Is Hard to Variate a Good Explanation?

This is not a regular ToKCast (about a chapter from "The Beginning of Infinity"). Instead it will serve in part firstly as a stand alone episode about an esoteric piece of epistemology: what is the function of the experiment in the natural sciences? (As explained by David Deutsch in his paper "The Logic of Experimental Tests particularly Everettian Quantum Theory"). I make many remarks - including many new remarks. The final third or so of this episode is largely devoted to a defense of Popper broadly and his criterion of demarcation in particular. 

Secondly this episode is like an "episode 1a" of Chapter 11 "The Multiverse". This episode contains some useful material for anyone interested in "the quantum multiverse" and its testability. Spoiler alert: it's testable, no matter what others say. 

Sources:

You can find David's Paper "The Logic of Experimental Tests" here

My exposition of that paper is here: http://www.bretthall.org/philosophy-of-science.html

You can download a free pdf copy of Popper's "The Logic of Scientific Discovery" here 

(it's well and truly out of copyright, so feel no guilt about the download!)