The Deutsch Files II

This post is by naval from Naval

Brett Hall and I interview David Deutsch, physicist and author of The Beginning of Infinity. Also see The Deutsch Files I.

The universality of computation and explanation

Naval: So let’s go through The Fabric of Reality—the four theories. Feel free to start wherever you’d like, but the four theories that you think comprise the Theory of Everything and maybe especially what are the biggest things that even peers, colleagues, contemporaries don’t understand or don’t fully appreciate that makes each one of these deeper or perhaps more counterintuitive or more interesting than it might be at first glance. David Deutsch: Well, I don’t know, we can start with computers. As I said in the book, it’s hard actually to speak about any one of those things without mentioning the other three. But if we start with computers, I think there’s something really fundamental that Turing discovered, or rediscovered, because I think that Babbage and Lovelace also understood it, more or less. That’s the universality of computation, that computation is physically universal. So there are several ways of putting this, like a computer can mimic any physical object, or a computer can perform the computations that any other computer can perform. Now putting it the second way, it sounds like it’s a statement about all kinds of different computers and has nothing to do with trees and garages and windows and so on, but actually it has to do with everything. And therefore, people still, even today, are (Read more…)