Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Incidentally, it doesn't interfere with itself - I misspoke. It 
>> interferes with other electrons.
> 
>   What other electrons?

The other electrons in the experiment. You don't get an interference 
pattern from a single electron - that's exactly why people say electrons 
are particles. You get an interference pattern when you average the 
probability of many electrons.

>> Sure, they only go through one at a 
>> time. What was that about time travel?
> 
>   The electron somehow magically knows that in the future more electrons
> will be there and act accordingly?

I don't know. Nobody knows. Except, apparently, you. :-)

> 1) The electron passes through both slits at the same time, interferes
>    with itself, and thus acts according to a logical mathematical formula.

And yet, somehow, whenever you look, it only goes through one slit at a 
time. How does it know?

> 2) Something completely unknown is happening which we can't even begin
>    to theoretize.

Yes, that. Actually, lots of theories. Little progress.

That's what all the "brane" theory and string theory and all that is about.

>   From these two you want me to choose number 2. 

Given the choice between a theory that has copious experimental evidence 
against it, and saying "we don't have a good theory", yes, picking "we 
don't have a good theory" is better.

 > Moreover, you seem to
> be saying that an electron passing through two slits at the same time is
> too hard to believe,

It's not too hard to believe. It's just counter to every experimental 
measurement.

> but things like time travel are completely believable
> and understandable.

Checked to 15 decimal places or so.

> Your reasoning doesn't make too much sense to me.

Common sense doesn't really apply to quantum electrodynamics.

> 
>>  Every time you measure whether it went through both 
>> slits, the answer is "no, there was only one electron."
> 
>   Of course there was only one electron. And yes, measuring messes up
> the electron. So what?

If every time you measure whether it went through both slits, the answer 
is "no", why do you think it ever goes through both slits? Even if you 
measure after it has already passed through the slits?

>> You keep 
>> asserting this, with no evidence other than "I can't think of any other 
>> explanation", along with rejecting both evidence and other explanations.
> 
>   You want me to believe some stories about time-travelling electrons
> instead of thinking that the interference is simply caused by the
> electron going through both slits as if it was a wave. Honestly, what
> do you expect me to believe more, as a rational person?

"You expect me to believe you could just pick up a lump of plastic, rub 
your fingers on it, and magically communicate with someone on the other 
side of the world? What kind of fool do you think I am?"

Quantum physics isn't intuitive. But you don't get to throw out 
experimental evidence just because you can't figure out *why* you get 
those results.

How do you explain electrons going through both slits if, after it goes 
through the slits, you measure which slit it went through, and you 
always get the answer "only one"?

> 
>> Your intuition is confusing you. How does it "know" there's a back 
>> surface to the glass and therefore needs to reflect differently? How 
>> does it "know" there's another electron already "on the way" to where 
>> it's going and hence that position needs to be avoided?
> 
>   What another electron? I don't understand.

Electrons don't interfere with or cancel themselves out. It's a 
probability thing. One flip of a coin doesn't give you a result of "one 
half head and one half tail."

>> Why is it a wave going through both slits but a particle by the time it 
>> gets to the detector?
> 
>   Why do quanta behave both like waves and particles? I don't know.
> It just seems they do.

Then why is it so hard to believe that's true even without it going thru 
both slits?

>>>> Yes. What makes you think that the only *possible* explanation is that 
>>>> the electron passed through both slits?
>>>   What is the other explanation?
> 
>> I don't know, and as far as I understand, nobody else does either. But 
>> all of the evidence so far suggests your interpretation is incorrect.
> 
>   *All* the evidence? Including the interference pattern?

How do you know it went thru both slits? Every time you ask, it only 
goes through one slit. You're saying "the only way you can have an 
interference pattern is for every electron to go through both slits." 
That's an invalid inference.

>   How come a phenomenon which was evidence for the electron passing as
> a wave through both slits has suddenly become evidence of the contrary?

It hasn't. You are mistaken that the only possible explanation is that 
the electron is a wave as it passes through both slits.

>> For example, if you do the same thing with photons, wait for them to go 
>> thru the slits, and after they've already passed through, you either 
>> turn on or off the detector that says which slit they went through, you 
>> always see them only go through one slit when the detector is on, and 
>> always generate interference probabilities when the detector is off. How 
>> do you explain that?
> 
>   I don't know why measuring quanta messes up with their behavior.

So do you believe in time travel or not? Because clearly the decision as 
to whether the electron went thru one slit or both is traveling back in 
time in this experiment, *if* that's what's happening.

>>>   The interference can be explained with the electron passing through both
>>> slits at the same time.
> 
>> Yes.
> 
>   First you say that *all* evidence suggests that the claim is incorrect,
> and now you admit that at least one piece of evidence doesn't.

No. The interference can also be "explained" by God screwing with our 
heads, by intelligent electrons trying to confuse you, or by magic fairy 
dust. None of those are correct either.

How does one determine this? One does experiments that would have 
different results if electrons were intelligent, or if fairies were 
present, and which consistently find negative results. Welcome to science.

>> But that's also at odds with many other experiments. If the 
>> electron goes through both slits, why is it that you never see it go 
>> through both slits when you put a detector behind each slit?
> 
>   I don't know why measuring quanta messes up with their behavior.

But you *do* know that they go through both slits. Interesting.

>> The sun rising can be explained by angels pushing it along, as well,
>   Or electrons travelling in time.

Mmmmm.  The sweet, sweet smell of assertive ignorance.

How come it's reasonable that time isn't comparable everywhere, but that 
subatomic particles can't travel in time?

-- 
   Darren New / San Diego, CA, USA (PST)
     "That's pretty. Where's that?"
          "It's the Age of Channelwood."
     "We should go there on vacation some time."

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