Harriet Hardy was born in October 1807 in Walworth, south London, the daughter of a surgeon.
Educated at home, she enjoyed writing poetry. In 1826, she married John Taylor, a prosperous merchant and together they had three children. The Taylors became active in the Unitarian Church and in 1830 a Unitarian minister introduced Harriet to the philosopher John Stuart Mill.
Their affair was to last for more than 20 years, and was generally tolerated by Harriet’s husband.
From 1833, the couple largely lived apart, enabling Harriet to see Mill more easily. Their behaviour scandalised society and as a couple they were socially isolated. But they inspired each other intellectually and often worked together.
Mills’ ‘The Principles of Political Economy’ (1848) has a chapter attributed to Harriet called ‘On the Probable Future of the Labouring Classes’ in which she argues for the importance of education for all in the future of the nation, both economically and socially.
Her essay, ‘The Enfranchisement of Women’ (1851), considered one of her most important works, was published under Mills’s name. The essay strongly advocated that women be given access to the same jobs as men, and that they should not have to live in ‘separate spheres’ – views more radical than those of Mills himself.
Harriet’s husband died in 1849 and in 1851 she and Mill were finally married.
In the autumn of 1858, the couple travelled to France where the climate was better for Harriet’s tuberculosis.
She died of respiratory failure in Avignon on 3 November 1858. John Stuart Mills’ most famous work ‘On Liberty’, which they had written together, was published in 1859 and was dedicated to Harriet.