How rarely it occurs to anyone to use his mind in a new way to make his life a better life. Inquire whether your thinking is true, healthy, necessary, sincere, pleasant. A man who would not eat unhealthy foods not only consumes but welcomes unhealthy thoughts. A good reason for removing errors of thinking is that we will cease to suffer from them. A mind living in a prison of its own making has the ability to become its own key to liberty.