This book, which won the North American Conference on British Studies’ John Ben Snow Prize for 2010, is a well-researched, attractively illustrated, and elegantly expressed account of the thought of Sir William Petty (1613–87) and especially of the political arithmetic that he pioneered. Petty is sometimes seen as the inventor of statistics, and Karl Marx regarded him as the founder of political economy. Ted McCormick challenges such views, suggesting that we should see Petty’s thinking in the context of his scientific interests—including alchemy and corpuscularian theories of matter—and his connections with the Hartlib Circle, and later the Royal Society, of which he was a founding member. His political arithmetic was concerned not to describe social and economic phenomena with statistical precision but to deploy rough and ready quantification in order to promote concrete, practical policies, especially in the demographic sphere. It was only after Petty’s death, McCormick convincingly contends, that political arithmetic came to emphasize “analysis rather than intervention” and “accuracy rather than utility” (296).

The first four chapters of the book are about Petty’s life and writings. The last four discuss political arithmetic as it was developed by him to solve problems in Ireland, the American colonies, and Britain. His father was a Hampshire clothier. As a youth, Petty was apprenticed aboard a merchant ship, but an accident left him stranded in Normandy. There he was educated by Jesuits. In later life, he retained a great respect for the writings of the Spanish Jesuit philosopher Francisco Suárez. McCormick suggests that Suárez was a “voice of moderation” on religious questions (25), but this is difficult to sustain as he was an outspoken papalist who defended in the strongest terms the papal power to depose Christian secular rulers who deviated from the Catholic faith. Petty returned to England after a few years but left again in 1643, studying medicine and traveling in the Netherlands and France. In 1645 he befriended Thomas Hobbes in Paris. The following year, he returned to England, where he associated with the Hartlib Circle. In 1650 he took the MD degree at Oxford, and in 1651 he became a professor of anatomy there. He became famous after he and some associates revived the apparently dead Anne Greene, who had been hanged for infanticide. In 1652 Petty went to Ireland as physician-general to the English army. While there, he proposed and oversaw a highly influential land survey—the Down Survey—and also acquired a great deal of land for himself, becoming very wealthy as a result. He served for a while as secretary to Henry Cromwell in Ireland, a trusted agent for Henry back in England, and a member of Richard Cromwell’s parliament, in which he was accused of corrupt practices in connection with Irish land. A key source on that parliament is the Diary of Thomas Burton, Esq. (ed. J. T. Rutt, 4 vols. [London, 1828]), and it has material on Petty, but McCormick does not apparently draw on it.

Despite his connection to Henry Cromwell, Petty negotiated the Restoration successfully, and in 1661 Charles II knighted him. The king was interested in Petty’s practical proposals for reforms and improvements. In the ensuing years, Petty devised many projects, only some of which featured political arithmetic. One that did not was his design for a new kind of ship. The third prototype of this double-hulled or “Double-Bottom” (152) vessel was launched in the presence of King Charles and his brother in 1664 but was lost in a storm the following year. In 1671–72 Petty worked on Political Arithmetick and The Political Anatomy of Ireland, which proved to be his most important books although neither was intended for publication. The first analyzed the economies of England and elsewhere in terms of geography, institutions, and policy, noting that religious tolerance and a large fleet promoted Dutch wealth. The Political Anatomy of Ireland proposed integrating the populations of the two countries by transporting 200,000 Irish people to England and the same number of English to Ireland. Additionally, 10,000 women were to be shipped in each direction each year. The English women were to be found Irish husbands, whose households and offspring they would Anglicize. He proposed a similar scheme for America, arguing that English colonists there should be permitted to buy young native American girls, bring them up as English, and then marry them, even in polygamy (since he doubted that God requires monogamy). Petty’s religious views were tolerant and doctrinally minimalist, and under James II he developed schemes to aid the king’s catholicizing policies.

McCormick has written a fine, lucidly argued book on the thought of an important figure who has been somewhat neglected (in part because much of his work remains unpublished in manuscripts). More could be added about biographical matters, including Petty’s finances, and about his political links. There is relatively little here on party politics or political factions, and the reader is left wondering whether Petty had any political principles beyond the Hobbesian goal of self-preservation. But this is a significant contribution to early modern British history and to European intellectual history, and it deserves a wide readership.