I did not finish this one. The whole premise seems to hinge on the idea that you can just arbitrarily reorder the steps of a deterministic computation. This clearly is not possible in general and the book does not even try to come up with an excuse why it should be possible in their setting. Am I just supposed to suspend my belief for that? It then goes on to expound lots of philosophy based on this premise, but it all rings rather hollow for me given that the lynch pin is so ridiculous.