Every once in a while nature gives us insight into the human condition by providing us with a unique case whose special properties illuminate the species as a whole. Christopher is such an example. Despite disabilities which mean that everyday tasks are burdensome chores, Christopher is a linguistic wonder who can read, write, speak, understand and translate more than twenty languages. On some tests he shows a severely low IQ, hinting at ineducability, yet his English language ability indicates an IQ in excess of 120 (a level more than sufficient to enter university). Christopher is a savant,...