We can do this by building on what we learned in chapter 2 about how clumps of matter can have emergent properties that are related to information. We saw that for something to be usable as a memory device that can store information, it needs to have many long-lived states. We also saw that being computronium, a substance that can do computations, in addition requires complex dynamics: the laws of physics need to make it change in ways that are complicated enough to be able to implement arbitrary information processing. Finally, we saw how a neural network, for example, is a powerful substrate
...more
