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The Life of Sir William Petty 1623-1687

Who Is Sir William Petty?

Sir William Petty was an English philosopher, physician, economist, and statistician who made significant contributions to his nation, particularly being among the first to associate demography, economics, and public health.

He was born into a very humble family; a series of chances and lucky events turned the boy of a simple weaver into a wealthy and renowned scientist in addition to receiving the title of Sir.

He was an English MP and friend of Oliver Cromwell, leader of the republican Commonwealth of England. Below, we will take a closer look at the life of this researcher and his participation in the study of population and the economy through a biography of William Petty

A Brief Biography of Sir William Petty

From modest origins to become a major British landowner—it could be said that William Petty's life goes from one extreme to another from here to there, especially considering that he had to leave rather hard times in his native England, halfway between the absolute monarchy, the failed republic, and prosperous English monarchical constitutionalism.

His economic ideas have been primarily for great figures such as Karl Marx or Adam Smith to expose their popular theories about equity both for better and for worse. Marx explored William Petty as such a significant figure that he even asserted that Petty was the founder of modern political economy. Be that as it may, this seventeenth-century character was truly well advanced for his time, which is why he is so well-known today.

His Early Life and Education

William Petty was born in Ramsey, England, on May 23, 1623. He grew up in a very modest family since his father was a weaver. His first years were spent studying at the Grammar School in his city and soon he began to stand out for his intelligence and abilities.

But despite excelling in his studies, he could not avoid having to work when he was very young. His family was still in great need and any salary that came into the home was welcome. So he enlisted as a cabin boy on a ship but was quite unlucky because when he docked on the coast of France, his companions abandoned him. But far from intimidating him, he saw an opportunity upon his arrival in France and decided to write to the Jesuits at the University of Caen, in Normandy.

The letter was written in the perfect Latin language, gained so much attention that the institute immediately accepted it. Upon his return to England, he could study philosophy, geometry, and astronomy at the age of 17 at the prestigious Oxford.

At the outbreak of the English Civil War, in which King Charles II and James II fought Parliament and eventually a republic would be formed under Oliver Cromwell, Petty fled to Holland. There he could study medicine, a science that would serve him by applying it to his later studies in economics. After finishing his studies, he went to Paris, a cosmopolitan city, where he would meet the philosopher Thomas Hobbes.

He returned back to London when he was 24. Despite his youth, his intelligence and his studies earned him a place among the intelligentsia of his time. From this, he would become a professor at the prestigious Oxford, the same place where he had studied.

Friend of Oliver Cromwell

The English invasion of Ireland would become a turning point in Petty's career. During this war, he enlisted as a doctor in the army and had the opportunity to interact with Oliver Cromwell himself, with whom he became very close friends. Thanks to this, after conquering the Emerald Isle, Cromwell commissioned Petty to produce several topographic maps of the new properties of the Commonwealth of England.

Thus, from 1655 to 1658, Petty traveled Ireland, producing maps, being rewarded with vast tracts of land as payment. Thus William Petty, whose childhood had been that of a poor weaver's son and abandoned in his youth in lands lost by the French hand of God, became a wealthy landowner. Rubbing shoulders with the figure of Cromwell earned him a wide reputation and properties.

His Contributions to the Economy

One of the geniuses that William Petty had and for which he is known, is the fact that he introduced the same methods and knowledge typical of medicine to the study of economics. He considered that each economic element should be a whole, using more mathematical, statistical and scientific tools in general to solve the problems that frustrate the national wealth. It is often believed that he was far removed from the commercialism prevailing in his time. He has a lot of contributions, some of them are as follows

HIis Theory of Value

William Petty considered that all economic exchange was subject to the rules that he considered natural that all opposition is useless. He believed that sooner or later, the prices of the products would end up returning to their natural level. According to Petty, the origin of value is at work. I have differentiated between two types of values ​​for each product:

On the one hand, we have the natural value, which refers to the internal value of each product—that is, what the product costs to produce it. To be able to calculate it, it is necessary to consider the work necessary to produce it and calculate productivity, considering two different measures: the land and the work itself. In his own words, it could be said that work is the father of wealth, and the earth is its mother.

The second value is the political one. It is about market value, which always depends on a multitude of factors, not so simple and easy to understand. How the production and labor are required to produce the product. These factors that make up the political value are alien to natural laws, depending on the subjectivity of the merchants themselves, demand, supply, and needs of the consumers themselves.

Generating Social Wealth

Petty developed a theory to explain what kind of taxes and fees were fit to generate social wealth. According to his theory, each person should contribute according to the assets and earnings earned, understanding that it was not fair to ask the richest for taxes that did not involve any effort, while those same amounts were abused for the poorer classes. Despite this, he was aware that most did not want to pay and were trying to get rid of their obligations.

Petty himself considered that taxes should not be excessively too high, that they would make the population tighten their belts and try to save, since this would harm national commerce. He considered that taxes would be beneficial as far as the proceeds were invested in national products, not to feed the baggy pockets of the elites and the wealthy classes.

The Petty-Clark Law

Petty's Law—later renamed The Petty-Clark Law, thanks to contributions from Colin Clark—is an economic law that proposes that, as technical progress reduces transportation costs, the market for non-agricultural goods expands. This means that the labor force dedicated to agriculture has to readjust and move to non-agricultural activities, leaving mostly agricultural production societies behind to more diverse societies in which other economic activities are carried out.

As the ways to transport agricultural products improve, less labor is required in the process. This causes structural changes to take place in society for those who were involved in this process, lose their jobs and are forced to look for work in the cities. This causes life in the countryside to be progressively abandoned and urban areas where artisan work and industry prevail, in addition to the service sector.

With Clark's contributions, it was concluded that one of the main ways in which economic progress manifests itself is in the continuous transfer of work from the primary to the secondary sector and later to the tertiary sector. In other words, as one moves from the agricultural sector to the industrial sector and later to the services, according to Petty and Clark's own ideas, economic progress is progressing.

The Life of Sir William Petty 1623-1687 by Lord Edmond Fitzmaurice (1895).

The Life of Sir William Petty 1623-1687 by Lord Edmond Fitzmaurice (1895).

Economic Improvement.

Petty had a great passion for demographics and often couldn't help but relate it to economics. It was he, along with statistician John Graunt, who created the first UK mortality tables, considered the beginning of modern demography. He believed that people added value to the economy and that increased population should be the basis for economic improvement.

According to his thinking, the more people there are, the more labor there will be and the more wealth there will be.

Health Council in London

Also related to his interest in increasing the population and combined with his training in medicine, William Petty believed that it was essential to improve health. He believed it necessary to create an English health system that would provide the good health of citizens, preventing them from contracting contagious diseases that decimated the population and reduced the economic productivity of the nation. This is why he proposed the creation of a Health Council in London, in addition to creating a hospital in which training English doctors was expanded.

Sir William Petty's Last years

William Petty no longer had any financial problems and even became a member of the English Parliament and being one of the founders of the Royal Society. From then on he devoted himself to the complete study of different sciences, writing several books where he presented his theories. He died on December 16, 1687, in London, taking the title of Sir for a lifetime of brilliant contributions to his native England.


A Treatise of Taxes and Contributions Book by William Petty (

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Misbah Sheikh


Misbah Sheikh (author) from — This Existence Is Only an Illusion on March 27, 2021:

Thanks Ravi for the appreciation

I am glad you found it informative

Blessings always :)

Misbah Sheikh (author) from — This Existence Is Only an Illusion on March 27, 2021:

Thanks a lot, Devika

I am glad you learned something new about history from my hub

Much Gratitude

Blessings to you :)

Ravi Rajan from Mumbai on March 27, 2021:

Interesting article of Sir William Petty. I knew that he was an economist but you have now added to my knowledge by creating this detailed hub about his achievements and his historical Timeline. Thanks for sharing Misbah.

Devika Primić from Dubrovnik, Croatia on March 27, 2021:

Hi Misbah786 this is interesting about Sir William Petty I had no idea of him and you informed me of a great history lesson.

Misbah Sheikh (author) from — This Existence Is Only an Illusion on March 25, 2021:

Thanks a lot for appreciating,Peggy

I am glad you liked it, yes, he was an intelligent person and achieved a lot in his life

Blessings to you dear

Misbah Sheikh (author) from — This Existence Is Only an Illusion on March 25, 2021:

Thanks for the appreciation, Liz

I am glad you learned something new from my article Although he is a great personality but sadly, history haven't covered his chapter largely

Blessings to you dear

Misbah Sheikh (author) from — This Existence Is Only an Illusion on March 25, 2021:

Thanks a lot, Rosina

I am glad you liked it

Thanks for sharing your thoughts

Blessings and Peace

Peggy Woods from Houston, Texas on March 25, 2021: