The Fabric of Reality - Chapter 2: Shadows

This week we'll be revisiting chapter 2 of The Fabric of Reality, by David Deutsch. In this chapter, without even invoking the full version of quantum theory, David explores the implications of the behaviour of light and argues that from it alone we may infer the existence of parallel universes.

Please read the chapter, or listen to Brett Hall's corresponding podcast episode, before attending.

Some additional resources:
1 - An interview from 1995 in which David analyses the behaviour of light and what it tells us about the multiverse.

2 - An interview on Closer to Truth in which David explains the logic underpinning the many worlds 'interpretation'.

3 - Richard Feynman's explanation of the double slit experiment, and quantum behaviour more broadly, from the Feynman Lectures. This version of the experiment makes use of electrons rather than light, but the logic of it is essentially the same.

Note that Feynman was writing at a time in which the many worlds 'interpretation' was not widely known or understood, and it was common for physicists to regard quantum theory as abstruse to the point of being outside the domain of full human understanding (an unfortunate cultural phenomenon to which even Feynman was, sadly, not immune).

Nevertheless his writing provides an insightful and rigorous account of why the results of the double slit experiment are deep and surprising to pre-quantum intuitions.

If this is your first time attending we meet in the cafe of the Barbican Cinema, look for people with copies of The Fabric of Reality.