The black hole information paradox presents an apparent theoretical contradiction between black hole radiation, which Hawking predicted carries no information about its past, and quantum theory, which conserves information at all times. The common sense belief would be that information is conserved, perhaps because there is something measurable inside a black hole and not a singularity.
Maybe I should have said that the ideas in the article are an approach to resolving the paradox, rather than invoking common sense.
> The common sense belief would be that information is conserved
I'll say it once more, since you didn't seem to understand my point the first time: "information is conserved" is not a "commonsense belief". (Unless you mean "commonsense within the quantum mechanics community".)
Commonsense is "I've seen a shredder. I know information can be destroyed."
Ok, well, would you expect a shredded book to be indistinguishable from a shredded bowl of jello, or a shredded pot of coffee, or a shredded parcel of ionized plasma?
But a shredder doesn't actually destroy information.
Back to the original discussion, though: Time and again I'm fascinated by the fact that it's the quantum mechanics community that believes in unitarity / information being preserved so strongly. After all, the collapse of the wave function violates unitarity, too.
> But a shredder doesn't actually destroy information.
See, people keep talking about the "common sense" idea. Well, in the common sense view, yes, a shredder actually does destroy information, because you can't read the page any longer. The "common sense" people don't have any notion of information in the quantum sense, or unitarity, or waveform collapse, or any of that stuff.
"Common sense" does not mean "common sense among postgrads in quantum mechanics". Those are two completely different things.
The "common sense" level is probably something like, black holes exist, and maybe some notion that something called "quantum mechanics" exists. Most people don't have any kind of "common sense" about the details.
Oh I didn't mean to say a shredder not destroying information was common sense. Maybe I just didn't like this particular example too much because I think even for non-physicists it's still imaginable someone could – in theory – piece together the shredded paper again.
Maybe I should have said that the ideas in the article are an approach to resolving the paradox, rather than invoking common sense.