Smith argues that religious liberty tempers the nefarious effects of fanaticism and allows for rational moderation to prevail in religious societies.
The institutions for the instruction of people of all ages are chiefly those for religious instruction. This is a species of instruction of which the object is not so much to render the people good citizens in this world, as to prepare them for another and a better world in a life to come. The teachers of the doctrine which contains this instruction, in the same manner as other teachers, may either depend altogether for their subsistence upon the voluntary contributions of their hearers, or they may derive it from some other fund to which the law of their country may entitle them; such as a landed estate, a tithe or land‐tax, an established salary or stipend. Their exertion, their zeal and industry, are likely to be much greater in the former situation than in the latter. In this respect the teachers of new religions have always had a considerable advantage in attacking those ancient and established systems of which the clergy, reposing themselves upon their benefices, had neglected to keep up the fervour of faith and devotion in the great body of the people, and having given themselves up to indolence, were become altogether incapable of making any vigorous exertion in defence even of their own establishment. The clergy of an established and well‐endowed religion frequently become men of learning and elegance, who possess all the virtues of gentlemen, or which can recommend them to the esteem of gentlemen: but they are apt gradually to lose the qualities, both good and bad, which gave them authority and influence with the inferior ranks of people, and which had perhaps been the original causes of the success and establishment of their religion. Such a clergy, when attacked by a set of popular and bold, though perhaps stupid and ignorant enthusiasts, feel themselves as perfectly defenceless as the indolent, effeminate, and full‐fed nations of the southern parts of Asia when they were invaded by the active, hardy, and hungry Tartars of the North. Such a clergy, upon such an emergency, have commonly no other resource than to call upon the civil magistrate to persecute, destroy or drive out their adversaries, as disturbers of the public peace. It was thus that the Roman catholic clergy called upon the civil magistrates to persecute the protestants, and the church of England to persecute the dissenters; and that in general every religious sect, when it has once enjoyed for a century or two the security of a legal establishment, has found itself incapable of making any vigorous defence against any new sect which chose to attack its doctrine or discipline. Upon such occasions the advantage in point of learning and good writing may sometimes be on the side of the established church. But the arts of popularity, all the arts of gaining proselytes, are constantly on the side of its adversaries. In England those arts have been long neglected by the well‐endowed clergy of the established church, and are at present chiefly cultivated by the dissenters and by the methodists. The independent provisions, however, which in many places have been made for dissenting teachers by means of voluntary subscriptions, of trust rights, and other evasions of the law, seem very much to have abated the zeal and activity of those teachers. They have many of them become very learned, ingenious, and respectable men; but they have in general ceased to be very popular preachers. The methodists, without half the learning of the dissenters, are much more in vogue.
In the church of Rome, the industry and zeal of the inferior clergy are kept more alive by the powerful motive of self‐interest than perhaps in any established protestant church. The parochial clergy derive, many of them, a very considerable part of their subsistence from the voluntary oblations of the people; a source of revenue which confession gives them many opportunities of improving. The mendicant orders derive their whole subsistence from such oblations. It is with them as with the hussars and light infantry of some armies; no plunder, no pay. The parochial clergy are like those teachers whose reward depends partly upon their salary, and partly upon the fees or honoraries which they get from their pupils, and these must always depend more or less upon their industry and reputation. The mendicant orders are like those teachers whose subsistence depends altogether upon the industry. They are obliged, therefore, to use every art which can animate the devotion of the common people. The establishment of the two great mendicant orders of St. Dominic and St. Francis, it is observed by Machiavel, revived, in the thirteenth and fourteenth centuries, the languishing faith and devotion of the catholic Church. In Roman catholic countries the spirit of devotion is supported altogether by the monks and by the poorer parochial clergy. The great dignitaries of the church, with all the accomplishments of gentlemen and men of the world, and sometimes with those of men of learning, are careful enough to maintain the necessary discipline over their inferiors, but seldom give themselves any trouble about the instruction of the people.
Most of the arts and professions in a state, [says by far the most illustrious philosopher and historian of the present age,] are of such a nature that, while they promote the interests of the society, they are also useful or agreeable to some individuals; and in that case, the constant rule of the magistrate, except perhaps on the first introduction of any art, is to leave the profession to itself, and trust its encouragement to the individuals who reap the benefit of it. The artizans, finding their profits to rise by the favour of their customers, increase as much as possible their skill and industry; and as matters are not disturbed by any injudicious tampering, the commodity is always sure to be at all times nearly proportioned to the demand.
But there are also some callings, which, though useful and even necessary in a state, bring no advantage or pleasure to any individual, and the supreme power is obliged to alter its conduct with regard to the retainers of those professions. It must give them public encouragement in order to their subsistence, and it must provide against that negligence to which they will naturally be subject, either by annexing particular honours to the profession, by establishing a long subordination of ranks and a strict dependence, or by some other expedient. The persons employed in the finances, fleets, and magistracy, are instances of this order of men.
It may naturally be thought, at first sight, that the ecclesiastics belong to the first class, and that their encouragement, as well as that of lawyers and physicians, may safely be entrusted to the liberality of individuals, who are attached to their doctrines, and who find benefit or consolation from their spiritual ministry and assistance. Their industry and vigilance will, no doubt, be whetted by such an additional motive; and their skill in the profession, as well as their address in governing the minds of the people, must receive daily increase from their increasing practice, study, and attention.
But if we consider the matter more closely, we shall find that this interested diligence of the clergy is what every wise legislator will study to prevent; because in every religion except the true it is highly pernicious, and it has even a natural tendency to pervert the true, by infusing into it a strong mixture of superstition, folly, and delusion. Each ghostly practitioner, in order to render himself more precious and sacred in the eyes of his retainers, will inspire them with the most violent abhorrence of all other sects, and continually endeavour, by some novelty, to excite the languid devotion of his audience. No regard will be paid to truth, morals, or decency in the doctrines inculcated. Every tenet will be adopted that best suits the disorderly affections of the human frame. Customers will be drawn to each conventicle by new industry and address in practising on the passions and credulity of the populace. And in the end, the civil magistrate will find that he has dearly paid for his pretended frugality, in saving a fixed establishment for the priests; and that in reality the most decent and advantageous composition which he can make with the spiritual guides, is to bribe their indolence by assigning stated salaries to their profession, and rendering it superfluous for them to be farther active than merely to prevent their flock from straying in quest of new pastures. And in this manner ecclesiastical establishments, though commonly they arose at first from religious views, prove in the end advantageous to the political interests of society.
But whatever may have been the good or bad effects of the independent provision of the clergy, it has, perhaps, been very seldom bestowed upon them from any view to those effects. Times of violent religious controversy have generally been times of equally violent political faction. Upon such occasions, each political party has either found it, or imagined it, for its interest to league itself with some one or other of the contending religious sects. But this could be done only by adopting, or at least by favouring, the tenets of that particular sect. The sect which had the good fortune to be leagued with the conquering party necessarily shared in the victory of its ally, by whose favour and protection it was soon enabled in some degree to silence and subdue all its adversaries. Those adversaries had generally leagued themselves with the enemies of the conquering party, and were therefore the enemies of that party. The clergy of this particular sect having thus become complete masters of the field, and their influence and authority with the great body of the people being in its highest vigour, they were powerful enough to over‐awe the chiefs and leaders of their own party, and to oblige the civil magistrate to respect their opinions and inclinations. Their first demand was generally that he should silence and subdue an their adversaries: and their second, that he should bestow an independent provision on themselves. As they had generally contributed a good deal to the victory, it seemed not unreasonable that they should have some share in the spoil. They were weary, besides, of humouring the people, and of depending upon their caprice for a subsistence. In making this demand, therefore, they consulted their own ease and comfort, without troubling themselves about the effect which it might have in future times upon the influence and authority of their order. The civil magistrate, who could comply with this demand only by giving them something which he would have chosen much rather to take, or to keep to himself, was seldom very forward to grant it. Necessity, however, always forced him to submit at last, though frequently not till after many delays, evasions, and affected excuses.
But if politics had never called in the aid of religion, had the conquering party never adopted the tenets of one sect more than those of another when it had gained the victory, it would probably have dealt equally and impartially with all the different sects, and have allowed every man to choose his own priest and his own religion as he thought proper. There would in this case, no doubt have been a great multitude of religious sects. Almost every different congregation might probably have made a little sect by itself, or have entertained some peculiar tenets of its own. Each teacher would no doubt have felt himself under the necessity of making the utmost exertion and of using every art both to preserve and to increase the number of his disciples. But as every other teacher would have felt himself under the same necessity, the success of no one teacher, or sect of teachers, could have been very great. The interested and active zeal of religious teachers can be dangerous and troublesome only where there is either but one sect tolerated in the society, or where the whole of a large society is divided into two or three great sects; the teachers of each acting by concert, and under a regular discipline and subordination. But that zeal must be altogether innocent where the society is divided into two or three hundred, or perhaps into as many thousand small sects, of which no one could be considerable enough to disturb the public tranquility. The teachers of each sect, seeing themselves surrounded on all sides with more adversaries than friends, would be obliged to learn that candour and moderation which is so seldom to be found among the teachers of those great sects whose tenets, being supported by the civil magistrate, are held in veneration by almost all the inhabitants of extensive kingdoms and empires, and who therefore see nothing round them but followers, disciples, and humble admirers. The teachers of each little sect, finding themselves almost alone, would be obliged to respect those of almost every other sect, and the concessions which they would mutually find it both convenient and agreeable to make to one another, might in time probably reduce the doctrine of the greater part of them to that pure and rational religion, free from every mixture of absurdity, imposture, or fanaticism, such as wise men have in all ages of the world wished to see established; but such as positive law has perhaps never yet established, and probably never will establish, in any country: because, with regard to religion, positive law always has been, and probably always will be, more or less influenced by popular superstition and enthusiasm. This plan of ecclesiastical government, or more properly of no ecclesiastical government, was what the sect called Independents, a sect no doubt of very wild enthusiasts, proposed to establish in England towards the end of the civil war. If it had been established, though of a very unphilosophical origin, it would probably by this time have been productive of the most philosophical good temper and moderation with regard to every sort of religious principle. It has been established in Pennsylvania, where, though the Quakers happen to be the most numerous, the law in reality favours no one sect more than another, and it is there said to have been productive of this philosophical good temper and moderation.
But though this equality of treatment should not be productive of this good temper and moderation in all, or even in the greater part of the religious sects of a particular country, yet provided those sects were sufficiently numerous, and each of them consequently too small to disturb the public tranquillity, the excessive zeal of each for its particular tenets could not well be productive of any very harmful effects, but, on the contrary, of several good ones: and if the government was perfectly decided both to let them all alone, and to oblige them all to let alone one another, there is little danger that they would not of their own accord subdivide themselves fast enough so as soon to become sufficiently numerous.