Editing David Hartley (philosopher) (section)

==Education and professional career==
At Cambridge, Hartley studied with [[Nicholas Saunderson]], who, though blind since infancy, became the fourth [[Lucasian Professor of Mathematics]]. Hartley was later instrumental in raising the subscription for the posthumous publication of Saunderson's ''Elements of Algebra'' (1740). Upon graduation, Hartley declined to sign the [[Thirty-nine Articles]], a requirement for ordination in the Church of England. Although one point at issue may have been the doctrine of the [[Trinity]], Hartley's main dissent from Anglican orthodoxy was his assent to [[universal reconciliation]]. Writing to his friend Joseph Lister in 1736, Hartley stated he believed "[t]hat Universal Happiness is the Fundamental Doctrine both of Reason & Scripture", adding that "nothing is so irreconcilable [with] Reason as eternal Punishment, nothing so contrary to all the Intimations God has given us in his Works. Have you read Sr. Is. Newton’s Commt. upon Danl. & the Apocalypse?"<ref>Hartley to Lister, 13 March 1736, quoted in Allen 1999'','' p. 44.</ref> For Hartley, on the gates of hell there could be no locks.

In the same letter to Lister, Hartley writes that "a Man who disregards himself, who entirely abandons Self-Interest & devotes his Labours to the Service of Mankind, or in that beautiful and expressive phrase of the Scriptures, ''who loves his neighbor as himself'' is sure to meet with private Happiness".<ref>Quoted in Allen 1999, p. 44.</ref> This conviction became a guiding principle in Hartley's life, and it led him to devote himself to a various philanthropic projects. These include the publication of Saunderson's ''Elements of Algebra'' and the promotion of the shorthand system of his friend [[John Byrom]] (a system that Hartley believed could be a "universal character" and step toward the creation of a [[philosophical language]]).<ref>Allen 1999, 231–33.</ref> 

Shortly after turning to medicine, Hartley became an advocate of variola inoculation for smallpox. [[Variolation]] confers personal immunity, and if widespread would be a "service to mankind" by furthering [[herd immunity]]. However, deliberate infection with the smallpox virus ran the risk of disfigurement or death. ([[Caroline of Ansbach|Queen Caroline]], wife of [[George II of Great Britain|George II]], was an advocate and had three of their children variolated, but [[Jonathan Edwards (theologian)|Jonathan Edwards]] died from it in 1758.) The public good, then, could appear to be at odds with private interest. In his first publication, ''Some Reasons why the Practice of Inoculation ought to be Introduced into the Town of Bury at Present'' (1733), Hartley developed a statistical argument to show that the conflict is only apparent, that being inoculated furthers both the public good and a person's self-interest.

By the time of his move to London in 1736, Hartley was known by other campaigners of variolation, such as [[Hans Sloane]] and [[James Jurin]], president of the [[Royal Society]]. He also had the support of important Whig families in Suffolk, notably of [[Charles Townshend, 2nd Viscount Townshend]] ('Turnip' Townshend). Hartley's daughter Mary wrote that "the old Lord Townshend (then Secretary of State) treated him with as much kindness as he had had been an additional son, and all the sons and daughters as an additional brother".<ref>Quoted in Allen 1999, p. 53.</ref> He was inducted into the Royal Society, and he also became a physician to [[Thomas Pelham-Holles, 1st Duke of Newcastle]], and his wife. In 1736 he offered to "recommend" John Byrom to George II.<ref>Allen 1999, p. 49.</ref>

By 1740, Hartley was known to every physician in London and to other medical men throughout Europe. He had thrown himself into a controversial attempt to harmonize private interest and public good. Hartley had started to experience symptoms of "the stone" ([[bladder stone]]) in early 1736. A bladder stone, sometimes as large as an egg, could function as a ball-cock on a toilet tank, causing an inability to urinate, excruciating pain, and sometimes death. ([[Benjamin Franklin]], a sufferer, sometimes had to stand on his head to relieve himself.)<ref>{{Cite book|title=Mortal Lessons: Lessons on the Art of Surgery|last=Selzer|first=Richard|publisher=Simon and Schuster, Touchstone Books|year=1974|location=New York|pages=89}}</ref> Treatment by surgical removal (lithotomy) was a procedure many failed to survive.

Hartley thought a herbalist called [[Joanna Stephens]] had developed a lithontriptic, an oral medicine that would dissolve a stone ''in situ''. He published ''Ten Cases of Persons who have Taken Mrs. Stephens’s Medicines for the Stone'' (1738), which includes an unsparing account of his own agonies. To make a proprietary medicine freely available to the public, Hartley convinced Parliament to pay Stephens £5,000 for her "secret".<ref>Allen 1999, p. 61.</ref>

With Stephens's recipe in hand, Hartley set to work with [[Stephen Hales]], along with two colleagues in France, to locate the medicine's chemically active ingredients. These were slaked lime (calcium hydroxide) and Alicant soap (predominantly potassium oleate, like other soaps an alkaline salt of a fatty acid). Hales had shown that some bladder stones rapidly dissolved in boiled soap-lye (caustic potash, potassium hydroxide). What was needed, then, was a safely ingestible preparation that would turn a person's urine alkaline; and this, they concluded, is what the slaked lime and soap combination did. In 1739 Hales won the [[Copley Medal]] for his work, and the following year Hartley published their results in a Latin volume, ''De Lithontriptico'', in [[Basel]] and [[Leiden]], the latter being home at the time to the foremost medical school in Europe.

In 1742 Hartley and his family moved to Bath, Somerset. He continued to practise medicine, and he devoted himself to writing his major work, ''Observations on Man, His Frame, His Duty, and His Expectations'', published in 1749 by [[Samuel Richardson]].

He was a [[vegetarian]].<ref>{{Cite book|title=Sins of the Flesh: A History of Ethical Vegetarian Thought|last=Preece|first=Rod|publisher=University of British Columbia Press|year=2009|pages=207–209}}</ref>