John Locke: how to think

From Locke’s Of the Conduct of the Understanding (published 1706).

“11. Indifferency.— First, he must not be in love with any opinion, or wish it to be true till he knows it to be so; and then he will not need to wish it; for nothing that is false can deserve our good wishes, nor a desire that it should have the place and force of truth; and yet nothing is more frequent than this. Men are fond of certain tenets upon no other evidence but respect and custom, and think they must maintain them or all is gone, though they have never examined the ground they stand on, nor have ever made them out to themselves or can make them out to others. We should contend earnestly for the truth, but we should first be sure that it is truth, or else we fight against God, who is the God of truth, and do the work of the devil, who is the father and propagator of lies; and our zeal, though ever so warm, will not excuse us, for this is plainly prejudice.

“12. Examine.—Secondly, he must do that which he will find himself very averse to, as judging the thing unnecessary, or himself incapable of doing it. He must try whether his principles be certainly true or not, and how far he may safely rely upon them. This, whether fewer have the heart or the skill to do, I shall not determine, but this I am sure is that which everyone ought to do who professes to love truth, and would not impose upon himself, which is a surer way to be made a fool of than by being exposed to the sophistry of others. The disposition to put any cheat upon ourselves works constantly, and we are pleased with it, but are impatient of being bantered or misled by others. The inability I here speak of, is not any natural defect that makes men incapable of examining their own principles. To such, rules of conducting their understandings are useless, and that is the case of very few. The great number is of those whom the ill habit of never exerting their thoughts has disabled; the powers of their minds are starved by disuse and have lost that reach and strength which nature fitted them to receive from exercise. Those who are in a condition to learn the first rules of plain arithmetic, and could be brought to cast up an ordinary sum, are capable of this, if they had but accustomed their minds to reasoning; but they that have wholly neglected the exercise of their understandings in this way, will be very far at first from being able to do it, and as unfit for it as one unpracticed in figures to cast up a shop-book, and perhaps think it as strange to be set about it. And yet it must nevertheless be confessed to be a wrong use of our understandings to build our tenets (in things where we are concerned to hold the truth) upon principles that may lead us into error. We take our principles at haphazard upon trust, and without ever having examined them, and then believe a whole system upon a presumption that they are true and solid: and what is all this but childish, shameful, senseless credulity?

“In these two things, viz., an equal indifferency for all truth—I mean the receiving it, the love of it, as truth, but not loving it for any other reason, before we know it to be true—and in the examination of our principles, and not receiving any for such, nor building on them, till we are fully convinced as rational creatures of their solidity, truth, and certainty, consists that freedom of the understanding which is necessary to a rational creature, and without which it is not truly an understanding. It is conceit, fancy, extravagance, anything rather than understanding, if it must be under the constraint of receiving and holding opinions by the authority of anything but their own, not fancied, but perceived evidence. This was rightly called imposition and is of all others the worst and most dangerous sort of it. For we impose upon ourselves, which is the strongest imposition of all others, and we impose upon ourselves in that part which ought with the greatest care to be kept free from all imposition. The world is apt to cast great blame on those who have an indifferency for opinions, especially in religion. I fear this is the foundation of great error and worse consequences. To be indifferent which of two opinions is true, is the right temper of the mind that preserves it from being imposed on, and disposes it to examine with that indifferency till it has done its best to find the truth; and this is the only direct and safe way to it. But to be indifferent whether we embrace falsehood or truth is the great road to error. Those who are not indifferent which opinion is true are guilty of this; they suppose, without examining, that what they hold is true, and then think they ought to be zealous for it. Those, it is plain by their warmth and eagerness, are not indifferent for their own opinions, but methinks are very indifferent whether they be true or false, since they cannot endure to have any doubts raised or objections made against them, and it is visible they never have made any themselves; and so never having examined them, know not, nor are concerned, as they should be, to know whether they be true or false.

“These are the common and most general miscarriages which I think men should avoid or rectify in a right conduct of their understandings, and should be particularly taken care of in education. The business whereof in respect of knowledge, is not, as I think, to perfect a learner in all or any one of the sciences, but to give his mind that freedom, that disposition, and those habits that may enable him to attain any part of knowledge he shall apply himself to, or stand in need of, in the future course of his life.

“This, and this only, is well principling, and not the instilling a reverence and veneration for certain dogmas under the specious title of principles, which are often so remote from that truth and evidence which belongs to principles that they ought to be rejected as false and erroneous, and often cause men so educated when they come abroad into the world and find they cannot maintain the principles so taken up and rested in, to cast off all principles, and turn perfect skeptics, regardless of knowledge and virtue.”