Today is World Philosophy Day, and what better way to celebrate than to give a nod to a few lesser-known philosophers associated with the classical liberal tradition. You may know the Hayeks and Nozicks and Lockes of the world, but have you heard of these seven liberty-loving thinkers?

1. Herbert Spencer
Recommended reading: Social Statics

A polymath, Herbert Spencer was originally known for his writing on biology. He coined the phrase “survival of the fittest,” used to describe the process of natural selection. Spencer rose to prominence by extending the lessons of biological evolution to politics and sociology.

Libertarian historian Brian Doherty writes in his tome Radicals for Capitalism that libertarian political theorist Murray Rothbard once described Spencer’s work Social Statics as “the greatest single work of libertarian political philosophy ever written.” In Social Statics, Spencer writes that one has a moral obligation to support charities, considering them “the highest forms of social evolution.” Spencer was ahead of his time in other ways as well, self-identifying as a “radical feminist” advocating for “complete suffrage” and a “right to ignore the state.”

2. Benjamin Tucker
Recommended reading: Individual Liberty

Benjamin Tucker was a 19th century American writer, editor, and publisher, and a self-proclaimed “individualist anarchist”. Tucker is probably best known for his periodical plainly titled Liberty, which ran for nearly 30 years. Feminist thinker Wendy McElroy would go on to describe Liberty as “widely considered to be the finest individualist-anarchist periodical ever issued in the English language.”

Liberty would eventually showcase the writings of some of the most influential political thinkers of its time, including fellow individualist anarchist Lysander Spooner as well as English translations of Friedrich Nietzsche. Tucker was influenced by and attempted to synthesize the political theories of Herbert Spencer, Pierre-Joseph Proudhon and others. He would describe this philosophical anarchism as “anarcho-socialism” predating Marxist definitions of socialism.

3. Lysander Spooner
Recommended reading: No Treason: The Constitution of No Authority

It’s hard to determine where to begin when discussing Lysander Spooner. There’s his hugely successful first class mail company that successfully competed with the United States Postal Service to the point that the USPS had to lower their cost for postage in order to compete. That is, until Congress passed legislation effectively banning people from competing with the USPS.

Or perhaps we could talk about his work as an abolitionist? Or as an advocate for women’s suffrage? Spooner’s underratedness is underscored by his forward-thinking nature. A 19th century lawyer, entrepreneur, essayist, pamphleteer, abolitionist, and labor movement-supporting anarchist, Spooner is the personification of everything we love about the rugged individualism of early America. He’s probably best known for his highly quotable essay on the illegitimacy of the U.S. Constitution titled No Treason: The Constitution of No Authority.

4. Isabel Paterson
Recommended reading: The God of the Machine

Isabel Paterson was a journalist, novelist, literary critic, and political philosopher. Canadian born, Paterson became an American citizen later in her life. She got her professional start as an editor for a Washington-based paper but would go on to write a regular column for the New York Herald Tribune where she wrote on a variety of topics, including the Harlem Renaissance, the New Deal, and the Great Depression.

During her tenure at the Herald Tribune she acted as mentor to an up and coming Ayn Rand. Rand and Paterson became ideological allies, using their platforms to promote the other. Rand described Paterson’s magnum opus The God of the Machine as “the best and most complete statement of the basic principles of our side, and the greatest defense of capitalism I have ever read. It does for capitalism what Das Kapital did for the Reds.”

5. Gustave de Molinari
Recommended reading: The Production of Security

Belgian Gustave de Molinari is the intellectual heir to the philosophy of free trade as espoused by Frederic Bastiat. Shortly before Bastiat’s death in 1850, Molinari published The Production of Security, one of the first works to lay out a theoretical framework for markets as a viable alternative to the coercive state. Murray Rothbard writes in the preface of the 1977 English translation that The Production of Security is the “first presentation anywhere in human history of what is now called anarcho-capitalism.”

Following the death of Bastiat, Molinari became the leading voice for free markets in France in the latter half of the 19th century. Molinari lives on today as the namesake for the market anarchist Molinari Institute.

6. William Lloyd Garrison
Recommended reading: Archive of the The Liberator

William Lloyd Garrison is best known for his work calling for an end to the institution of slavery in the United States. Garrison was the editor and co-founder of the abolitionist newspaper The Liberator. He was also one of the co-founders of the American Anti-Slavery Society.

Following the abolishment of slavery at the conclusion of the Civil War, Garrison went on to become a major player in the movement for women’s suffrage almost a century before women would finally attain the right to vote.

7. Auberon Herbert
Recommended reading: A Politician in Trouble About His Soul

Auberon Herbert was a 19th century writer, philosopher, and individualist. During his time in Parliament he was an outspoken advocate of secularism, especially as it related to public education. Following political life, he was an avid supporter of the aforementioned Herbert Spencer. He would later dub his Spencerian-like flavor of individualism as “voluntaryism.”

Ever critical of the political system and the behavior it rewards, Herbert was a vocal critic of political parties. In his best known book, A Politician in Trouble about his Soul, Herbert advocated a radical laissez-faire ideology that argued for “voluntary taxation.” Herbert also started a monthly paper titled The Organ of Voluntary Taxation and the Voluntary State, which ran for 11 years.

So there you have it. Seven lesser known classical liberal theorists who were united by the common goal of human liberation. The classical liberal tradition is a rich one with a vibrant and diverse cast of individuals dating as far back as the 18th century. Their writings and interactions with one another are woven together over centuries, resulting in a compelling and, in some cases, a surprisingly prophetic argument for individual autonomy. Many of them were the earliest advocates of abolitionism and women’s suffrage, while others were creating theoretical frameworks for anarchist societies well before the First World War.