“This is the basic answer to the question of why we see the particular worlds that we do: the preferred-basis states are those that describe coherent objects in space, because such objects interact consistently with their environments. These are often called pointer states, as they are the states in which the pointer of a macroscopic measuring device will indicate a definite value, rather than being in a superposition. The pointer basis is where a well-behaved classical approximation makes sense, and therefore it’s that kind of basis that defines emergent worlds. Decoherence is the phenomenon that ultimately links the austere simplicity of Everettian quantum mechanics to the messy particularity of the world we see.”