aware of the problems). The cause was probably otosclerosis, perhaps accompanied by degeneration of the auditory nerve.  On the advice of his doctor, Beethoven moved to the small Austrian town of Heiligenstadt, just outside Vienna, from April to October 1802 in an attempt to come to terms

The 'heroic' style.

Beethoven's return to Vienna from Heiligenstadt was marked by a change in musical style, and is now often designated as the start of his middle or "heroic" period characterised by many original works composed on a grand scale. According to Carl Czerny, Beethoven said, "I am not satisfied with the work I have done so far. From now on I intend to take a new way." An early major work employing this new style was the Third Symphony in E flat Op. 55, known as the "Eroica", written in 1803-04. The idea of creating a symphony based on the career of Napoleon may have been suggested to Beethoven by Count Bernadotte in 1798. Beethoven, sympathetic to the ideal of the heroic revolutionary leader, originally gave the symphony the title "Bonaparte", but disillusioned by Napoleon declaring himself Emperor in 1804, he scratched Napoleon's name from the manuscript's title page, and the symphony was published in 1806 with its present title and the subtitle "to celebrate the memory of a great

Goethe.

At the end of 1809 Beethoven was commissioned to write incidental music for Goethe's play "Egmont". The result (an overture, and nine additional entractes and vocal pieces, Op. 84), which appeared in 1810 fitted well with Beethoven's "heroic" style and he became interested in Goethe, setting three of his poems as songs (Op. 83) and learning about the poet from a mutual acquaintance, Bettina Brentano (who also wrote to Goethe at this time about Beethoven). Other works of this period in a similar vein were the F minor String Quartet Op. 95, to which Beethoven gave the subtitle "Quartetto serioso", and the Op. 97 Piano Trio in B flat major known, from its dedication to his patron Rudolph as the "Archduke Trio".  In the spring of 1811 Beethoven became seriously ill,

"The Immortal Beloved".

While he was at Teplitz in 1812 he wrote a ten-page love letter to his "Immortal Beloved", which he never sent to its addressee. The identity of the intended recipient was long a subject of debate, although the musicologist Maynard Solomon has convincingly demonstrated that the intended recipient must have been Antonie Brentano; other candidates have included Julie Guicciardi, Therese Malfatti and Josephine Brunsvik.  All of these had been regarded by Beethoven as possible soulmates during his first decade in Vienna. Guicciardi, although she flirted with Beethoven, never had any serious interest in him and married Wenzel Robert von Gallenberg in November 1803. (Beethoven insisted to his later secretary and biographer, Anton Schindler, that Gucciardi had "sought me out, crying, but I scorned her.") Josephine had since Beethoven's initial infatuation with her married the elderly Count Joseph Deym, who died in 1804. Beethoven

1813–1822: Acclaim.

Family problems.

In early 1813 Beethoven apparently went through a difficult emotional period, and his compositional output dropped. His personal appearance degraded—it had generally been neat—as did his manners in public, notably when dining.  Family issues may have played a part in this. Beethoven had visited his brother Johann at the end of October 1812. He wished to end Johann's cohabitation with Therese Obermayer, a woman who already had an illegitimate child. He was unable to convince Johann to end the relationship and appealed to the local civic and religious authorities, but Johann and Therese married on 8 November.  The illness and eventual death of his brother Kaspar from tuberculosis became an increasing concern. Kaspar had been ill for some time; in 1813 Beethoven

Post-war Vienna.

Beethoven was finally motivated to begin significant composition again in June 1813, when news arrived of Napoleon's defeat at the Battle of Vitoria by a coalition led by the Duke of Wellington. The inventor Mälzel persuaded him to write a work commemorating the event for his mechanical instrument the Panharmonicon. This Beethoven also transcribed for orchestra as "Wellington's Victory" (Op. 91, also known as the "Battle Symphony"). It was first performed on 8 December, along with his Seventh Symphony, Op.

Pause.

Between 1815 and 1819 Beethoven's output dropped again to a level unique in his mature life. He attributed part of this to a lengthy illness (he called it an "inflammatory fever") that he had for more than a year, starting in October 1816. His biographer Maynard Solomon suggests it is also doubtless a consequence of the ongoing legal problems concerning his nephew Karl, and of Beethoven finding himself increasingly at odds with current musical trends. Unsympathetic to developments in German romanticism that featured the supernatural (as in operas by Spohr, Heinrich Marschner and Carl Maria von Weber), he also "resisted the impending Romantic fragmentation of the... cyclic forms of the Classical era into small forms and lyric mood pieces" and turned towards study of Bach, Handel and Palestrina. An old connection was renewed in 1817 when Maelzel sought, and obtained, Beethoven's endorsement for his newly developed metronome. During these years the few major works completed include Beethoven's only song

Resurgence.

Despite the time occupied by his ongoing legal struggles over Karl, which involved continuing extensive correspondence and lobbying, two events sparked off Beethoven's major composition projects in 1819. The first was the announcement of Archduke Rudolf's promotion to Cardinal-Archbishop as Archbishop of Olomouc (now in Czechia), which triggered the "Missa Solemnis" Op. 123, intended to be ready for his installation in Olomouc in March 1820. The other was the invitation by the publisher Antonio Diabelli to fifty Viennese composers, including Beethoven, Franz Schubert, Czerny and the 8-year old Franz Liszt, to compose a variation each on a theme which he provided. Beethoven was spurred to outdo the competition and by mid-1819 had already completed 20 variations of what were to become the 33 "Diabelli Variations" op. 120. Neither of these works were to be completed for a few years. A significant tribute of 1819, however, was Archduke Rudolf's set of forty piano variations on a theme written for him by Beethoven (WoO 200), and dedicated to the master. Beethoven's portrait by of this year, which was one of the most familiar images of him for the next century, was described by Schindler as, despite its artistic weaknesses, "in the rendering of that particular look, the majestic forehead... the firmly shut mouth and the chin shaped like a shell,... truer to nature than any other picture."  Beethoven's determination over the following years to write the "Mass" for Rudolf was not motivated by any devout Catholicism. Although born a Catholic, the form of religion as practised at the court in Bonn where he grew up was, in the words of Maynard Solomon, "a compromise ideology that permitted a relatively peaceful coexistence between the Church and rationalism.". Beethoven's "Tagebuch" (a diary he kept on an occasional basis between 1812 and 1818) shows his interest in a variety of relgious philosophies, including those of India, Egypt and the Orient and the writings of the Rig-Veda. In a letter to Rudolf of July 1821 Beethoven shows his belief in a personal God: "God... sees into my innermost heart and knows that

1823–1827: The final years.

The year 1823 saw the completion of three notable works, all of which had occupied Beethoven for some years, namely the "Missa Solemnis", the Ninth Symphony and the "Diabelli Variations".  Beethoven at last presented the manuscript of the completed "Missa" to Rudolph on 19 March (more than a year after the Archduke's enthronement as Archbishop). He was not however in a hurry to get it published or performed as he had formed a notion that he could profitably sell manuscripts of the work to various courts in Germany and Europe at 50 ducats each. One of the few who took up this offer was Louis XVIII of France, who also sent Beethoven a heavy gold medallion. The Symphony and the variations took up most of the rest of Beethoven's working year. Diabelli hoped to publish both works,

Death.

On his return journey to Vienna from Gneixendorf in December 1826, illness struck Beethoven again. He was attended until his death by Dr. Andreas Wawruch, who throughout December noticed symptoms including fever, jaundice and dropsy, with swollen limbs, coughing and breathing difficulties. Several operations were carried out to tap off the excess fluid from Beethoven's abdomen.  Karl stayed by Beethoven's bedside during December, but left after the beginning of January to join the army at Iglau and did not see his uncle again, although he wrote to him shortly afterwards "My dear father... I am living in contentment and regret only that I am separated from you." Immediately following Karl's departure, Beethoven wrote a will making his nephew his sole heir. Later in January, Beethoven was attended by Dr. Malfatti, whose treatment (recognizing the seriousness of his patient's condition) was largely centred on alcohol. As the news spread of the severity of Beethoven's condition, many old friends came to visit, including Diabelli, Schuppanzigh, Lichnowsky, Schindler, the composer Johann Nepomuk Hummel and his pupil Ferdinand Hiller. Many tributes and gifts were also sent, including £100 from the Philharmonic

Music.

The "three periods".

The historian William Drabkin notes that as early as 1818 a writer had proposed a three-period division of Beethoven's works, and that such a division (albeit often adopting different dates or works to denote changes in period) eventually became a convention adopted by all of Beethoven's biographers, starting with Schindler, F.-J. Fétis and Wilhelm von Lenz. Later writers sought to identify sub-periods within this generally accepted structure. Its drawbacks include that it generally omits a fourth period, that is, the early years in Bonn, whose works are less often considered;

Bonn 1782-1792.

Some forty compositions, including ten very early works written by Beethoven up to 1785, survive from the years that Beethoven lived in Bonn. It has been suggested that Beethoven largely abandoned composition between 1785 and 1790, possibly as a result of negative critical reaction to his first published works. A 1784 review in Johann Nikolaus Forkel's influential "Musikalischer Almanack" compared Beethoven's efforts to those of rank beginners. The three early piano quartets of 1785 (WoO 36), closely modelled on violin sonatas of Mozart, show his dependency on music of the period. Beethoven himself was

The first period.

The conventional "first period" begins after Beethoven's arrival in Vienna in 1792. In the first few years he seems to have composed less than he did at Bonn, and his Piano Trios, op.1 were not published until 1795. From this point onward, he had mastered the 'Viennese style' (best known today from Haydn and Mozart) and was making the style his own. His works from 1795 to 1800 are larger in scale than was the norm (writing

The middle period.

His middle (heroic) period began shortly after the personal crisis brought on by his recognition of encroaching deafness. It includes large-scale works that express heroism and struggle. Middle-period works include six symphonies (Nos. 3–8), the last two piano concertos, the Triple Concerto and violin concerto, five string quartets (Nos. 7–11), several piano sonatas (including the "Waldstein" and "Appassionata" sonatas), the "Kreutzer" violin sonata

The late period.

Beethoven's late period began in the decade 1810-1819. He began a renewed study of older music, including works by Johann Sebastian Bach and George Frideric Handel, that were then being published in the first attempts at complete editions. Many of Beethoven's late works include fugal material. The overture "The Consecration of the House" (1822) was an early work to attempt to incorporate these influences. A new style emerged, now called his "late period". He returned to the keyboard to compose

Legacy.

The Beethoven Monument in Bonn was unveiled in August 1845, in honour of the 75th anniversary of his birth. It was the first statue of a composer created in Germany, and the music festival that accompanied the unveiling was the impetus for the very hasty construction of the original Beethovenhalle in Bonn (it was designed and built within less than a month, on the urging of Franz Liszt). A statue to Mozart had been unveiled in Salzburg, Austria, in 1842. Vienna did not honour Beethoven with a statue until 1880.  There is a museum, the Beethoven House, the place of his birth, in central Bonn. The same city has hosted a musical festival, the Beethovenfest, since 1845. The festival was initially irregular but has been organised annually since 2007.  The Ira F. Brilliant Center for Beethoven Studies serves as a museum, research center, and host of lectures and performances devoted solely to this life and works.  His music features twice on the Voyager Golden Record, a phonograph record containing a broad sample of the images, common sounds, languages, and music of Earth, sent into outer space with the two Voyager probes.  The third largest crater on Mercury is named in his honour, as is the main-belt asteroid 1815 Beethoven.  A 7-foot cast bronze statue of Beethoven by sculptor Arnold Foerster was installed in 1932 in Pershing Square, Los Angeles; it was dedicated to William Andrews Clark Jr., founder of the Los Angeles Philharmonic.

Ludwig van Beethoven (; ; baptised 17 December 177026 March 1827) was a German composer and pianist; his music is amongst the most performed of the classical music repertoire, and he is one of the most admired composers in the history of Western music. His works span the transition from the classical period to the romantic era in classical music. His career has conventionally been divided into early, middle, and late periods. The "early" period in which he forged his craft is typically seen to last until 1802. His "middle" period, sometimes characterised as "heroic", showing an individual development from the "classical" styles of Joseph Haydn and Wolfgang Amadeus Mozart, covers the years 1802 to 1812, during which he increasingly suffered from deafness. In the "late" period from 1812 to his death in 1827, he extended his innovations in musical form and expression.

路德维希·范·贝多芬(,1770年-12月16日-1827年-3月26日),德意志作曲家、钢琴演奏家。贝多芬上承古典乐派传统,下启浪漫乐派之风格与精神,因而在音乐史上占有非常重要的地位。自1814年开始他的听力急剧下降,于是放弃了钢琴演奏和指挥,但却坚持创作。贝多芬一生共创作了9首编号交响曲、36首钢琴奏鸣曲(其中32首带有编号,1首未完成)、10部小提琴奏鸣曲、16首弦乐四重奏、1部歌剧及2部弥撒曲等等。这些作品对音乐发展有着深远影响,贝多芬因此在华语世界中被尊称为「乐圣」。


Questions.

Questions about the meaning of life have been expressed in a broad variety of ways, including

Scientific inquiry and perspectives.

Many members of the scientific community and philosophy of science communities think that science can provide the relevant context, and set of parameters necessary for dealing with topics related to the meaning of life. In their view, science can offer a wide range of insights on topics ranging from the science of happiness to death anxiety. Scientific inquiry facilitates this through nomological investigation into various aspects of life and reality, such as the Big Bang, the origin of life, and evolution, and by studying the objective factors which correlate with the subjective experience of meaning and happiness.

Psychological significance and value in life.

Researchers in positive psychology study empirical factors that lead to life satisfaction, full engagement in activities, making a fuller contribution by utilizing one's personal strengths, and meaning based on investing in something larger than the self. Large-data studies of flow experiences have consistently suggested that humans experience meaning and fulfillment when mastering challenging tasks and that the experience comes from the way tasks are approached and performed rather than the particular choice of task. For example, flow experiences can be obtained by prisoners in concentration camps with minimal facilities, and occur only slightly more often in billionaires. A

Origin and nature of biological life.

The exact mechanisms of abiogenesis are unknown: notable hypotheses include the RNA world hypothesis (RNA-based replicators) and the iron-sulfur world hypothesis (metabolism without genetics). The process by which different lifeforms have developed throughout history via genetic mutation and natural selection is explained by evolution. At the end of the 20th century, based upon insight gleaned from the gene-centered view of evolution, biologists George C. Williams, Richard Dawkins, and David Haig, among others, concluded that if there is a primary function to life, it is the replication of DNA and the survival of one's genes. This view has not achieved universal agreement; Jeremy Griffith is a notable exception, maintaining that the meaning of life is to be integrative. Responding to an interview question from Richard Dawkins about "what it is all for",

Origins and ultimate fate of the universe.

Though the Big Bang theory was met with much skepticism when first introduced, it has become well-supported by several independent observations. However, current physics can only describe the early universe from 10 seconds after the Big Bang (where zero time corresponds to infinite temperature); a theory of quantum gravity would be required to understand events before that time. Nevertheless, many physicists have speculated about what would have preceded this limit, and how the universe came into being. For example, one interpretation is that the

Scientific questions about the mind.

The nature and origin of consciousness and the mind itself are also widely debated in science. The explanatory gap is generally equated with the hard problem of consciousness, and the question of free will is also considered to be of fundamental importance. These subjects are mostly addressed in the fields of cognitive science, neuroscience (e.g. the neuroscience of free will) and philosophy of mind, though some evolutionary biologists and theoretical physicists have also made several allusions to the subject. Reductionistic and eliminative materialistic approaches, for example the Multiple Drafts Model, hold that consciousness can be wholly explained by neuroscience

Parapsychology.

Based on the premises of non-materialistic explanations of the mind, some have suggested the existence of a cosmic consciousness, asserting that consciousness is actually the "ground of all being". Proponents of this view cite accounts of paranormal phenomena, primarily extrasensory perceptions and psychic powers, as evidence for an incorporeal higher consciousness. In hopes of proving the existence of these phenomena, parapsychologists have orchestrated various experiments, but successful results might be due to poor experimental controls and might have alternative explanations.

Nature of meaning in life.

The most common definitions of meaning in life involve three components. First, Reker and Wong define personal meaning as the "cognizance of order, coherence and purpose in one's existence, the pursuit and attainment of worthwhile goals, and an accompanying sense of fulfillment" (p. 221). In 2016 Martela and Steger defined meaning as coherence, purpose, and significance. In contrast, Wong has proposed a four-component solution to the question of

Western philosophical perspectives.

The philosophical perspectives on the meaning of life are those ideologies that explain life in terms of ideals or abstractions defined by humans.

Ancient Greek philosophy.

Platonism.

Plato, a pupil of Socrates, was one of the earliest, most influential philosophers. His reputation comes from his idealism of believing in the existence of universals. His theory of forms proposes that universals do not physically exist, like objects, but as heavenly forms. In the dialogue

Aristotelianism.

Aristotle, an apprentice of Plato, was another early and influential philosopher, who argued that ethical knowledge is not "certain" knowledge (such as metaphysics and epistemology), but is "general" knowledge. Because it is not a theoretical discipline, a person had to study and practice in order to become "good"; thus if the person were to become virtuous, he could not simply study what virtue "is", he had to "be" virtuous,

Cynicism.

Antisthenes, a pupil of Socrates, first outlined the themes of Cynicism, stating that the purpose of life is living a life of Virtue which agrees with Nature. Happiness depends upon being self-sufficient and master of one's mental attitude; suffering is the consequence of false judgments of value, which cause negative emotions

Cyrenaicism.

Aristippus of Cyrene, a pupil of Socrates, founded an early Socratic school that emphasized only one side of Socrates's teachings—that happiness is one of the ends

Epicureanism.

Epicurus, a pupil of the Platonist Pamphilus of Samos, taught that the greatest good is in seeking modest pleasures, to attain tranquility and freedom from fear (ataraxia) via knowledge, friendship, and virtuous, temperate living; bodily pain (aponia) is absent through one's knowledge of the workings of the world and of the limits of one's desires. Combined, freedom from pain and freedom from fear are happiness in its highest form. Epicurus' lauded enjoyment of simple pleasures is quasi-ascetic "abstention" from sex and the appetites: "When we say... that pleasure is the end and aim, we do not mean the pleasures of the

Stoicism.

Zeno of Citium, a pupil of Crates of Thebes, established the school which teaches that living according to reason and virtue is to be in harmony with the universe's divine order, entailed by one's recognition of the universal "logos", or reason, an essential value of all people. The meaning of life is "freedom from suffering" through "apatheia" (Gr: απαθεια), that is, being objective and having "clear judgement", "not" indifference.  Stoicism's prime directives are virtue, reason, and natural law, abided to develop personal self-control and mental fortitude as means of overcoming destructive emotions. The Stoic does not seek to extinguish emotions, only to avoid emotional troubles, by developing clear judgment and inner calm through diligently practiced logic, reflection, and concentration.  The Stoic ethical foundation is that "good lies in the state of the soul", itself, exemplified in wisdom and self-control, thus improving one's spiritual well-being: ""Virtue" consists in a "will" which is in agreement with Nature." The principle applies to one's personal relations thus: "to be free from anger, envy, and jealousy".

Enlightenment philosophy.

The Enlightenment and the colonial era both changed the nature of European philosophy and exported it worldwide. Devotion and subservience to God were largely replaced by notions of inalienable natural rights and the potentialities of reason, and universal ideals of love and compassion gave way to civic notions of freedom, equality, and citizenship. The meaning of life changed as well, focusing less on humankind's relationship to God and more on the relationship between individuals and their society. This era is filled with theories that equate meaningful existence with the social order.

Classical liberalism.

Classical liberalism is a set of ideas that arose in the 17th and 18th centuries, out of conflicts between a growing, wealthy, propertied class and the established aristocratic and religious orders that dominated Europe. Liberalism cast humans as beings with inalienable natural rights (including the right to retain the wealth generated by one's own work), and sought out means to

Kantianism.

Kantianism is a philosophy based on the ethical, epistemological, and metaphysical works of Immanuel Kant. Kant is known for his deontological theory where there is a single moral obligation, the "Categorical Imperative", derived from the concept of duty. Kantians believe all actions are performed in accordance with some underlying maxim or principle, and for actions to be ethical, they must adhere to the categorical imperative.  Simply put, the test is that one must universalize the maxim (imagine that all people acted in this way) and

19th-century philosophy.

Utilitarianism.

The origins of utilitarianism can be traced back as far as Epicurus, but, as a school of thought, it is credited to Jeremy Bentham, who found that "nature has placed mankind under the governance of two sovereign masters, pain and pleasure"; then, from that moral insight,

Nihilism.

Nihilism suggests that life is without objective meaning.  Friedrich Nietzsche characterized nihilism as emptying the world, and especially human existence, of meaning, purpose, comprehensible truth, and essential value; succinctly, nihilism is the process of "the devaluing of the highest values". Seeing the nihilist as a natural result of the idea that God is dead, and insisting it was something to overcome, his questioning of the nihilist's life-negating values returned meaning to the Earth. To Martin Heidegger, nihilism is the movement whereby "being" is forgotten, and is transformed into value, in other words, the reduction of being to exchange

20th-century philosophy.

The current era has seen radical changes in both formal and popular conceptions of human nature. The knowledge disclosed by modern science has effectively rewritten the relationship of humankind to the natural world. Advances in medicine and technology have freed humans from significant limitations and ailments of previous eras; and philosophy—particularly following the linguistic turn—has altered how the relationships people have with themselves and each other are conceived. Questions about the meaning of life have also seen radical changes, from attempts to reevaluate human existence in biological and scientific terms (as in pragmatism and logical positivism) to efforts to meta-theorize about meaning-making as a personal, individual-driven activity (existentialism, secular humanism).

Pragmatism.

Pragmatism originated in the late-19th-century US, concerning itself (mostly) with truth, and positing that "only in struggling with the environment" do data, and derived theories, have meaning, and that "consequences", like utility and practicality, are also components of truth. Moreover, pragmatism posits that "anything" useful and practical is not always true, arguing that what most contributes to

Theism.

Theists believe God created the universe and that God had a purpose in doing so. Theists also hold the view that humans

Existentialism.

According to existentialism, each man and each woman creates the essence (meaning) of their life; life is not determined by a supernatural god or an earthly authority, one is free. As such, one's ethical prime directives are "action", "freedom", and "decision", thus, existentialism opposes rationalism and positivism. In seeking meaning to life, the existentialist looks to where people find meaning in life, in course of which using only reason as a source of meaning is insufficient; this gives rise to the emotions of anxiety and dread, felt in considering one's free will, and the concomitant awareness of death. According to Jean-Paul Sartre, existence precedes essence; the (essence) of one's life arises "only" after one comes to existence.  Søren

Absurdism.

In absurdist philosophy, the Absurd arises out of the fundamental disharmony between the individual's search for meaning and the apparent meaninglessness of the universe.

Secular humanism.

Per secular humanism, the human species came to be by reproducing successive generations in a progression of unguided evolution as an integral expression of nature, which is self-existing. Human knowledge comes from human observation, experimentation, and rational analysis (the scientific method), and not from supernatural sources; the nature of the universe is what people discern it to be. Likewise, "values and realities" are determined "by means of intelligent inquiry" and "are derived from human need and interest as tested by experience", that is, by critical intelligence. "As far as we know, the total personality is [a function] of the biological organism transacting in a social and cultural context."  People determine human purpose without supernatural influence; it is the human personality (general sense) that is the purpose of a human being's life. Humanism seeks to develop and fulfill: "Humanism affirms our ability and responsibility to lead ethical lives of personal fulfillment that aspire to the greater good of humanity". Humanism aims to promote

Logical positivism.

Logical positivists ask: "What is the meaning of life?", "What is the meaning in asking?" and "If there are no objective values, then, is life meaningless?" Ludwig Wittgenstein and the logical positivists said: "Expressed in language, the question is meaningless"; because, "in" life the statement the "meaning of x", usually denotes the "consequences" of x, or the "significance" of x, or "what is notable" about x, etc., thus, when the meaning of life concept equals "x", in the statement the "meaning of x", the statement becomes recursive, and, therefore, nonsensical, or it might refer to the fact that biological life is essential to having a meaning in life.  The things (people, events) in the life of a person can have meaning (importance) as parts of a whole, but a discrete meaning of (the) life, itself, aside from those things, cannot be discerned. A person's life has meaning (for themselves, others) as the life events resulting from their achievements, legacy, family, etc., but, to say that life, itself, has meaning, is a misuse of language, since any note of significance, or of consequence,

Postmodernism.

Postmodernist thought—broadly speaking—sees human nature as constructed by language, or by structures and institutions of human society. Unlike other forms of philosophy, postmodernism rarely seeks out "a priori" or innate meanings in human existence, but instead focuses on analyzing or critiquing "given" meanings in order to rationalize or reconstruct them. Anything resembling a "meaning of life", in postmodernist terms, can

Naturalistic pantheism.

According to naturalistic pantheism, the meaning of life

Embodied cognition.

Embodied cognition uses the neurological basis of emotion, speech, and cognition to understand the nature of thought. Cognitive neuropsychology has identified brain areas necessary for these abilities, and genetic studies show that the gene FOXP2 affects neuroplasticity which underlies language fluency. George Lakoff, a professor of cognitive linguistics and philosophy, advances the view that metaphors are the usual basis of meaning, not the logic of verbal symbol manipulation. Computers use logic programming to effectively query databases but humans rely on a trained biological neural network. Postmodern philosophies that use the indeterminacy of symbolic language to deny definite meaning ignore those who feel they know what they mean and feel that their interlocutors know what they mean. Choosing the correct metaphor results in enough common understanding to pursue questions such as the meaning of life. Improved knowledge of brain function should result in better treatments producing healthier brains. When combined with more effective training, a sound personal assessment as to the meaning of one's life should be straightforward.

East Asian philosophical perspectives.

Mohism.

The Mohist philosophers believed that the purpose of life was universal, impartial love. Mohism promoted a philosophy of impartial caring—a person should care equally for all other individuals, regardless of their actual relationship to him or her. The expression of

Confucianism.

Confucianism recognizes human nature in accordance with the need for discipline and education. Because humankind is driven by both positive and negative influences, Confucianists see a goal

Legalism.

The Legalists believed that finding the purpose of life was a meaningless effort.

Religious perspectives.

The religious perspectives on the meaning of life are those ideologies that explain life in terms of an implicit purpose not defined by humans. According to the [[Charter for Compassion],] signed by many of the world's leading religious and secular organizations, the core of religion is the [[golden rule]] of 'treat others as you would have them treat you'. The Charter's founder, [[Karen Armstrong]], quotes the ancient Rabbi [[Hillel the Elder|Hillel]] who suggested that 'the rest is commentary'. This is not to reduce the commentary's importance, and Armstrong considers that its study, interpretation, and ritual are the means by which religious people [[Internalisation (sociology)|internalize]] and live the golden rule.

Abrahamic religions.

[[File:ReligionSymbolAbr.PNG|thumb|left|Symbols of the three main Abrahamic religions – [[Judaism]], [[Christianity]], and [[Islam]]]]

Judaism.

In the [[Judaism|Judaic]] world view, the meaning of life is to elevate the physical world ('Olam HaZeh') and prepare it for the world to come ('[[Jewish eschatology|Olam HaBa]]'), the [[Jewish messianism|messianic era]]. This is called [[Tikkun Olam]] ("Fixing the World"). Olam HaBa can also mean the spiritual afterlife, and there is debate concerning the eschatological order. However, Judaism is not focused on personal salvation, but on communal (between man and man) and individual (between man and God) spiritualised actions in this world.

Christianity.

[[File:Cristo Redentor - Rio.jpg|thumb|upright|"[[Christ the Redeemer (statue)|Christ the Redeemer]]" statue on [[Corcovado (Brazil)|Corcovado]] mountain in [[Rio de Janeiro]] is symbolic of Christianity, illustrating the concept of seeking [[redemption (theology)|redemption]] through [[Jesus Christ]].]]  [[Christianity]] has its roots in Judaism, and shares much of the latter faith's [[ontology]]. Its central beliefs derive from the teachings of [[Jesus Christ]] as presented in the [[New Testament]]. Life's purpose in Christianity is to seek divine [[Salvation in Christianity|salvation]] through the grace of God and intercession of Christ ([[Gospel of John|John]] 11:26). The New Testament speaks of God wanting to have a relationship with humans both in this life and the life to come, which can happen only if one's [[Atonement in Christianity|sins are forgiven]] (John 3:16–21; 2 Peter 3:9).  In the Christian view, humankind was made in the [[Image of God]] and perfect, but the [[Fall of Man]] caused the progeny of the [[Adam and Eve|first

Islam.

In [[Islam]], humanity's ultimate purpose is to worship their creator, [[Allah]] (), through his signs, and be grateful to him through sincere love and devotion. This is practically shown by following the divine guidelines revealed in the [[Qur'an]] and the tradition of the [[Muhammad|Prophet]] (for non-koranist). Earthly life is a test, determining one's position of closeness to [[Allah]] in the hereafter. A person will either be close to him and his love in "[[Jannah]]" (Paradise) or far away in "[[Jahannam]]" (Hell).  For Allah's satisfaction, via the Qur'an, all Muslims must believe in God, his revelations, his [[Angels in Islam|angels]], his [[Prophets in Islam|messengers]], and in the "[[Qiyamah|Day of Judgment]]". The Qur'an describes the purpose of creation as follows: "Blessed be he in whose hand is the kingdom, he is powerful over all things, who created death and life that he might examine which of you is best in deeds, and he is the almighty, the forgiving" (Qur'an 67:1–2) and "And I (Allâh) created not the jinn and mankind except that they should be obedient (to Allah)." (Qur'an

Bahá'í Faith.

[[File:Ringstone.svg|thumb|The [[Bahá'í symbols#Ringstone symbol|Ringstone symbol]] represents humanity's connection to God]]  The [[Bahá'í Faith]] emphasizes the unity of humanity. To Bahá'ís, the purpose of life is focused on spiritual growth and service to humanity. Human beings are viewed as intrinsically spiritual beings. People's lives in this material world provide extended opportunities to grow, to develop divine qualities and virtues, and the [[Manifestation of God|prophets]] were sent by God to facilitate this.

South Asian religions.

Hindu philosophies.

[[File:Golden Aum.png|left|thumb|A golden [[Om|Aum]] written in [[Devanagari]]. The Aum is sacred in [[Hinduism|Hindu]], [[Jainism|Jain]] and [[Buddhism|Buddhist]] religions.]]  [[Hinduism]] is a religious category including many beliefs and traditions. Since Hinduism was the way of expressing meaningful living for a long time, before there was a need for naming it as a separate religion, Hindu doctrines are supplementary and complementary in nature, generally non-exclusive, suggestive and tolerant in content. Most believe that the [[Ātman (Hinduism)|ātman]] (spirit, soul)—the person's true "self"—is eternal. In part, this stems from Hindu beliefs that spiritual development occurs across many lifetimes, and goals should match the state of development of the individual. There are four possible aims to human life, known as the "[[purusharthas]]" (ordered from least to greatest): (i)"[[Kāma]]" (wish, desire, love and sensual pleasure), (ii)"[[Artha]]" (wealth,

Jainism.

[[Jainism]] is a religion originating in [[Iron Age India|ancient India]], its ethical system promotes self-discipline above all else. Through following the [[asceticism|ascetic]] teachings of [[Tirthankara|Jina]], a [[human]] achieves [[Moksa (Jainism)|enlightenment (perfect knowledge)]]. Jainism divides the universe into living and non-living beings. Only when the living becomes attached to the non-living does suffering result. Therefore, happiness is the result of self-conquest and freedom from external objects. The meaning of life may then be said to be to use the physical body to achieve self-realization and bliss.  Jains

Buddhism.

Sikhism.

[[File:Khanda.svg|thumb|The [[Khanda (religious symbol)|Khanda]], an important symbol of [[Sikhism]].]]  The followers of Sikhism are ordained to follow the teachings of the ten [[Sikh Gurus]], or enlightened leaders, as well as the holy scripture entitled the "[[Gurū Granth Sāhib]]", which includes selected works of many philosophers from diverse socio-economic and religious backgrounds.  The Sikh Gurus say that salvation can be obtained by following various spiritual paths, so Sikhs do not have a monopoly on salvation: "The Lord dwells in every heart, and every heart has its own way to reach Him." Sikhs believe that all people are equally important before [[Waheguru|God]]. Sikhs balance their moral and spiritual values

East Asian religions.

Taoism.

[[File:Yin yang.svg|thumb|"[[Taijitu]]" symbolizes the [[unity of opposites]] between yin and yang.]]  [[Taoist]] [[cosmogony]] emphasizes the need for all sentient beings and all men to return to the "primordial" or to rejoin with the "Oneness" of the Universe by way of self-cultivation

Shinto.

[[File:Shinto torii vermillion.svg|thumb|Shinto [[torii]], a traditional Japanese gate]]  [[Shinto]] is the native religion of Japan. Shinto means "the path of the [[kami]]", but more specifically, it can be taken to mean "the divine crossroad where the kami chooses his way". The "divine" crossroad signifies that all the universe is divine spirit. This foundation of [[free will]], choosing one's way, means that life is a creative process.  Shinto wants life

New religions.

There are many [[new religious movements]] in East Asia, and some with millions of followers: [[Chondogyo]], [[Tenrikyo]], [[Cao Đài]], and [[Seicho-No-Ie]]. New religions typically have unique explanations for the meaning of life. For example, in Tenrikyo, one is expected to live a [[Joyous Life]] by participating in practices that create happiness for oneself and others.

Iranian religions.

Zoroastrianism.

Zoroastrians believe in a universe created by a transcendental God, [[Ahura Mazda]], to whom all worship is ultimately directed. Ahura Mazda's creation is "[[asha]]", truth and order, and it is in conflict with its [[antithesis]], "druj", falsehood and disorder. (See also [[Zoroastrian eschatology]]).  Since humanity possesses [[free will]], people must be responsible for their moral choices. By using free will, people must take an active role in the universal conflict, with good thoughts, good words and good deeds to ensure happiness and to keep chaos at bay.

Popular views.

"What is the meaning of life?" is a question many people ask themselves at some point during their lives, most in the context "What is the purpose of life?". Some popular answers include:

To [[ethics|do good, to do the right]] thing.

[[File:Paradiso Canto 31.jpg|thumb|Dante and Beatrice see God as a

In popular culture.

[[File:Allisvanity.jpg|thumb|[[Charles Allan Gilbert]]'s "All is Vanity," an example of "[[vanitas]]," depicts a young [[woman]] amidst her makeup and perfumes, preoccupied with her own beauty at the [[mirror]] of her [[lowboy|vanity]]. But all is positioned in such a way as to make the image of a [[human skull|skull]] appear, expressing "[[memento mori]]", that no matter how good she looks, it won't last, as death is inevitable.]]  The mystery of life and its true meaning is an often recurring subject in [[popular culture]], featured in [[mass media|entertainment media]] and [[the arts|various forms]] of [[art]].  In "[[Monty Python's The Meaning of Life]]", there are several allusions to the meaning of life. At the end of the film, a character played by [[Michael Palin]] is handed an envelope containing "the meaning of life", which she opens and reads out to the audience: "Well, it's nothing very special. Uh, try to be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try to live together in peace and harmony with people of all creeds and nations."  Many other [[Monty Python]] sketches and songs are also existential in nature, questioning the importance we place on life ("[[Always Look on the Bright Side of Life]]") and other meaning-of-life related questioning. [[John Cleese]] also had his sit-com character [[Basil Fawlty]] contemplating the futility of his own existence in "[[Fawlty Towers]]".  In [[Douglas Adams]]' popular comedy book, movie, television, and radio series "[[The Hitchhiker's Guide to the Galaxy]]", the [[Answer to the Ultimate Question of Life, the Universe, and Everything]] is given the

External links.

[[Category:Existentialist concepts]] [[Category:Metaphysics]] [[Category:Philosophical concepts]] [[Category:Philosophical problems]] [[Category:Philosophy of life]] [[Category:Religion and science]] [[Category:Spirituality]]

The meaning of life, or the answer to the question: "What is the meaning of life?", pertains to the significance of living or existence in general. Many other related questions include: "Why are we here?", "What is life all about?", or "What is the purpose of existence?" There have been many proposed answers to these questions from many different cultural and ideological backgrounds. The search for life's meaning has produced much philosophical, scientific, theological, and metaphysical speculation throughout history. Different people and cultures believe different things for the answer to this question.

生命的意义是一个解构人类存在的目的与意义的哲学问题。


Etymology.

"Shellac" comes from "shell" and "lac", a calque of French "laque en écailles", "lac in thin pieces", later "gomme-laque", "gum lac". Most European languages (except Romance ones and Greek) have borrowed the word for the substance from English or from the German equivalent "Schellack".

Production.

Shellac is scraped from the bark of the trees where the female lac bug, "Kerria lacca" (order Hemiptera, family Kerriidae, also known as "Laccifer lacca"), secretes it to form a tunnel-like tube as it traverses the branches of the tree. Though these tunnels are sometimes referred to as "cocoons", they are not cocoons in the entomological sense. This insect is in the same superfamily as the insect from which cochineal is obtained. The insects suck the sap of the tree and excrete "sticklac" almost constantly. The least-coloured shellac is produced when the insects feed on the kusum tree ("Schleichera").  The number of lac bugs required to produce of shellac has variously been estimated as,, or. The root word lakh is a unit in Indian numbering system for and presumably refers to the huge numbers of insects that swarm on host trees, up to 150 per square inch.  The raw shellac, which contains bark shavings and lac bugs removed during scraping, is placed in canvas tubes (much like long socks) and heated over a fire. This causes the shellac to liquefy, and it seeps out of the canvas, leaving the bark and bugs behind. The thick, sticky shellac is then dried into a flat sheet and broken into flakes, or dried into "buttons" (pucks/cakes), then bagged and sold. The end-user then crushes it into a fine powder and mixes it with ethyl alcohol before use, to dissolve the flakes and make liquid shellac.  Liquid shellac has a limited shelf life (about 1 year), so is sold in dry form for dissolution before use. Liquid shellac sold in hardware stores is often marked with the production (mixing) date, so the consumer can know whether the shellac inside is still good. Some manufacturers (e.g., Zinsser) have ceased labeling shellac with the production date, but the production date may be discernible from the production lot code. Alternatively, old shellac may be tested to see if it is still usable: a few drops on glass should quickly dry to a hard surface. Shellac that remains tacky for a long time is no longer usable. Storage life depends on peak temperature, so refrigeration extends shelf life.  The thickness (concentration) of shellac is measured by the unit "pound cut", referring to the amount (in pounds) of shellac flakes dissolved in a gallon of denatured alcohol. For example: a 1-lb. cut of shellac is the strength obtained by dissolving one pound of shellac flakes in a gallon of alcohol. Most pre-mixed commercial preparations come at a 3-lb. cut. Multiple thin layers of shellac produce a significantly better end result than a few thick layers. Thick layers of shellac do not adhere to the substrate or to each other well, and thus can peel off with relative ease; in addition, thick shellac will obscure fine details in carved designs in wood and other substrates.  Shellac naturally dries to a high-gloss sheen. For applications where a flatter (less shiny) sheen is desired, products containing amorphous silica, such as "Shellac Flat", may be added to the dissolved shellac.  Shellac naturally contains a small amount of wax (3%–5% by volume), which comes from the lac bug. In some preparations, this wax is removed (the resulting product being called "dewaxed shellac"). This is done for applications where the shellac will be coated with something else (such as paint or varnish), so the topcoat will adhere. Waxy (non-dewaxed) shellac appears milky in liquid form, but dries clear.

Colours and availability.

Shellac comes in many warm colours, ranging from a very light blonde ("platina") to a very dark brown ("garnet"), with many varieties of brown, yellow, orange and red in between. The colour is influenced by the sap of the tree the lac bug is living on and by the time of harvest. Historically, the most commonly sold shellac is called "orange shellac", and was used extensively as a combination stain and protectant for wood panelling and cabinetry in the 20th century.  Shellac was once very common anywhere paints or varnishes were sold (such as hardware stores). However, cheaper and more abrasion- and chemical-resistant finishes, such as polyurethane, have almost completely replaced it in decorative residential wood finishing such as hardwood floors, wooden wainscoting plank panelling, and kitchen cabinets. These alternative products, however, must be applied over a stain if the user wants the wood to be coloured; clear or blonde shellac may be applied over a stain without affecting the colour of the finished piece, as a protective topcoat. "Wax over shellac" (an application of buffed-on paste wax over several coats of shellac) is often regarded as a beautiful, if fragile, finish for hardwood floors. Luthiers still use shellac to "French polish" fine acoustic stringed instruments, but it has been replaced by synthetic plastic lacquers and varnishes in many workshops, especially high-volume production environments.  Shellac dissolved in alcohol, typically more dilute than French-Polish, is now commonly sold as "sanding sealer" by several companies. It is used to seal wooden surfaces, often as preparation for a final more durable finish; it reduces the amount of final coating required by reducing its absorption into the wood.

Properties.

Shellac is a natural bioadhesive polymer and is chemically similar to synthetic polymers, and thus can be considered a natural form of plastic. It can be turned into a moulding compound when mixed with wood flour and moulded under heat and pressure methods, so it can also be classified as thermoplastic.  Shellac scratches more easily than most lacquers and varnishes, and application is more labour-intensive, which is why it has been replaced by plastic in most areas. But damaged shellac can easily be touched up with another coat of shellac (unlike polyurethane) because the new coat merges with and bonds to the existing coat(s). Shellac is much softer than Urushi lacquer, for instance, which is far superior with regard to both chemical and mechanical resistance.  Shellac is soluble in alkaline solutions such as ammonia, sodium borate, sodium carbonate, and sodium hydroxide, and also in various organic solvents. When dissolved in de-natured alcohol or ethanol, shellac yields a coating of good durability and hardness.  Upon mild hydrolysis shellac gives a complex mix of aliphatic and alicyclic hydroxy acids and their polymers that varies in exact composition depending upon the source of the shellac and the season of collection. The major component of the aliphatic component is aleuritic acid, whereas the main alicyclic component is shellolic acid.  Shellac is UV-resistant, and does not darken as it ages (though the wood under it may do so, as in the case of pine).

History.

The earliest written evidence of shellac goes back years, but shellac is known to have been used earlier. According to the ancient Indian epic poem, the Mahabharata, an entire palace was built out of dried shellac.  Shellac was in rare use as a dyestuff for as long as there was a trade with the East Indies. Merrifield cites 1220 for the introduction of shellac as an artist's pigment in Spain. Lapis lazuli, an ultramarine pigment from Afghanistan, was already being imported long before this.  The use of overall paint or varnish decoration on large pieces of furniture was first popularised in Venice (then later throughout Italy). There are a number of 13th-century references to painted or varnished cassone, often dowry cassone that were made deliberately impressive as part of dynastic marriages. The definition of varnish is not always clear, but it seems to have been a spirit varnish based on gum benjamin or mastic, both traded around the Mediterranean. At some time, shellac began to be used as well. An article from the "Journal of the American Institute of Conservation" describes using infrared spectroscopy to identify shellac coating on a 16th-century cassone. This is also the period in history where "varnisher" was identified as a distinct trade, separate from both carpenter and artist.  Another use for shellac is sealing wax. Woods's "The Nature and Treatment of Wax and Shellac Seals" discusses the various formulations, and the period when shellac started to be added to the previous beeswax recipes.  The "period of widespread introduction" would seem to be around 1550 to 1650, when the substance moved from being a rarity on highly decorated pieces to being described in the standard texts of the day.

Uses.

Historical.

In the early- and mid-twentieth century, orange shellac was used as a one-product finish (combination stain and varnish-like topcoat) on decorative wood panelling used on walls and ceilings in homes, particularly in the US. In the American South, use of knotty pine plank panelling covered with orange shellac was once as common in new construction as drywall is today. It was also often used on kitchen cabinets and hardwood floors, prior to the advent of polyurethane.  Until the advent of vinyl, most gramophone records were pressed from shellac compounds. From 1921 to 1928, tons of shellac were used to create 260 million records for Europe. In the 1930s, it was estimated that half of all shellac was used for gramophone records. Use of shellac for records was common until the 1950s and continued into the 1970s in some non-Western countries.  Until recent advances in technology, shellac (French polish) was the only glue used in the making of ballet dancers' pointe shoes, to stiffen the box (toe area) to support the dancer en pointe. Many manufacturers of pointe shoes still use the traditional techniques, and many dancers use shellac to revive a softening pair of shoes.  Shellac was historically used as a protective coating on paintings.  Sheets of Braille were coated with shellac to help protect them from wear due to being read by hand.  Shellac was used from the mid-nineteenth century to produce small moulded goods such as picture frames, boxes, toilet articles, jewelry, inkwells and even dentures. Advances in plastics have rendered shellac obsolete as a moulding compound.  Shellac (both orange and white varieties) was used both in the field and laboratory to glue and stabilise dinosaur bones until about the mid-1960s. While effective at the time, the long-term negative effects of shellac (being organic in nature) on dinosaur bones and other fossils is debated, and shellac is very rarely used by professional conservators and fossil preparators today.  Shellac was used for fixing inductor, motor, generator and transformer windings. It was applied directly to single-layer windings in an alcohol solution. For multi-layer windings, the whole coil was submerged in shellac solution, then drained and placed in a warm place to allow the alcohol to evaporate. The shellac locked the wire turns in place, provided extra insulation, prevented movement and vibration and reduced buzz and hum. In motors and generators it also helps transfer force generated by magnetic attraction and repulsion from the windings to the rotor or armature. In more recent times, shellac has been replaced in these applications by synthetic resins such as polyester resin. Some applications use shellac mixed with other natural or synthetic resins, such as pine resin or phenol-formaldehyde resin, of which Bakelite is the best known, for electrical use. Mixed with other resins, barium sulfate, calcium carbonate, zinc sulfide, aluminium oxide and/or cuprous carbonate (malachite), shellac forms a component of heat-cured capping cement used to fasten the caps or bases to the bulbs of electric lamps.

Current.

It is the central element of the traditional "French polish" method of finishing furniture, fine string instruments, and pianos.  Shellac, edible, is used as a glazing agent on pills (see excipient) and sweets, in the form of "pharmaceutical glaze" (or, "confectioner's glaze"). Because of its acidic properties (resisting stomach acids), shellac-coated pills may be used for a timed enteric or colonic release. Shellac is used as a 'wax' coating on citrus fruit to prolong its shelf/storage life. It is also used to replace the natural wax of the apple, which is removed during the cleaning process. When used for this purpose, it has the food additive E number E904.  Shellac coating applied with either a standard or modified Huon-Stuehrer nozzle, can be economically micro-sprayed onto various smooth sweets, such as chocolate coated peanuts. Irregularities on the surface of the product being sprayed typically result in the formation of unsightly aggregates ("lac-aggs") which precludes the use of this technique on foods such as walnuts or raisins (however, chocolate-coated raisins being smooth surfaced, are able to be sprayed successfully using a modified Huon-Stuehrer nozzle).  Shellac is an odour and stain blocker and so is often used as the base of "solves all problems" primers. Although its durability against abrasives and many common solvents is not very good, shellac provides an excellent barrier against water vapour penetration. Shellac-based primers are an effective sealant to control odours associated with fire damage.  Shellac has traditionally been used as a dye for cotton and, especially, silk cloth in Thailand, particularly in the north-eastern region. It yields a range of warm colours from pale yellow through to dark orange-reds and dark ochre. Naturally dyed silk cloth, including that using shellac, is widely available in the rural northeast, especially in Ban Khwao District, Chaiyaphum province. The Thai name for the insect and the substance is "khrang" (Thai: ครั่ง).  Wood finish  Wood finishing is one of the most traditional and still popular uses of shellac mixed with solvents or alcohol. This dissolved shellac liquid, applied to a piece of wood, is an evaporative finish: the alcohol of the shellac mixture evaporates, leaving behind a protective film.  Shellac as wood finish is natural and non-toxic in its pure form. A finish made of shellac is UV-resistant. For water-resistance and durability, it does not keep up with synthetic finishing products.  Because it is compatible with most other finishes, shellac is also used as a barrier or primer coat on wood to prevent the bleeding of resin or pigments into the final finish, or to prevent wood stain from blotching.

Other.

Shellac is used:

Shellac is a resin secreted by the female lac bug on trees in the forests of India and Thailand. It is processed and sold as dry flakes (pictured) and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish. Shellac functions as a tough natural primer, sanding sealant, tannin-blocker, odour-blocker, stain, and high-gloss varnish. Shellac was once used in electrical applications as it possesses good insulation qualities and it seals out moisture. Phonograph and 78 rpm gramophone records were made of it until they were replaced by vinyl long-playing records from the 1950s onwards.

虫胶,香港粤语俗作士叻(英文Shellac的译音),是一种从雌性的Kerria lacca介壳虫(或者其他同为胶介壳虫科的物种)分泌出来的树脂。这些虫一般生活于印度或泰国的森林。


Stages.

The Carnot cycle when acting as a heat engine consists of the following steps:  In this case,  or,  This is true as formula_3 and formula_4 are both lower and in fact are in the same ratio as formula_5.

The pressure–volume graph.

When the Carnot cycle is plotted on a pressure–volume diagram (), the isothermal stages follow the isotherm lines for the working fluid, the adiabatic stages move between isotherms, and the area bounded by the complete cycle path represents the total work that can be done during one cycle. From point 1 to 2 and point 3 to 4 the temperature is constant. Heat transfer from point 4 to 1 and point 2 to 3 are equal to zero.

Properties and significance.

The temperature–entropy diagram.

The behaviour of a Carnot engine or refrigerator is best understood by using a temperature–entropy diagram (T–S diagram), in which the thermodynamic state is specified by a point on a graph with entropy (S) as the horizontal axis and temperature (T) as the vertical axis (). For a simple closed system (control mass analysis), any point on the graph will represent a particular state of the system. A thermodynamic process will consist of a curve connecting an initial state (A) and a final state (B). The area under the curve will be:  which is the amount of thermal energy transferred in the process. If the process moves to greater entropy, the area under the curve will be the amount of heat absorbed by the system in that process. If the process moves towards lesser entropy, it will be the amount of heat removed. For any cyclic process, there will be an upper portion of the cycle and a lower portion. For a clockwise cycle, the area under the upper portion will be the thermal energy absorbed during the cycle, while the area under the lower portion will be the thermal energy removed during the cycle. The area inside the cycle will then be the difference between the two, but since the internal energy of the system must have returned to its initial value, this difference must be the amount of work done by the system over the cycle. Referring to, mathematically, for a reversible process we may write the amount of work done over a cyclic process as:  Since "dU" is an exact differential, its integral over any closed loop is zero and it follows that the area inside the loop on a T–S diagram is equal to the total work performed if the loop is traversed in a clockwise direction, and is equal to the total work done on the system as the loop is traversed in a counterclockwise direction.

The Carnot cycle.

Evaluation of the above integral is particularly simple for the Carnot cycle. The amount of energy transferred as work is  The total amount of thermal energy transferred from the hot reservoir to the system will be  and the total amount of thermal energy transferred from the system to the cold reservoir will be  The efficiency formula_9 is defined to be: where This definition of efficiency makes sense for a heat engine, since it is the fraction of the heat energy extracted from the hot reservoir and converted to mechanical work. A Rankine cycle is usually the practical approximation.

Reversed Carnot cycle.

The Carnot heat-engine cycle described is a totally reversible cycle. That is all the processes that compose it can be reversed, in which case it becomes the Carnot refrigeration cycle. This time, the cycle remains exactly the same except that the directions of any heat and work interactions are reversed. Heat is absorbed from the low-temperature reservoir, heat is rejected to a high-temperature reservoir, and a work input is required to accomplish all this. The P–V diagram of the reversed Carnot cycle is the same as for the Carnot cycle except that the directions of the processes are reversed.

Carnot's theorem.

It can be seen from the above diagram, that for any cycle operating between temperatures formula_13 and formula_12, none can exceed the efficiency of a Carnot cycle.  Carnot's theorem is a formal statement of this fact: "No engine operating between two heat reservoirs can be more efficient than a Carnot engine operating between those same reservoirs." Thus, Equation gives the maximum efficiency possible for any engine using the corresponding temperatures. A corollary to Carnot's theorem states that: "All reversible engines operating between the same heat reservoirs are equally efficient." Rearranging the right side of the equation gives what may be a more easily understood form of the equation, namely that the theoretical maximum efficiency of a heat engine equals the difference in temperature between the hot and cold reservoir divided by the absolute temperature of the hot reservoir. Looking at this formula an interesting fact becomes apparent: Lowering the temperature of the cold reservoir will have more effect on the ceiling efficiency of a heat engine than raising the temperature of the hot reservoir by the same amount. In the real world, this may be difficult to achieve since the cold reservoir is often an existing ambient temperature.  In other words, maximum efficiency is achieved if and only if no new entropy is created in the cycle, which would be the case if e.g. friction leads to dissipation of work into heat. In that case, the cycle is not reversible and the Clausius theorem becomes an inequality rather than an equality. Otherwise, since entropy is a state function, the required dumping of heat into the environment to dispose of excess entropy leads to a (minimal) reduction in efficiency. So Equation gives the efficiency of any reversible heat engine.  In mesoscopic heat engines, work per cycle of operation in general fluctuates due to thermal noise. If the cycle is performed quasi-statically, the fluctuations vanish even on the mesoscale. However, if the cycle is performed faster than the relaxation time of the working medium, the fluctuations of work are inevitable. Nevertheless, when work and heat fluctuations are counted, there is exact equality that relates the exponential average of work performed by any heat engine and the heat transfer from the hotter heat bath.

Efficiency of real heat engines.

Carnot realized that in reality it is not possible to build a thermodynamically reversible engine, so real heat engines are even less efficient than indicated by Equation 3. In addition, real engines that operate along this cycle are rare. Nevertheless, Equation 3 is extremely useful for determining the maximum efficiency that could ever be expected for a given set of thermal reservoirs.  Although Carnot's cycle is an idealisation, the expression of Carnot efficiency is still useful. Consider the average temperatures,  at which heat is input and output, respectively. Replace "T" and "T" in Equation () by 〈"T"〉 and 〈"T"〉 respectively.  For the Carnot cycle, or its equivalent, the average value 〈"T"〉 will equal the highest temperature available, namely "T", and 〈"T"〉 the lowest, namely "T". For other less efficient cycles, 〈"T"〉 will be lower than "T", and 〈"T"〉 will be higher than "T". This can help illustrate, for example, why a reheater or a regenerator can improve the thermal efficiency of steam power plants—and why the thermal efficiency of combined-cycle power plants (which incorporate gas turbines operating at even higher temperatures) exceeds that of conventional steam plants. The first prototype of the diesel engine was based on the Carnot cycle.

The Carnot cycle is a theoretical ideal thermodynamic cycle proposed by French physicist Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. It provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system. It is not an actual thermodynamic cycle but is a theoretical construct.

卡诺循环(英语:Carnot cycle)是一个特别的热力学循环,使用在一个假想的卡诺热机上,由法国人尼古拉·卡诺于1824年提出,埃米尔·克拉佩龙于1830年代至1840年代扩充,是为了找出热机的最大的工作效率而分析热机的工作过程。