Thus the law of nature stands as an eternal rule to all men, legislators as well as others. The rules that they make for other mens actions, must, as well as their own and other mens actions, be conformable to the law of nature, i.e. to the will of God, of which that is a declaration, and the fundamental law of nature being the preservation of mankind, no human sanction can be good, or valid against it.
John LockeAll men are liable to error; and most men are, in many points, by passion or interest, under temptation to it.
John LockeYou shall find, that there cannot be a greater spur to the attaining what you would have the eldest learn, and know himself, than to set him upon teaching it his younger brothers and sisters.
John LockeVague and mysterious forms of speech, and abuse of language, have so long passed for mysteries of science; and hard or misapplied words with little or no meaning have, by prescription, such a right to be mistaken for deep learning and height of speculation, that it will not be easy to persuade either those who speak or those who hear them, that they are but the covers of ignorance and hindrance of true knowledge.
John Locke