If there is one thing that binds us humans together it is the fact that each one of us has doubt about ourselves in some subjective way. For one reason or the other we get hit with doubt usually at the most inopportune times. Like a baseball player striking out or a bowler getting a 7-10 split. If it happens once, doubt says that it can happen again. Overcoming doubt means that success is possible. It means that humanity has a chance to better itself. We all have that chance.