Often a person says, "I am stupid, I cannot think," and when he has said this several times naturally he becomes stupid. Sometimes he says it out of modesty, humility, or politeness; but this virtue will prove to be a sin. Also, many have lost their memory through suggestion. When they have forgotten something, which is a natural thing for a human being to do, they repeat to themselves, "How stupid! How forgetful on my part!" and that idea repeated twice or thrice deepens their forgetfulness.