¶ … religious faith seems to most of us living in the United States at the beginning of the 21st century to be a purely private one. We (most of us believe) that a person's choice of religion, of congregation, of philosophy is something that each individual must decide for himself or herself. If a person finds most intellectual and emotional comfort in being a Muslim or a Jew or an atheist or a Theosophist we believe that such choices are between that person and his or her conscience alone. However, this acceptance that people must choose their own moral path in life as a purely individual choice is a relatively new idea and one that we owe very much to the beliefs promulgated by the thinkers and writers of the Enlightenment who for the first time began a systematic exploration of the ways in which questions of morality, religion and conscience could be considered as questions entirely separate from questions about the ways in which societies were constituted and governed. It was writers like John Locke and Denis Diderot - along with other members of the group of French progressive thinkers known as the philosophes - who laid the groundwork for our own, essentially secular society. This paper examines the views of Enlightenment writers towards the ideas of deism and atheism, focusing on Locke's 1689 "Letter Concerning Toleration" and Denis Diderot's 1763 "Rameau's Nephew." It is essential, as suggested above, when examining these texts and others contemporaneous with those by Locke and Diderot, to understand that the question of atheism was not viewed by those people living at the beginning of the modern era as a personal question but rather as a public and social one. Atheism was not a choice that (most people would have argued at the beginning of the Enlightenment) that a person could reasonably make because a belief in God by everyone was essential to the maintenance of communal order.

Locke argues this point:

Lastly, those are not at all to be tolerated who deny the being of a God. Promises, covenants, and oaths, which are the bonds of human society, can have no hold upon an atheist. The taking away of God, though but even in thought, dissolves all; besides also, those that by their atheism undermine and destroy all religion, can have no pretence of religion whereupon to challenge the privilege of a toleration.

We can perhaps appreciate Locke's point even as it makes us (at least those of us who believe in the importance of the separation of church and state) uncomfortable. While there are certainly ethical problems with the imposition of a single set of moral beliefs on an entire population, it is also true that if all members of a community believe in a single set of ideas and moral precepts it is far easier to maintain social order and promote a sense of community.

The importance of orthodoxy as a way of maintaining stability and even tranquility in a community had been in the centuries leading up to the Enlightenment an article of (political) faith. However, as colonization and exploration began to bring Europeans into greater and greater contact with people with very different belief systems from their own - and as Protestantism challenged the power of the Catholic Church and some people began to be repelled by the excesses of Rome and its Inquisition - new ideas about how societies might be governed began to be considered. These new ideas included both intellectual and later practical explorations into democratic governance (both the French Revolution and the American Revolution are very much practical applications of the ideas of the great writers of the Enlightenment) as well as ideas about political governance that was entirely separate from religious authority.

This is not to say that political philosophers like Locke were entirely modern in their thinking about the relationship between...

For example, even as he condemns atheism for its corrupting influence on society, in the very next sentence he admits that if atheists do no real harm than perhaps they should be tolerated and left unmolested by civil authorities.
As for other practical opinions, though not absolutely free from all error, if they do not tend to establish domination over others, or civil impunity to the Church in which they are taught, there can be no reason why they should not be tolerated.

Locke's arguments that people should be free to believe in whatever they wished, even including the belief in a humanistic rather than a deistic framework for the universe, was based in broader Enlightenment ideals about the relationship between the individual and social institutions - whether the state or the church. The history of Enlightenment thought is in large measure the history of the ways in which individuals have come to have increasing importance and power as individuals rather than simply as members of groups.

Locke also argues in this treatise - and indeed this point is far more central to his argument than are particular comments of his about specific elements of religious belief or practice - that common standards must apply to different sets of belief. While he is primarily arguing that different religious sects respect each other, it also seems clear that he is at least willing to consider the fact that such respect should also be extended by those who adhere to a specific religion to those who are either deists or atheists.

Nobody, therefore, in fine, neither single persons nor churches, nay, nor even commonwealths, have any just title to invade the civil rights and worldly goods of each other upon pretence of religion. Those that are of another opinion would do well to consider with themselves how pernicious a seed of discord and war, how powerful a provocation to endless hatreds, rapines, and slaughters they thereby furnish unto mankind. No peace and security, no, not so much as common friendship, can ever be established or preserved amongst men so long as this opinion prevails, that dominion is founded in grace and that religion is to be propagated by force of arms.

Locke's tone in this essay is rational, calm, persuasive. He is attempting to give his readers tools through which they may analyze their own society, techniques through which they could understand the ways in which humans interact with each other. Diderot was in part trying to do this in his writing, but he is far less convinced of the rationality of human society or of humans in general than is Locke. Diderot is more concerned with exposing both human folly and human cruelty than is Locke, who seems to be much more convinced than is Diderot that society can be made better.

In part, Diderot's condemnation of society and the ways in which people act within it stem from his own observations of the ways in which religious institutions so very often bring out the worst excesses of human nature. That the two should disagree about the nature of religion (with Locke being far more sanguine than Diderot was) reflects the different experiences that would have been common to an Englishman living in a Protestant nation and French citizen of a Catholic country that had seen its share of bloody Inquisatorial horrors.

La fortune du Juif est a bord. Demain, a la pointe du jour, ils mettent a la voile. Ils peuvent souper gaiement et dormir en surete. Demain, ils echappent a leurs persecuteurs. Pendant la nuit, le renegat se leve, depouille le Juif de son portefeuille, de sa bourse et de ses bijoux; se rend a bord, et le voila parti. Et vous croyez que c'est la tout?... Le sublime de sa mechancete, c'est d'avoir ete lui-m me le delateur de son bon…