John Locke

“ Knowing is seeing, and if it be so, it is madness to persuade ourselves that we do so by another man’s eyes, let him use ever so many words to tell us that what he asserts is very visible. Till we ourselves see it with our own eyes and perceive it by our own understandings, we are as much in the dark and as void of knowledge as before, let us believe any learned author as much as we will. ”

“ Universality.—I do not here speak against the taking a taste of every sort of knowledge; it is certainly very useful and necessary to form the mind; but then it must be done in a different way and to a different end. Not for talk and vanity to fill the head with shreds of all kinds, that he who is possessed of such a frippery may be able to match the discourses of all he shall meet with, as if nothing could come amiss to him, and his head was so well stored a magazine that nothing could be proposed which he was not master of, and was readily furnished to entertain anyone on. ”

“ There is a correspondence in things, and agreement and disagreement in ideas, discernible in very different degrees, and there are eyes in men to see them if they please; only their eyes may be dimmed or dazzled, and the discerning sight in them impaired or lost. Interest and passion dazzle; the custom of arguing on any side, even against our persuasions, dims the understanding, and makes it by degrees lose the faculty of discerning clearly between truth and falsehood, and so of adhering to the right side. ”

“ I do not expect that by this way the assent should in everyone be proportioned to the grounds and clearness wherewith every truth is capable to be made out, or that men should be perfectly kept from error; that is more than human nature can by any means be advanced to; I aim at no such unattainable privilege: I am only speaking of what they should do, who would deal fairly with their own minds, and make a right use of their faculties in the pursuit of truth; we fail them a great deal more than they fail us. ”

“ This distinct gradual growth in knowledge is firm and sure; it carries its own light with it in every step of its progression in an easy and orderly train; than which there is nothing of more use to the understanding. And though this perhaps may seem a very slow and lingering way to knowledge, yet I dare confidently affirm, that whoever will try it in himself, or anyone he will teach, shall find the advances greater in this method, than they would in the same space of time have been in any other he could have taken. ”

“ This is that science which would truly enlarge men’s minds were it studied or permitted to be studied everywhere with that freedom, love of truth, and charity which it teaches, and were not made, contrary to its nature, the occasion of strife, faction, malignity, and narrow impositions. I shall say no more here of this, but that it is undoubtedly a wrong use of my understanding to make it the rule and measure of another man’s, a use which it is neither fit for nor capable of. ”

“ This being objected on all sides, it is agreed that it is a fault and a hindrance to knowledge. What now is the cure? No other but this, that every man should let alone others’ prejudices and examine his own. Nobody is convinced of his by the accusation of another; he recriminates by the same rule, and is clear. The only way to remove this great cause of ignorance and error out of the world is, for everyone impartially to examine himself. ”

“ This has been the less taken notice of because every one in his private affairs uses some sort of reasoning or other enough to denominate him reasonable. But the mistake is that he that is found reasonable in one thing is concluded to be so in all, and to think or to say otherwise is thought so unjust an affront and so senseless a censure that nobody ventures to do it. It looks like the degradation of a man below the dignity of his nature. ”

“ To turn to the business in hand, the end and use of a little insight in those parts of knowledge which are not a man’s proper business, is to accustom our minds to all sorts of ideas, and the proper ways of examining their habitudes and relations. This gives the mind a freedom, and the exercising the understanding in the several ways of inquiry and reasoning which the most skillful have made use of, teaches the mind sagacity and wariness, and a suppleness to apply itself more closely and dexterously to the bents and turns of the matter in all its researches. ”

“ They have a pretty traffic with known correspondents, in some little creek; within that they confine themselves, and are dexterous managers enough of the wares and products of that corner with which they content themselves, but will not venture out into the great ocean of knowledge, to survey the riches that nature hath stored other parts with, no less genuine, no less solid, no less useful than what has fallen to their lot, in the admired plenty and sufficiency of their own little spot, which to them contains whatsoever is good in the universe. ”

“ Fashion, discipline, and education have put eminent differences in the ages of several countries: and made one generation much differ from another in arts and sciences: but truth is always the same; time alters it not, nor is it the better or worse for being of ancient or modern tradition. Many were eminent in former ages of the world for their discovery and delivery of it; but though the knowledge they have left us be worth our study, yet they exhausted not all its treasure; they left a great deal for the industry and sagacity of after-ages, and so shall we. ”

“ But common or uncommon are not the marks to distinguish truth or falsehood, and therefore should not be any bias to us in our inquiries. We should not judge of things by men’s opinions, but of opinions by things. The multitude reason but ill, and therefore may be well suspected, and cannot be relied on, nor should be followed as a sure guide; but philosophers who have quitted the orthodoxy of the community and the popular doctrines of their countries have fallen into as extravagant and as absurd opinions as ever common reception countenanced. ”

“ Let not men, therefore, that would have a sight of what everyone pretends to be desirous to have a sight of, truth in its full extent, narrow and blind their own prospect. Let not men think there is no truth but in the sciences that they study, or books that they read. To prejudge other men’s notions, before we have looked into them, is not to show their darkness, but to put out our own eyes. ”

“ Nature commonly lodges her treasure and jewels in rocky ground. If the matter be knotty and the sense lies deep, the mind must stop and buckle to it, and stick upon it with labor and thought and close contemplation, and not leave it till it has mastered the difficulty and got possession of truth. ”

“ It were better indeed to be without such impertinent and useless repetitions: any obvious idea, when it is roving carelessly at a venture, being of more use, and apter to suggest something worth consideration, than the insignificant buzz of purely empty sounds. But since the rousing of the mind, and setting the understanding on work with some degree of vigor, does for the most part presently set it free from these idle companions, it may not be amiss whenever we find ourselves troubled with them, to make use of so profitable a remedy that is always at hand. ”

“ Stones and timber grow of themselves, but yet there is no uniform pile with symmetry and convenience to lodge in without toil and pains. God has made the intellectual world harmonious and beautiful without us; but it will never come into our heads all at once; we must bring it home piecemeal, and there sect it up by our own industry, or else we shall have nothing but darkness and a chaos within, whatever order and light there be in things without us. ”

“ This is the effect of ignorance and not knowledge, the being vainly puffed up with a flatulency arising from a weak and narrow comprehension. It is not amiss that everyone should relish the science that he has made his peculiar study; a view of its beauties and a sense of its usefulness carry a man on with the more delight and warmth in the pursuit and improvement of it. ”

“ Those who have read of everything are thought to understand everything too, but it is not always so. Reading furnishes the mind only with materials of knowledge, it is thinking makes what we read ours. We are of the ruminating kind, and it is not enough to cram ourselves with a great load of collections; unless we chew them over again they will not give us strength and nourishment. There are indeed in some writers visible instances of deep thoughts, close and acute reasoning, and ideas well pursued. The light these would give would be of great use if their reader would observe and imitate them ”

“ By this one easy and unheeded miscarriage of the understanding, sandy and loose foundations become infallible principles, and will not suffer themselves to be touched or questioned; such unnatural connections become by custom as natural to the mind as sun and light, fire and warmth go together, and so seem to carry with them as natural an evidence as self-evident truths themselves. And where then shall one with hopes of success begin the cure? Many men firmly embrace falsehood for truth ”

“ He that is strongly of any opinion must suppose (unless he be self-condemned) that his persuasion is built upon good grounds, and that his assent is no greater than what the evidence of the truth he holds forces him to, and that they are arguments, and not inclination or fancy, that make him so confident and positive in his tenets. Now if, after all his profession, he cannot bear any opposition to his opinion, if he cannot so much as give a patient hearing, much less examine and weigh the arguments on the other side, does he not plainly confess it is prejudice governs him? ”

“ Sometimes they will stick a long time at a part of a demonstration, not for want of will and application, but really for want of perceiving the connection of two ideas that, to one whose understanding is more exercised, is as visible as anything can be. The same would be with a grown man beginning to study mathematics, the understanding for want of use often sticks in every plain way, and he himself that is so puzzled, when he comes to see the connection wonders what it was he stuck at in a case so plain. ”