Dirty Secrets of…Quantum Foundations: Matt Leifer at the 5th FQXi Meeting

_{Updated on 11 November 2016.} Video of Matt Leifer's' talk is now up. More video is available on FQXi's youtube channel.

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From 20 August 2016:

Audio from Matt Leifer's talk from the FQXi meeting has now been posted here (video of this, and all other talks from the meeting will follow). If you've been following our essay contests over recent years, you'll know that Leifer tends to place highly, and usually has something both profound and entertaining to say. His talk in the "Dirty Secrets" session lived up to expectations.

Leifer's main target in his talk was the Copenhagen interpretation of quantum mechanics, which he says most physicists subscribe to (though there were doubts expressed about that in the room). I'm wary of attempting to define what it is because a large part of Leifer's argument is that there is no consistent definition. But it's the interpretation attributed to a bunch of quantum theory's founding fathers -- and the one that physicists are often taught at school. It says that before you look, a quantum object is described by a wavefunction that encompasses a number of possibilities (a particle being here and there, a cat being dead and alive), and that when you look, this collapses into definiteness. Schrödinger's equation allows you to calculate the probability of the outcome of a quantum experiment, but you can't really know, and probably shouldn't even worry about, what's happening before you look.

On top of that, Leifer argues that Copenhagen-like interpretations, rather than being the most sensible option (as is often claimed), are actually just as whacky as, for instance, the Many World's Interpretation.

More to follow soon.