In the last episode I asked the question 'Are we unique?' and then set about showing why it is we are not by looking at the animal kingdom. From tool use to altruism it appears that we are not as special as we might think. But, of all of earth's creatures we seem to be the only species cursed with the ability to ask 'why ?' We alone appear to have the ability to look back into the past to help us to explain the present and to prepare for the future. Is it, as Darwin said, only a matter of degree, or is it something more?