Re: Miscellaneous ideas, for what they're worth.
I just liked to remind you the old Greek paradox that demonstrates
rigorously that there cannot exist any sand heap:
Let N be the number of sand grains in the collection:
if N=1, it is not a sand heap.
if you add a single grain to what is not a heap, you cannot transform it
into a heap.
So the proposition is logically demonstrated.
May be you think this has nothing to do with this debate. For me it has. It
demonstrates first that formal logic may be insufficient to handle common
sense. Second that the very large majority of concepts we use don't have a
precise meaning, and most things "are" not intrinsically something or other
thing; "To be AND not to be, that is the question".
(You can easily extend the paradox to any material thing, made of a finite
number of atoms, nothing to say about moral concepts!)
Conciousness, intelligence, memory, knowledge, but also computers, do not
exist by themselves. As we cannot define them properly, we cannot measure
them and tell anything about there *precise* properties. You can try to
define computers as machines handling information, but then how do you
define information?
May be they are many computers scientists who think that the reality *is* a
computation. They are also many theologist that think that the reality was
created by God. But the number of believers has nothing to do with the
pertinence of ideas.
The modern science has begun when scientists have stopped to ask themselves
about the "true" nature of reality. You must accept that physics offers
only a representation of the universe suited for our brain. It does no more
pretend tell anything about the profound nature of it.
Most of you seem to think that a computation can represent adequately the
reality, or better "be" the reality. I think that computations offer only
an approximation of theories, that are themselves approximations of
reality. I must remind you that there is currently no theory of physics
that can assess without contradiction what is a state of the Universe, and
by which kind of object it must be represented. I think you have very hard
time to demonstrate that a state of the Universe is a string of 0 and 1,
that is an integer number.
Those who believe in that seem to forget that behind their computations,
there is a computer made of physical elements! Explaining A with B that
require A seems to me a little bit strange. It's like if you said that
molecules of water are made of water!
Furthermore, once again, a string can be interpreted as something (a word,
the solution of Wheeler-DeWitt equation or anything else) only by an
intelligent observer. It does not contain information per se.
So I'm ready to buy any theory that :
1) is logically consistant
2) allows to make the most precise predictions of what we actually observe.
I really don't see how a set of all possible finite strings (if I don't
mistake, the simple set of integer numbers N), can be used to tell anything
reasonable about the Universe! Physical theories are interesting exactly
because they do the opposite: the *forbid* most things to appear!!
QM is currently very precise, but not logically consistent. MWI adds
logical consistency, but is not yet for me in a state of completion.
À (At) 13:43 +0000 31/01/99, Saj Malhi écrivait (wrote) :
> Let's try to establish a few cogent premisses. I realise you
>probably won't agree with them all, but I'd be interested to know why:
>1]. Consciousness is neither dependent upon nor implied by intelligence
>(a man with Downs' syndrome is no less conscious than a genius).
<GH> : you cannot quantify precisely both of them. You can define many
kinds of intelligence, and there is many states of consciousness. They are
famous "idiots savants", who were totally dumb but could calculate much
more rapidly than ordinary people. Were they intelligent? You cannot deny
that intelligence and consciousness are linked in some way.
>2]. Consciousness is neither dependent upon nor implied by memory (a man
>suffering from amnesia is no less conscious than a man who remembers every
>detail of his life).
cf Hal's answer.
>3]. Consciousness is neither dependent upon nor implied by knowledge (you
>cannot increase your consciousness through memorising the Encyclopaedia
>Britannica).
<GH> : same as 1). You cannot have consciouness without any knowledge. I
don't know what "increase consciouness" means.
> 4]. Consciousness is fundamentally a physical phenomenon since it is
>clearly affected by physical processes (alcohol, injury, sleeping).
<GH> : I agree but, I would personnaly define physical processes by all
what we can observe. So it's a truism.
> Two people make a bet based on the toss of a coin while a third
>unobserved >person looks on discretely from the corner. The probability
>of heads or tails >is fifty-fifty, 0.5. The coin lands heads, one of them
>loses, fair enough. >Having seen this, our voyeur steps out of the
>room, gets in his time machine, >and returns to witness the same event.
>But what are the probabilities of heads >and tails now? Are they still
>fifty-fifty, or are they now 1 and 0 >respectively? This little
>argument seems to pose 3 possible conclusions. 1. >Time travel is
>impossible
<GH> : May be not following general relativity. However if a time machine
exists, it should transport you in a world where you already arrived in the
past. If you don't see you arriving before entering the time machine, it
means that you will not arrive in this world after your trip. This is not
contradictory since in MWI a world has many possible futures. In some of
them you wouldn't see you, and in other you would see you arriving from
future. You need quantum gravity to avoid paradoxes!!
>2. Probability (and therefore our human concept of free will) is an
>illusion >(assuming of course, that someone with a capital S is watching
>over the >proceedings).
<GH> : Free will is an illusion. Apparent probabilities exist for quantum
processes (measure of the spin of an electron), because of different
worlds, that may have different measures. For macroscopic process like the
toss of a coin, 1/2 probability is an illusion because the result is
probably largely determined by unknown macroscopic parameters (state of the
muscles, wind,..).
> 3. There is a fundamental flaw in this line of reasoning. The
>responses I >got (thanks by the way) were based entirely on the MWI which
>said that the >probability remained unchanged.
<GH> :
Not for macroscopic processes. You should choose a much higher probability
for the winning case, unless you think your arrival from future has
strongly perturbed the toss (by the wind it has produced, for example).
Replace the toss by a Stern and Gerlach experiment, then you must keep the
1/2 probability.
>Your view of the 2 to 1 event splitting 3 ways, with 2 identical
>universes is really an equivalent way of looking at it when there are
>only a finite number of outcomes. I don't believe it is a useful
>picture when there is a continuum of outcomes. These answers do not
>seem so clear-cut to me, particularly as there seems to have been so much
>confusion about what 'measure' is. Furthermore, I do not understand the
>notion of 'splits on a continuum'. Either time is discrete (with the unit
>of Planck-length) or it is infinitely divisible. If it is discrete, then
>the MWI seems to limit the splitting process to once every Planck-length.
>However, it is reasonable to suggest that there may be two totally
>different events occurring far away from each other at the same time.
>Does this mean therefore that there are multitude of universes springing
>up at every instant?
> How are simultaneous events integrated into the MWI? On the other hand,
>if time is continuous we are faced with the possibility of an infinite
>number of universes springing up at every instant - a daunting prospect.
>A third possibility which gets around these problems is that time is
>indeed continuous but we define an instant as the time between the two
>most closely separated events ever to occur. This will mean that no two
>events can be simultaneous since we can proceed to the nth decimal place
>along the measure of time to find a difference. Anyway, I've probably
>said enough for now.
<GH>:
The term "many world" is in fact misleading (and has not been used by
Everett). There is only one Universe, whose wavefunction contains as a
superposition an infinite number of macroscopic worlds, as we can perceive
it. The problem of defining what is a macroscopic world (by a suitable
projection operator) has not been solved yet. Although Everett and many
people still visualize the wave function as evolving in time and branching
in many "daughter components", I think it is more probably a stationary
state (with null energy), containing all components at each moment. So time
does not really exist. However, a particular classical subcomponent is
linked to some other called "past(s)" and "future(s)" by the memory of all
recording devices it contains (all kind of clocks, brains...). These
particular links disappear at the Planck scale.
Received on Mon Feb 01 1999 - 02:15:57 PST
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