Alexis de Tocqueville wrote one of the most profound discussions of
American democracy in the 19th century. He was particularly impressed by
the role of First Amendment freedoms.

Algernon Sidney was the world’s most celebrated martyr for free speech.
Sidney became a hero to American Founding Fathers who used the First
Amendment to protect free speech.

The philosophy of John Locke and other Englishmen is most associated with the American Founding and its emphasis on rights that are embodied in the Declaration of Independence, the First Amendment, and other provisions of the Bill of Rights. But one of the framers’ most quoted philosophers was Charles Louis de Secondat De Montesquieu of

David Hume (1711-1776) was a prominent Scottish historian and philosopher who was well known to the American Founders. Part of the Scottish common sense school of philosophy, Hume put great emphasis on experience and scientific methods and was skeptical of speculative philosophy and the fanaticism that he associated with political and religious ideologies. Hume praised

The Englishman John Lilburne (1615–1657) was a prominent defender of
religious liberties and free speech and a celebrated political prisoner.

English philosopher John Locke’s ideas of natural law, religious
toleration, and the right to revolution proved essential to the American
Revolution and the U.S. Constitution.

John Milton made an important contribution to the idea of free speech and
free press in a pamphlet, Areopagitica, published in response to a
restrictive printing ordinance.

John Stuart Mill became a guiding light for individual liberty. Practical
applications of First Amendment principles often rest upon allusions to his
ideas.

John Wilkes was an Englishman who championed free expression and
individualism during the 18th century. He was prosecuted for seditious
libel and obscenity.

Joseph Priestley was a notable figure of the 18th century Enlightenment. He
had a major influence on the First Amendment principles of religious
liberty in the U.S. Constitution.

Philip Furneaux (1726-1783) was an English dissenting minister who influenced American views on freedom of conscience. He supported Protestant Christians who did not conform to the rules of the Church of England.

Voltaire was a French author and philosopher of the Enlightenment period
who was an inspiration to those on both sides of the Atlantic interested in
free inquiry and secularism.