AI and cognitive psychology rant (getting more and more OT - tell me if I should shut up)

Stephen Horne steve at ninereeds.fsnet.co.uk
Sun Nov 2 07:11:47 CET 2003


On Sat, 01 Nov 2003 16:28:09 +0100, anton at vredegoor.doge.nl (Anton
Vredegoor) wrote:

>>As should be clear, my understanding of the specifics of quantum
>>theory is extremely limited - but my understanding of general
>>scientific principles isn't too bad. That is why I earlier pointed out
>>that maybe the MWI wouldn't cause me such a problem if it was
>>expressed in some other way - after all, most current theory is so
>>abstract that the explanations should be taken as metaphors rather
>>than reality anyway.
>
>Abstractness doesn't preclude effectiveness, but to try to use
>abstractions to understand the world is foolish since it doesn't work
>the other way around. It's a many to one mapping, as in plotting a
>sinus function on an xy-plane and not being able to find a
>x-coordinate to a certain y-coordinate, while at he same time being
>perfectly able to predict an y-coordinate if given an x-coordinate.

Oh dear, here we go again...

The human brain simply doesn't have the 'vocabulary' to handle
concepts which are outside of our direct experience. 'Gravity' we can
deal with as it is in our everyday direct experience. Space-time
curvature, OTOH, is not - it is an abstract concept (relative to what
we perceive directly) and we can only understand it by relating it to
things that we do understand - metaphor being a very common way of
doing so.

So in the case of space-time curvature, for instance, 'curvature'
itself is a metaphor. It relates to the geometry of a non-Euclidean
space (or rather space-time, in this case). The intuitive meaning of
the word 'curve' relates to shape - in mathematical terms, a locus of
points in space. But the concept of non-Euclidian curvature is not
intended to suggest that the non-Euclidian space exists within some
higher order space. Sometimes it does (e.g. the non-Euclidean space
defined by the surface of the Earth exists within the 3D space of,
well, space ;-) ) but equally, often it does not.

So far as we know, space-time is 'curved' but does not exist in a
higher-order space - it just happens to have a non-Euclidean geometry.
And as that geometry is entirely defined (so far as we currently know)
by the content of space-time (gravity), there is no need to
hypothesise a higher level space. In fact it may not be possible to
create appropriate space-time 'shapes' within any higher order space -
it is certainly possible to define non-Euclidian 2D surfaces that
cannot be implemented using a real surface shape in flat 3D space.

You can point out that there is a specialist definition of the word
'curve' which relates specifically to non-Euclidian geometry, and deny
any connection to earlier meanings of the word 'curve' or to peoples
intuitive sense of what a curve is, but that would be pretty abstruse.
The simple fact is that that word has considerable explanatory power -
it presents an abstract concept in terms that make sense to people,
and which allows them to visualise the concept. That is why the term
'curve' was selected when non-Euclidian geometry was first defined and
studied and, despite the later specialist definition of the word, it
remains relevant - it is still how people understand the geometry of
non-Euclidean spaces and it is still how people understand the concept
of space-time curvature. The real phenomena described by the term
'space-time curvature' simply don't exist in peoples direct
experience.


I have just been through the same point (ad nauseum) in an e-mail
discussion. Yet I can't see what is controversial about my words.
Current theory is abstract (relative to what we can percieve) and we
simply don't have the right vocabulary (both in language, and within
the mind) to represent the concepts involved. We can invent words to
solve the language problem, of course, but at some point we have to
explain what the new words mean.

Thus, as I said, "most current theory is so abstract that the
explanations should be taken as metaphors rather than reality anyway."

The point being that different metaphors may equally have been chosen
to explain the same models - presumably emphasising different aspects
of them - and such explanations may work better for people who can't
connect with the existing explanations. The model would still be the
same, though, just as it remains the same even if you describe it in a
language other than English. The terminology changes, but not the
model.


I get the feeling that there must be some 'ism' relating to metaphor
in physics, and people are jumping to the conclusion that I'm selling
that 'ism'. But seriously, whatever a 'metaphorianist' may be, I am
not one of them.

Read very carefully, and you will note that I said the EXPLANATIONS
should be taken as metaphors - NOT the models themselves.

And yes, a model is distinct from the real thing that it models, but
that is a rather uninteresting point and not one that I would normally
bother commenting on.

As I know from the e-mail discussion that this point can be serially
misunderstood no matter how I state it, I will make one final attempt
to clarify my point as far as I am able and that is it - I am bored to
death with the issue, and have no interest in continuing it. So here
it is...

I don't deny that, for instance, quarks are real. They are just as
real as protons, atoms, molecules, bricks and galaxy clusters. The
fact that the concept of a quark is more than a little abstract
(relative to what humans can experience directly) does not stop it
being real.

The word "curvature" in "space-time curvature" is a metaphor, however.
Space-time does not exist as a locus of points in some higher-order
space. But space-time really does have a non-Euclidean geometry, which
is easier to understand if you visualise it in terms of curvature.
Hence the common ball-on-a-rubber-sheet analogy (the rubber sheet
being an easily understood 2D curved 'space' within a 3D space).

At no time did I say that relativity is a metaphor. The model
described by relativity is real (within limits, as with any model), as
is clear from the fact that it has been proven.

But if you believe you can describe relativity (or equally, quantum
mechanics) in entirely literal terms - at all, let alone in a way that
people can understand it - I'll be very *very* impressed.


I hope that is sufficient to lay that issue to rest, but in any case I
cannot be bothered with it any more. I *HAVE* asked several people IRL
what they thought I meant by that half scentence in case I was going
nuts, and it was clear that they all understood what I meant. This is
not, in other words, an Asperger syndrome based misunderstanding.

I stand by what I said 100%, but I can't write a book explaining every
half-scentence I write. Life is too short.


With appols, BTW, to those who have written rather large books dealing
with my misunderstandings and thus helped me to understand how they
arise. But I really don't think my AS is the problem here.


-- 
Steve Horne

steve at ninereeds dot fsnet dot co dot uk




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