This worldview, known in France as Libre-Pensée and in Germany as Freidenker, has deep origins, but the actual term ‘free-thinking’ that constellated the ideas originated in 17th century England. Freethought quickly gained popularity in Britain, France, the Netherlands and America. By the 19th century, there were freethinkers throughout Western Europe and parts of North America. Freethought is based on the concept that the world can be understood through rational thought and consideration of nature as opposed to any scripture or religious authority. Early freethinkers were Christian deists (their belief in God based on reason and observation), usually Protestant, but by the second half of the 18th century freethought had detached from Christianity, in large part due to the philosopher Voltaire’s influence. The first documented use of the term ‘freethinker’ was in a 1697 letter from Anglo-Irish philosopher William Molyneux (1656–1698) to English philosopher John Locke (1632–1704). The concept of freethought was expanded upon in a 1713 essay, ‘Discourse of Free-Thinking’, by English philosopher Anthony Collins (1676–1729). Most contemporary freethinkers reject the notion of deities or supernatural phenomena and believe religion to be based on falsehood, unable to withstand rational scrutiny. In the early 20th century freethought influenced the Young Turks political reform movement. Important people in the freethought movement include major figures of the European Enlightenment such as French philosophers Voltaire (1694–1778) and Denis Diderot (1713–1784), American polymath Benjamin Franklin (1706–1790), British-American political writer Thomas Paine (1737–1809), English philosopher and activist Mary Wollstonecraft (1759–1797), American writers Frederick Douglass (1818–1895), Mark Twain (1835–1910), Moncure Daniel Conway (1832–1907), Zora Neal Hurston (1891–1960), W.E.B. Du Bois (1868–1963), Richard Wright (1908–1960), James Forman (1928–2005) and Christopher Hitchens (1949–2011) and Mexican painter Frida Kahlo (1907–1954). There are overlaps in the freethought worldview with atheism, agnosticism, secularism, humanism, anti-clericism and deism. The essence of freethought is the ability and right to think and express thoughts free from the constraints of tradition, authority, established belief, ideology or dogma. Freethinkers reject hegemonic structures: their aim is to transform society to promote social justice, equity and pluralism. Many freethinkers are artists or writers who can keep independent from those who hold institutional power. While not occupying a homogenous political position, freethinkers have always been on the frontline of social justice and reform movements like abolition of slavery and child labour, anti-racism, feminism and prison reform. There are many freethought organisations throughout the world but no centralised authority. Nor are there universal special rituals or days. However, Secular Day of the Dead, held on 1 November each year, was created in 2014 by American freethinkers Victoria De la Torre and Margaret Downey.