Locke was not historicist. He based liberalism squarely on a doctrine of natural, not historical rights. Very astutely, Areshidze remarks that the argument for religious toleration made by Locke in his 1689 Letter on Toleration differs from his argument in the Essay Concerning Human Understanding, which he was writing at the same time. The Letter “bases toleration on a religious argument about the sanctity of human conscience” as each individual searches for “religious truth.” The Essay “grounds toleration on the limits of human knowledge”—on a form of skepticism. The Letter rests on an appeal to the prevailing opinion of the time, relying on Biblical exegesis; the Essay relies on reason alone. One book is “popular,” the other “philosophic.”
Not that the Biblical exegesis Locke propounds in the Letter fully comports with the prevailing Christian orthodoxy of his time—or indeed with the teaching of the Bible itself. Mutual toleration among Christians is alleged to be “the chief characteristic of a true church,” although the New Testament attests to love, not toleration. When Locke does testify to the fact of Christian lovingkindness, he makes it serve toleration and good works.
Crucially, in enlisting the support of Paul’s Epistle to the Galatians, Locke accurately quotes Paul as to sins not to be tolerated by Christians—“works of the Flesh,” generally—but leaves out such Pauline sins as “seditions and heresies”—works of the mind, as it were. It was dissenters’ public declarations of such spiritual sins that persuaded Augustine, Thomas Aquinas, and John Calvin to enlist governments in the task of suppressing the full range of un-Christian acts; Aquinas went so far as to urge the death penalty for heretics. (Perhaps glancing back at Rawls and Obama, Areshidze describes this as a “nearly uninterrupted Christian consensus”—bad news indeed for Rawlsian liberals.)
To this Locke replies in the Letter that coercion can never genuinely persuade, and that only a persuaded soul can enter Heaven through the strait gate. But in the Essay Locke admits that, on the contrary, beliefs are indeed formed by a mixture of coercion and consent. There, he argues not from the Bible but from what later writers would call epistemology: the Bible speaks of “knowing” God, but what is knowledge?