Locke on reason and revelation

John Locke was the major English philosopher of the Enlightenment. I'll be quoting from his Essay Concerning Human Understanding:

A forwardness to dictate another's beliefs, from whence. The assuming an authority of dictating to others, and a forwardness to prescribe to their opinions, is a constant concomitant of this bias and corruption of our judgments. For how almost can it be otherwise, but that he should be ready to impose on another's belief, who has already imposed on his own? Who can reasonably expect arguments and conviction from him in dealing with others, whose understanding is not accustomed to them in his dealing with himself? Who does violence to his own faculties, tyrannizes over his own mind, and usurps the prerogative that belongs to truth alone, which is to command assent by only its own authority, i.e. by and in proportion to that evidence which it carries with it (4.19.2).

Immediate revelation is a much easier way for men to establish their opinions and regulate their conduct than the boring and not always successful labour of strict reasoning. So it is no wonder that some people have claimed to have received revelations, and have persuaded themselves that they are under the special guidance of heaven in their actions and opinions, especially in opinions that they can’t account for by the ordinary methods of knowledge and principles of reason. Thus we see that in all ages men in whom melancholy has mixed with devotion, or whose self-importance has led them to think they have a greater familiarity with God than others and are more favoured by him than others are, have often flattered themselves with the conviction that they are in immediate communication with the Deity and receive frequent messages from the Divine Spirit (4.19.5).

Once their minds have been prepared in this way, any baseless opinion that comes to settle itself strongly on their imaginations is ·taken by them to be· an illumination from the spirit of God. And when they find themselves strongly inclined to perform some strange action, they conclude that this impulse is a call or direction from heaven, and must be obeyed (4.19.6).

These men accept a certain proposition as true because they presume that God revealed it. So oughtn’t they to examine what grounds they have for presuming that? If they don’t, their confidence is only presumption, and this ‘light’ they are so dazzled with is nothing but a will-o’-the-wisp that leads them constantly round in this circle: it is a revelation because they firmly believe it, and they believe it because it is a revelation (4.19.10).

Reason and faith not opposite, for faith must be regulated by reason. There is another use of the word reason, wherein it is opposed to faith: which, though it be in itself a very improper way of speaking, yet common use has so authorized it, that it would be folly either to oppose or hope to remedy it. Only I think it may not be amiss to take notice that, however faith be opposed to reason, faith is nothing but a firm assent of the mind: which, if it be regulated, as is our duty, cannot be afforded to anything but upon good reason; and so cannot be opposite to it. He that believes without having any reason for believing, may be in love with his own fancies; but neither seeks truth as he ought, nor pays the obedience due to his Maker, who would have him use those discerning faculties he has given him, to keep him out of mistake and error. He that does not this to the best of his power, however he sometimes lights on truth, is in the right but by chance; and I know not whether the luckiness of the accident will excuse the irregularity of his proceeding (4.17.24).

i) Here he's assailing "enthusiasts". These were the 17C counterpart to modern-day charismatics. And his strictures are applicable to many modern-day charismatics. 

ii) However, his strictures overlook the possibility that some contemporary Christians might enjoy veridical private revelations. Not just spiritual impressions, but something for which there's corroborative evidence, viz. a premonitory dream. 

Thus, someone who takes away reason to make way for revelation puts out the light of both—like persuading a man to put out his eyes so that he can better to receive the remote light of an invisible star through a telescope! (4.19.4).

That's pithy and quotable. And it's applicable to fideists. But it depends on how Locke defines and relates the concepts of reason and revelation, faith and knowledge. 

These are two wholly distinct ways by which truth comes into the mind: what I see I know to be so by the evidence of the thing itself; what I believe I take to be so upon the testimony of someone else. But I must know that this testimony has been given, for otherwise what ground have I for believing? (4.19.10).

This is a crucial Lockean distinction. He dichotomizes faith and knowledge. Knowledge is something we know from firsthand experience whereas faith is something we believe based on testimonial evidence. Faith falls short of knowledge. At best, faith is warranted opinion. 

But why is testimonial evidence necessarily inferior to sensory evidence? Both are fallible. And there are cases in which testimonial evidence can correct our sensory misimpressions or misinterpretations of sensory impressions. Likewise, memory is fallible. 

So if you don’t want to give yourself up to all the extravagances of delusion and error, you must make critical use of this guide of your light within. God, when he makes the prophet, doesn’t unmake the man. He leaves all his faculties in their natural state so that he can judge whether his inspirations are of divine origin. When he illuminates the mind with supernatural light, he doesn’t extinguish the light that is natural. If he wants us to assent to the truth of a proposition, he either makes its truth evident by the usual methods of natural reason, or else makes it known to be a truth which wants us to assent to because of his authority, and convinces us that it is from him by some marks that reason can’t be mistaken about. Reason must be our last judge and guide in everything. I don’t mean that we must consult reason and use it to· examine whether a proposition revealed from God can be justified by natural principles and reject it if it can’t. But we must consult it and use it to examine whether the proposition in question is a revelation from God. And if reason finds that it is revealed by God, reason then declares in its favour as much as it does for any other truth, and makes it one of her own dictates. If we have nothing by which to judge our opinions except the strength with which we have them, every thought thrown up by a heated imagination will count as an inspiration. If reason can’t examine their truth of our opinions by some external standard, inspirations will have the same measure as delusions, and truth the same as falsehood, and there will be no way to distinguish one from the other (4.19.14).

This may be true as Locke defines reason and revelation, but the problem is that "reason" can be a euphemism for opinion or certainty. Yet certitude is not the same thing as knowledge. The most intellectually gifted representatives of the Enlightenment era had wildly divergent views regarding what reason could prove or disprove, viz. Bach, Baxter, Bentley, Berkeley, Butler, Descartes, Edwards, Euler, Gill, Handel, Hume, Johnson, Kant, Leibniz, Mather, Milton, Newton, Owen, Pascal, Racine, Reid, Rutherford, Spinoza, Swift, Voltaire, Wesley.

Thus we see the holy men of old, who had revelations from God, had something else besides that internal light of assurance in their own minds, to testify to them that it was from God. They were not left to their own persuasions alone, that those persuasions were from God, but had outward signs to convince them of the Author of those revelations. And when they were to convince others, they had a power given them to justify the truth of their commission from heaven, and by visible signs to assert the divine authority of a message they were sent with. Moses saw the bush burn without being consumed, and heard a voice out of it: this was something besides finding an impulse upon his mind to go to Pharaoh, that he might bring his brethren out of Egypt: and yet he thought not this enough to authorize him to go with that message, till God, by another miracle of his rod turned into a serpent, had assured him of a power to testify his mission, by the same miracle repeated before them whom he was sent to. Gideon was sent by an angel to deliver Israel from the Midianites, and yet he desired a sign to convince him that this commission was from God. These, and several the like instances to be found among the prophets of old, are enough to show that they thought not an inward seeing or persuasion of their own minds, without any other proof, a sufficient evidence that it was from God; though the Scripture does not everywhere mention their demanding or having such proofs (4.19.15).

There's some truth to that, although there's no evidence that all biblical prophets received miraculous confirmation of their revelations. Conversely, Locke doesn't address the possibility that contemporary Christians might have corroboration for their "revelations". 

For whatsoever truth we come to the clear discovery of, from the knowledge and contemplation of our own ideas, will always be certainer to us, than those which are conveyed to us by traditional revelation. For the knowledge we have, that this revelation came at first from God, can never be so sure, as the knowledge we have from the clear and distinct perception of the agreement or disagreement of our own ideas; v.g. if it were revealed some ages since, that the three angles of a triangle were equal to two right ones, I might assent to the truth of that proposition, upon the credit of the tradition, that it was revealed; but that would never amount to so great a certainty, as the knowledge of it, upon the comparing and measuring my own ideas of two right angles, and the three angles of a triangle. The like holds in matter of fact, knowable by our senses; v. g. the history of the deluge is conveyed to us by writings, which had their original from revelation: and yet nobody, I think, will say he has as certain and clear a knowledge of the flood, as Noah that saw it; or that he himself would have had, had he then been alive and seen it. For he has no greater assurance than that of his senses, that it is writ in the book supposed writ by Moses inspired: but he has not so great an assurance that Moses writ that book, as if he had seen Moses write it. So that the assurance of its being a revelation is less still than the assurance of his senses (4.18.4).

i) By "traditional revelation," he means the transmission of revelation–in contrast to the firsthand experience of the original recipient. One problem with his dichotomy is failure to consider the possibility of contemporary confirmation for biblical revelation. Take answered prayer. A Christian prays to the Christian God, based on Bible promises. If the answer is unmistakable, then that's independent of whatever miracles, if any, originally attested a biblical prophet. Similarly, Locke antedates Biblical archeology, which often provides independent corroboration for the historicity (or prophecies) of Scripture.

ii) If, moreover, God has indeed chosen to reveal himself and rule his people by means of "traditional revelation," then should it not rank higher than Locke rates it? 

But yet nothing, I think, can, under that title, shake or over-rule plain knowledge; or rationally prevail with any man to admit it for true, in a direct contradiction to the clear evidence of his own understanding. For since no evidence of our faculties, by which we receive such revelations, can exceed, if equal, the certainty of our intuitive knowledge, we can never receive for a truth any thing that is directly contrary to our clear and distinct knowledge: v. g. the ideas of one body, and one place, do so clearly agree, and the mind has so evident a perception of their agreement, that we can never assent to a proposition, that affirms the same body to be in two distant places at once, however it should pretend to the authority of a divine revelation: since the evidence, first, that we deceive not ourselves, in ascribing it to God; secondly, that we understand it right; can never be so great, as the evidence of our own intuitive knowledge, whereby we discern it impossible for the same body to be in two places at once. And therefore no proposition can be received for divine revelation, or obtain the assent due to all such, if it be contradictory to our clear intuitive knowledge. Because this would be to subvert the principles and foundations of all knowledge, evidence, and assent whatsoever: and there would be left no difference between truth and falsehood, no measures of credible and incredible in the world, if doubtful propositions shall take place before self-evident; and what we certainly know give way to what we may possibly be mistaken in. In propositions therefore contrary to the clear perception of the agreement or disagreement of any of our ideas, it will be in vain to urge them as matters of faith. They cannot move our assent, under that or any other title whatsoever. For faith can never convince us of any thing that contradicts our knowledge. Because though faith be founded on the testimony of God (who cannot lye) revealing any proposition to us; yet we cannot have an assurance of the truth of its being a divine revelation, greater than our own knowledge: since the whole strength of the certainty depends upon our knowledge that God revealed it, which in this case, where the proposition supposed revealed contradicts our knowledge or reason, will always have this objection hanging to it, viz. that we cannot tell how to conceive that to come from God, the bountiful Author of our being, which, if received for true, must overturn all the principles and foundations of knowledge he has given us; render all our faculties useless; wholly destroy the most excellent part of his workmanship, our understandings; and put a man in a condition, wherein he will have less light, less conduct than the beast that perisheth. For if the mind of man can never have a clearer (and perhaps not so clear) evidence of any thing to be a divine revelation, as it has of the principles of its own reason, it can never have a ground to quit the clear evidence of its reason, to give a place to a proposition, whose revelation has not a greater evidence than those principles have (4.18.5).

i) In a sense, what he says is irrefutable. True by definition. But that's an artifact of how he frames the alternatives. He has no category for revelation as a rational norm. No room for the possibility that revelation might function as a standard of comparison to correct fallible reason. Indeed, divine revelation is higher reason–divine reason! A disclosure of divine reason to man. In that respect, revelation has a superior rational pedigree than unaided reason. 

ii) There is, of course, the question of how to verify revelatory claimants. In that regard, there's a symbiotic relationship between reason and revelation. Reason evaluates revelation while revelation underwrites reason.