Freethought — or free thought — is a philosophical viewpoint which holds that positions regarding truth should be formed on the basis of logic, reason, and empiricism, rather than authority, tradition, revelation, or other dogma. The cognitive application of freethought is known as “freethinking”, and practitioners of freethought are known as “freethinkers”. The term first came into use in the 17th century to indicate people who inquired into the basis of traditional religious beliefs.
A free thinker is defined as a person who forms his or her own opinions about important subjects (such as religion and politics) instead of accepting what others say. Freethinkers are heavily committed to the use of scientific inquiry, and logic. The skeptical application of science implies freedom from the intellectually limiting effects of confirmation bias, cognitive bias, conventional wisdom, popular culture, prejudice, or sectarianism.
Atheist author Adam Lee defines freethought as thinking independent of revelation, tradition, established belief, and authority, also defining it as a “broader umbrella” than atheism “that embraces a rainbow of unorthodoxy, religious dissent, skepticism, and unconventional thinking.”
The basic summarizing statement of the essay The Ethics of Belief by the 19th-century British mathematician and philosopher William Kingdon Clifford is: “It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.” The essay became a rallying cry for freethinkers when published in the 1870s, and has been described as a point when freethinkers grabbed the moral high ground. Clifford was himself an organizer of freethought gatherings, the driving force behind the Congress of Liberal Thinkers held in 1878.
Regarding religion, freethinkers often hold that there is insufficient evidence to support the existence of supernatural phenomena. According to the Freedom from Religion Foundation, “No one can be a freethinker who demands conformity to a bible, creed, or messiah. To the freethinker, revelation and faith are invalid, and orthodoxy is no guarantee of truth.” and “Freethinkers are convinced that religious claims have not withstood the tests of reason. Not only is there nothing to be gained by believing an untruth, but there is everything to lose when we sacrifice the indispensable tool of reason on the altar of superstition. Most freethinkers consider religion to be not only untrue, but harmful.”
However, philosopher Bertrand Russell in his 1957 essay “The Value of Free Thought” wrote
What makes a freethinker is not his beliefs but the way in which he holds them. If he holds them because his elders told him they were true when he was young, or if he holds them because if he did not he would be unhappy, his thought is not free; but if he holds them because, after careful thought he finds a balance of evidence in their favor, then his thought is free, however odd his conclusions may seem.
Fred Edwords, former executive of the American Humanist Association, suggests that by Russell’s definition, even liberal religionists who have challenged established orthodoxies might be considered freethinkers.
In the 18th and 19th century, many thinkers regarded as freethinkers were deists, arguing that the nature of God can only be known from a study of nature rather than from religious revelation. In the 18th century, “deism” was as much of a ‘dirty word’ as “atheism”, and deists were often stigmatized as either atheists or at least as freethinkers by their Christian opponents. Deists today regard themselves as freethinkers, but are now arguably less prominent in the freethought movement than atheists.