William Molyneux

William Molyneux FRS (; 17 April 1656 – 11 October 1698) was an Anglo-Irish writer on science, politics and natural philosophy. He is noted as a close friend of fellow philosopher John Locke, and for proposing Molyneux's Problem, a thought experiment widely discussed. Life He was born in Dublin to Samuel Molyneux (1616–1693), lawyer, landowner and Master Gunner for Ireland, (whose grandfather, Sir Thomas Molyneux, had come to Dublin from Calais in the 1560s), and his wife, Anne, née Dowdall. The second of five children, William Molyneux came from a relatively prosperous Anglican background, with his father established at Castle Dillon in County Armagh, and his uncle Colonel Adam Molyneux holding large estates inherited from the Dowdall's in Ballymulvey, near Ballymahon in County Longford. He was close to his brother Sir Thomas Molyneux, with whom he later shared philosophical interests. His sister Jane married Anthony Dopping, the eventual Anglican Bishop of Meath. In 1671 Molyneux started at Trinity College Dublin where he became an avid reader of the leading figures of the Scientific Revolution. After attaining a Bachelor of Arts there, Molyneux was sent to study law in the Middle Temple, London from 1675 to 1678. In 1678 he married Lucy Domville (?–1691), the youngest daughter of Sir Wiliam Domville, the Attorney-General for Ireland, and his wife Bridget Lake. His wife became ill, which led to blindness after their marriage, and died young. Of their 3 children, only Samuel Molyneux (1689–1728) lived past childhood. Samuel went on to become an astronomer and politician who worked with his father on various scientific endeavours. Career and publications Because of his inheritance, Molyneux was financially independent. Nonetheless, he held a number of official positions throughout his life. He was appointed Joint Surveyor General of the King's buildings and works in Ireland in 1684, serving alongside William Robinson. In 1687 he invented a new type of sundial called a Sciothericum telescopicum that used a special double gnomon and a telescope to measure the time of noon to within 15 seconds. He represented Dublin University in Parliament from 1692 until his death. He had also served as a commissioner of forfeited estates in 1693, resigning a few months later due to ill health.