Sean Carroll in Preposterous Universe:
Which is why I become sad when people continue to misunderstand it. And even sadder when they misunderstand it for what are — let’s face it — obviously wrong reasons. The particular objection I’m thinking of is:
MWI is not a good theory because it’s not testable.
It has appeared recently in this article by Philip Ball — an essay whose snidely aggressive tone is matched only by the consistency with which it is off-base. Worst of all, the piece actually quotes me, explaining why the objection is wrong. So clearly I am either being too obscure, or too polite.
I suspect that almost everyone who makes this objection doesn’t understand MWI at all. This is me trying to be generous, because that’s the only reason I can think of why one would make it. In particular, if you were under the impression that MWI postulated a huge number of unobservable worlds, then you would be perfectly in your rights to make that objection. So I have to think that the objectors actually are under that impression.
An impression that is completely incorrect.
More here.