The multiverse, branching, and information

TBoI, p 281

"Thus the information in the fictional multiverse flows along a branching tree, whose branches--histories--have different thicknesses (measures) and never rejoin once they have separated."

I have been disdaining the 'branching' descriptions of the Everettian multiverse, but this makes sense. The universe itself does not branch; but the information flow may. The quantum nature of the universe is critical for this discrete branching, as apposed to a continuous, uncountably infinite branching of information flows that would occur if infinitesimal differences were allowed.

The directionality of this branching is basically the arrow of time itself.

p. 282-283

"In an interference phenomenon, differentiated histories rejoin... Interference is the phenomenon that can provide the inhabitants of the multiverse with evidence of the existence of multiple histories in their world without allowing the histories to communicate."

p. 284-285

"Interference can happen only in objects that are unentangled with the rest of the world... If differential effects can all be undone, then interference between those original values becomes possible again... [but] that rapidly becomes infeasible. The process of becoming infeasible is known as decoherence."

p. 293

"Spheres of differentiation tend to grow at nearly the speed of light, so, on the scale of everyday life and above, those course-grained histories can justly be called 'universes' in the ordinary sense of the word."

p. 300

"All fiction that does not violate the laws of physics is fact."

p. 302

"Whenever we observe anything... what we are actually seeing is a single-universe perspective on a larger object that extends some way into other universes."

"Since the growth of knowledge is a process of error-correction, and since there are many more ways of being wrong than right, knowledge-creating entities rapidly become more alike in different histories than other entities."