If I were to give a software analogy, I would say Deutsch's proposal is like trying to describe physics by specifying it in terms of the data types that the "co

If I were to give a software analogy, I would say Deutsch's proposal is like trying to describe physics by specifying it in terms of the data types that the "code" of the physical equations satisfy. Instead of saying the "underlying implementation code" is what is fundamental in physics, he is suggesting that the types are fundamental. And the way to figure out what the code is doing is to figure out the types because the types are what ultimately constrain the code. His view would be something like every possible set of implementation code that satisfies the types is in fact instantiated in the multiverse. Therefore figuring out the fundamental layer of physics means figuring out the types because they are what define the multiverse.