“But simply to possess the power like a bird to fly from one peak to another would not bring to us additional or higher experience. No height was ever gained that was worth the gaining without toil and effort, and if the walker were presented by the good fairy with a pair of wings, I think he would … refuse them. He would prefer to walk or climb to the mountain top, to experience all the physical pleasure of well-being, and obtain a true equipoise of mind and spirit to register the varied emotions which through the sense of vision are transmitted to the sense of feeling.”