John Locke (1632—1704) was a British philosopher, academic, and medical researcher. His best-known and most influential philosophical works include An Essay Concerning Toleration (1667), An Essay Concerning Human Understanding (1690), and The Reasonableness of Christianity as Delivered in the Scriptures (1695).
In An Essay Concerning Human Understanding, Locke examines the limits of reason, how we know things, and what we can know with certainty. He gives faith a seat at the table, but his emphasis is on human reason and observation. He stops short of saying that faith in divine revelation can provide certainty. For Locke, what we claim to know by faith must always conform to reason: “Faith must be regulated by reason” (Book IV, Chapter XVII, “Of Reason,” section 24). John Locke sets forth the principle that there are some things that could have been revealed by God but that people can also discover on their own. Principles of mathematics and human anatomy are examples of things that can be discovered using human reason. However, there are other things that could never be discovered by human reason, and they must be revealed by God if we are to know them. Locke uses the existence of angels as an example of knowledge we cannot possess except through divine revelation: “We have no certain information, so much as of the existence of other spirits, but by revelation. Angels of all sorts are naturally beyond our discovery; and all those intelligences, whereof it is likely there are more orders than of corporeal substances, are things whereof our natural faculties give us no certain account at all” (An Essay Concerning Human Understanding, Book IV, Chapter III, “Of the Extent of Human Knowledge,” section 27). He does the same with the resurrection from the dead: “That Part of the Angels rebelled against GOD, and thereby lost their first happy state: and that the dead shall rise, and live again: These and the like, being Beyond the Discovery of Reason, are purely matters of Faith; with which Reason has nothing to do” (ibid., Book IV, Chapter XVIII, “Of Faith and Reason, and their Distinct Provinces,” section 8).
Locke promoted reason to a high place in the Christian life. While the content of divine revelation cannot be evaluated by reason, we should use reason to evaluate whether actual divine revelation has taken place. The claim that someone has received revelation should be rationally verified before it is believed. Locke warned against the dangers of “enthusiasm,” which was becoming popular at the time and still expresses itself today in many Christian groups that emphasize emotion and direct personal revelation. Locke warned that the excitement of personal revelation can often overrule the rational faculties and cause some people to believe things that were not actually revealed by God. He also makes this point in The Conduct of the Understanding and the Reasonableness of Christianity. According to Locke, abandoning reason in favor of personal revelation leads to “odd opinions and extravagant actions” (op. cit., Chapter XIX, “Of Enthusiasm,” section 8). Unfortunately, Locke’s warning is unheeded in many churches today, and some engage in all kinds of odd and extravagant actions.
John Locke also put forward arguments for the existence of God and the possibility of miracles. He gives a detailed and convincing argument for God’s existence in Book IV, Chapter X of his Essay Concerning Human Understanding. Locke accepted the miracles recorded in the gospel accounts as things God did to draw our attention to His revelation. See his “Discourse on Miracles,” published posthumously in 1706.
Locke’s considered himself an Anglican until the day he died, but his theology departed from orthodox doctrine. It is fairly certain that Locke did not accept the doctrine of the Trinity. To quote a recent book on Locke, “His Christological reflections and his consideration of Trinitarian issues denote a heterodox, non-Trinitarian conception of the Godhead, which presents both Socinian and Arian elements, although he never expressly denied the Trinity. Irenic and prudential reasons contributed to his choice to avoid public discussion of the Trinitarian dogma” (Lucci, D., John Locke’s Christianity, chapter 5, “The Trinity and Christ,” Cambridge University Press, 2020, p. 134).
At least at one point, Locke accepted the virgin birth (The Reasonableness of Christianity, as Delivered in the Scriptures, from The Works of John Locke in Nine Volumes, Vol. 6, London: Rivington, 1824, 12th ed.). And Locke saw Jesus as the Jewish Messiah who performed miracles. But there is ample proof that Locke rejected the Trinity, so he would not have considered Jesus Christ divine. His theology would be more in line with Unitarianism or Christian liberalism.
John Locke’s most lasting impact upon Christianity came indirectly, from his writings on ethics and government. Locke held that natural law (also expressed in the Golden Rule) teaches us that “being all equal and independent, no one ought to harm another in his life, health, liberty or possessions; for men being all the workmanship of one omnipotent and infinitely wise maker” (The Second Treatise on Government, Chapter II, “Of the State of Nature,” section 6). It was from John Locke that Thomas Jefferson got the ideas he expressed in the Declaration of Independence: “We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.”
The freedom of American society, rooted in the philosophy of John Locke, allowed Christianity to flourish and for Christians to accumulate wealth used to fund mission endeavors worldwide. The American ideals of democracy and tolerance are due in large part to the heavy reliance of the Founding Fathers on the writings of John Locke. To the extent that the United States has been able to sway other governments in the direction of freedom and tolerance, those governments have been more tolerant of Christians within their borders. As American society strays further from the principles articulated by John Locke, Christian morality becomes increasingly intolerable, and Christians become more susceptible to persecution.