John Locke, An Essay Concerning Human Understanding

"Liberty is not an Idea belonging to Volition, or preferring; but to the Person having the Power of doing, or forbearing to do, according as the Mind shall chuse or direct."

"[M]an is not permitted without censure to follow his own thoughts in the search of truth, when they lead him ever so little out of the common road."

"One unerring mark of the love of truth is not entertaining any proposition with greater assurance than the proofs it is built upon will warrant."

"It is therefore worthwhile, to search out the bounds between opinion and knowledge; and examine by what measures, in things, whereof we have no certain knowledge, we ought to regulate our assent, and moderate our persuasions."

"For where is the man that has incontestable evidence of the truth of all that he holds, or of the falsehood of all he condemns; or can say that he has examined to the bottom all his own, or other men's opinions? 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."