In urging the necessity of a more substantial basis of morals than one built upon a theory of arbitrary dictation, he says: "The worship of a deity who is represented as unfair or unfriendly to any portion of the community is a wrong thing, however great may be the threats and promises by which it is commended. And still worse, the reference of right and wrong to his arbitrary will as a standard, the diversion of the allegiance of the moral sense from the community to him, is the most insidious and fatal of social diseases.... If I let myself believe anything on insufficient evidence, there may be no great harm done by the mere belief; it may be true after all, or I may never have occasion to exhibit it in outward acts. _But I cannot help doing this great wrong toward Man, that I make myself credulous_. The danger to society is not merely that it should believe wrong things, though that is great enough; but that it should become credulous, and lose the habit of testing things and inquiring into them; for then it must sink back into savagery. "The harm which is done by credulity in a man is not confined to the fostering of a credulous character in others, and consequent support of false beliefs. Habitual want of care about what I believe leads to habitual want of care in others about the truth of what is told to me. Men speak the truth to one another when each reveres the truth in his own mind and in the other's mind; but how shall my friend revere the truth in my mind when I myself am careless about it, when I believe things because I want to believe them, and because they are comforting and pleasant? Will he not learn to cry, 'Peace,' to me, when there is no peace? By such a course I shall surround myself with a thick atmosphere of falsehood and fraud, and in that I must live. It may matter little to me, in my cloud-castle of sweet illusions and darling lies; but it matters much to Man that I have made my neighbors ready to deceive. The credulous man is father to the liar.... "We all suffer severely enough from the maintenance and support of false beliefs and the fatally wrong actions which they lead to; and the evil born when one such belief is entertained is great and wide. But a greater and wider evil arises when the _credulous character_ is maintained and supported, when a habit of believing for unworthy reasons is fostered and made permanent.... "The fact that believers have found joy and peace in believing gives us the right to say that the doctrine is a comfortable doctrine, and pleasant to the soul; but it does not give us the right to say that it is true.... "And the question which our conscience is always asking about that which we are tempted to believe is not, 'Is it comfortable and pleasant?' but, 'Is it true?'"