Re: Quantum Weirdness

From: Marc Geddes (
Date: Sat Dec 11 2004 - 23:52:28 MST

 --- Patrick Crenshaw <>
> The main problem I see is that the many-worlds thing
> is a
> philosophical solution looking for a problem. There
> are much simpler
> philosophical explanations than many-worlds and it
> is only to the
> extent that they have predictive power that any of
> them are useful. I
> don't think anyone has proposed an experiment that
> would differentiate
> the many-worlds interpretation from the others.

I think that skepticism about MWI comes from a
misunderstanding about what science actually is.

Skeptics tend to regard science as simply a practical
tool for manipulating the world, rather than a method
of *explanation*

MWI is not "a philosophical solution looking for a
problem", it's a metaphysical *conclusion* based on
what our best current theories of the world (QM) are
telling us. The mathematics of QM is *telling us*
that multiple alternative outcomes co-exist with each
other. Since QM makes correct predictions about
things that we *can* observe, there is good and
sufficient reason for trusting it on the things we
can't directly observe.

Now skpetics tend to view the mathematics as simply a
tool or device used to get practical results. So they
don't take the mathematical 'picture' coming from QM
as seriously representing reality, instead regarding
all such pictures as simply existing in human heads.
This is to misunderstand what science is all about.
Science is *not* just a tool for manipulating the
world. It's also about trying to *explain* reality.
I call the mistake the skeptics are making: 'The
Fallacy Of Logical Positivism'. Here is how I
summarized this fallacy:

The Logical Positivist Fallacy

Skeptics about the efficacy of the scientific method
think that the role of reason is simply to describe or
predict directly perceivable things, and abstract
concepts are merely ‘devices’ invented by humans for
this purpose. They regard abstract concepts as models
which don’t represent anything real. This is a
philosophical position known as positivism (also

But the role of reason is not merely to describe or
predict things, it is to explain reality. The nature
of reality is what we are trying to find out. One
cannot presuppose in advance which things should
qualify as being part of ‘observable reality’ and
which are mere ‘mental devices’. Reality is infinite.
 A rational observer will only have a partial
understanding of it at any given time. The very
foundation-head of scientific thought is the idea that
there are things in reality beyond what we currently
understand. The role of reason is to broaden our
understanding of what constitutes reality by
attempting to extrapolate beyond our direct
observations to parts of reality that are currently
hidden to us. Positivists who refuse to grant that
there are as yet unobservable things that exist ‘out
there’ that we are capable of understanding none the
less have prevented themselves from ever finding these
things! This is comparable to a cave man watching
shadows on the wall who thinks that the shadows are
reality and thus doesn’t bother turning his head to
find the source.

A 'realist'(a person who believes in the existence of
objective reality) has to trust the pictures being
suggested by the best avaliable theories of the world
do in fact correspond to actual reality, until proven
underwise. The MWI of QM is the only sensible realist
picture of reality consistent with QM. Therefore the
rational person has to accept it.

> The power of the many-worlds interpretation is
> mostly psychological.
> It seems to me, and is the consensus among the
> people I know who
> understand quantum mechanics, that some people,
> especially when they
> learn it when they are older, just get weirded out
> by quantum
> mechanics. If you look at quotes from physicists who
> were around near
> the birth of quantum mechanics, you'll see this.
> Things like: "No one
> understands quantum mechanics." My friends and I got
> really tired of
> hearing freshmen quote things like this before they
> ever learned
> quantum.
> It is possible to understand quantum mechanics, and
> many people have
> done it without resorting to philosophical nonsense.

We cannot presuppose in advance what the nature of
reality is. The nature of reality is what we are
trying to find out. Therefore we must assume that
there is a reality wider than the one we can currently
directly perceive, and that we can use reason to grasp
these portions of reality currently hidden from us.
In order to make progress, we must trust that the
pictures of reality suggested by our best avaliable
theories are correct, until proven otherwise.

We cannot presuppose the nature of reality in advance.
 Therefore *we cannot be certain* which aspects of
what we currently think of as 'philosophy' may
actually later turn be testable. The history of
science shows that what starts out as philosophy can
later become science. Every thing on the frontier of
knowledge starts out as philosophy But without
philosophical speculation no progress could ever be
made. Later the philosophy gets turned into science,
after a way to test it is found.

In the case of the differing interpretations of QM, it
simply isn't true that they are untestable. David
Deutsch has suggested actual experiments to
distinguish the MWI from other interpretations. And
just recently, Shariar S. Afshar perfromed a variation
of the famous double slit experiment which appears to
disprove "The Copenhagen Intepretation'of QM. So you
see, what started out as philosophy got turned into
science as people later figured out how to test the
different interpretations. But if no one had bothered
doing the philosophy to start with, no progress would
have been made.

For a hugely powerful case for the MWI I recommend you
read the book 'The Fabric Of Reality, by David
Deutsch. That gets my vote as the best science book I
ever read.

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