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Central Pacific Railroad

The Central Pacific Railroad (CPRR) was a rail company chartered by U.S. Congress in 1862 to build a railroad eastwards from Sacramento, California, to complete most of the western part of the "First transcontinental railroad" in North America. Incorporated in 1861, CPRR ceased independent operations in 1875 when the railroad was leased to the Southern Pacific Railroad. Its assets were formally merged into Southern Pacific in 1959.

Following the completion of the Pacific Railroad Surveys in 1855, several national proposals to build a transcontinental railroad failed because of political disputes over slavery. With the secession of the South in 1861, the modernizers in the Republican Party controlled the US Congress. They passed legislation in 1862 authorizing the central rail route with financing in the form of land grants and government railroad bond, which were all eventually repaid with interest. The government and the railroads both shared in the increased value of the land grants, which the railroads developed. The construction of the railroad also secured for the government the economical "safe and speedy transportation of the mails, troops, munitions of war, and public stores".

Authorization and construction
In the fall of 1860, Charles Marsh, a surveyor, civil engineer and water company owner, met with Theodore Judah, a civil engineer, who had recently built the Sacramento Valley Railroad from Sacramento to Folsom, California and was working on the California Central Railroad to extend the former from Folsom to Marysville. Marsh, who had already surveyed a potential railroad route between Sacramento and Nevada City, California, a decade earlier, went with Judah into the Sierra Nevada Mountains. There they examined the Henness Pass Turnpike Company's route (Marsh was a founding director of that company). They measured elevations and distances, and discussed the possibility of a transcontinental railroad. Both were convinced that it could be done.

In December 1860 or early January 1861, Marsh met with Judah and Daniel Strong in Strong's drug store in Dutch Flat, California, to discuss the project, which they called the Central Pacific Railroad of California. James Bailey, a friend of Judah, told Leland Stanford that Judah had a feasible route for a railroad across the Sierras, and urged Stanford to meet with Judah. In early 1861, Marsh, Judah and Strong met with Collis P. Huntington, Leland Stanford, Mark Hopkins Jr. and Charles Crocker to obtain financial backing. Papers were filed to incorporate the new company, and on April 30, 1861, the eight of them, along with Lucius Anson Booth, became the first board of directors of the Central Pacific Railroad.

Planned by Judah, the Central Pacific Railroad was promoted by Congress by the Pacific Railway Act of 1862 which authorized the issuance of government bonds and land grants for each mile that was constructed. Stanford served as president (at the same time he was elected governor of California), Huntington served as vice-president in charge of fundraising and purchasing, Hopkins was treasurer and Crocker was in charge of construction. They called themselves "The Associates," but became known as "The Big Four." Construction began in 1863 when the first rails were laid in Sacramento.

Construction proceeded in earnest in 1865 when James Harvey Strobridge, the head of the construction work force, hired the first Cantonese emigrant workers at Crocker's suggestion. The construction crew grew to include 12,000 Chinese laborers by 1868, when they breached Donner summit and constituted eighty percent of the entire work force. The "Golden spike", connecting the western railroad to the Union Pacific Railroad at Promontory, Utah, was hammered on May 10, 1869. Coast-to-coast train travel in eight days became possible, replacing months-long sea voyages and lengthy, hazardous travel by wagon trains.

In 1885 the Central Pacific Railroad was acquired by the Southern Pacific Company as a leased line. Technically the CPRR remained a corporate entity until 1959, when it was formally merged into Southern Pacific. (It was reorganized in 1899 as the Central Pacific "Railway".) The original right-of-way is now controlled by the Union Pacific, which bought Southern Pacific in 1996.

The Union Pacific-Central Pacific (Southern Pacific) main line followed the historic Overland Route from Omaha, Nebraska, to San Francisco Bay.

Chinese labor was the most vital source for constructing the railroad. Most of the railroad workers in the west were Chinese, as they could be hired at a lower cost to do the difficult work. Fifty Cantonese emigrant workers were hired by the Central Pacific Railroad in February 1865 on a trial basis, and soon more and more Cantonese emigrants were hired. Working conditions were harsh, and Chinese were compensated less than their white counterparts, leading to far less white workers being hired. Chinese laborers were paid thirty-one dollars each month, and while white workers were paid the same, they were also given room and board. In time, CPRR came to see the advantage of good workers employed at low wages: "Chinese labor proved to be Central Pacific's salvation."

The difficulties faced by the Central Pacific in the Sierra Nevada – particularly the extensive tunneling required – were far more formidable than those encountered by the Union Pacific Railroad in the Rocky Mountains. The story that Chinese workers were suspended in wicker baskets over vertical granite cliffs at Cape Horn, California, to drill and blast a ledge for the Central Pacific has been repeated and exaggerated by uncritical historians.

There is reliable, primary-source evidence stating that surveyors used safety ropes while staking out the route, but nothing about construction workers using ropes. Digging the cut was done downward from the top, and from each horizontal end of the cut. It is conceivable that a safety rope would have been useful when digging an initial footpath, that could then be enlarged into a shelf, but there was no reason to be suspended by ropes to dig or drill into the face of the cut. It wasn't done that way. And, most of the Chinese labor was not hired until later. So, the gangs that did the digging at Cape Horn were probably Irish.

Central Pacific Director Charles Marsh had extensive civil engineering experience in projects of this nature, both from planning an earlier proposed railroad into the Sierras, and from building ditches and flumes through those mountains for his water company.

Financing

Construction of the road was financed primarily by 30-year, 6% U.S. government bonds authorized by Sec. 5 of the Pacific Railroad Act of 1862. They were issued at the rate of $16,000 ($265,000 in 2017 dollars) per mile of tracked grade completed east of the designated base of the Sierra Nevada range near Roseville, CA where California state geologist Josiah Whitney had determined were the geologic start of the Sierras' foothills. Sec. 11 of the Act also provided that the issuance of bonds "shall be treble the number per mile" (to $48,000) for tracked grade completed over and within the two mountain ranges (but limited to a total of 300 mi at this rate), and "doubled" (to $32,000) per mile of completed grade laid between the two mountain ranges. The U.S. Government Bonds, which constituted a lien upon the railroads and all their fixtures, were repaid in full (and with interest) by the company as and when they became due.

Sec. 10 of the 1864 amending Pacific Railroad Act (13 Statutes at Large, 356) additionally authorized the company to issue its own "First Mortgage Bonds" in total amounts up to (but not exceeding) that of the bonds issued by the United States. Such company-issued securities had priority over the original Government Bonds. (Local and state governments also aided the financing, although the City and County of San Francisco did not do so willingly. This materially slowed early construction efforts.) Sec. 3 of the 1862 Act granted the railroads 10 sqmi of public land for every mile laid, except where railroads ran through cities and crossed rivers. This grant was apportioned in 5 sections on alternating sides of the railroad, with each section measuring 0.2 mi by 10 mi. These grants were later doubled to 20 sqmi per mile of grade by the 1864 Act.

Although the Pacific Railroad eventually benefited the Bay Area, the City and County of San Francisco obstructed financing it during the early years of 1863–1865. When Stanford was Governor of California, the Legislature passed on April 22, 1863, "An Act to Authorize the Board of Supervisors of the City and County of San Francisco to take and subscribe One Million Dollars to the Capital Stock of the Western Pacific Rail Road Company and the Central Pacific Rail Road Company of California and to provide for the payment of the same and other matters relating thereto" (which was later amended by Section Five of the "Compromise Act" of April 4, 1864). On May 19, 1863, the electors of the City and County of San Francisco passed this bond by a vote of 6,329 to 3,116, in a highly controversial Special Election.

The City and County's financing of the investment through the issuance and delivery of Bonds was delayed for two years, when Mayor Henry P. Coon, and the County Clerk, Wilhelm Loewy, each refused to countersign the Bonds. It took legal actions to force them to do so: in 1864 the Supreme Court of the State of California ordered them under Writs of Mandamus (The People of the State of California ex rel the Central Pacific Railroad Company vs. Henry P. Coon, Mayor; Henry M. Hale, Auditor; and Joseph S. Paxson, Treasurer, of the City and County of San Francisco. 25 Cal. 635) and in 1865, a legal judgment against Loewy (The People ex rel The Central Pacific Railroad Company of California vs. The Board of Supervisors of the City and County of San Francisco, and Wilhelm Lowey, Clerk 27 Cal. 655) directing that the Bonds be countersigned and delivered.

In 1863 the State legislature's forcing of City and County action became known as the "Dutch Flat Swindle". Critics claimed the CPRR's Big Four intended to build a railroad only as far as Dutch Flat, California, to connect to the Dutch Flat-Donner Pass Wagon Road to monopolize the lucrative mining traffic, and not push the track east of Dutch Flat into the more challenging and expensive High Sierra effort. CPRR's chief engineer, Theodore Judah, also argued against such a road and hence against the Big Four, fearing that its construction would siphon money from CPRR's paramount trans-Sierra railroad effort. Despite Judah's strong objection, the Big Four incorporated in August 1863 the Dutch Flat-Donner Lake Wagon Road Company. Frustrated, Judah headed off for New York via Panama to raise funds to buy out the Big Four from CPRR and build his trans-Sierra railroad. Unfortunately, Judah contracted yellow fever in Panama and died in New York in November 1863.

Museums and archives
A replica of the Sacramento, California, Central Pacific Railroad passenger station is part of the California State Railroad Museum, located in the Old Sacramento State Historic Park.

Nearly all the company's early correspondence is preserved at Syracuse University, as part of the Collis Huntington Papers collection. It has been released on microfilm (133 reels). The following libraries have the microfilm: University of Arizona at Tucson; and Virginia Commonwealth University at Richmond. Additional collections of manuscript letters are held at Stanford University and the Mariners' Museum at Newport News, Virginia. Alfred A. Hart was the official photographer of the CPRR construction.

Locomotives

The Central Pacific's first three locomotives were of the then common 4-4-0 type, although with the American Civil War raging in the east, they had difficulty acquiring engines from eastern builders, who at times only had smaller 4-2-4 or 4-2-2 types available. Until the completion of the Transcontinental rail link and the railroad's opening of its own shops, all locomotives had to be purchased from builders in the northeastern U.S. The engines had to be dismantled, loaded on a ship, which would embark on a four-month journey that went around South America's Cape Horn until arriving in Sacramento where the locomotives would be unloaded, re-assembled, and placed in service.

Locomotives at the time came from many manufacturers, such as Cooke, Schenectady, Mason, Rogers, Danforth, Norris, Booth, and McKay & Aldus, among others. The railroad had been on rather unfriendly terms with the Baldwin Locomotive Works, one of the more well-known firms. It is not clear as to the cause of this dispute, though some attribute it to the builder insisting on cash payment (though this has yet to be verified). Consequently, the railroad refused to buy engines from Baldwin, and three former Western Pacific Railroad (which the CP had absorbed in 1870) engines were the only Baldwin engines owned by the Central Pacific. The Central Pacific's dispute with Baldwin remained unresolved until well after the road had been acquired by the Southern Pacific.

In the 1870s, the road opened up its own locomotive construction facilities in Sacramento. Central Pacific's 173 was rebuilt by these shops and served as the basis for CP's engine construction. The locomotives built before the 1870s were given names as well as numbers. By the 1870s, it was decided to eliminate the names and as each engine was sent to the shops for service, their names would be removed. However, one engine that was built in the 1880s did receive a name: the El Gobernador.

Preserved locomotives
The following CP engines have been preserved:

 * Central Pacific 1, Gov. Stanford
 * CP 233, a 2-6-2T the railroad had built, is stored at the California State Railroad Museum.
 * Central Pacific 3, C. P. Huntington, later purchased by the Southern Pacific Transportation Company.
 * Former Western Pacific Mariposa, Central Pacific's second number 31. Was sold to Stockton Terminal and Eastern in 1914 and renumbered 1. Currently at the Travel Town Museum in Los Angeles.
 * Virginia and Truckee 18 Dayton was built for the Virginia and Truckee Railroad and never served on the Central Pacific, but the engine was one of two locomotives built by the CP's Sacramento shops in preservation (the other being CP 233). Moreover, its specifications were derived from CP 173, and thus is the only surviving example of that engine's design.
 * Central Pacific's numbers 60 Jupiter, and 63 Leviathan. Although both engines have been scrapped, and therefore technically do not count as having been preserved, there are exact, full-size operating replicas built in recent years. The Jupiter was built for the National Park Service along with a replica of Union Pacific's 119 for use at their Golden Spike National Historic Site. Leviathan was finished in 2009, and was privately owned, traveling to various railroads to operate, until sold in 2018 to Stone Gable Estates of Elizabethtown, Pennsylvania. Stone Gable relettered the locomotive as Pennsylvania Railroad No. 331, a now-scrapped steam locomotive that pulled Abraham Lincoln's funeral train, and operates on the estate's Harrisburg, Lincoln and Lancaster Railroad.

Timeline
1861
 * June 28, 1861: "Central Pacific Rail Road of California" incorporated; name changed to "Central Pacific Railroad of California" on October 8, 1864, after the Pacific Railway Act amendment passes that summer.

1862 1863 1864
 * July 1, 1862: President Lincoln signs the Pacific Railway Act, which authorized the Central Pacific and the Union Pacific to build a railroad to the Pacific Ocean.
 * January 8, 1863: Ground-breaking ceremonies take place at Sacramento, California, at the foot of "K" Street at the waterfront of the Sacramento River.
 * October 26, 1863: First rail of the Pacific Railroad laid at Sacramento.
 * April 26, 1864: Central Pacific opened to Roseville, 18 mi, where it makes a junction with the California Central Railroad, operating from Folsom north to Lincoln.
 * June 3, 1864: The first revenue train on the Central Pacific operates between Sacramento and Newcastle, California
 * October 8, 1864: Following passage of the amendment to the Pacific Railroad Act, the company's name is changed to "Central Pacific Railroad of California," a new corporation.

1865 1866
 * February 1865: Central Pacific hired its first 50 Cantonese emigrant laborers on a trial basis.
 * May 13, 1865: Central Pacific opened 36 mi to Auburn, California.
 * September 1, 1865: Central Pacific opened 54 mi to Colfax, California (formerly known as "Illinoistown.")
 * December 3, 1866: Central Pacific opened 92 mi to Cisco, California.

1867

1868 1869 1870 1876 1877 1883 1885 1888 1899 1959
 * June 25, 1867: 5,000 Chinese railroad workers went on strike in protest against the longer hours and wage inequality they were facing.
 * August 28, 1867: The Sierra Nevadas were finally "conquered" by the Central Pacific Railroad, after almost five years of sustained construction effort by its mainly Chinese crew about 10,000 strong, with the successful completion at Donner Pass of its 1,659-foot (506 m) Tunnel No. 6 (a.k.a. the "Summit Tunnel").
 * December 1, 1867: Central Pacific opened to Summit of the Sierra Nevada, 105 mi.
 * June 18, 1868: The first passenger train crosses the Sierra Nevada to Lake's Crossing (modern day Reno, Nevada) at the eastern foot of the Sierra in Nevada.
 * April 28, 1869: Track crews on the Central Pacific lay 10 mi of track in one day. To date, this is the longest stretch of track to have been built in one day.
 * May 10, 1869: The Central Pacific and Union Pacific tracks meet in Promontory, Utah.
 * May 15, 1869: The first transcontinental trains are run over the new line to Sacramento.
 * September 6, 1869: The first transcontinental train reaches the San Francisco Bay at Alameda Terminal, achieving the first coast-to-coast railroad line.
 * November 8, 1869: Central Pacific subsidiaries, Western Pacific Railroad (1862–1870) and San Francisco and Oakland Railroad, complete the final leg of the route, connecting Sacramento to Oakland Pier.
 * June 23, 1870: Central Pacific is consolidated with the Western Pacific Railroad (1862–1870), San Francisco and Alameda Railroad and San Francisco and Oakland Railroad to form the "Central Pacific Railroad Co." (of June 1870).
 * August 22, 1870: Central Pacific Railroad Co. is consolidated with the California & Oregon; San Francisco, Oakland & Alameda; and San Joaquin Valley Railroad; to form the "Central Pacific Railroad Co.", a new corporation.
 * April 30, 1876: Operates the California Pacific Railroad between South Vallejo and Sacramento, Calistoga and Marysville until April 1, 1885 (see below).
 * July 16, 1877: Start of the Great railroad strike of 1877 when railroad workers on strike in Martinsburg, West Virginia, derail and loot a train; United States President Rutherford B. Hayes calls in Federal troops to break the strike.
 * November 18, 1883: A system of one-hour standard time zones for American railroads was first implemented. The zones were named Intercolonial, Eastern, Central, Mountain, and Pacific. Within one year, 85% of all cities having populations over 10,000, about 200 cities in total, were using standard time.
 * April 1, 1885: Central Pacific is leased to Southern Pacific.
 * June 30, 1888: Listed by ICC as a "non-operating" subsidiary of Southern Pacific.
 * July 29, 1899: Central Pacific is reorganized as the "Central Pacific Railway".
 * June 30, 1959: Central Pacific is formally merged into the Southern Pacific.

Acquisitions

 * San Joaquin Valley Railroad (1868–1870)
 * Stockton and Copperopolis Railroad
 * Stockton and Visalia Railroad
 * Western Pacific Railroad (1862–1870)

title: Central Pacific Railroad


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Clairvoyance

Clairvoyance is the claimed ability to acquire information that would be considered impossible to get through scientifically proven sensations, thus classified as extrasensory perception, or "sixth sense". Any person who is claimed to have such ability is said to be a clairvoyant (one who sees clearly).

Claims for the existence of paranormal and psychic abilities such as clairvoyance have not been supported by scientific evidence. Parapsychology explores this possibility, but the existence of the paranormal is not accepted by the scientific community. The scientific community widely considers parapsychology, including the study of clairvoyance, a pseudoscience.

Usage
Pertaining to the ability of clear-sightedness, clairvoyance refers to the paranormal ability to see persons and events that are distant in time or space. It can be divided into roughly three classes: precognition, the ability to perceive or predict future events, retrocognition, the ability to see past events, and remote viewing, the perception of contemporary events happening outside the range of normal perception.

In history and religion
Throughout history, there have been numerous places and times in which people have claimed themselves or others to be clairvoyant.

In several religions, stories of certain individuals being able to see things far removed from their immediate sensory perception are commonplace, especially within pagan religions where oracles were used. Prophecy often involved some degree of clairvoyance, especially when future events were predicted. This ability has sometimes been attributed to a higher power rather than to the person performing it.

Christianity
A number of Christian saints were said to be able to see or know things that were far removed from their immediate sensory perception as a kind of gift from God, including Charbel Makhlouf, Padre Pio and Anne Catherine Emmerich in Catholicism and Gabriel Urgebadze, Paisios Eznepidis and John Maximovitch in Orthodoxy. Jesus Christ in the Gospels is also recorded as being able to know things that were far removed from his immediate human perception. Some Christians today also share the same claim.

Jainism
In Jainism, clairvoyance is regarded as one of the five kinds of knowledge. The beings of hell and heaven (devas) are said to possess clairvoyance by birth. According to Jain text Sarvārthasiddhi, "this kind of knowledge has been called avadhi as it ascertains matter in downward range or knows objects within limits".

Anthroposophy
Rudolf Steiner, famous as a clairvoyant himself, claimed that for a clairvoyant, it is easy to confuse his own emotional and spiritual being with the objective spiritual world.

Early research
The earliest record of somnambulist clairvoyance is credited to the Marquis de Puységur, a follower of Franz Mesmer, who in 1784 was treating a local dull-witted peasant named Victor Race. During treatment, Race reportedly would go into trance and undergo a personality change, becoming fluent and articulate, and giving diagnosis and prescription for his own disease as well as those of others. Clairvoyance was a reported ability of some mediums during the spiritualist period of the late 19th and early 20th centuries, and psychics of many descriptions have claimed clairvoyant ability up to the present day.

Early researchers of clairvoyance included William Gregory, Gustav Pagenstecher, and Rudolf Tischner. Clairvoyance experiments were reported in 1884 by Charles Richet. Playing cards were enclosed in envelopes and a subject put under hypnosis attempted to identify them. The subject was reported to have been successful in a series of 133 trials but the results dropped to chance level when performed before a group of scientists in Cambridge. J. M. Peirce and E. C. Pickering reported a similar experiment in which they tested 36 subjects over 23,384 trials which did not obtain above chance scores.

Ivor Lloyd Tuckett (1911) and Joseph McCabe (1920) analyzed early cases of clairvoyance and came to the conclusion they were best explained by coincidence or fraud. In 1919, the magician P. T. Selbit staged a séance at his own flat in Bloomsbury. The spiritualist Arthur Conan Doyle attended the séance and declared the clairvoyance manifestations to be genuine.

A significant development in clairvoyance research came when J. B. Rhine, a parapsychologist at Duke University, introduced a standard methodology, with a standard statistical approach to analyzing data, as part of his research into extrasensory perception. A number of psychological departments attempted to repeat Rhine's experiments, with failure. W. S. Cox (1936) from Princeton University with 132 subjects produced 25,064 trials in a playing card ESP experiment. Cox concluded, "There is no evidence of extrasensory perception either in the 'average man' or of the group investigated or in any particular individual of that group. The discrepancy between these results and those obtained by Rhine is due either to uncontrollable factors in experimental procedure or to the difference in the subjects." Four other psychological departments failed to replicate Rhine's results. It was revealed that Rhine's experiments contained methodological flaws and procedural errors.

Eileen Garrett was tested by Rhine at Duke University in 1933 with Zener cards. Certain symbols that were placed on the cards and sealed in an envelope, and she was asked to guess their contents. She performed poorly and later criticized the tests by claiming the cards lacked a psychic energy called "energy stimulus" and that she could not perform clairvoyance to order. The parapsychologist Samuel Soal and his colleagues tested Garrett in May 1937. Most of the experiments were carried out in the Psychological Laboratory at the University College London. A total of over 12,000 guesses were recorded but Garrett failed to produce above chance level. In his report Soal wrote "In the case of Mrs. Eileen Garrett we fail to find the slightest confirmation of Dr. J. B. Rhine's remarkable claims relating to her alleged powers of extra-sensory perception. Not only did she fail when I took charge of the experiments, but she failed equally when four other carefully trained experimenters took my place."

Remote viewing
Remote viewing, also known as remote sensing, remote perception, telesthesia and travelling clairvoyance is the alleged paranormal ability to perceive a remote or hidden target without support of the senses.

A well known study of remote viewing in recent times has been the US government-funded project at the Stanford Research Institute during the 1970s through the mid-1990s. In 1972, Harold Puthoff and Russell Targ initiated a series of human subject studies to determine whether participants (the viewers or percipients) could reliably identify and accurately describe salient features of remote locations or targets. In the early studies, a human sender was typically present at the remote location, as part of the experiment protocol. A three-step process was used, the first step being to randomly select the target conditions to be experienced by the senders. Secondly, in the viewing step, participants were asked to verbally express or sketch their impressions of the remote scene. Thirdly, in the judging step, these descriptions were matched by separate judges, as closely as possible, with the intended targets. The term remote viewing was coined to describe this overall process. The first paper by Puthoff and Targ on remote viewing was published in Nature in March 1974; in it, the team reported some degree of remote viewing success. After the publication of these findings, other attempts to replicate the experiments were carried out with remotely linked groups using computer conferencing.

The psychologists David Marks and Richard Kammann attempted to replicate Targ and Puthoff's remote viewing experiments that were carried out in the 1970s at the Stanford Research Institute. In a series of 35 studies, they were unable to replicate the results so investigated the procedure of the original experiments. Marks and Kammann discovered that the notes given to the judges in Targ and Puthoff's experiments contained clues as to which order they were carried out, such as referring to yesterday's two targets, or they had the date of the session written at the top of the page. They concluded that these clues were the reason for the experiment's high hit rates. Marks was able to achieve 100 per cent accuracy without visiting any of the sites himself but by using cues. James Randi has written controlled tests by several other researchers, eliminating several sources of cuing and extraneous evidence present in the original tests, produced negative results. Students were also able to solve Puthoff and Targ's locations from the clues that had inadvertently been included in the transcripts.

In 1980, Charles Tart claimed that a rejudging of the transcripts from one of Targ and Puthoff's experiments revealed an above-chance result. Targ and Puthoff again refused to provide copies of the transcripts and it was not until July 1985 that they were made available for study when it was discovered they still contained sensory cues. Marks and Christopher Scott (1986) wrote "considering the importance for the remote viewing hypothesis of adequate cue removal, Tart's failure to perform this basic task seems beyond comprehension. As previously concluded, remote viewing has not been demonstrated in the experiments conducted by Puthoff and Targ, only the repeated failure of the investigators to remove sensory cues."

In 1982 Robert Jahn, then Dean of the School of Engineering at Princeton University wrote a comprehensive review of psychic phenomena from an engineering perspective. His paper included numerous references to remote viewing studies at the time. Statistical flaws in his work have been proposed by others in the parapsychological community and within the general scientific community.

Scientific reception
According to scientific research, clairvoyance is generally explained as the result of confirmation bias, expectancy bias, fraud, hallucination, self-delusion, sensory leakage, subjective validation, wishful thinking or failures to appreciate the base rate of chance occurrences and not as a paranormal power. Parapsychology is generally regarded by the scientific community as a pseudoscience. In 1988, the US National Research Council concluded "The committee finds no scientific justification from research conducted over a period of 130 years, for the existence of parapsychological phenomena."

Skeptics say that if clairvoyance were a reality, it would have become abundantly clear. They also contend that those who believe in paranormal phenomena do so for merely psychological reasons. According to David G. Myers (Psychology, 8th ed.):

"The search for a valid and reliable test of clairvoyance has resulted in thousands of experiments. One controlled procedure has invited 'senders' to telepathically transmit one of four visual images to 'receivers' deprived of sensation in a nearby chamber (Bem & Honorton, 1994). The result? A reported 32 percent accurate response rate, surpassing the chance rate of 25 percent. But follow-up studies have (depending on who was summarizing the results) failed to replicate the phenomenon or produced mixed results (Bem & others, 2001; Milton & Wiseman, 2002; Storm, 2000, 2003).

One skeptic, magician James Randi, had a longstanding offer of U.S. $1 million—'to anyone who proves a genuine psychic power under proper observing conditions' (Randi, 1999). French, Australian, and Indian groups have parallel offers of up to 200,000 euros to anyone with demonstrable paranormal abilities (CFI, 2003). Large as these sums are, the scientific seal of approval would be worth far more to anyone whose claims could be authenticated. To refute those who say there is no ESP, one need only produce a single person who can demonstrate a single, reproducible ESP phenomenon. So far, no such person has emerged. Randi's offer has been publicized for three decades and dozens of people have been tested, sometimes under the scrutiny of an independent panel of judges. Still, nothing. 'People's desire to believe in the paranormal is stronger than all the evidence that it does not exist.' Susan Blackmore, 'Blackmore's first law', 2004."

Clairvoyance is considered a hallucination by mainstream psychiatry.

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

title: Clairvoyance


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Chiropractic

Chiropractic is a form of alternative medicine concerned with the diagnosis, treatment and prevention of mechanical disorders of the musculoskeletal system, especially of the spine. It has esoteric origins and is based on several pseudoscientific ideas. For an explanation regarding the description of chiropractic as a pseudoscience, see:
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9
 * Williams, William F. (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy. Facts on File Inc. p. 51. ISBN 1-57958-207-9

Many chiropractors, especially those in the field's early history, have proposed that mechanical disorders of the joints, especially of the spine, affect general health, and that regular manipulation of the spine (spinal adjustment) improves general health. The main chiropractic treatment technique involves manual therapy, especially manipulation of the spine, other joints, and soft tissues, but may also include exercises and health and lifestyle counseling. A chiropractor may have a Doctor of Chiropractic (D.C.) degree and be referred to as "doctor" but is not a Doctor of Medicine (M.D.) or a Doctor of Osteopathic Medicine (D.O.). While many chiropractors view themselves as primary care providers, chiropractic clinical training does not meet the requirements for that designation.

Systematic reviews of controlled clinical studies of treatments used by chiropractors have found no evidence that chiropractic manipulation is effective, with the possible exception of treatment for back pain. A 2011 critical evaluation of 45 systematic reviews concluded that the data included in the study "fail[ed] to demonstrate convincingly that spinal manipulation is an effective intervention for any condition." Spinal manipulation may be cost-effective for sub-acute or chronic low back pain, but the results for acute low back pain were insufficient. No compelling evidence exists to indicate that maintenance chiropractic care adequately prevents symptoms or diseases.

There is not sufficient data to establish the safety of chiropractic manipulations. It is frequently associated with mild to moderate adverse effects, with serious or fatal complications in rare cases. There is controversy regarding the degree of risk of vertebral artery dissection, which can lead to stroke and death, from cervical manipulation. Several deaths have been associated with this technique and it has been suggested that the relationship is causative, a claim which is disputed by many chiropractors.

Chiropractic is well established in the United States, Canada, and Australia. It overlaps with other manual-therapy professions such as osteopathy and physical therapy. Most who seek chiropractic care do so for low back pain. Back and neck pain are considered the specialties of chiropractic, but many chiropractors treat ailments other than musculoskeletal issues. Chiropractic has two main groups: "straights", now the minority, emphasize vitalism, "Innate Intelligence", and consider vertebral subluxations to be the cause of all disease; and "mixers", the majority, are more open to mainstream views and conventional medical techniques, such as exercise, massage, and ice therapy.

D. D. Palmer founded chiropractic in the 1890s, after saying he received it from "the other world"; Palmer maintained that the tenets of chiropractic were passed along to him by a doctor who had died 50 years previously. His son B. J. Palmer helped to expand chiropractic in the early 20th century. Throughout its history, chiropractic has been controversial. Its foundation is at odds with evidence-based medicine, and has been sustained by pseudoscientific ideas such as vertebral subluxation and Innate Intelligence. Despite the overwhelming evidence that vaccination is an effective public health intervention, among chiropractors there are significant disagreements over the subject, which has led to negative impacts on both public vaccination and mainstream acceptance of chiropractic. The American Medical Association called chiropractic an "unscientific cult" in 1966 and boycotted it until losing an antitrust case in 1987. Chiropractic has had a strong political base and sustained demand for services. In the last decades of the twentieth century, it gained more legitimacy and greater acceptance among conventional physicians and health plans in the United States. During the COVID-19 pandemic, chiropractic professional associations advised chiropractors to adhere to CDC, WHO, and local health department guidance. Despite these recommendations, a small but vocal and influential number of chiropractors spread vaccine misinformation.

Philosophy
Chiropractic is generally categorized as complementary and alternative medicine (CAM), which focuses on manipulation of the musculoskeletal system, especially the spine. Its founder, D.D. Palmer, called it "a science of healing without drugs".

Chiropractic's origins lie in the folk medicine of bonesetting, and as it evolved it incorporated vitalism, spiritual inspiration and rationalism. Its early philosophy was based on deduction from irrefutable doctrine, which helped distinguish chiropractic from medicine, provided it with legal and political defenses against claims of practicing medicine without a license, and allowed chiropractors to establish themselves as an autonomous profession. This "straight" philosophy, taught to generations of chiropractors, rejects the inferential reasoning of the scientific method, and relies on deductions from vitalistic first principles rather than on the materialism of science. However, most practitioners tend to incorporate scientific research into chiropractic, and most practitioners are "mixers" who attempt to combine the materialistic reductionism of science with the metaphysics of their predecessors and with the holistic paradigm of wellness. A 2008 commentary proposed that chiropractic actively divorce itself from the straight philosophy as part of a campaign to eliminate untestable dogma and engage in critical thinking and evidence-based research.

Although a wide diversity of ideas exist among chiropractors, they share the belief that the spine and health are related in a fundamental way, and that this relationship is mediated through the nervous system. Some chiropractors claim spinal manipulation can have an effect on a variety of ailments such as irritable bowel syndrome and asthma.

Chiropractic philosophy includes the following perspectives:

Holism assumes that health is affected by everything in an individual's environment; some sources also include a spiritual or existential dimension. In contrast, reductionism in chiropractic reduces causes and cures of health problems to a single factor, vertebral subluxation. Homeostasis emphasizes the body's inherent self-healing abilities. Chiropractic's early notion of innate intelligence can be thought of as a metaphor for homeostasis.

A large number of chiropractors fear that if they do not separate themselves from the traditional vitalistic concept of innate intelligence, chiropractic will continue to be seen as a fringe profession. A variant of chiropractic called naprapathy originated in Chicago in the early twentieth century. It holds that manual manipulation of soft tissue can reduce "interference" in the body and thus improve health.

Straights and mixers
Straight chiropractors adhere to the philosophical principles set forth by D.D. and B.J. Palmer, and retain metaphysical definitions and vitalistic qualities. Straight chiropractors believe that vertebral subluxation leads to interference with an "innate intelligence" exerted via the human nervous system and is a primary underlying risk factor for many diseases. Straights view the medical diagnosis of patient complaints, which they consider to be the "secondary effects" of subluxations, to be unnecessary for chiropractic treatment. Thus, straight chiropractors are concerned primarily with the detection and correction of vertebral subluxation via adjustment and do not "mix" other types of therapies into their practice style. Their philosophy and explanations are metaphysical in nature and they prefer to use traditional chiropractic lexicon terminology such as "perform spinal analysis", "detect subluxation", "correct with adjustment". They prefer to remain separate and distinct from mainstream health care. Although considered the minority group, "they have been able to transform their status as purists and heirs of the lineage into influence dramatically out of proportion to their numbers."

Mixer chiropractors "mix" diagnostic and treatment approaches from chiropractic, medical or osteopathic viewpoints and make up the majority of chiropractors. Unlike straight chiropractors, mixers believe subluxation is one of many causes of disease, and hence they tend to be open to mainstream medicine. Many of them incorporate mainstream medical diagnostics and employ conventional treatments including techniques of physical therapy such as exercise, stretching, massage, ice packs, electrical muscle stimulation, therapeutic ultrasound, and moist heat. Some mixers also use techniques from alternative medicine, including nutritional supplements, acupuncture, homeopathy, herbal remedies, and biofeedback.

Although mixers are the majority group, many of them retain belief in vertebral subluxation as shown in a 2003 survey of 1,100 North American chiropractors, which found that 88 percent wanted to retain the term "vertebral subluxation complex", and that when asked to estimate the percent of disorders of internal organs that subluxation significantly contributes to, the mean response was 62 percent. A 2008 survey of 6,000 American chiropractors demonstrated that most chiropractors seem to believe that a subluxation-based clinical approach may be of limited utility for addressing visceral disorders, and greatly favored non-subluxation-based clinical approaches for such conditions. The same survey showed that most chiropractors generally believed that the majority of their clinical approach for addressing musculoskeletal/biomechanical disorders such as back pain was based on subluxation. Chiropractors often offer conventional therapies such as physical therapy and lifestyle counseling, and it may for the lay person be difficult to distinguish the unscientific from the scientific.

Vertebral subluxation
In science-based medicine, the term "subluxation" refers to an incomplete or partial dislocation of a joint, from the Latin luxare for 'dislocate'. While medical doctors use the term exclusively to refer to physical dislocations, Chiropractic founder D. D. Palmer imbued the word subluxation with a metaphysical and philosophical meaning drawn from pseudoscientific traditions such as Vitalism.

Palmer claimed that vertebral subluxations interfered with the body's function and its inborn ability to heal itself. D. D. Palmer repudiated his earlier theory that vertebral subluxations caused pinched nerves in the intervertebral spaces in favor of subluxations causing altered nerve vibration, either too tense or too slack, affecting the tone (health) of the end organ. He qualified this by noting that knowledge of innate intelligence was not essential to the competent practice of chiropractic. This concept was later expanded upon by his son, B. J. Palmer, and was instrumental in providing the legal basis of differentiating chiropractic from conventional medicine. In 1910, D. D. Palmer theorized that the nervous system controlled health:

"Physiologists divide nerve-fibers, which form the nerves, into two classes, afferent and efferent. Impressions are made on the peripheral afferent fiber-endings; these create sensations that are transmitted to the center of the nervous system. Efferent nerve-fibers carry impulses out from the center to their endings. Most of these go to muscles and are therefore called motor impulses; some are secretory and enter glands; a portion are inhibitory, their function being to restrain secretion. Thus, nerves carry impulses outward and sensations inward. The activity of these nerves, or rather their fibers, may become excited or allayed by impingement, the result being a modification of functionality – too much or not enough action – which is disease."

Vertebral subluxation, a core concept of traditional chiropractic, remains unsubstantiated and largely untested, and a debate about whether to keep it in the chiropractic paradigm has been ongoing for decades. In general, critics of traditional subluxation-based chiropractic (including chiropractors) are skeptical of its clinical value, dogmatic beliefs and metaphysical approach. While straight chiropractic still retains the traditional vitalistic construct espoused by the founders, evidence-based chiropractic suggests that a mechanistic view will allow chiropractic care to become integrated into the wider health care community. This is still a continuing source of debate within the chiropractic profession as well, with some schools of chiropractic still teaching the traditional/straight subluxation-based chiropractic, while others have moved towards an evidence-based chiropractic that rejects metaphysical foundings and limits itself to primarily neuromusculoskeletal conditions.

In 2005, the chiropractic subluxation was defined by the World Health Organization as "a lesion or dysfunction in a joint or motion segment in which alignment, movement integrity and/or physiological function are altered, although contact between joint surfaces remains intact. It is essentially a functional entity, which may influence biomechanical and neural integrity." This differs from the medical definition of subluxation as a significant structural displacement, which can be seen with static imaging techniques such as X-rays. The use of X-ray imaging in the case of vertebral subluxation exposes patients to harmful ionizing radiation for no evidentially supported reason. The 2008 book Trick or Treatment states "X-rays can reveal neither the subluxations nor the innate intelligence associated with chiropractic philosophy, because they do not exist." Attorney David Chapman-Smith, Secretary-General of the World Federation of Chiropractic, has stated that "Medical critics have asked how there can be a subluxation if it cannot be seen on X-ray. The answer is that the chiropractic subluxation is essentially a functional entity, not structural, and is therefore no more visible on static X-ray than a limp or headache or any other functional problem." The General Chiropractic Council, the statutory regulatory body for chiropractors in the United Kingdom, states that the chiropractic vertebral subluxation complex "is not supported by any clinical research evidence that would allow claims to be made that it is the cause of disease."

As of 2014, the US National Board of Chiropractic Examiners states "The specific focus of chiropractic practice is known as the chiropractic subluxation or joint dysfunction. A subluxation is a health concern that manifests in the skeletal joints, and, through complex anatomical and physiological relationships, affects the nervous system and may lead to reduced function, disability or illness."

Pseudoscience versus spinal manipulation therapy
While some chiropractors limit their practice to short-term treatment of musculoskeletal conditions, many falsely claim to be able treat a myriad of other conditions. Some dissuade patients from seeking medical care, others have pretended to be qualified to act as a family doctor.

Quackwatch, an alternative medicine watchdog, cautions against seeing chiropractors who:
 * Treat young children
 * Discourage immunization
 * Pretend to be a family doctor
 * Take full spine X-rays
 * Promote unproven dietary supplements
 * Are antagonistic to scientific medicine
 * Claim to treat non-musculoskeletal problems

Writing for the Skeptical Inquirer, one physician cautioned against seeing even chiropractors who solely claim to treat musculoskeletal conditions: "I think Spinal Manipulation Therapy (SMT) is a reasonable option for patients to try ... But I could not in good conscience refer a patient to a chiropractor... When chiropractic is effective, what is effective is not 'chiropractic': it is SMT. SMT is also offered by physical therapists, DOs, and others. These are science-based providers ... If I thought a patient might benefit from manipulation, I would rather refer him or her to a science-based provider."

Scope of practice

Chiropractors emphasize the conservative management of the neuromusculoskeletal system without the use of medicines or surgery, with special emphasis on the spine. Back and neck pain are the specialties of chiropractic but many chiropractors treat ailments other than musculoskeletal issues. There is a range of opinions among chiropractors: some believed that treatment should be confined to the spine, or back and neck pain; others disagreed. For example, while one 2009 survey of American chiropractors had found that 73% classified themselves as "back pain/musculoskeletal specialists", the label "back and neck pain specialists" was regarded by 47% of them as a least desirable description in a 2005 international survey. Chiropractic combines aspects from mainstream and alternative medicine, and there is no agreement about how to define the profession: although chiropractors have many attributes of primary care providers, chiropractic has more attributes of a medical specialty like dentistry or podiatry. It has been proposed that chiropractors specialize in nonsurgical spine care, instead of attempting to also treat other problems, but the more expansive view of chiropractic is still widespread.

Mainstream health care and governmental organizations such as the World Health Organization consider chiropractic to be complementary and alternative medicine (CAM); and a 2008 study reported that 31% of surveyed chiropractors categorized chiropractic as CAM, 27% as integrated medicine, and 12% as mainstream medicine. Many chiropractors believe they are primary care providers, including US and UK chiropractors, but the length, breadth, and depth of chiropractic clinical training do not support the requirements to be considered primary care providers, so their role on primary care is limited and disputed.

Chiropractic overlaps with several other forms of manual therapy, including massage therapy, osteopathy, physical therapy, and sports medicine. Chiropractic is autonomous from and competitive with mainstream medicine, and osteopathy outside the US remains primarily a manual medical system; physical therapists work alongside and cooperate with mainstream medicine, and osteopathic medicine in the U.S. has merged with the medical profession. Practitioners may distinguish these competing approaches through claims that, compared to other therapists, chiropractors heavily emphasize spinal manipulation, tend to use firmer manipulative techniques, and promote maintenance care; that osteopaths use a wider variety of treatment procedures; and that physical therapists emphasize machinery and exercise.

Chiropractic diagnosis may involve a range of methods including skeletal imaging, observational and tactile assessments, and orthopedic and neurological evaluation. A chiropractor may also refer a patient to an appropriate specialist, or co-manage with another health care provider. Common patient management involves spinal manipulation (SM) and other manual therapies to the joints and soft tissues, rehabilitative exercises, health promotion, electrical modalities, complementary procedures, and lifestyle advice.

Chiropractors are not normally licensed to write medical prescriptions or perform major surgery in the United States (although New Mexico has become the first US state to allow "advanced practice" trained chiropractors to prescribe certain medications ). In the US, their scope of practice varies by state, based on inconsistent views of chiropractic care: some states, such as Iowa, broadly allow treatment of "human ailments"; some, such as Delaware, use vague concepts such as "transition of nerve energy" to define scope of practice; others, such as New Jersey, specify a severely narrowed scope. US states also differ over whether chiropractors may conduct laboratory tests or diagnostic procedures, dispense dietary supplements, or use other therapies such as homeopathy and acupuncture; in Oregon they can become certified to perform minor surgery and to deliver children via natural childbirth. A 2003 survey of North American chiropractors found that a slight majority favored allowing them to write prescriptions for over-the-counter drugs. A 2010 survey found that 72% of Swiss chiropractors considered their ability to prescribe nonprescription medication as an advantage for chiropractic treatment.

A related field, veterinary chiropractic, applies manual therapies to animals and is recognized in many US states, but is not recognized by the American Chiropractic Association as being chiropractic. It remains controversial within certain segments of the veterinary and chiropractic professions.

No single profession "owns" spinal manipulation and there is little consensus as to which profession should administer SM, raising concerns by chiropractors that other medical physicians could "steal" SM procedures from chiropractors. A focus on evidence-based SM research has also raised concerns that the resulting practice guidelines could limit the scope of chiropractic practice to treating backs and necks. Two US states (Washington and Arkansas) prohibit physical therapists from performing SM, some states allow them to do it only if they have completed advanced training in SM, and some states allow only chiropractors to perform SM, or only chiropractors and physicians. Bills to further prohibit non-chiropractors from performing SM are regularly introduced into state legislatures and are opposed by physical therapist organizations.

Treatments

Spinal manipulation, which chiropractors call "spinal adjustment" or "chiropractic adjustment", is the most common treatment used in chiropractic care. Spinal manipulation is a passive manual maneuver during which a three-joint complex is taken past the normal range of movement, but not so far as to dislocate or damage the joint. Its defining factor is a dynamic thrust, which is a sudden force that causes an audible release and attempts to increase a joint's range of motion. High-velocity, low-amplitude spinal manipulation (HVLA-SM) thrusts have physiological effects that signal neural discharge from paraspinal muscle tissues, depending on duration and amplitude of the thrust are factors of the degree in paraspinal muscle spindles activation. Clinical skill in employing HVLA-SM thrusts depends on the ability of the practitioner to handle the duration and magnitude of the load. More generally, spinal manipulative therapy (SMT) describes techniques where the hands are used to manipulate, massage, mobilize, adjust, stimulate, apply traction to, or otherwise influence the spine and related tissues.

There are several schools of chiropractic adjustive techniques, although most chiropractors mix techniques from several schools. The following adjustive procedures were received by more than 10% of patients of licensed US chiropractors in a 2003 survey: Diversified technique (full-spine manipulation, employing various techniques), extremity adjusting, Activator technique (which uses a spring-loaded tool to deliver precise adjustments to the spine), Thompson Technique (which relies on a drop table and detailed procedural protocols), Gonstead (which emphasizes evaluating the spine along with specific adjustment that avoids rotational vectors), Cox/flexion-distraction (a gentle, low-force adjusting procedure which mixes chiropractic with osteopathic principles and utilizes specialized adjusting tables with movable parts), adjustive instrument, Sacro-Occipital Technique (which models the spine as a torsion bar), Nimmo Receptor-Tonus Technique, applied kinesiology (which emphasises "muscle testing" as a diagnostic tool), and cranial. Chiropractic biophysics technique uses inverse functions of rotations during spinal manipulation. Koren Specific Technique (KST) may use their hands, or they may use an electric device known as an "ArthroStim" for assessment and spinal manipulations. Insurers in the US and UK that cover other chiropractic techniques exclude KST from coverage because they consider it to be "experimental and investigational". Medicine-assisted manipulation, such as manipulation under anesthesia, involves sedation or local anesthetic and is done by a team that includes an anesthesiologist; a 2008 systematic review did not find enough evidence to make recommendations about its use for chronic low back pain.

Many other procedures are used by chiropractors for treating the spine, other joints and tissues, and general health issues. The following procedures were received by more than one-third of patients of licensed US chiropractors in a 2003 survey: Diversified technique (full-spine manipulation; mentioned in previous paragraph), physical fitness/exercise promotion, corrective or therapeutic exercise, ergonomic/postural advice, self-care strategies, activities of daily living, changing risky/unhealthy behaviors, nutritional/dietary recommendations, relaxation/stress reduction recommendations, ice pack/cryotherapy, extremity adjusting (also mentioned in previous paragraph), trigger point therapy, and disease prevention/early screening advice.

A 2010 study describing Belgian chiropractors and their patients found chiropractors in Belgium mostly focus on neuromusculoskeletal complaints in adult patients, with emphasis on the spine. The diversified technique is the most often applied technique at 93%, followed by the Activator mechanical-assisted technique at 41%. A 2009 study assessing chiropractic students giving or receiving spinal manipulations while attending a United States chiropractic college found Diversified, Gonstead, and upper cervical manipulations are frequently used methods.

Practice guidelines
Reviews of research studies within the chiropractic community have been used to generate practice guidelines outlining standards that specify which chiropractic treatments are legitimate (i.e. supported by evidence) and conceivably reimbursable under managed care health payment systems. Evidence-based guidelines are supported by one end of an ideological continuum among chiropractors; the other end employs antiscientific reasoning and makes unsubstantiated claims. Chiropractic remains at a crossroads, and that in order to progress it would need to embrace science; the promotion by some for it to be a cure-all was both "misguided and irrational". A 2007 survey of Alberta chiropractors found that they do not consistently apply research in practice, which may have resulted from a lack of research education and skills. Specific guidelines concerning the treatment of nonspecific (i.e., unknown cause) low back pain are inconsistent between countries.

Effectiveness
Numerous controlled clinical studies of treatments used by chiropractors have been conducted, with varied results. There is no conclusive evidence that chiropractic manipulative treatment is effective for the treatment of any medical condition, except perhaps for certain kinds of back pain.

Generally, the research carried out into the effectiveness of chiropractic has been of poor quality. Research published by chiropractors is distinctly biased: reviews of SM for back pain tended to find positive conclusions when authored by chiropractors, while reviews by mainstream authors did not.

There is a wide range of ways to measure treatment outcomes. Chiropractic care benefits from the placebo response, but it is difficult to construct a trustworthy placebo for clinical trials of spinal manipulative therapy (SMT). The efficacy of maintenance care in chiropractic is unknown.

Available evidence covers the following conditions:
 * Low back pain. A 2013 Cochrane review found very low to moderate evidence that SMT was no more effective than inert interventions, sham SMT or as an adjunct therapy for acute low back pain. The same review found that SMT appears to be no better than other recommended therapies. A 2012 overview of systematic reviews found that collectively, SM failed to show it is an effective intervention for pain. A 2011 Cochrane review found strong evidence that suggests there is no clinically meaningful difference between SMT and other treatments for reducing pain and improving function for chronic low back pain. A 2010 Cochrane review found no difference between the effects of combined chiropractic treatments and other treatments for chronic or mixed duration low back pain. A 2010 systematic review found that most studies suggest SMT achieves equivalent or superior improvement in pain and function when compared with other commonly used interventions for short, intermediate, and long-term follow-up.
 * Radiculopathy. A 2013 systematic review and meta-analysis found a statistically significant improvement in overall recovery from sciatica following SM, when compared to usual care, and suggested that SM may be considered. There is moderate quality evidence to support the use of SM for the treatment of acute lumbar radiculopathy and acute lumbar disc herniation with associated radiculopathy. There is low or very low evidence supporting SM for chronic lumbar spine-related extremity symptoms and cervical spine-related extremity symptoms of any duration and no evidence exists for the treatment of thoracic radiculopathy.
 * Whiplash and other neck pain. There is no consensus on the effectiveness of manual therapies for neck pain. A 2013 systematic review found that the data suggests that there are minimal short- and long-term treatment differences when comparing manipulation or mobilization of the cervical spine to physical therapy or exercise for neck pain improvement. A 2013 systematic review found that although there is insufficient evidence that thoracic SM is more effective than other treatments, it is a suitable intervention to treat some patients with non-specific neck pain. A 2011 systematic review found that thoracic SM may offer short-term improvement for the treatment of acute or subacute mechanical neck pain; although the body of literature is still weak. A 2010 Cochrane review found low quality evidence that suggests cervical manipulation may offer better short-term pain relief than a control for neck pain, and moderate evidence that cervical manipulation and mobilization produced similar effects on pain, function and patient satisfaction. A 2010 systematic review found low level evidence that suggests chiropractic care improves cervical range of motion and pain in the management of whiplash.
 * Headache. There is conflicting evidence surrounding the use of chiropractic SMT for the treatment and prevention of migraine headaches. A 2006 review found no rigorous evidence supporting SM or other manual therapies for tension headache. A 2005 review found that the evidence was weak for effectiveness of chiropractic manipulation for tension headache, and that it was probably more effective for tension headache than for migraine.
 * Extremity conditions. A 2011 systematic review and meta-analysis concluded that the addition of manual mobilizations to an exercise program for the treatment of knee osteoarthritis resulted in better pain relief than a supervised exercise program alone and suggested that manual therapists consider adding manual mobilization to optimize supervised active exercise programs. There is silver level evidence that manual therapy is more effective than exercise for the treatment of hip osteoarthritis, however this evidence could be considered to be inconclusive. There is a small amount of research into the efficacy of chiropractic treatment for upper limbs, limited to low level evidence supporting chiropractic management of shoulder pain and limited or fair evidence supporting chiropractic management of leg conditions.
 * Other. A 2012 systematic review found insufficient low bias evidence to support the use of spinal manipulation as a therapy for the treatment of hypertension. A 2011 systematic review found moderate evidence to support the use of manual therapy for cervicogenic dizziness. There is very weak evidence for chiropractic care for adult scoliosis (curved or rotated spine) and no scientific data for idiopathic adolescent scoliosis. A 2007 systematic review found that few studies of chiropractic care for nonmusculoskeletal conditions are available, and they are typically not of high quality; it also found that the entire clinical encounter of chiropractic care (as opposed to just SM) provides benefit to patients with cervicogenic dizziness, and that the evidence from reviews is negative, or too weak to draw conclusions, for a wide variety of other nonmusculoskeletal conditions, including ADHD/learning disabilities, dizziness, high blood pressure, and vision conditions. Other reviews have found no evidence of significant benefit for asthma, baby colic, bedwetting, carpal tunnel syndrome, fibromyalgia, gastrointestinal disorders, kinetic imbalance due to suboccipital strain (KISS) in infants, menstrual cramps, insomnia, postmenopausal symptoms, or pelvic and back pain during pregnancy. As there is no evidence of effectiveness or safety for cervical manipulation for baby colic, it is not endorsed.

Safety

The World Health Organization found chiropractic care in general is safe when employed skillfully and appropriately. There is not sufficient data to establish the safety of chiropractic manipulations. Manipulation is regarded as relatively safe but complications can arise, and it has known adverse effects, risks and contraindications. Absolute contraindications to spinal manipulative therapy are conditions that should not be manipulated; these contraindications include rheumatoid arthritis and conditions known to result in unstable joints. Relative contraindications are conditions where increased risk is acceptable in some situations and where low-force and soft-tissue techniques are treatments of choice; these contraindications include osteoporosis. Although most contraindications apply only to manipulation of the affected region, some neurological signs indicate referral to emergency medical services; these include sudden and severe headache or neck pain unlike that previously experienced. Indirect risks of chiropractic involve delayed or missed diagnoses through consulting a chiropractor.

Spinal manipulation is associated with frequent, mild and temporary adverse effects, including new or worsening pain or stiffness in the affected region. They have been estimated to occur in 33% to 61% of patients, and frequently occur within an hour of treatment and disappear within 24 to 48 hours; adverse reactions appear to be more common following manipulation than mobilization. The most frequently stated adverse effects are mild headache, soreness, and briefly elevated pain fatigue. Chiropractic is correlated with a very high incidence of minor adverse effects. Rarely, spinal manipulation, particularly on the upper spine, can also result in complications that can lead to permanent disability or death; these can occur in adults and children. Estimates vary widely for the incidence of these complications, and the actual incidence is unknown, due to high levels of underreporting and to the difficulty of linking manipulation to adverse effects such as stroke, which is a particular concern. Adverse effects are poorly reported in recent studies investigating chiropractic manipulations. A 2016 systematic review concludes that the level of reporting is unsuitable and unacceptable. Reports of serious adverse events have occurred, resulting from spinal manipulation therapy of the lumbopelvic region. Estimates for serious adverse events vary from 5 strokes per 100,000 manipulations to 1.46 serious adverse events per 10 million manipulations and 2.68 deaths per 10 million manipulations, though it was determined that there was inadequate data to be conclusive. Several case reports show temporal associations between interventions and potentially serious complications. The published medical literature contains reports of 26 deaths since 1934 following chiropractic manipulations and many more seem to remain unpublished.

Vertebrobasilar artery stroke (VAS) is statistically associated with chiropractic services in persons under 45 years of age, but it is similarly associated with general practitioner services, suggesting that these associations are likely explained by preexisting conditions. Weak to moderately strong evidence supports causation (as opposed to statistical association) between cervical manipulative therapy (CMT) and VAS. There is insufficient evidence to support a strong association or no association between cervical manipulation and stroke. While the biomechanical evidence is not sufficient to support the statement that CMT causes cervical artery dissection (CD), clinical reports suggest that mechanical forces have a part in a substantial number of CDs and the majority of population controlled studies found an association between CMT and VAS in young people. It is strongly recommended that practitioners consider the plausibility of CD as a symptom, and people can be informed of the association between CD and CMT before administering manipulation of the cervical spine. There is controversy regarding the degree of risk of stroke from cervical manipulation. Many chiropractors state that, the association between chiropractic therapy and vertebral arterial dissection is not proven. However, it has been suggested that the causality between chiropractic cervical manipulation beyond the normal range of motion and vascular accidents is probable or definite. There is very low evidence supporting a small association between internal carotid artery dissection and chiropractic neck manipulation. The incidence of internal carotid artery dissection following cervical spine manipulation is unknown. The literature infrequently reports helpful data to better understand the association between cervical manipulative therapy, cervical artery dissection and stroke. The limited evidence is inconclusive that chiropractic spinal manipulation therapy is not a cause of intracranial hypotension. Cervical intradural disc herniation is very rare following spinal manipulation therapy.

Chiropractors sometimes employ diagnostic imaging techniques such as X-rays and CT scans that rely on ionizing radiation. Although there is no clear evidence to justify the practice, some chiropractors still X-ray a patient several times a year. Practice guidelines aim to reduce unnecessary radiation exposure, which increases cancer risk in proportion to the amount of radiation received. Research suggests that radiology instruction given at chiropractic schools worldwide seem to be evidence-based. Although, there seems to be a disparity between some schools and available evidence regarding the aspect of radiography for patients with acute low back pain without an indication of a serious disease, which may contribute to chiropractic overuse of radiography for low back pain.

Risk-benefit
A 2012 systematic review concluded that no accurate assessment of risk-benefit exists for cervical manipulation. A 2010 systematic review stated that there is no good evidence to assume that neck manipulation is an effective treatment for any medical condition and suggested a precautionary principle in healthcare for chiropractic intervention even if a causality with vertebral artery dissection after neck manipulation were merely a remote possibility. The same review concluded that the risk of death from manipulations to the neck outweighs the benefits. Chiropractors have criticized this conclusion, claiming that the author did not evaluate the potential benefits of spinal manipulation. Edzard Ernst stated "This detail was not the subject of my review. I do, however, refer to such evaluations and should add that a report recently commissioned by the General Chiropractic Council did not support many of the outlandish claims made by many chiropractors across the world." A 1999 review of 177 previously reported cases published between 1925 and 1997 in which injuries were attributed to manipulation of the cervical spine (MCS) concluded that "The literature does not demonstrate that the benefits of MCS outweigh the risks." The professions associated with each injury were assessed. Physical therapists (PT) were involved in less than 2% of all cases, with no deaths caused by PTs. Chiropractors were involved in a little more than 60% of all cases, including 32 deaths.

A 2009 review evaluating maintenance chiropractic care found that spinal manipulation is associated with considerable harm and no compelling evidence exists to indicate that it adequately prevents symptoms or diseases, thus the risk-benefit is not evidently favorable.

Cost-effectiveness
A 2012 systematic review suggested that the use of spine manipulation in clinical practice is a cost-effective treatment when used alone or in combination with other treatment approaches. A 2011 systematic review found evidence supporting the cost-effectiveness of using spinal manipulation for the treatment of sub-acute or chronic low back pain; the results for acute low back pain were insufficient.

A 2006 systematic cost-effectiveness review found that the reported cost-effectiveness of spinal manipulation in the United Kingdom compared favorably with other treatments for back pain, but that reports were based on data from clinical trials without placebo controls and that the specific cost-effectiveness of the treatment (as opposed to non-specific effects) remains uncertain. A 2005 American systematic review of economic evaluations of conservative treatments for low back pain found that significant quality problems in available studies meant that definite conclusions could not be drawn about the most cost-effective intervention. The cost-effectiveness of maintenance chiropractic care is unknown.

Analysis of a clinical and cost utilization data from the years 2003 to 2005 by an integrative medicine independent physician association (IPA) which looked the chiropractic services utilization found that the clinical and cost utilization of chiropractic services based on 70,274 member-months over a 7-year period decreased patient costs associate with the following use of services by 60% for in-hospital admissions, 59% for hospital days, 62% for outpatient surgeries and procedures, and 85% for pharmaceutical costs when compared with conventional medicine (visit to a medical doctor primary care provider) IPA performance for the same health maintenance organization product in the same geography and time frame.

Education, licensing, and regulation
Requirements vary between countries. In the U.S. chiropractors obtain a non-medical accredited diploma in the field of chiropractic. Chiropractic education in the U.S. has been criticized for failing to meet generally accepted standards of evidence-based medicine. The curriculum content of North American chiropractic and medical colleges with regard to basic and clinical sciences has little similarity, both in the kinds of subjects offered and in the time assigned to each subject. Accredited chiropractic programs in the U.S. require that applicants have 90 semester hours of undergraduate education with a grade point average of at least 3.0 on a 4.0 scale. Many programs require at least three years of undergraduate education, and more are requiring a bachelor's degree. Canada requires a minimum three years of undergraduate education for applicants, and at least 4200 instructional hours (or the equivalent) of full‐time chiropractic education for matriculation through an accredited chiropractic program. Graduates of the Canadian Memorial Chiropractic College (CMCC) are formally recognized to have at least 7–8 years of university level education. The World Health Organization (WHO) guidelines suggest three major full-time educational paths culminating in either a DC, DCM, BSc, or MSc degree. Besides the full-time paths, they also suggest a conversion program for people with other health care education and limited training programs for regions where no legislation governs chiropractic.

Upon graduation, there may be a requirement to pass national, state, or provincial board examinations before being licensed to practice in a particular jurisdiction. Depending on the location, continuing education may be required to renew these licenses. Specialty training is available through part-time postgraduate education programs such as chiropractic orthopedics and sports chiropractic, and through full-time residency programs such as radiology or orthopedics.

In the U.S., chiropractic schools are accredited through the Council on Chiropractic Education (CCE) while the General Chiropractic Council (GCC) is the statutory governmental body responsible for the regulation of chiropractic in the UK. The U.S. CCE requires a mixing curriculum, which means a straight-educated chiropractor may not be eligible for licensing in states requiring CCE accreditation. CCEs in the U.S., Canada, Australia and Europe have joined to form CCE-International (CCE-I) as a model of accreditation standards with the goal of having credentials portable internationally. Today, there are 18 accredited Doctor of Chiropractic programs in the U.S., 2 in Canada, 6 in Australasia, and 5 in Europe. All but one of the chiropractic colleges in the U.S. are privately funded, but in several other countries they are in government-sponsored universities and colleges. Of the two chiropractic colleges in Canada, one is publicly funded (UQTR) and one is privately funded (CMCC). In 2005, CMCC was granted the privilege of offering a professional health care degree under the Post-secondary Education Choice and Excellence Act, which sets the program within the hierarchy of education in Canada as comparable to that of other primary contact health care professions such as medicine, dentistry and optometry.

Regulatory colleges and chiropractic boards in the U.S., Canada, Mexico, and Australia are responsible for protecting the public, standards of practice, disciplinary issues, quality assurance and maintenance of competency. There are an estimated 49,000 chiropractors in the U.S. (2008), 6,500 in Canada (2010), 2,500 in Australia (2000), and 1,500 in the UK (2000).

Chiropractors often argue that this education is as good as or better than medical physicians', but most chiropractic training is confined to classrooms with much time spent learning theory, adjustment, and marketing. The fourth year of chiropractic education persistently showed the highest stress levels. Every student, irrespective of year, experienced different ranges of stress when studying. The chiropractic leaders and colleges have had internal struggles. Rather than cooperation, there has been infighting between different factions. A number of actions were posturing due to the confidential nature of the chiropractic colleges in an attempt to enroll students.

Ethics
The chiropractic oath is a modern variation of the classical Hippocratic Oath historically taken by physicians and other healthcare professionals swearing to practice their professions ethically. The American Chiropractic Association (ACA) has an ethical code "based upon the acknowledgement that the social contract dictates the profession's responsibilities to the patient, the public, and the profession; and upholds the fundamental principle that the paramount purpose of the chiropractic doctor's professional services shall be to benefit the patient." The International Chiropractor's Association (ICA) also has a set of professional canons.

A 2008 commentary proposed that the chiropractic profession actively regulate itself to combat abuse, fraud, and quackery, which are more prevalent in chiropractic than in other health care professions, violating the social contract between patients and physicians. According to a 2015 Gallup poll of U.S. adults, the perception of chiropractors is generally favorable; two-thirds of American adults agree that chiropractors have their patient's best interest in mind and more than half also agree that most chiropractors are trustworthy. Less than 10% of US adults disagreed with the statement that chiropractors were trustworthy. Chiropractors, especially in America, have a reputation for unnecessarily treating patients. In many circumstances the focus seems to be put on economics instead of health care. Sustained chiropractic care is promoted as a preventive tool, but unnecessary manipulation could possibly present a risk to patients. Some chiropractors are concerned by the routine unjustified claims chiropractors have made. A 2010 analysis of chiropractic websites found the majority of chiropractors and their associations made claims of effectiveness not supported by scientific evidence, while 28% of chiropractor websites advocate lower back pain care, which has some sound evidence.

The US Office of the Inspector General (OIG) estimated that for calendar year 2013, 82% of payments to chiropractors under Medicare Part B, a total of $359 million, did not comply with Medicare requirements. There have been at least 15 OIG reports about chiropractic billing irregularities since 1986.

In 2009, a backlash to the libel suit filed by the British Chiropractic Association (BCA) against Simon Singh inspired the filing of formal complaints of false advertising against more than 500 individual chiropractors within one 24-hour period, prompting the McTimoney Chiropractic Association to write to its members advising them to remove leaflets that make claims about whiplash and colic from their practice, to be wary of new patients and telephone inquiries, and telling their members: "If you have a website, take it down NOW" and "Finally, we strongly suggest you do NOT discuss this with others, especially patients." An editorial in Nature suggested that the BCA may have been trying to suppress debate and that this use of English libel law was a burden on the right to freedom of expression, which is protected by the European Convention on Human Rights. The libel case ended with the BCA withdrawing its suit in 2010.

Reception
Chiropractic is established in the U.S., Canada, and Australia, and is present to a lesser extent in many other countries. It is viewed as a marginal and non-clinically–proven attempt at complementary and alternative medicine, which has not integrated into mainstream medicine.

Australia
In Australia, there are approximately 2488 chiropractors, or one chiropractor for every 7980 people. Most private health insurance funds in Australia cover chiropractic care, and the federal government funds chiropractic care when the patient is referred by a medical practitioner. In 2014, the chiropractic profession had a registered workforce of 4,684 practitioners in Australia represented by two major organizations – the Chiropractors' Association of Australia (CAA) and the Chiropractic and Osteopathic College of Australasia (COCA). Annual expenditure on chiropractic care (alone or combined with osteopathy) in Australia is estimated to be between AUD$750–988 million with musculoskeletal complaints such as back and neck pain making up the bulk of consultations; and proportional expenditure is similar to that found in other countries. While Medicare (the Australian publicly funded universal health care system) coverage of chiropractic services is limited to only those directed by a medical referral to assist chronic disease management, most private health insurers in Australia do provide partial reimbursement for a wider range of chiropractic services in addition to limited third party payments for workers compensation and motor vehicle accidents.

Of the 2,005 chiropractors who participated in a 2015 survey, 62.4% were male and the average age was 42.1 (SD = 12.1) years. Nearly all chiropractors (97.1%) had a bachelor's degree or higher, with the majority of chiropractor's highest professional qualification being a bachelor or double bachelor's degree (34.6%), followed by a master's degree (32.7%), Doctor of Chiropractic (28.9%) or PhD (0.9%). Only a small number of chiropractor's highest professional qualification was a diploma (2.1%) or advanced diploma (0.8%).

Germany
In Germany, chiropractic may be offered by medical doctors and alternative practitioners. Chiropractors qualified abroad must obtain a German non-medical practitioner license. Authorities have routinely required a comprehensive knowledge test for this, but in the recent past, some administrative courts have ruled that training abroad should be recognised.

Switzerland
In Switzerland, only trained medical professionals are allowed to offer chiropractic. There are 300 chiropractors in Switzerland.

United Kingdom
In the United Kingdom, there are over 2,000 chiropractors, representing one chiropractor per 29,206 people. Chiropractic is available on the National Health Service in some areas, such as Cornwall, where the treatment is only available for neck or back pain.

A 2010 study by questionnaire presented to UK chiropractors indicated only 45% of chiropractors disclosed to patients the serious risk associated with manipulation of the cervical spine and that 46% believed there was possibility patients would refuse treatment if the risks were correctly explained. However 80% acknowledged the ethical/moral responsibility to disclose risk to patients.

United States and Canada
The percentage of the population that utilizes chiropractic care at any given time generally falls into a range from 6% to 12% in the U.S. and Canada, with a global high of 20% in Alberta in 2006. In 2008, chiropractors were reported to be the most common CAM providers for children and adolescents, these patients representing up to 14% of all visits to chiropractors.

There were around 50,330 chiropractors practicing in North America in 2000. In 2008, this has increased by almost 20% to around 60,000 chiropractors. In 2002–03, the majority of those who sought chiropractic did so for relief from back and neck pain and other neuromusculoskeletal complaints; most do so specifically for low back pain. The majority of U.S. chiropractors participate in some form of managed care. Although the majority of U.S. chiropractors view themselves as specialists in neuromusculoskeletal conditions, many also consider chiropractic as a type of primary care. In the majority of cases, the care that chiropractors and physicians provide divides the market, however for some, their care is complementary.

In the U.S., chiropractors perform over 90% of all manipulative treatments. Satisfaction rates are typically higher for chiropractic care compared to medical care, with a 1998 U.S. survey reporting 83% of respondents satisfied or very satisfied with their care; quality of communication seems to be a consistent predictor of patient satisfaction with chiropractors.

Utilization of chiropractic care is sensitive to the costs incurred by the co-payment by the patient. The use of chiropractic declined from 9.9% of U.S. adults in 1997 to 7.4% in 2002; this was the largest relative decrease among CAM professions, which overall had a stable use rate. As of 2007 7% of the U.S. population is being reached by chiropractic. They were the third largest medical profession in the US in 2002, following physicians and dentists. Employment of U.S. chiropractors was expected to increase 14% between 2006 and 2016, faster than the average for all occupations.

In the U.S., most states require insurers to cover chiropractic care, and most HMOs cover these services.

History
Chiropractic's origins lie in the folk medicine practice of bonesetting, in which untrained practitioners engaged in joint manipulation or resetting fractured bones. Chiropractic was founded in 1895 by Daniel David (D. D.) Palmer in Davenport, Iowa. Palmer, a magnetic healer, hypothesized that manual manipulation of the spine could cure disease. The first chiropractic patient of D. D. Palmer was Harvey Lillard, a worker in the building where Palmer's office was located. He claimed that he had severely reduced hearing for 17 years, which started shortly following a "pop" in his spine. A few days following his adjustment, Lillard claimed his hearing was almost completely restored. Another of Palmer's patients, Samuel Weed, coined the term chiropractic, from Greek χειρο- chiro- 'hand' (itself from χείρ cheir 'hand') and πρακτικός praktikos 'practical'. Chiropractic is classified as a field of pseudomedicine on account of its esoteric origins.

Chiropractic competed with its predecessor osteopathy, another medical system based on magnetic healing; both systems were founded by charismatic midwesterners in opposition to the conventional medicine of the day, and both postulated that manipulation improved health. Although initially keeping chiropractic a family secret, in 1898 Palmer began teaching it to a few students at his new Palmer School of Chiropractic. One student, his son Bartlett Joshua (B. J.) Palmer, became committed to promoting chiropractic, took over the Palmer School in 1906, and rapidly expanded its enrollment.

Early chiropractors believed that all disease was caused by interruptions in the flow of innate intelligence, a vitalistic nervous energy or life force that represented God's presence in man; chiropractic leaders often invoked religious imagery and moral traditions. D. D. Palmer said he "received chiropractic from the other world". D. D. and B. J. both seriously considered declaring chiropractic a religion, which might have provided legal protection under the U.S. constitution, but decided against it partly to avoid confusion with Christian Science. Early chiropractors also tapped into the Populist movement, emphasizing craft, hard work, competition, and advertisement, aligning themselves with the common man against intellectuals and trusts, among which they included the American Medical Association (AMA).

Chiropractic has seen considerable controversy and criticism. Although D. D. and B. J. were "straight" and disdained the use of instruments, some early chiropractors, whom B. J. scornfully called "mixers", advocated the use of instruments. In 1910, B. J. changed course and endorsed X-rays as necessary for diagnosis; this resulted in a significant exodus from the Palmer School of the more conservative faculty and students. The mixer camp grew until by 1924 B. J. estimated that only 3,000 of the United States' 25,000 chiropractors remained straight. That year, B. J.'s invention and promotion of the neurocalometer, a temperature-sensing device, was highly controversial among B. J.'s fellow straights. By the 1930s, chiropractic was the largest alternative healing profession in the U.S.

Chiropractors faced heavy opposition from organized medicine. D. D. Palmer was jailed in 1907 for practicing medicine without a license. Thousands of chiropractors were prosecuted for practicing medicine without a license, and D. D. and many other chiropractors were jailed. To defend against medical statutes, B. J. argued that chiropractic was separate and distinct from medicine, asserting that chiropractors "analyzed" rather than "diagnosed", and "adjusted" subluxations rather than "treated" disease. B. J. cofounded the Universal Chiropractors' Association (UCA) to provide legal services to arrested chiropractors. Although the UCA won their first test case in Wisconsin in 1907, prosecutions instigated by state medical boards became increasingly common and in many cases were successful. In response, chiropractors conducted political campaigns to secure separate licensing statutes, eventually succeeding in all fifty states, from Kansas in 1913 through Louisiana in 1974. The longstanding feud between chiropractors and medical doctors continued for decades. The AMA labeled chiropractic an "unscientific cult" in 1966, and until 1980 advised its members that it was unethical for medical doctors to associate with "unscientific practitioners". This culminated in a landmark 1987 decision, Wilk v. AMA, in which the court found that the AMA had engaged in unreasonable restraint of trade and conspiracy, and which ended the AMA's de facto boycott of chiropractic.

Serious research to test chiropractic theories did not begin until the 1970s, and is continuing to be hampered by antiscientific and pseudoscientific ideas that sustained the profession in its long battle with organized medicine. By the mid-1990s there was a growing scholarly interest in chiropractic, which helped efforts to improve service quality and establish clinical guidelines that recommended manual therapies for acute low back pain. In recent decades chiropractic gained legitimacy and greater acceptance by medical physicians and health plans, and enjoyed a strong political base and sustained demand for services. However, its future seemed uncertain: as the number of practitioners grew, evidence-based medicine insisted on treatments with demonstrated value, managed care restricted payment, and competition grew from massage therapists and other health professions. The profession responded by marketing natural products and devices more aggressively, and by reaching deeper into alternative medicine and primary care.

Public health
Some chiropractors oppose vaccination and water fluoridation, which are common public health practices. Within the chiropractic community there are significant disagreements about vaccination, one of the most cost-effective public health interventions available. Most chiropractic writings on vaccination focus on its negative aspects, claiming that it is hazardous, ineffective, and unnecessary. Some chiropractors have embraced vaccination, but a significant portion of the profession rejects it, as original chiropractic philosophy traces diseases to causes in the spine and states that vaccines interfere with healing. The extent to which anti-vaccination views perpetuate the current chiropractic profession is uncertain. The American Chiropractic Association and the International Chiropractors Association support individual exemptions to compulsory vaccination laws, and a 1995 survey of U.S. chiropractors found that about a third believed there was no scientific proof that immunization prevents disease. The Canadian Chiropractic Association supports vaccination; a survey in Alberta in 2002 found that 25% of chiropractors advised patients for, and 27% against, vaccinating themselves or their children.

Early opposition to water fluoridation included chiropractors, some of whom continue to oppose it as being incompatible with chiropractic philosophy and an infringement of personal freedom. Other chiropractors have actively promoted fluoridation, and several chiropractic organizations have endorsed scientific principles of public health. In addition to traditional chiropractic opposition to water fluoridation and vaccination, chiropractors' attempts to establish a positive reputation for their public health role are also compromised by their reputation for recommending repetitive lifelong chiropractic treatment.

Controversy
Throughout its history chiropractic has been the subject of internal and external controversy and criticism. According to Daniel D. Palmer, the founder of chiropractic, subluxation is the sole cause of disease and manipulation is the cure for all diseases of the human race. A 2003 profession-wide survey found "most chiropractors (whether 'straights' or 'mixers') still hold views of innate intelligence and of the cause and cure of disease (not just back pain) consistent with those of the Palmers." A critical evaluation stated "Chiropractic is rooted in mystical concepts. This led to an internal conflict within the chiropractic profession, which continues today." Chiropractors, including D. D. Palmer, were jailed for practicing medicine without a license. For most of its existence, chiropractic has battled with mainstream medicine, sustained by antiscientific and pseudoscientific ideas such as subluxation. Collectively, systematic reviews have not demonstrated that spinal manipulation, the main treatment method employed by chiropractors, is effective for any medical condition, with the possible exception of treatment for back pain. Chiropractic remains controversial, though to a lesser extent than in past years.

title: Chiropractic