" The earth was a grave: our life was lent to it by its elements and had to be returned: a time came when the simple elements seemed to long for release from the complicated forms of life, when every element of every cell said, " Enough!" The planet was our mother and our burial ground. No wonder the human spirit wished to leave. Leave this prolific belly. Leave also this great tomb. Passion for the infinite caused by the terror, by timor mortis, needed material appeasement. "