An important aspect of psychology is attitude of mind. The mind takes a certain attitude, and then the whole world comes under the shadow of this attitude. If one has a fear, a doubt, or a suspicion it becomes the attitude of the mind, and everything that one sees one begins to suspect, to fear, or to doubt, and, as Sa'di says, every brain may have a little of it. One never knows when one changes one's attitude. Life is an intoxication; whatever happens to be a person's attitude, it is according to that attitude that he looks at life. He may be the most thoughtful, wise, qualified, and learned man there is, but if he happens to have one of these attitudes of fear, doubt, or suspicion, the whole world will become the subject for proving to him the truth of whatever he has at the back of his mind. This does not mean that things and people in the world actually become what he fears; what happens is that first the shadow of his mind falls on them, and then the action of the shadow convinces him of the rightness of his doubt, of the truth of his suspicion, and of the reality of his fear. In other words, his doubt, his suspicion, or his fear becomes like a living entity before him.