 Dawkins addresses this point in his debate with John Lennox over "The God Delusion", saying that it would be perfectly reasonable to infer from artifacts on earth or another planet that an intelligence existed, but that you would still need to explain that intelligence, which evolution does, while for God's existence there is no such explanation.Alister McGrath suggests that the leap from the recognition of complexity to the assertion of improbability is problematic, as a theory of everything would be more complex than the theories it would replace, yet one would not conclude that it is less probable.Dawkins has responded to this point in his debate with Lennox and at other times, saying that while physics is hard to understand, fundamentally, unlike biology, it is simple.