RE: Quantum theory of measurement

From: Jesse Mazer <lasermazer.domain.name.hidden>
Date: Wed, 12 Oct 2005 20:11:16 -0400

Ben Goertzel wrote:

>My own understanding is that whether Fred, a pigeon or a printer is
>involved
>in the experiment should be basically irrelevant. That is, I don't think
>"registration in consciousness" (whatever that means) is the important
>thing, but rather registration in the sense of "statistical correlation
>with some macroscopic system effectively obeying classical probability
>theory." However, I realize that not everyone agrees with me on this; my
>reading of Penrose, for instance, is that he would predict a different
>outcome for 2 versus 1, because he believes that Fred's brain (via
>unspecified quantum gravity related effects) does something special to
>collapse the wave function, which the printer does not.

By the way, I also wanted to point out that this actually isn't Penrose's
position, although given his unusual views about the relationship between
consciousness and QM it's a pretty common misunderstanding. It's been a
while since I read his book, but my memory is that Penrose advocates a
"gravitationally-induced collapse" view where the wavefunction of an
entangled system spontaneously collapses once it exceeds a certain threshold
in mass (due to interactions with the outside world which result in more and
more particles becoming entangled with the original system), which he
speculates is likely to be around the Planck mass, about 5*10^-8 kg (close
to the mass of a flea). He also speculates that the theory of quantum
gravity which deals with this may be noncomputable, and that the human brain
may somehow take advantage of such noncomputable effects to solve problems
that could not be solved by a computational system.

The "consciousness collapses the wavefunction" view has been advocated by a
few serious physicists like Eugene Wigner, and of course by lots of new-agey
types.

Jesse
Received on Wed Oct 12 2005 - 20:12:42 PDT