I haven't read the book, but I am assuming it is based on his writings back in February and I am commenting with those writings in mind. The thing that is still puzzling about the second law is that regardless of whether or not the laws are reversible, it is still an open question on if it is possible to have observers in our universe that, to our perspective, are traveling "backwards" in time. What I mean is that it is easy enough to run a tape backwards in time to get this kind of behavior, and similarly, you could extrapolate to simulated minds on a computer running backwards in time from our perspective. The question then becomes, why do I experience time flowing forwards instead of backwards? You could easily say that the observer is actually being resurrected from the dead and then enters the womb, with his memories gradually being erased, but we do not "experience" time in this manner. In this sense, there seems to be a "directionality" to how we perceive time itself. In fact, I do not know if it is possible to experience the reverse, that is being resurrected from the dead, since from our perspective, they are just going about life as usual, in the "forwards" direction. But then what would happen to simulated observers that are running backwards in time? Do they experience time flowing in the reverse direction? Or is such a simulation impossible? Unless, there is a real directionality to time itself, and that the future and past are distinct in this manner. If the future exists, then there would seem to be a valid observer that concludes that he/she is being resurrected from the dead and traveling backwards in time rather than perceiving time in the forwards direction.