Contributed by Taylor Yu Zhong, Reader's Digest, July, 1996, p. 66
Robert, an experienced sky diver, was readying himself for a jump when he spotted another man outfitted to dive wearing dark glasses, carrying a white cane and holding a seeing-eye dog by a leash. Shocked that the blind man was also going to jump, Robert struck up a conversation, expressing his admiration for the man's courage. Then curious, he asked, "How do you know when the ground is getting close?"
"Easy," the blind man replied. "The leash goes slack."