In these modern times people consider an intellectual life, or a life of manual labor, a normal life. A practical man is considered a man of common sense, and common sense reaches no further than its limited boundaries. A practical man is the one who knows best how to guard his material interests in the continual struggle of life. Some call common sense positivism: believing only in all that proves to be real to our senses and in all that can be perceived, felt, and experienced by our mind. For this reason, in spite of great and unceasing progress in the material world, we have closed the door to another world of progress which can only be entered by opening the door to the deeper side of life. By his form and features, by his physical construction, man looks at one side and covers the other side with his own self. Man sees what is before him, but not what is behind him. As he is made so by nature he cannot look into the deeper side, being absorbed in the life on the surface.