Historians have a bad habit of airbrushing women out of philosophy.

John Stuart Mill's Co-author Harriet Taylor Mill
Paul Meany
Editor for Intellectual History, Lib​er​tar​i​an​ism​.org

Paul Meany is the editor for intellectual history at Lib​er​tar​i​an​ism​.org, a project of the Cato Institute. Most of his work focuses on examining thinkers who predate classical liberalism but still articulate broadly liberal attitudes and principles. He is the host of Portraits of Liberty, a podcast about uncovering and exploring underrated figures throughout history who have argued for a freer world. His writing covers a broad range of topics, including proto-​feminist writers, Classical Greece and Rome’s influence on the American Founding, ancient Chinese philosophy, tyrannicide, and the first argument for basic income.

John Stuart Mill’s On Liberty is rightfully considered one of the greatest defenses of free speech ever penned. But despite all of the praise for On Liberty, few are aware of its co-​author, Harriet Taylor Mill, John Stuart’s wife and lifelong intellectual companion.

Although the 19th-​century was an era of significant social change and political reform, women were still treated as second-​class citizens. Women were barred from formal education and most professions besides low-​paid work that men refused to do or which was deemed suitable for women. The only role open to most women was that of wife and mother, held subservient to her husband by numerous laws that deprived women of their wages, property, and even custody over their children.

Harriet was born in 1807 in Walworth, South London, and her parents expected her to become a wife and a mother. However, Harriet was more fortunate than most of her contemporaries in that she received an informal education at home that cultivated an early passion for poetry. By the age of eighteen, Harriet was wedded to John Taylor, a pharmaceutical wholesaler and almost twelve years her senior. Though Victorian-​era marriage could be cruel, Taylor treated Harriet with a degree of generosity and care, both encouraging and funding her interest in literature.

The couple had three children together: Herbert, Algernon, and Helen. Harriet loved her children and motherhood, but she yearned for a life outside of the home and intellectual companionship. Later, Harriet would lament that women “are educated for one single object, to gain their living by marrying” and that after that, they cease to exist for anything beyond looking after children.

When Harriet was twenty-​five years old, her husband invited John Stuart Mill to his house for dinner, having connected through their mutual support of women’s rights. Harriet entranced Mill as the dinner progressed, and he found himself in awe of her assertive and passionate character. Mill recounted that he found her “the most admirable person” he had ever known. The pair became close friends, writing extensive letters back and forth discussing marriage, divorce, and women’s rights.

Harriet undoubtedly was in love with Mill and vice versa, but Victorian mores were strict and unbending. If Harriet left her husband for Mill, she would bring the full brunt of social stigma on every part of their love triangle. Thus Mill and Harriet kept their meetings secret to avoid bringing any unwanted attention. Sometimes the pair met next to a rhino cage at London zoo as onlookers would be too distracted by the exotic beast to notice the forbidden rendezvous. Mill and Harriet affectionately called the rhino “our old friend rhino.” With Taylor’s permission, the pair remained platonic friends but fully-​fledged intellectual partners.

Their correspondence reveals their collaborative dynamic, with Mill authoring the majority of their joint work while Harriet provided critiques and edits. Harriet was no philosophical fangirl. She was not afraid to challenge Mill, especially on the topic of women’s rights, where Harriet held more radical opinions. Indeed, Mill would later include elements of Harriet’s thought in his 1869 essay “The Subjection of Women.”

Alongside Mill, Harriet authored articles on domestic violence. She also provided extensive critiques of Mill’s 1848 book Principles of Political Economy, so much so that Mill wanted to include a passage in the first edition praising Harriet’s contributions. But he was stopped by Harriet’s husband out of fear of public outcry. However, Mill kept this dedicatory passage on editions of his book distributed to close friends. Mill later described Principles of Political Economy as “a joint production.”

John Taylor died in 1849 from cancer. After two years, Mill and Harriet married, though they been companions for almost twenty years. Although their tale of forbidden but ultimately requited love seems romantic to modern eyes, their marriage was disapproved of by Victorian standards, leading to Mill’s estrangement from most of his family. After experiencing the power of social pressure and conformity, it is no wonder Mill and Harriet greatly feared a world without free speech.

The newlyweds resided most of their married life in Blackheath Park with Harriet’s children for company. Due to social ostracization, the couple became increasingly reclusive, spending their days debating, discussing, and writing, blissfully happy after waiting so long to be together. As partners, they were complete equals. After thirty-​five years of service for the East India Company, Mill retired and decided to travel with Harriet to Montpellier. While passing through Avignon in Southwestern France, Harriet fell ill. Her condition rapidly deteriorated, and Harriet passed away on November 3rd, 1858.

After losing the love of his life, Mill bought a house near Harriet’s grave, where he spent most of his time. A year after Harriet’s death, Mill would publish the essay he and his wife had been working on, the now-​famous On Liberty. In his autobiography, Mill recorded how, as with much of his writings, On Liberty was a collaborative effort with his wife stating it “was more directly and literally our joint production than anything else which bears my name, for there was not a sentence of it that was not several times gone through by us together, turned over in many ways, and carefully weeded of any faults.” Mill even went as far as to say, “The whole mode of thinking of which the book was the expression, was emphatically hers.” Mill dedicated the book to his deceased wife. It isn’t an exaggeration to say that without Harriet, On Liberty would have never existed.

Mill passed away in 1873 and was buried next to his wife. Harriet’s headstone had a heartfelt and lengthy inscription written by Mill, so long that his own name would not fit on the gravestone when Mill was buried, a rare instance where Harriet’s legacy is more prominent than Mill’s.

Until quite recently, scholars were highly dismissive of Harriet’s influence on Mill’s philosophical writing. But thanks to the diligent scholarship of people such as Alice Rossi and Jo Ellen Jacob, we can see a clearer picture of how intellectually indebted Mill was to Harriet.

Mill had an extremely demanding education and feared he had become an unfeeling reasoning machine incapable of expressing higher ideas. On the other hand, Harriet was much more spontaneous and passionate. Mill thought of himself as reformer first and philosopher second, wanting to influence public opinion and political debate. Thanks to Harriet’s intellectual influence, Mill was capable of writing in a rigorously logical manner while keeping in mind higher ideals and values.

All too often, women’s achievements in history are obscured either due to the sexism of their own time or downplayed due to the intellectual biases of the present day. It is a tragedy that Mill is often perceived to be a lone genius intellect when the reality is that he collaborated with his wife, who he credited both as an intellectual equal and as the co-​author of his most impactful works. Recognizing Harriet’s contributions to Mill’s philosophy helps us understand why Mill feared stultifying conformity and instead advocated for “experiments in living.”

Mill’s thought greatly informed the classical liberal and libertarian principles adopted by seminal thinkers like economists Milton Friedman and Frederich Hayek. What we call “Mill’s thought” is really a result of Mill and Harriet’s partnership. Today, On Liberty is famous as one of the preeminent defenses of free speech and individualism ever penned in the English language. For her contributions, Harriet Taylor Mill ought to be praised and recognized as one of the great minds behind classical liberalism.