Brett: At the beginning of The Fabric of Reality, David Deutsch presents this idea that you don’t need to know every single fact to fundamentally understand everything that can be understood.
He presents this vision that there are four fundamental theories from science and outside science: quantum theory, the theory of computation, evolution by natural selection, and epistemology—which is the theory of knowledge. Together they form the worldview, or lens, through which you can understand anything that can be understood.
Naval: I saw a beautiful video with him on YouTube where he was making the same points. He said, “You don’t have to memorize and know every fact. You don’t have to know where every particle moved. If you understand the deep underlying theories behind everything, then you know at a high level how everything works.” And this can all be understood by a single person, a single brain, a single human being. It’s accessible to anybody.
That is a jaw-droppingly powerful idea. We can have explanations that can reach the entire universe. It’s interesting that the theory of relativity is not in the list of four theories.
Brett: Deutsch regards quantum theory as being deeper than the theory of relativity. It’s not to say that we’re dismissing relativity, but his guess is that quantum theory will be more foundational than the theory of relativity. There’ll be a space-time of the multiverse, and the multiverse is David’s explanation of quantum theory. That’s why relativity doesn’t appear among them.
At some point most physicists expect that we’re going to have a unification of quantum theory and the theory of relativity.