Smith explains the basic tenets of deism and why it posed a political threat.

George H. Smith was formerly Senior Research Fellow for the Institute for Humane Studies, a lecturer on American History for Cato Summer Seminars, and Executive Editor of Knowledge Products. Smith’s fourth and most recent book, The System of Liberty, was published by Cambridge University Press in 2013.

In 1730 the Anglican Bishop of London, Edmund Gibson, warned his flock to be on guard against two dangerous and heretical arguments. First was the argument that “there is not sufficient Evidence of the Truth and Authority of the Gospel‐​Revelation”; this convinced many people “to reject the Gospel” as the word of God. Second was the argument that “Reason being a sufficient Guide in Matters of Religion, there was no need of such a Revelation”; this convinced many people that they could rely on their reason alone to discern moral principles, and to live a moral life without recourse to divine revelation.

Gibson was referring to the deists, and he understood their basic approach quite well. The deists believed in a God of Nature—a noninterventionist creator who lets the universe run according to natural laws without tinkering with his handiwork. Those natural laws can be known through reason, and knowledge of them (including knowledge of human nature) is both necessary and sufficient to guide our conduct. The derivation, elaboration, and justification of an objective moral code was seen as the essential task of a rational religion—the religion of nature.

Knowledge of nature, for the deists, is the means by which God reveals himself to man, so they often referred to this as natural revelation, or knowledge that is available to everyone through the use of reason. And they contrasted natural revelation with special revelation, or knowledge supposedly communicated by god to a particular person or group of persons. Special revelation was often said to be “above,” though not contrary to, reason, so it collided with the deistic agenda to subject all knowledge claims to rational examination. Reason should render the final verdict in all spheres of knowledge.

Deistic reactions to special revelation ranged from skepticism to outright rejection (most typically the latter). The deists therefore undertook critical examinations of the Bible, miracles, prophecy, religious experience, and beliefs based on faith. But this aspect of deistic thought—critical deism, as the historian Leslie Stephen called it—was only one part of the deistic agenda. The other part, which Stephen called constructive deism, was to explain and defend the particular ethical precepts of the religion of nature. This meant justifying moral and political principles by reason alone, without appealing to any kind of authority, whether human or divine. And this naturalistic approach, which appealed to natural laws of human conduct, generated a good deal of skepticism about political authorities. If such authorities could not justify by rational means their claims to wield legitimate power, then they deserved neither respect nor obedience.

The deistic controversy dominated the theological and political scene in England for the first several decades of the eighteenth century. Many deists were among the libertarians of their day, and this put them in the front line of the battle for religious and civil liberties. Deistic tracts and books elicited hundreds of replies, which assailed the ideas of this troublesome movement. Orthodox rulers were especially alarmed because some prominent deists hailed from lower class backgrounds, and they circumvented the elite intellectuals by addressing the working class directly, often ridiculing religious and political authorities in language that ordinary people could understand. In a country with an Established Church, this posed a serious threat to both the religious and political status quo. A primary purpose of the Anglican Church, for example, was to instill the virtue of passive obedience in the masses. As King Charles I said, “Religion is the only firm foundation of all power.” Bishop Goodman agreed: “The church and state do mutually support and give assistance to each other.” Or in the words of another astute observer, “The state pays the clergy, and thus they have dependence upon the state.”

In 1790 Edmund Burke claimed that deism had spent its force decades earlier: “Who, born within the last forty years, has read one word of Collins, and Toland, and Tindal, and Chubb, and Morgan, and that whole race who called themselves Free Thinkers? Who now reads Bolingbroke? Who ever read him through?” The freethinkers named by Burke were among the leading English deists, and it is quite true that by 1750 deism had peaked in England and that the popularity of deistic works was on the decline. But two things should be noted.

First, if the popularity of deistic works had ebbed by the later eighteenth century, this was partly because deism had become far less controversial, having been embraced by leading Enlightenment intellectuals, such as Adam Smith, David Hume, Edward Gibbon, Thomas Jefferson, Benjamin Franklin, Voltaire, and many others. It is usually unnecessary to argue vociferously for a belief that has become part of the intellectual mainstream.

Second, with the publication of Thomas Paine’s polemical defense of deism, The Age of Reason, in 1794 and 1795, public interest in deism picked up considerably—an interest that was fueled by vigorous governmental efforts to suppress the book. In 1819, for example, the publisher and bookseller Richard Carlile was convicted of blasphemous libel for publishing The Age of Reason. Carlile published that book, in part, as a test case; in his libertarian‐​freethought periodical, The Republican, he repeatedly mocked the authorities and challenged them to come and get him. And the government, prodded by the Society for the Suppression of Vice, finally did precisely that. Carlile’s three‐​day trial was closely covered by the press, and it was a fascinating trial indeed. (I shall discuss the details of Carlile’s trial in a subsequent essay.) Prominent people, including some Members of Parliament, attended Carlile’s trial, and thousands of commoners gathered outside the London courthouse to support their doughty champion in his battle against government censorship.

To publish anything by Thomas Paine was a hazardous enterprise, given Paine’s previous conviction for seditious libel in 1792. (See my discussion of the trial in Thomas Paine Versus Edmund Burke, Part 2.) As the eminent legal historian Leonard W. Levy observed in his important book Blasphemy: Verbal Offense Against the Sacred, from Moses to Salman Rushdie (Knopf 1993, p. 346):

Political radicalism, in the tradition of Paine, frequently intersected religious radicalism. A weekly newspaper demanding revocation of the stamp tax, freedom of the press, and equal voting rights most likely also preached deist doctrine, or satirized the Bible, or flirted with atheism.

On the first day of his trial Carlile read the entire text of The Age of Reason to the jury as part of his defense, a process that consumed nearly twelve hours. He then printed and sold the book as part of a cheap edition of the trial transcript, and in that form it was reported in parliament to have sold 15,000 copies. There is no doubt that Carlile was a clever and determined defender of civil liberties, but he paid a heavy price for those qualities. He was sentenced to two years imprisonment for publishing The Age of Reason and to an additional year for publishing Principles of Nature, a deistic work by the American freethinker Elihu Palmer. The verdict also demanded that Carlile post a bond of 1500 pounds before his release in order to insure his future good conduct, but this he refused to do. As a result, Carlile served an additional three years. Carlile entered jail a deist but emerged, six years later, an atheist, and he continued to thumb his nose at the government by selling seditious and blasphemous works.

After Carlile had been imprisoned, his wife kept their bookshop going; and, due to the publicity surrounding the trial, she sold thousands of copies of The Age of Reason within a short time. That commercial success earned Mrs. Carlile two years behind bars. She was followed by Carlile’s sister, Mary Ann, who served three years. Then came a long line of employees who continued Carlile’s work and suffered the same fate. Of this remarkable display of mass civil disobedience, Hypatia Bradlaugh Bonner (daughter of the prominent atheist and MP Charles Bradlaugh) wrote, in Penalties Upon Opinion:

Not only Carlile’s wife and sister, but his shopmen and shopwomen, came forward to sell the condemned work, and they also were sent to prison after their leader. Volunteers came from all parts of the country to quietly fill their places, first behind the counter in the shop, next in the dock, and finally in the gaol. There were at one time as many as eight of Carlile’s shopmen in Newgate under sentence for blasphemy, in addition to the three Carliles, who lay in Dorchester Gaol, and those in the Compter and other prisons. It has been estimated that about 150 persons were imprisoned in this way. This has always seemed to me one of the most honourable and most affecting incidents in the history of the Freethought movement of the first half of the nineteenth century, those obscure men and women coming from different parts of the country, when travelling was difficult, and almost certainly in the face of the greatest opposition from family and friends, to silently offer themselves to martyrdom for the sake of an unpopular opinion. Their martyrdom was a real martyrdom, for their imprisonment was seldom for days or weeks, but usually for a year or years. The good of their fellow‐​men was the sole motive which inspired their heroism, even as it was their sole reward. Their action seems to have been accepted without comment as a duty performed; and so little publicity was given to their devotion that we do not even know, and I am not aware that there are any means of ascertaining, the exact number of those who actually suffered. But for all that their work was done so quietly, it was effectual, and gained that freedom for The Age of Reason for which they sacrificed themselves. So far as I can ascertain, since the gallant stand made by Carlile and his band of co‐​workers The Age of Reason has never again been made the subject of prosecution in this country, although it has been sold continuously and openly up to this day.

It was with good reason that Leonard Levy dubbed Carlile “England’s foremost blasphemer,” and said that he “achieved more for the freedom of the press than any other person in the country’s history.”