“Whenever you find yourself getting angry about a difference of opinion, be on your guard; you will probably find, on examination, that your belief is going beyond what the evidence warrants.”

“If an opinion contrary to your own makes you angry, that is a sign that you are subconsciously aware of having no good reason for thinking as you do.”

“The Ten Commandments that, as a teacher, I should wish to promulgate, might be set forth as follows:1- Do not feel absolutely certain of anything.2- Do not think it worth while to proceed by concealing evidence, for the evidence is sure to come to light.3- Never try to discourage thinking for you are sure to succeed.4- When you meet with opposition, even if it should be from your husband or your children, endeavor to overcome it by argument and not by authority, for a victory dependent upon authority is unreal and illusory.5- Have no respect for the authority of others, for there are always contrary authorities to be found.6- Do not use power to suppress opinions you think pernicious, for if you do the opinions will suppress you.7- Do not fear to be eccentric in opinion, for every opinion now accepted was once eccentric.8- Find more pleasure in intelligent dissent than in passive agreement, for, if you value intelligence as you should, the former implies a deeper agreement than the latter.9- Be scrupulously truthful, even if the truth is inconvenient, for it is more inconvenient when you try to conceal it.10- Do not feel envious of the happiness of those who live in a fool’s paradise, for only a fool will think that it is happiness.”

“The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widely spread belief is more likely to be foolish than sensible.”

“The extent to which beliefs are based upon evidence is very much less than believers suppose. Take the kind of action which is most nearly rational: the investment of money by a rich City man. You will often find that his view (say) on the question whether the French franc will go up or down depends upon his political sympathies, and yet is so strongly held that he is prepared to risk money on it.”

“What we firmly believe, if it is true, is called knowledge, provided it is either intuitive or inferred (logically or psychologically) from intuitive knowledge from which it follows logically. What we firmly believe, if it is not true, is called error. What we firmly believe, if it is neither knowledge nor error, and also what we believe hesitatingly, because it is, or is derived from, something which has not the highest degree of self-evidence, may be called probable opinion. Thus the greater part of what would commonly pass as knowledge is more or less probable opinion.”

“The use of self control is like the use of brakes on train. It is useful when you find yourself in wrong direction but merely harmful when the direction is right”