An inconsistency in The Grand Design by Stephen Hawking

1) While conceding that human behavior is indeed determined by the laws of nature, it also seems reasonable to conclude that the outcome is determined in such a complicated way and with so many variables as to make it impossible in practice to predict. For that one would need a knowledge of the initial state of each of the thousand trillion trillion molecules in the human body and to solve something like that number of equations. That would take a few billion years, which would be a bit late to duck when the person opposite aimed a blow. (Chapter 2 THE RULE OF LAW)

2)
We cannot even solve exactly the equations for three or more particles interacting with each other. Since an alien the size of a human would contain about a thousand trillion trillion particles even if the alien were a robot, it would be impossible to solve the equations and predict what it would do. We would therefore have to say that any complex being has free will-not as a fundamental feature, but as an effective theory, an admission of our inability to do the calculations that would enable us to predict its actions.
(Chapter 8 THE GRAND DESIGN)