In Chapter 9 we discussed the idea of a universal Turing machine. This machine is capable of simulating any other machine given sufficient time and energy. For example, we discussed how your fridge microprocessor could be programmed to run Microsoft Windows, then we described Moore’s logic, that computers are becoming faster and smaller. Therefore, one day, a single atom may be able to simulate fully what a present day PC can do. This leads us to the fascinating possibility that every little constituent of our Universe may be able to simulate any other, given enough time and energy. The Universe therefore consists of a great number of little universal quantum computers. But this surely makes the Universe itself the largest quantum computer. So how powerful is our largest quantum computer? How many bits, how many computational steps? What is the total amount of information that the computer can hold? Since our view is that everything in reality is composed of information, it would be useful to know how much information there is in total and whether this total amount is growing or shrinking. The Second Law already tells us that the physical entropy in the Universe is always increasing. Since physical entropy has the same form as Shannon’s information, the Second Law also tells us that the information content of the Universe can only ever increase too. But what does this mean for us? If we consider our objective to be a full understanding of the Universe then we have to accept that the finish line is always moving further and further away from us. We define our reality through the laws and principles that we establish from the information that we gather. Quantum mechanics, for example, gives us a very different reality to what classical mechanics told us. In the Stone Age, the caveman’s perception of reality and what was possible was also markedly different from what Newton would have understood. In this way we process information from the Universe to create our reality. We can think of the Universe as a large balloon, within which there is a smaller balloon, our reality.