Hi there, I'm trying to figure out the logic in the construction of the phrase "I don't know him from Adam." I read it means "I don't know him at all" (found a nice explanation here: http://www.worldwidewords.org/qa/qa-ada1.htm) but why "from Adam"? Consider also "I don't know him from Adam's off ox." So the explanation would be: Just as Adam didn't know much about his off ox, I don't know much about this man. Still, how does this fit with the way "know someone from something"? Does "know" in this phrase work like "tell" in "tell an apple from an orange"? How exactly does "I don't know him from Adam's off ox" work then? I found the phrase in one of Raymond Carver's short stories, called "The Calm," which takes place in a barber's shop. Two guys begin to argue. Then, "Take it outside," the fellow with the newspaper said, flushed and hoping for something. "That'll be enough," the barber said. "Charles, I don't want to hear anything more on the subject. Albert, you're next in line. Now." The barber turned to the fellow with the newspaper. "I don't know you from Adam, mister, but I'd appreciate if you wouldn't put your oar in." Thank you!