I haven't seen last night's episode yet. (I wait for the HDTV rebroadcast, on Friday nights.) However, I'm pretty sure he's not a robot. Remember, he was fully examined by a physician. He is therefore surely organic, and at least an almost perfect replica of a human. Indeed, one of the weakest part of the show so far is that they haven't explained what his x-rays showed with regard to where humans have a naval.