A Critique of John Locke’s Letter Concerning Toleration

by Derek Remus

The following is the first part of a critique of John Locke’s Letter Concerning Toleration in the light of Catholic doctrine on the relation between Church and state. It a slightly revised version of Derek Remus’s thesis at Thomas Aquinas College.
– The Editors

Arise, be enlightened, O Jerusalem: for thy light is come,
And the glory of the Lord is risen upon thee…
And the Gentiles shall walk in thy light,
And kings in the brightness of thy rising.
—Isaiah 60: 1, 3


The first three centuries of the Catholic Church’s existence were a period of violent and bloody persecution at the hands of the Roman Empire–that is, the state. The Church persevered through this trial, however, and, instead of diminishing, increased in proportion to the persecutions she suffered, until at last she was granted freedom of worship and made the official religion of the Empire. This was the beginning of that harmonious union between Church and state which gave rise to Christendom–a union in which the state recognized that its proper good was ordered toward a higher good, namely, eternal beatitude, and the Church, to the extent that affairs of state bore upon the salvation of souls, was solicitous about those affairs.

This union lasted throughout Europe for twelve hundred years. Then came the Protestant Reformation. The divine origin of the papacy was challenged; the religious unity of Europe was shattered; Christendom was no more. The Church still existed, however, and the question of how governments ought to deal with her under the new order of things became an urgent problem for political philosophers.

Thomas Hobbes and Benedict Spinoza held that the head of state ought to be the head of the Church, since otherwise the citizens’ loyalties would be divided.[1] John Locke, on the other hand, took an apparently more benign position by calling not for the subjection of the Church to the state but for the total separation of the two powers. In his Letter Concerning Toleration, he said that there is no connection, and hence no conflict, between the salvation of souls and the goods of this world. Therefore, the state must grant equal status and liberty to all religions within its domain, provided that they do not teach any doctrines dangerous to the state’s welfare (which doctrines would then not be, properly speaking, religious), and those religions in turn must in no way concern themselves with political affairs.

While the positions of Hobbes and Spinoza have more or less found expression historically in regimes such as those of Protestant England and the People’s Republic of China,[2] the Lockean position has perhaps found no better expression than in that of the United States of America. Indeed, the influence of Locke on several of the American Founding Fathers with regard to the question of Church and state (not to mention several other questions) cannot be contested.[3] As a consequence, many American Catholics, whether wittingly or unwittingly, tend to espouse positions on Church and state that are more or less Lockean in principle and to regard the American status of Church and state, where the state treats all religious bodies equally, as an ideal toward which the rest of the world ought to strive.

Such thinking, however, is clearly opposed to that of the Church’s Magisterium. While the Magisterium teaches that the ecclesiastical and civil powers have “fixed limits within which” each “is contained, limits which are defined by the nature and special object of the province of each,”[4] these limits do not mean that there are no areas that fall within the jurisdiction of both powers or that the ends of Church and state, while distinct, have no order existing between them. On the contrary, Pope Leo XIII teaches that the state is bound by divine law to engage in the “public profession of religion…not such religion as [men] may have a preference for, but the religion which God enjoins, and which certain and most clear marks show to be the only one true religion.”[5] Pope Pius IX condemns the proposition that “it has been wisely decided by law, in some Catholic countries, that persons coming to reside therein shall enjoy the public exercise of their own peculiar worship.”[6] Pope Pius XI declares that the “kingly dignity” of Christ “demands that the State should take account of the commandments of God and of Christian principles, both in making laws and in administering justice, and also in providing for the young a sound moral education.”[7] All of these papal pronouncements make it clear that the Lockean position on Church and state is irreconcilable with Catholic doctrine.

In this thesis, I shall attempt to show that the Catholic Church is right about the relation between Church and state and that Locke is wrong. I shall do so principally through the teachings of the Common Doctor of the Church, St. Thomas Aquinas. The thesis will consist of three parts: 1) an exposition of Locke’s position as expressed in A Letter Concerning Toleration; 2) an exposition and defense of the Church’s position; 3) a refutation of Locke’s position in light of that defense.

I. Exposition of A Letter Concerning Toleration

Before we examine the substance of Locke’s Letter Concerning Toleration, we must point out two possible sources of confusion in understanding it.

First, throughout the Letter, Locke complains that in his day Christians are killing and persecuting each other on account of differences in belief and that they are often using the power of the state to do so. His repeated condemnation of this state of affairs can make one think that the unjustness of using the state to kill and persecute one’s neighbors on account of religion is really what the Letter is all about. In fact, however, the main purpose of the Letter is to establish a general doctrine concerning the very natures of Church and state from which the unjustness of using the state to kill and persecute one’s neighbors on account of religion follows as a consequence. It is this general doctrine which constitutes the central target of our attack on the Letter.

Second, throughout the Letter, Locke speaks of the “mutual toleration of Christians in their different professions of religion” [emphasis added].[8] This can make it seem that Locke intends the equal toleration of different religions implied by the separation of Church and state to extend only to Christian bodies. Later in the Letter, however, Locke speaks of toleration not only for the “different professions of religion” within Christianity but for all religions. He asks:

Shall we suffer a Pagan to deal and trade with us, and shall we not suffer him to pray unto and worship God? If we allow the Jews to have private houses and dwellings amongst us, why should we not allow them to have synagogues?[9]

Therefore, the reason that Locke refers frequently to toleration for different Christian religious bodies is merely that he is writing for Europeans, nearly all of whom happen to be Christian; his principles, however, demand toleration for all religious bodies.[10]

Let us now examine the substance of the Letter. As we have said, the central contention of the Letter is that the state can have no interest in the salvation of souls and that the Church can have no interest in civil affairs. Concretely, this means that the state must grant equal status and liberty to all religious bodies within its domain and that those religious bodies must in turn refrain from all intervention in affairs of state.

To show the first part of the Letter’s central contention, namely, that the state can have no interest in the salvation of souls, Locke begins by defining the state as “a society of men constituted only for the procuring, preserving, and advancing their own civil interests.”[11] By civil interests Locke means “life, liberty, health, and indolency of body; and the possession of outward things, such as money, lands, houses, furniture, and the like.”[12]

If we wish to understand fully what Locke has in mind when he defines the state in this way, we must turn to his Second Treatise of Government, where he gives an account of how the state comes to be. Here he says that prior to the existence of the state, men are in a state of nature, that is, “a state of perfect freedom to order their actions, and dispose of their possessions and persons, as they think fit, within the bounds of the law of nature, without asking leave, or depending upon the will of any other man.”[13] This “state of perfect freedom” belongs to all men equally, so that the state of nature is also a state of equality, “wherein all the power and jurisdiction is reciprocal, no one having more than another.”[14]   Further, the “state of perfect freedom” is not unlimited but is bounded by the “law of nature,” which obliges every man to preserve himself and “teaches all mankind…that being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions.”[15] In other words, since all men possess the freedom to dispose of themselves as they please equally, the only limit to one man’s exercise of that freedom, aside from not destroying himself, is not to hinder another man’s exercise of that same freedom. Every one may do as he likes, so long as he lets others do as they like.

Most men, however, do not let others do as they like. Hence, Locke declares that while man always has the “right” to enjoy his “state of perfect freedom,” his actual enjoyment of that state is “very uncertain, and constantly exposed to the invasion of others.”[16] In order to make that enjoyment certain, men form a contract with each other whereby they agree to unite into a society and to create some authority to whom they confer the power of protecting their lives, liberties, and possessions from the encroachments of others. The society thus instituted is the state. While it is true that, in entering the state, men give up certain “rights” belonging to their natural “state of perfect freedom”–most notably, the right to punish those who attempt to harm them without appeal to a higher power–, they do so only in order to enjoy the remainder of those “rights,” which they value more, more securely.[17] The end of the state, therefore, is to protect those natural rights which its citizens value most and hence want to enjoy most without the interference of others. When these rights become the object of the state’s protection, they become “civil interests” or “civil rights.” Hence, in the Letter, Locke defines the state as “a society of men constituted only for the procuring, preserving, and advancing their own civil interests.”

Having defined the state, Locke briefly describes the duty and power of the civil magistrate. He says that the duty of the civil magistrate is to secure the aforementioned civil interests to “the people in general and to every one of his subjects in particular” through “the impartial execution of equal laws.”[18] To execute these laws, the magistrate must have the power to punish those who violate them, and to have this power, he must be “armed with the force and strength of all his subjects.”[19] The power of the magistrate, therefore, “consists only in outward force.”[20]

In light of his definition of the state and his account of the duty and power of the civil magistrate, Locke provides four arguments for why the power of the civil magistrate does not in any way bear upon the salvation of souls.[21]

The first argument is that care of souls has not been committed to the magistrate by anyone. It has not been committed to him by God because God has not given any man the authority “to compel anyone to his religion.”[22] But for the magistrate to have a care of souls would be for him to compel men to his religion, since the power of the magistrate “consists only in outward force.” Care of souls has not been committed to the magistrate by the consent of the people because no one may so “abandon the care of his own salvation as blindly to leave to the choice of any other, whether prince or subject, to prescribe to him what faith or worship he shall embrace.”[23] The reason for this is that “faith is not faith” without “the inward and full persuasion of the mind,” which cannot be effected by making someone “blindly” follow the dictates of someone else.[24]

The second argument is that the power of the magistrate “consists only in outward force,” as stated, but outward force cannot affect what one holds in the mind. Faith, however, as stated in the previous argument, demands “the inward and full persuasion of the mind.” Therefore, the magistrate has no power by which he can influence the religion of his subjects. Therefore, he cannot have a care of souls.

Note that both of these arguments rely on the claim that, since the power of the magistrate “consists only in outward force,” the magistrate cannot exercise care of souls in any other way than by forcing his citizens to perform acts by which they embrace the religion of the state. If we deny this claim, then the arguments fall apart.

The third argument is that, even if outward force could affect what one holds in the mind, that would bring about the damnation rather than the salvation of most men. For given “the variety and contradiction”[25] of the opinions of princes with regard to religion, most princes would force false religions on their subjects.

The fourth argument is that the salvation or damnation of one’s neighbor in no way advances or harms one’s civil interests. If one’s neighbor goes to hell, one’s health or money, for example, will still remain fully intact. The duty of the magistrate, however, is to secure everyone’s civil interests. Therefore, matters pertaining to salvation are wholly outside of the magistrate’s jurisdiction.

One might conclude from the foregoing arguments that the basis for religious toleration is the mere fact that the practice of one’s religion is something outside the state’s jurisdiction. Later in the Letter, however, Locke implies that the practice of one’s religion is something more than that, namely, a natural right:

These accusations [that assemblies of religious bodies are nurseries of factions and seditions] would soon cease if the law of toleration were once so settled that all Churches were obliged to lay down toleration as the foundation of their own liberty, and teach that liberty of conscience is every man’s natural right, equally belonging to dissenters as to themselves [emphasis added].[26]

The language of “natural right” calls to mind the state of nature. Locke seems to be implying that the freedom to practice the religion which one’s conscience judges to be acceptable to God is really a particular determination or expression of man’s natural “state of perfect freedom.” In other words, man’s natural freedom to dispose of himself as he pleases implies his freedom to practice the religion of his choosing. This makes sense, if we bear in mind that the only limit to the “state of perfect freedom” is the law of nature, which forbids a man from destroying himself and from harming the “life, health, liberty” and “possessions” of others. Inasmuch as practicing the religion that one deems acceptable to God violates neither of these prescriptions of the law of nature, it must necessarily be a determination of man’s “state of perfect freedom,” and in particular, one of the determinations that man does not give up when he enters political society. If this is true, then it would follow that the practice of one’s religion, precisely because it in no way encroaches on other men’s civil interests, is itself one of the civil interests that constitute the object of the state’s protection.

Having argued that the state can have no interest in the salvation of souls, Locke then argues that churches can have no interest in affairs of state. He begins by defining a church as “a voluntary society of men, joining themselves together of their own accord in order to the public worshipping of God in such manner as they judge acceptable to Him, and effectual to the salvation of their souls.”[27] As a consequence of this definition, Locke declares that each man is free to join that church “in which he believes he has found that profession and worship which is truly acceptable to God” and that he is free to leave the same church “if afterwards he discover anything either erroneous in [its] doctrine or incongruous in [its] worship.”[28] Moreover, since a church comes to exist through the voluntary coming together of its members, the right of making the church’s laws “can belong to none but the society itself; or at least (which is the same thing), to those whom the society by common consent has authorized thereunto.”[29] In other words, the power of a church resides in the wills of its members.

When Locke says that each man is free to enter that church which he judges to be acceptable to God and to leave the same church if he later comes to think that it is unacceptable to God, he is in effect maintaining that in matters of religion each man is his own judge of what is true and false. Later, he says this explicitly:

Every man in that [religion] has the supreme and absolutely authority of judging for himself.[30]

Though he does not mean that an individual’s judgment makes religious doctrines to be true or false, he does mean that an individual may and even should submit each doctrine to his own scrutiny before accepting it and allow for the possibility that later on, upon scrutinizing the doctrine again, he may find it to be false. This, of course, is a consequence of Locke’s doctrine of the natural right to liberty of conscience, according to which the practice of religion is a mere determination of man’s natural “state of perfect freedom,” and a man may therefore hold whatever religious doctrines and perform whatever religious activities he judges to be acceptable to God. We should note here that Locke himself is “personally” a believer and thus thinks that God has made some kind of special revelation to man, but from what we have said, he clearly thinks that this revelation is ultimately a matter solely between God and the individual and that its interpretation is subject to the individual’s supreme judgment.

Locke’s definition of a church helps us to see more explicitly a consideration that was implicit in his fourth argument for why the state cannot have a care of souls, namely, that the basis for the state’s toleration of the religions within its domain has nothing to do with a duty of the state to worship God. If a church, as far as the state is concerned, is nothing but a voluntary society of men, then its claim to toleration cannot be based on a claim that it is of divine origin and must be accorded freedom as a requirement of divine law; rather, such a claim must be based solely on the church’s status as a free society whose affairs do not jeopardize civil affairs and on the natural right of men to profess whatever religion they choose.

In his arguments for why the state has no care of souls, Locke already attempted to show that there is no connection between civil affairs and the salvation of souls,[31] inasmuch as jurisdiction over civil affairs demands the use of force, whereas jurisdiction over the salvation of souls does not (and in fact cannot). From the proposition that there is no connection between civil affairs and the salvation of souls, however, it automatically follows that churches cannot concern themselves with politics. Moreover, since the exercise of religion is really the exercise of a natural right, that is, a determination of man’s natural “state of perfect freedom,” religion is a purely individual affair and therefore has no bearing on political life. Therefore, just as the state has no interest in the salvation of souls, so the Church has no interest in affairs of state.

To conclude our discussion of the Letter, let us examine Locke’s attitude toward the Catholic Church. One might think that a Lockean regime would be friendly toward the Catholic Church, since a Lockean regime is governed by the principle of religious toleration, and, after all, the Catholic Church is a religion. Moreover, about two thirds into the Letter, in order to illustrate how religious opinions do not harm civil rights, Locke mentions the belief of Roman Catholics in the Real Presence of Christ in the Eucharist, asserting that even though that belief is false and absurd, Catholics do “no injury” to their neighbors by holding it.[32]

Later, however, Locke makes it clear that there are other reasons which make the Catholic Church an exception to the rule of toleration. There are cases, he says, when churches exist of which the members “arrogate to themselves…some peculiar prerogative covered over with a specious show of deceitful words.”[33] As an example of such a church, Locke mentions one which holds “that faith is not to be kept with heretics” and “that kings excommunicated forfeit their crowns and kingdoms.”[34] Such a church interferes with civil affairs and therefore affairs that are outside the proper domain of religion. Locke is clearly thinking of the Catholic Church here, since he is clearly thinking of those popes who in previous centuries had excommunicated certain European monarchs for persecuting the Church and then declared that their subjects no longer owed them allegiance.

Another exception to the rule of toleration, says Locke, is a church “which is constituted upon such a bottom that all those who enter into it do thereby ipso facto deliver themselves up to the protection and service of another prince.”[35] Here Locke explicitly mentions Islam, the members of which are subject to the Mufti of Constantinople, who is himself subject to the Ottoman Emperor. Locke no doubt has the Catholic Church in mind as well, however, since in addition to being the spiritual head of the Catholic Church, the pope really is the head of a temporal dominion, namely, Vatican City and, at the time of Locke, the Papal States.

It should be emphasized that for Locke to regard the Catholic Church as an exception to the rule of toleration is perfectly consistent with his principles. For even if he is wrong about the subjection of Catholics to a foreign prince, since the pope’s authority as head of Vatican City (and formerly the Papal States) is accidental to his authority as pope, it is still true that when the pope excommunicates a political ruler and absolves that ruler’s subjects of the duty of allegiance toward him, he has become involved in a nation’s political affairs precisely in virtue of his universal solicitude for the salvation of souls, that is, precisely in virtue of his office as pope.[36]

Moreover, an enormous part of Catholic doctrine is concerned with temporal matters—a point that Locke does not make but that certainly strengthens his case. What, for example, are the Church’s teachings on marriage, education, and economics if not teachings that pertain to civil affairs? These considerations should give those Catholics pause who subscribe in principle to an essentially Lockean understanding of Church and State relations but nevertheless demand that the state grant the Church liberty. For the Catholic Church, a Lockean regime can turn out to be just as oppressive as a Hobbesian or Spinozan regime.


[1]         Cf. Thomas Hobbes, Leviathan, ed. Edwin Curley (Indianapolis: Hackett Publishing Company, Inc., 1994) p. 413: “Which second coming not yet being, the kingdom of God is not yet come, and we are not now under any other kings by pact, but our civil sovereigns…This power regal under Christ, being challenged universally by the Pope and in particular commonwealths by assemblies of the pastors of the place (when the Scripture gives it to none but to civil sovereigns), comes to be so passionately disputed that it putteth out the light of nature, and causeth so great a darkness in men’s understanding that they see not who it is to whom they have engaged their obedience.”

Cf. Benedict Spinoza, Theologico-Political Treatise, trans. Martin D. Yaffe (Newburyport, MA: Focus Publishing, R. Pullins Company, 2004), p. 219: “It is shown that the right concerning sacred matters is altogether in the possession of the highest powers, and Religion’s outward worship has to be accommodated to the peace of the Republic if we want to comply with God Properly.”

[2]         I say that this is true more or less. The regimes enumerated do not agree with those theorized about by Hobbes and Spinoza or (obviously) with each other in every respect.

[3]         As examples of this influence on one of the Founding Fathers, consider the following statements from Thomas Jefferson. The resemblance that the thought contained in these statements bears to Lockean thought on Church and state may not be clear in every way right now, but it will no doubt become clear as the thesis proceeds.

“Believing with you that religion is a matter which lies solely between man and his God, that he owes account to none other for his faith or his worship, that the legislative powers of government reach actions only, and not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should ‘make no law respecting an establishment of religion, or prohibiting the free exercise thereof,’ thus building a wall of separation between Church and State” (Letter to the Danbury Baptist Association in The Portable Thomas Jefferson, ed. Merrill D. Peterson (London: Penguin Books, 1983.), p. 303).

“But our rulers can have authority over such natural rights only as we have submitted to them. The rights of conscience we never submitted, we could not submit. We are answerable for them to our God. The legitimate powers of government extend to such acts only as are injurious to others. But it does me no injury for my neighbor to say there are twenty gods, or no God. It neither picks my pocket nor breaks my leg” (Notes on Virginia, Query VII, in The Political Writings of Thomas Jefferson: Representative Selections, ed. Edward Dumbauld (New York: The Liberal Arts Press, 1955), p. 36.

[4]         Pope Leo XIII, Immortale Dei (On the Christian Constitution of States), n. 13.

[5]         Ibid., n. 6.

[6]         Pope Pius IX, Syllabus of Errors, n. 78; also see Quanta Cura (Condemning Current Errors), the encyclical attached to the syllabus.

[7]         Pope Pius XI, Quas Primas (On the Feast of Christ the King), n. 32.

[8]         John Locke, A Letter Concerning Toleration, p. 1.

[9]         Ibid., p. 20.

[10]       This is, of course, under the condition that all religious bodies refrain from interfering in matters outside the proper domain of religion. As will become clear later, there are certain religious bodies which do not refrain from doing so, and therefore, there are exceptions to the rule of toleration.

[11]       Letter, p. 3.

[12]       Ibid.

[13]       Locke, Second Treatise of Government, p. 8.

[14]       Ibid.

[15]       Second Treatise, p. 9.

[16]       Ibid., p. 66.

[17]       There are several texts in the Second Treatise of Government in which Locke speaks as though men leave the state of nature behind when they enter political society. Since, however, in entering political society, men give up certain natural rights in order to enjoy others more securely, it is clear that they only leave the state of nature behind in part.

[18]       Letter, p. 3.

[19]       Ibid.

[20]       Ibid.

[21]       The first three arguments immediately follow Locke’s account of the power and duty of the civil magistrate and are explicitly stated to be arguments for the conclusion that civil power “neither can nor ought in any manner to be extended to the salvation of souls” (p. 3). The fourth argument, however, does not show up till several pages later when Locke treats the duty of the magistrate “in the business of toleration” (p. 8) in greater detail. Moreover, Locke does not explicitly refer to it as a new argument for the said conclusion, even though that is in fact what it is. The structure of the Letter does not always follow the best order.

[22]       Letter, p. 3.

[23]       Ibid.

[24]       Letter, p. 3.

[25]       Ibid., p. 4.

[26]       Letter, p. 18.

[27]       Ibid., p. 4.

[28]         Letter, p. 4.

[29]         Ibid.

[30]         Ibid., p. 16.

[31]       If we wish to keep Locke consistent with himself, the claim that there is no connection between civil affairs and the salvation of souls is not true absolutely, since the practice of religion is a civil interest itself. Nevertheless, the reason that the practice of religion is a civil interest is precisely that it has nothing to do with all other civil interests.

[32]       Letter, p. 15.

[33]       Ibid., p. 17.

[34]       Ibid.

[35]       Ibid., p. 18.

[36]       How this is the case will become clear later.