A Letter Concerning Toleration

Locke argues that civil government and religious institutions have distinct jurisdictions that must not be conflated. The magistrate's authority extends only to external interests—life, liberty, and property—while the care of souls belongs to each individual and their voluntary church. This rejects the prevailing doctrine that political authority includes the right to enforce religious conformity. Locke's argument is not primarily about the value of diversity but about the limits of political power: the magistrate has no commission to compel belief because belief cannot be compelled by force, and because the magistrate is no more likely to know the true path to salvation than the private person.

Locke explicitly denies toleration to atheists, Catholics, and those who themselves teach intolerance. Atheists are excluded because Locke argues that without belief in a divine lawgiver, promises, covenants, and oaths—the bonds of human society—cannot be trusted to hold. Catholics are excluded on political grounds: Locke claims their allegiance to a foreign sovereign makes them unreliable subjects, a position reflecting contemporary English fears of Catholic political power. The exclusion of the intolerant follows a principle Locke states explicitly: groups that will not extend toleration to others forfeit the right to receive it.

Hobbes saw religious uniformity as essential to civil peace and granted the sovereign authority over public worship, permitting private belief only if outward conformity was maintained. Locke inverts this: religious diversity, not uniformity, is the safer foundation for civil order. For Locke, unrest arises not from tolerating multiple religions but from the magistrate's attempts to suppress them. Where Hobbes subordinated religion to the sovereign's authority, Locke separates the two spheres entirely, arguing that the church's power is persuasive and voluntary, while the magistrate's is coercive and limited to civil interests.

Locke grounds toleration in both rational right and general utility. He argues that each person has a duty to seek their own salvation and cannot legitimately delegate that care to the magistrate, who is no better positioned to know the true religion. This duty implies a right to exercise conscience freely in worship. Simultaneously, Locke appeals to prudence: persecution breeds civil unrest and hypocrisy rather than sincere belief. The Letter's persuasive force lies in this dual structure—toleration is owed as a matter of conscience and is also the only policy consistent with civil peace and the limits of political knowledge.

Locke composed the Letter in Latin while in exile in the Dutch Republic, likely around 1685, following Louis XIV's revocation of the Edict of Nantes, which intensified fears of Catholic persecution across Europe. It was published in 1689 after Locke's return to England. The context matters: the Letter responds to the specific problem of Protestant dissenters facing coercion in England and the broader threat of Catholic absolutism. Locke's exclusions of Catholics and atheists are not philosophical oversights but tactical judgments embedded in this political moment. Reading the Letter as abstract principle misses the strategic logic of its limits.

The Letter was not Locke's final word. An Anglican cleric named Jonas Proast attacked its argument, prompting Locke to write three subsequent Letters on Toleration—published in 1690, 1692, and posthumously in 1704—totaling nearly six hundred pages. In these later writings, Locke elaborated his arguments in response to Proast's objection that coercion could be legitimate if it made people consider the truth. Locke's replies developed a more explicit account of the irrationality of persecution, emphasizing the distinction between force and rational persuasion. These later texts reveal that the original Letter is a compressed manifesto rather than a complete theory.