John Locke

All men are liable to error; and most men are, in many points, by passion or interest, under temptation to it.

Whoever goes beyond this measure of assent, it is plain receives not the truth in the love of it; loves not truth for truth's sake, but for some other bye-end.

there are very few lovers of truth, for truth's sake, even amongst those who persuade themselves that they are so.

He that would seriously set upon the search of truth, ought in the first place to prepare his mind with a love of it. For he that loves it not, will not take much pains to get it; nor be much concerned when he misses it.

Religion, which should most distinguish us from the beasts, and ought most particularly elevate us, as rational creatures, above brutes, is that wherein men often appear most irrational, and more senseless than beasts.

these are so few in number, and find so little reason to be magisterial in their opinions, that nothing insolent and imperious is to be expected from them: and there is reason to think, that, if men were better instructed themselves, they …

The necessity of believing without knowledge, nay often upon very slight grounds, in this fleeting state of action and blindness we are in, should make us more busy and careful to inform ourselves than constrain others.

It is one thing to show a man that he is in error, and another to put him in possession of the truth.

False and doubtful positions, relied upon as unquestionable maxims, keep those who build on them in the dark from truth. Such are usually the prejudices imbibed from education, party, reverence, fashion, interest, et cetera.

He that knows anything, knows this, in the first place, that he need not seek long for instances of his ignorance."

I doubt not, but from self-evident Propositions, by necessary Consequences, as incontestable as those in Mathematics, the measures of right and wrong might be made out.

He that uses words without any clear and steady meaning, what does he but lead himself and others into errors? And he that designedly does it, ought to be looked on as an enemy to truth and knowledge.

He that uses his words loosely and unsteadily will either not be minded or not understood.

Since sounds have no natural connection with our ideas ... the doubtfulness and uncertainty of their signification ... has its cause more in the ideas they stand for than in any incapacity there is in one sound more than another to signify …

The boundaries of the species, whereby men sort them, are made by men.

Preference of vice to virtue, a manifest wrong judgment.

No man's knowledge here can go beyond his experience.

There cannot any one moral Rule be propos'd, whereof a Man may not justly demand a Reason.

I have always thought the actions of men the best interpreters of their thoughts.

New opinions are always suspected, and usually opposed, without any other reason but because they are not already common.

This life affords no solid satisfaction, but in the consciousness of having done well, and the hopes of another life.

If Papists can be supposed to be as good subjects as others, they may be equally tolerated... If all subjects should be equally countenanced, & imployd by the Prince. the Papist[s] have an equall title.

Discourse of Port de Set with P. & Mr. [blank] at Petit Paris, & the teaching biding to cheat the Hugenots: Nulla fides servanda cum Hereticis, nisi satis validi sunt ad se defendendos [faith need not be kept with heretics].

Reading furnishes the mind only with materials of knowledge; it is thinking that makes what we read ours.