William Petty, Sir | Biography

Sir William Petty was a sailor, physician, professor, inventor, surveyor, and member of Parliament, as well as a political economist and statistician. He was born in Romsey, Hampshire, England, on May 26, 1623. His father was a clothier, and the family had little money for the boy's education. The details of his early years are sketchy, but Petty was apparently schooled to some degree in the small village. In his writings he remembered his greatest joy as a youth was watching the different artisans--carpenters, watchmaker, blacksmiths--at their work. By the time he was 12 years old, he felt that he could have acquitted himself at any of those trades, so well did he know them by watching. But, instead, at the age of 15 he managed to get aboard a sea vessel heading for Caen in France. Once there, he educated himself in French, Latin, Greek, and mathematics, and also spent time in the navy. About the age of 18, he went to Paris to study anatomy and to read with Thomas Hobbes.

In 1648, Petty went to Oxford, where he taught anatomy to young students. He also taught music at Gresham College in London and was a physician to the British army in Ireland in 1652. Three years later, he completed a survey of Irish lands that had been forfeited in 1641. His next assignment was as commissioner of the distribution of land grants to soldiers, and then as secretary to Henry Cromwell (1657), the lord deputy of Ireland.

Charles II, known as the Merry Monarch, king of England from 1660 to 1685, appointed Petty to be surveyor general of Ireland and during this period, Petty opened quarries, fisheries, and mines and set up ironworks in the country. A sailor at heart, Petty also designed a two-hulled ship in 1662. It sailed well until it was lost during a storm in the Irish Sea some years later.

Petty built a wooden model of his ship, wrote a treastise on ship building, and gave them to the Royal Society of London for the Promotion of Natural Knowledge, of which he was a founder. It is the oldest scientific society in England and one of the oldest in Europe. The Royal Society was granted a charter in 1662 by Charles II, newly restored to the throne, but it received little attention from the crown after that. The idea was for interested members to meet periodically to discuss scientific subjects. This stimulus of free expression would result in international fame for the society by the eighteenth century. Besides Petty, other distinguished members have included inventor Robert Hooke, architect Christopher Wren, physicist Isaac Newton, and astronomer Edmond Halley.

Petty was an originator of political arithmetic, which he called the art of reasoning with figures about things that relate to government. He presented Essays in Political Arithmetick and Political Survey or Anatomy of Ireland in 1672. In it were calculations and population estimates about social income. Later works Verbum Sapienti(1665) and Quantulumcunque Concerning Money further developed his ideas on money theory and policy.

However, Petty's most significant work is Treatise of Taxes and Contributions (1662). In it, he argued that the price of a product depends upon the labor necessary for its production. He favored giving free rein to the natural forces of individual self-interest, but he disagreed with many other liberals by declaring a high level of employment to be a duty of the state.

Sir William Petty, who married Elizabeth Fenton, daughter of an Irish knight, in 1667, died in his home on Piccadilly Street in London, on December 16, 1687. The cause of death was gangrene of the foot, exacerbated by gout. He is buried near his parents in Romsey. Some of his manuscripts can be found in the British Museum and their scope gives an idea of his varied interests and talents, such as expenses of a state and the branches of its revenues, people and religions of the world, growth of London, observations on the births, burials, and marriages of London, Paris, and Dublin, and the commercial world and the great emporium. A collection of his printed works is also housed at Oxford in the library of Brasenose College.