Re: Why is there something, not nothing?

Scott Erb <scotterb@xxxxxxxxx> wrote:

[...]
First, the impact of observation on quantum phenomena makes it seem
that human behavior does have an impact -- without observation it
seems like all that exists are probabilities.

That's not correct, although this idea has crept into a bunch of
popularizations of quantum mechanics.

First, there is no real argument about the formalism of quantum mechanics,
that is, the equations and the means of using those equations to obtain
predictions. This is not to say that everyone in the field believes those
equations are complete -- a number of very good physicists, ranging from
Penrose to 't Hooft, are looking for extensions or modifications -- but they
will readily admit that so far there is no evidence for any failure of the
existing formalism.

There are certainly debates over the "interpretation" of the formalism,
that is, the way to "picture" or "explain" various objects in the equations.
With a few exceptions that really amount to changes in quantum mechanics,
these interpretations agree on the procedure for obtaining predictions of
the outcomes of experiments, and can't be distinguished except by personal
preference. This doesn't make them worthless -- they suggest interesting
new questions to ask, and might point toward different, distinguishable
ways of extending quantum mechanics -- but none of them is part of quantum
theory itself.

It is also true that some of the interpretations give a special role to
"measurement." This leads to a certain amount of awkwardness, because
it is very hard to specify just what constitutes a measurement, as opposed
to any other interaction. But even in the "measurement" interpretations,
there is generally no special role for "humans." If you read the real physics
literature, and not just the New Age popularizations, you'll see lots of
discussion of macroscopic objects, irreversibility, loss of coherence, and
the like; you will not see anything about human behavior. (There is, in fact,
a famous proof due to von Neumann that in interpretations that involve
"wave function collapse" to go from probabilities to definite outcomes, it
doesn't matter where in a chain of observations you put the collapse. There
is certainly nothing special about the last step of a person looking at the
reading of an instrument.)

Off hand, I can think of one exception to what I've just said. John Wheeler
proposed giving the act of observation a special role in "creating" the
object being observed. But at least when I talked to him about this, and
in the writings on this I've read, he was always very careful to label this
as speculation, not as some inevitable conclusion of quantum mechanics.

Steve Carlip

.

Relevant Pages

  • Re: Why is there something, not nothing?
    ... First, there is no real argument about the formalism of quantum mechanics, ... It is also true that some of the interpretations give a special role to ... you will not see anything about human behavior. ... I don't think I've read any new age interpretations. ...
    (talk.origins)
  • Re: Interpreting Quantum Mechanics
    ... an accurate classification of QM interpretations, then that's a good example of the inaccuracy I predicted above. ... In the first category are mathematically rigorous reformulations that give some insight into the structure of quantum mechanics and suggest possible reasons why quantum mechanics might "have to be true". ... These days the people who say that they subscribe to the Copenhagen interpretation are the people who aren't interested in the whole debate. ... Einstein lost the debate because he was wrong: QM is logically consistent. ...
    (sci.physics)
  • Re: Quantum Mechanics: established fact?
    ... There's a difference between incoherent and distasteful. ... Quantum mechanics is strictly causal. ... There are quite a number of interpretations of quantum mechanics, some of which include hidden variables or hidden determinism, and no consensus in the scientific community that any of them must be the right one. ... They don't have to be scientists to form their own opinions about it. ...
    (sci.physics)
  • Re: Why physicists should pay attention to the mind
    ... In this post I will restrict my comments to one point, relating to the interpretation of Quantum Mechanics. ... namely the debate between ontologists and epistemologists. ... can't talk sensibly about interpretations of quantum mechanics, ... physicists are trained to be epistemologists. ...
    (sci.physics.research)