Moreover, the attitude that one ought to believe such and such a proposition, independently of the question whether there is evidence in its favor, is an attitude which produces hostility to evidence and causes us to close our minds to every fact that does not suit our prejudices.

Scientific men get an awkward habit — no, I won't call it that, for it is a valuable habit — of believing nothing unless there is evidence for it; and they have a way of looking upon belief which is not based upon evidence, not only as illogical, but as immoral.

Habit... makes the endurance of evil easy (which, under the name of patience, is falsely honored as a virtue), because sensations of the same type, when continued without alteration for a long time, draw our attention away from the senses so that we are scarcely conscious of them at all. On the other hand, habit also makes the consciousness and the remembrance of good that has been received more difficult, which then gradually leads to ingratitude (a real vice). [...] Acquired habit deprives good actions of their moral value because it undermines mental freedom and, moreover, it leads to thoughtless repetitions of the same acts (monotony), and thus becomes ridiculous.

You humans seem to have a profound capacity for ignoring obvious evidence.

It is a mistake always to contemplate the good and ignore the evil, because by making people neglectful it lets in disaster. There is a dangerous optimism of ignorance and indifference.

To sum up: it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence. If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind, purposely avoids the reading of books and the company of men that call into question or discuss it, and regards as impious those questions which cannot easily be asked without disturbing it--the life of that man is one long sin against mankind.

empirical evidence is frequently ignored when drug policy is formulated.

Do you know what we call opinion in the absence of evidence? We call it prejudice.

In our own inner selves, we find operating the same trio—ignorance, indifference, and carelessness. We are ignorant of our own latent capacities, of the degree of our likeness to God, of the possibilities of our lives. We are indifferent to the higher values and are content to the lower level of physical appetites and pleasures. Even when we recognize to some extent our possibilities and when we seek after a fashion to realize them, we grow careless, become swamped by the temporary, and lose sight of the eternal. ...A lack of appreciation of the intrinsic worth and latent possibilities of every man we meet, indifference to his welfare, and carelessness as to his rights and privileges, prevent us from living on friendly terms with him.

Someone who is determined to disbelieve something can manage to disregard an Everest of evidence for it.

Ignorance of the beautiful, of the good, of the true would make man an amoral being and would make ‘morality’ a word devoid of meaning.

He, who the rules of temperance neglects, From a good cause may produce vile effects.

It is not the facts which guide the conduct of men, but their opinions about facts; which may be entirely wrong. We can only make them right by discussion.

Indifference of every kind is reprehensible, even indifference towards one’s self.