Fragments of Thought

This chapter primarily focuses on the first strand of The Fabric of Reality , namely, quantum theory . The main goal of this chapter is to logically, via the axioms established in the first chapter, argue for the existence of parallel universes . The logical reasoning presented in this chapter is worthwhile to read due to its remarkable coherence and internal consistency. The nature of Deutsch's argument is such that it evolves from a seemingly innocent concept to a rather remarkable conclusion. Before getting into the core of his argument, Deutsch sets it up for readers who may not be familiar with quantum theory. First, Deutsch shows, via a thought experiment , that light is not infinitely malleable, in the sense that there is a limit to how thinly light can be spread. He then compares light to a gold sheet and argues that, just like gold, after a certain limit of being beaten, light also gets lumpy. Continuing with the same analogy of gold, he further argues that light is made u...