BBT 5

"A man with only one theory is a lost man."

-Bertolt Brecht

Mr Brecht is claiming that close mindedness leads to a man's downfall. An individual has to be able to look at issues from various perspectives, to open up the mind to others' opinions. One belief is not enough, one perspective  cannot lead to success. One theory, one foundation for one's beliefs and knowledge, is not stable or strong enough. As soon as that foundation is shaken, the knowledge is destroyed and not valid anymore. And at that moment, the man has lost the whole of his knowledge, and he is lost. In that aspect, Brecht may have meant that a man should base his knowledge on more than one theory to obtain a stronger foundation, to have more stability to support his driving force. A man should not constrain to one window of knowledge, to one perspective. A man should be open to the world around him to have a more comprehensive view.