One afternoon I got a phone call from a professor of engineering who said he wanted to assign a problem for his students–they were to build a robotic guide dog. “What?” he wanted to know, “does a guide dog do?”
“Well,” I said, “they’re trained to guide blind people along sidewalks and stop at curbs–both the down curb and the up curb.”
“Check,” he said.
“They’re also trained to stop for stairs.”
“Check.”
“In addition,” I said, “they must account for the combined width of the dog-human team–they won’t squeeze through a narrow space just because they might navigate it if they were on their own. They stop and search for another way.”
“Check,” he said. I could tell he was feeling pretty good about his chances. He probably had some experience with the Mars rover program.
“But here’s the kicker,” I said. “Guide dogs are trained in a thing called ‘intelligent disobedience’. When a blind person thinks its safe to cross the street he or she issues the ‘forward’ command. And if the dog thinks its unsafe it won’t move. It may even back up.”
“Oh,” he said. “Oh.” He was silent for a time and then said: “I guess we’ll have to come up with something else.”
Planet of the Blind 