The Fabric of Reality: The Science of Parallel Universes--and Its Implications

by David Deutsch

However, there is a question we can still ask. Suppose that someone were imprisoned in a small, unrepresentative portion of our own reality — for instance, inside a universal virtual-reality generator that was programmed with the wrong laws of physics. What could such prisoners learn about our external reality? At first sight, it seems impossible that they could discover anything at all about it. It may seem that the most they could discover would be the laws of operation, i.e. the program, of the computer that operated their prison. But that is not so! Again, we must bear in mind that if the prisoners are scientists, they will be seeking explanations as well as predictions. In other words, they will not be content with merely knowing the program that operates their prison: they will want to explain the origin and attributes of the various entities, including themselves, that they observe in the reality they inhabit. But in most virtual-reality environments no such explanation exists, for the rendered objects do not originate there but have been designed in the external reality.