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

[Michele Simionato]

Stephen Horne <steve at ninereeds.fsnet.co.uk> wrote in message news:<ff7tpvknjm2fa99ab6068lilthn8h0dmhr at 4ax.com>...
> Not exactly. When we look at superpositions of subatomic particles,
> there are observable artifacts of the interactions between
> superpositions - the interference patterns. Without those
> interactions, the theory of superpositions would be pointless as there
> would be no effects of superposition to observe - the theory would
> have no predictive or explanatory power.
> 
> My point is that the cat is superposed in the same way as the
> subatomic particle, and yet we are unable to observe any artifact of
> that superposition. *All* we can see is a single state resulting from
> the waveform collapse when we observe the cat, but this is
> emphatically not the case with subatomic particles where we can
> observe artifacts of the superposition itself.
> 

There is no such a big difference between the Scroedinger's cat experiment
and the narrow slits experiment:


               |           | 
               |           |
                 A         | S
 P             |           |
 ->            |           |
                 B         |
               |           |
               |           |

The particle P passes through one of the slits A,B and ends its life on the 
screen S, producing a spot. Getting the spor corresponds to opening the box in
the cat experiment. If you repeat the experiment many times 
with many particles, the distribution of the spots is an interference 
pattern. But if you perform the experiment with a single particle, then
you have 50% of probability of getting the spot in the upper side of the 
screen, and 50% in the lower side (assuming a symmetrical experimental
disposition). This corresponds to have the cat  50% of times alive
and 50% of times dead when we open the box. Having only seen the spot in S, 
it does not make sense to ask whether the particle passed through A or through 
B, exactly in the same sense that it does not make sense to ask if the cat 
is dead or alive before opening the box (this according to the
orthodox interpretation). If you watch to see if the particle really passes 
for A you necessarely perturb the system. For instance, you can close the 
slit B, and make sure that the particle passes trought A, but then the 
interference disappear.
When the particle reach S and you get the spot, then the collapse
of the wave function happens. It is less spectacular than opening
the box, but in principle it is the same operation. I will not
claim that the collapse is understood, not that it is an easy
task to understand it :-(

                     Michele Simionato