Nature exists for man, not man for Nature ; but if she exists for him, it is to teach him to transcend her, to make him ever more of a man, raising each generation above its predecessor. To do this she must awaken the energy and forethought that are in him, compel him to study that he may know, to imitate that he may prevail. And for this reason Nature, in order that she may be beneficent, must be inexorable in her laws.