To AC -- on electrons
Zoe
exist. Here's why:
Even though electrons are not themselves observable, they apparently
have properties that can be observed. Some of these properties are
charge, spin, velocity, energy, position, and so on. By observation
of these properties, and through experimentation, scientists find it
reasonable to extrapolate the existence of the electron, and I accept
their extrapolation based on solid experiments.
It is also just as reasonable to extrapolate the existence of the
photon. While neither the electron nor the photon can be observed,
they are evident through their interaction with matter.
Or take the wind. "Who has seen the wind? Neither you nor I, but
when the trees bow down their heads, the wind is passing by." A
simple childhood poem, but the same principle of extrapolation is
involved here. The existence of something called "wind" is evidenced
by its activity.
In the same way, I extrapolate the existence of Intelligence in nature
-- through observing the properties of mental activity as reflected in
nature.
Now, again, I ask you, why did you ask me that question?
John Harshman
> AC, sorry about the delay. You had asked me why I think electrons
> exist. Here's why:
>
> Even though electrons are not themselves observable, they apparently
> have properties that can be observed. Some of these properties are
> charge, spin, velocity, energy, position, and so on. By observation
> of these properties, and through experimentation, scientists find it
> reasonable to extrapolate the existence of the electron, and I accept
> their extrapolation based on solid experiments.
>
> It is also just as reasonable to extrapolate the existence of the
> photon. While neither the electron nor the photon can be observed,
> they are evident through their interaction with matter.
I would have thought that photons would be the only things we actually
can observe. But I suppose that what we really observe are nerve
impulses, or the pictures they summon up in our heads, eh?
> Or take the wind. "Who has seen the wind? Neither you nor I, but
> when the trees bow down their heads, the wind is passing by." A
> simple childhood poem, but the same principle of extrapolation is
> involved here. The existence of something called "wind" is evidenced
> by its activity.
>
> In the same way, I extrapolate the existence of Intelligence in nature
> -- through observing the properties of mental activity as reflected in
> nature.
Except that the inferences you draw are not validly connected to your
observations. This is a problem.
> Now, again, I ask you, why did you ask me that question?
Bet I know. He was trying to get you to agree that we can make reliable
inferences about things we can't observe directly. And so we know that
electrons exist, and in the same manner we know that radioactivity
exists, and that nuclides decay in predictable ways, and that the rocks
they are embedded in are frequently millions or billions of years old.
Same sort of inference, yet you accept one but not the other. And the
difference is that one doesn't threaten your religious beliefs, but the
other does.
Ian H Spedding
[...]
> In the same way, I extrapolate the existence of Intelligence in nature
> -- through observing the properties of mental activity as reflected in
> nature.
The only intelligence for which we have any evidence at all is our own,
so we can only infer the products of design in nature where they are
similar enough to our own artefacts. In other words, as has been
pointed out many times before, it is an argument from analogy, and an
argument from analogy is only as good as the extent to which the two
cases being compared are similar.
The human eye, for example, has some similarities to the video cameras
we design. There is an iris to control the amount of light admitted to
the interior of the eye, there is a lens to focus the image-forming
light and photoreceptors in the retina which transduce the light into
electrical signals transmitted through the nervous system to the brain
for processing.
On the other hand, the eye is not constructed of glass, metal and
plastic. The image formed by the eye's lens is usable but optically
much inferior to that produced by modern camera lenses. The verted
arrangement of the retina has blood vessels and nerves between the
photoreceptors and the incoming light but, as far as I am aware, no
digital camera has wiring running in front of the CCD.
There is no question that the human visual system works very well but,
while the eye has some things in common with a camera, it differs in
others. And, crucially, those differences are evidence that the eye,
viewed as a design, lacks the optimality which a human designer would
try to achieve and which, by extension, we could reasonably expect a
more advanced alien designer to aim for as well.
The fact is, the only "intelligence in nature" we know of for sure is
what we have here on this planet, in other words, human artefacts.
But, since we did not design what we see in the natural world around
us, it must have been the product either of alien designers or of
natural processes. We have, as yet, no evidence for the existence of
alien designers so it is more reasonable to infer that what we see in
nature is the outcome of natural processes suc as evolution.
Ian
--
Ian H Spedding
Denis Loubet
"Zoe" <muz...@aol.com> wrote in message
news:nf6k82t8e0lubttp1...@4ax.com...
> AC, sorry about the delay. You had asked me why I think electrons
> exist. Here's why:
If they didn't, I'd be looking at a blank monitor screen.
--
Denis Loubet
dlo...@io.com
http://www.io.com/~dloubet
http://www.ashenempires.com
NashtOn
> Zoe wrote:
>
>> AC, sorry about the delay. You had asked me why I think electrons
>> exist. Here's why:
>>
>> Even though electrons are not themselves observable, they apparently
>> have properties that can be observed. Some of these properties are
>> charge, spin, velocity, energy, position, and so on. By observation
>> of these properties, and through experimentation, scientists find it
>> reasonable to extrapolate the existence of the electron, and I accept
>> their extrapolation based on solid experiments.
>>
>> It is also just as reasonable to extrapolate the existence of the
>> photon. While neither the electron nor the photon can be observed,
>> they are evident through their interaction with matter.
>
> I would have thought that photons would be the only things we actually
> can observe. But I suppose that what we really observe are nerve
> impulses, or the pictures they summon up in our heads, eh?
You don't see photons, Harshman. Just like you can't see electrons when
you've just touched a live wire and feel the current going through your
body.
It's that like must be comprised of photons, since it *behaves* as if it
does, some of the time, when it doesn't behave as a wave.
>
>> Or take the wind. "Who has seen the wind? Neither you nor I, but
>> when the trees bow down their heads, the wind is passing by." A
>> simple childhood poem, but the same principle of extrapolation is
>> involved here. The existence of something called "wind" is evidenced
>> by its activity.
>>
>> In the same way, I extrapolate the existence of Intelligence in nature
>> -- through observing the properties of mental activity as reflected in
>> nature.
>
> Except that the inferences you draw are not validly connected to your
> observations. This is a problem.
>
>> Now, again, I ask you, why did you ask me that question?
>
> Bet I know. He was trying to get you to agree that we can make reliable
> inferences about things we can't observe directly. And so we know that
> electrons exist, and in the same manner we know that radioactivity
> exists, and that nuclides decay in predictable ways, and that the rocks
> they are embedded in are frequently millions or billions of years old.
> Same sort of inference, yet you accept one but not the other. And the
> difference is that one doesn't threaten your religious beliefs, but the
> other does.
If you're trained in biology, no wonder you can't be adequately rigorous
in your definition of terms in the real sciences, such as physics.
>
--
Nicolas
"And, heaving alljawbreakical expressions out of Sare Isaac's universal
of specious aristmystic unsaid, A is for Anna like L is for liv."
Finnegans Wake (293)
".... It means that all living things are the product of mindless
material forces such as chemical laws, natural selection, and random
variation. So God is totally out of the picture, and humans (like
everything else) are the accidental product of a purposeless universe.
Do you wonder why a lot of people suspect that these claims go far
beyond the available evidence?" Phillip E.Johnson, The Church Of Darwin
Kleuskes & Moos
NashtOn schreef:
> John Harshman wrote:
> > Zoe wrote:
> >
> >> AC, sorry about the delay. You had asked me why I think electrons
> >> exist. Here's why:
> >>
> >> Even though electrons are not themselves observable, they apparently
> >> have properties that can be observed. Some of these properties are
> >> charge, spin, velocity, energy, position, and so on. By observation
> >> of these properties, and through experimentation, scientists find it
> >> reasonable to extrapolate the existence of the electron, and I accept
> >> their extrapolation based on solid experiments.
> >>
> >> It is also just as reasonable to extrapolate the existence of the
> >> photon. While neither the electron nor the photon can be observed,
> >> they are evident through their interaction with matter.
> >
> > I would have thought that photons would be the only things we actually
> > can observe. But I suppose that what we really observe are nerve
> > impulses, or the pictures they summon up in our heads, eh?
>
> You don't see photons, Harshman.
Then what _do_ do see, Oh great Grandpoobah, if it isn't the photons?
> Just like you can't see electrons when you've just touched a live wire and feel the current going
> through your body.
>
> It's that like must be comprised of photons, since it *behaves* as if it
> does, some of the time, when it doesn't behave as a wave.
Huh? Care to elucidate on that?
<snip>
> If you're trained in biology, no wonder you can't be adequately rigorous
> in your definition of terms in the real sciences, such as physics.
And biology isn't a real science in what sense exactly? And if biology
isn't that what is?
Might I also inqquire what exactly your credentials are? Since if you
make claims like that, surely you _have_ mastered real sciences like
physics.
Shane
I'm betting he can't, as fascinating as it would be to see him try.
snip
NashtOn
> NashtOn schreef:
>
>> John Harshman wrote:
>>> Zoe wrote:
>>>
>>>> AC, sorry about the delay. You had asked me why I think electrons
>>>> exist. Here's why:
>>>>
>>>> Even though electrons are not themselves observable, they apparently
>>>> have properties that can be observed. Some of these properties are
>>>> charge, spin, velocity, energy, position, and so on. By observation
>>>> of these properties, and through experimentation, scientists find it
>>>> reasonable to extrapolate the existence of the electron, and I accept
>>>> their extrapolation based on solid experiments.
>>>>
>>>> It is also just as reasonable to extrapolate the existence of the
>>>> photon. While neither the electron nor the photon can be observed,
>>>> they are evident through their interaction with matter.
>>> I would have thought that photons would be the only things we actually
>>> can observe. But I suppose that what we really observe are nerve
>>> impulses, or the pictures they summon up in our heads, eh?
>> You don't see photons, Harshman.
>
> Then what _do_ do see, Oh great Grandpoobah, if it isn't the photons?
You see light. You perceive it through your retina, after it has
stimulated specialized nerve endings that excite specific regions of the
brain in the OC.
Then the whole shebang is processed through associative areas of the brain.
Nobody has actually seen photons, no more than nobody has actually seen
protons or neutrinos, even though they are abundant.
HTH
>
>> Just like you can't see electrons when you've just touched a live wire and feel the current going
>> through your body.
>>
>> It's that like must be comprised of photons, since it *behaves* as if it
>> does, some of the time, when it doesn't behave as a wave.
>
> Huh? Care to elucidate on that?
Do your own research. If you can't understand the dual nature of light,
you need to take up high school physics.
>
> <snip>
>
>> If you're trained in biology, no wonder you can't be adequately rigorous
>> in your definition of terms in the real sciences, such as physics.
>
> And biology isn't a real science in what sense exactly? And if biology
> isn't that what is?
Physics, chemistry, geology etc.
>
> Might I also inqquire what exactly your credentials are? Since if you
> make claims like that, surely you _have_ mastered real sciences like
> physics.
I know quite a it about about physics and obviously a heck of a lot more
than the schmucks that can't differentiate between seeing light,
perceiving darkness and photons and how the latter serves to explain the
nature of the beast.
r norman
wrote:
>
>NashtOn schreef:
>
>> John Harshman wrote:
>> > Zoe wrote:
>> >
>> >> AC, sorry about the delay. You had asked me why I think electrons
>> >> exist. Here's why:
>> >>
>> >> Even though electrons are not themselves observable, they apparently
>> >> have properties that can be observed. Some of these properties are
>> >> charge, spin, velocity, energy, position, and so on. By observation
>> >> of these properties, and through experimentation, scientists find it
>> >> reasonable to extrapolate the existence of the electron, and I accept
>> >> their extrapolation based on solid experiments.
>> >>
>> >> It is also just as reasonable to extrapolate the existence of the
>> >> photon. While neither the electron nor the photon can be observed,
>> >> they are evident through their interaction with matter.
>> >
>> > I would have thought that photons would be the only things we actually
>> > can observe. But I suppose that what we really observe are nerve
>> > impulses, or the pictures they summon up in our heads, eh?
>>
>> You don't see photons, Harshman.
>
>Then what _do_ do see, Oh great Grandpoobah, if it isn't the photons?
>
NashtOn is certainly an idiot but that doesn't me he can't
accidentally have an ounce of truth in what he posts. John Harshman
got it right in saying that we claim to "see" is really the result of
nerve activity. We just as easily "see" electrical stimulation of the
retina, the optic nerve, or visual regions of the brain. And even if
you want to argue that we really do "see" light, that doesn't mean we
actually observe photons. I "feel" the keys underneath my fingers as
I type but that doesn't mean that I am detecting individual atoms on
the keyboard. The more accurate statement is Zoe's: "While neither
the electron nor the photon can be observed they are evident through
their interaction with matter.". Even "photographs" of atoms are not
direct observation. They are representations of the way that atoms
interact with highly specialized and elaborate machinery presented in
a graphical form.
John Harshman
> John Harshman wrote:
>
>>Zoe wrote:
>>
>>
>>>AC, sorry about the delay. You had asked me why I think electrons
>>>exist. Here's why:
>>>
>>>Even though electrons are not themselves observable, they apparently
>>>have properties that can be observed. Some of these properties are
>>>charge, spin, velocity, energy, position, and so on. By observation
>>>of these properties, and through experimentation, scientists find it
>>>reasonable to extrapolate the existence of the electron, and I accept
>>>their extrapolation based on solid experiments.
>>>
>>>It is also just as reasonable to extrapolate the existence of the
>>>photon. While neither the electron nor the photon can be observed,
>>>they are evident through their interaction with matter.
>>
>>I would have thought that photons would be the only things we actually
>>can observe. But I suppose that what we really observe are nerve
>>impulses, or the pictures they summon up in our heads, eh?
>
>
> You don't see photons, Harshman.
Then what exactly do you see?
[snip]
>
> If you're trained in biology, no wonder you can't be adequately rigorous
> in your definition of terms in the real sciences, such as physics.
Silly Nashton.
John Harshman
> On 10 Jun 2006 05:08:35 -0700, "Kleuskes & Moos" <kle...@xs4all.nl>
> wrote:
>
>
>>NashtOn schreef:
>>
>>
>>>John Harshman wrote:
>>>
>>>>Zoe wrote:
>>>>
>>>>
>>>>>AC, sorry about the delay. You had asked me why I think electrons
>>>>>exist. Here's why:
>>>>>
>>>>>Even though electrons are not themselves observable, they apparently
>>>>>have properties that can be observed. Some of these properties are
>>>>>charge, spin, velocity, energy, position, and so on. By observation
>>>>>of these properties, and through experimentation, scientists find it
>>>>>reasonable to extrapolate the existence of the electron, and I accept
>>>>>their extrapolation based on solid experiments.
>>>>>
>>>>>It is also just as reasonable to extrapolate the existence of the
>>>>>photon. While neither the electron nor the photon can be observed,
>>>>>they are evident through their interaction with matter.
>>>>
>>>>I would have thought that photons would be the only things we actually
>>>>can observe. But I suppose that what we really observe are nerve
>>>>impulses, or the pictures they summon up in our heads, eh?
>>>
>>>You don't see photons, Harshman.
>>
>>Then what _do_ do see, Oh great Grandpoobah, if it isn't the photons?
>>
>
>
> NashtOn is certainly an idiot but that doesn't me he can't
> accidentally have an ounce of truth in what he posts.
But in this case he doesn't. His point has nothing to do with nerve
activity. He's saying that the idea of photons only takes into account
the particle nature of light, not its wave nature. This would come as a
big surprise to physicists.
> John Harshman
> got it right in saying that we claim to "see" is really the result of
> nerve activity. We just as easily "see" electrical stimulation of the
> retina, the optic nerve, or visual regions of the brain. And even if
> you want to argue that we really do "see" light, that doesn't mean we
> actually observe photons. I "feel" the keys underneath my fingers as
> I type but that doesn't mean that I am detecting individual atoms on
> the keyboard. The more accurate statement is Zoe's: "While neither
> the electron nor the photon can be observed they are evident through
> their interaction with matter.". Even "photographs" of atoms are not
> direct observation. They are representations of the way that atoms
> interact with highly specialized and elaborate machinery presented in
> a graphical form.
A better way to put this is that we can't perceive individual photons (I
believe it takes around 6 or 7 to produce a visible flash), and so have
no capability to notice that light is quantized.
But the big question would be "What is direct perception, anyway?" All
sense impressions are heavily processed in our brains. Our images of the
world contain all manner of shortcuts and inferences, which is why
optical illusions work as they do. "Direct observation" is a mystical
concept not unlike "free will".
Ian H Spedding
The simplest evidence is that, if you go out on a dark and clear night
and shine a torch/flashlight away from you, the beam of light is not
visible. We cannot see the photons themselves. We see when photons
strike photoreceptors in the retina and the absorption of of that
energy by certain chemicals stimulates the cell to emit an electrical
signal.
Windy
r norman wrote:
> The more accurate statement is Zoe's: "While neither
> the electron nor the photon can be observed they are evident through
> their interaction with matter.". Even "photographs" of atoms are not
> direct observation. They are representations of the way that atoms
> interact with highly specialized and elaborate machinery presented in
> a graphical form.
Even "photographs" of anything are not direct observation. They are
representations of the way that photons interact first with matter,
then with a highly specialized chemical substrate or a set of
electronic sensors.
-- w.
Windy
NashtOn wrote:
> Kleuskes & Moos wrote:
> > NashtOn schreef:
> >> through your body.
> >>
> >> It's that like must be comprised of photons, since it *behaves* as if it
> >> does, some of the time, when it doesn't behave as a wave.
> >
> > Huh? Care to elucidate on that?
>
> Do your own research. If you can't understand the dual nature of light,
> you need to take up high school physics.
Perhaps you should do that as well, Mr. "when light behaves exclusively
as a wave, there are no photons involved."
-- w.
Kleuskes & Moos
NashtOn schreef:
Nope... No-one's ever seen a neutrino. That's for sure, we do not have
any sensors
to detect them.
However, the dispute is not about what "seeing" is, but what we see,
and what we see is light. What you, in your own way, try to describe is
how we see, which is an entirely different matter. So, technically, all
we see is photons, _how_ we see them, is still very much an open
question.
> >> Just like you can't see electrons when you've just touched a live wire and feel the current going
> >> through your body.
> >>
> >> It's that like must be comprised of photons, since it *behaves* as if it
> >> does, some of the time, when it doesn't behave as a wave.
> >
> > Huh? Care to elucidate on that?
>
> Do your own research. If you can't understand the dual nature of light,
> you need to take up high school physics.
Ah... So you _do_ understand, or so you claim. Hence I ask, do you
seriously try to imply that a photon acts like a particle some of the
time and as a wave when it's not?
>
> >
> > <snip>
> >
> >> If you're trained in biology, no wonder you can't be adequately rigorous
> >> in your definition of terms in the real sciences, such as physics.
> >
> > And biology isn't a real science in what sense exactly? And if biology
> > isn't that what is?
>
> Physics, chemistry, geology etc.
And what, pray tell, is the (notoriously) B I G difference?
> > Might I also inqquire what exactly your credentials are? Since if you
> > make claims like that, surely you _have_ mastered real sciences like
> > physics.
>
> I know quite a it about about physics and obviously a heck of a lot more
> than the schmucks that can't differentiate between seeing light,
> perceiving darkness and photons and how the latter serves to explain the
> nature of the beast.
I freely admit I haven't a clue what you're talking on about. Would you
care to explain that paragraph in a little more detail? How do
perceiving darkness and/or photons serve to explain the nature of the
beast, for instance? I do admit i find that sentence fascinating.
Did you have any particular schmucks in mind, or do you mean schmucks
in general?
Baron Bodissey
<snip>
> If you're trained in biology, no wonder you can't be adequately rigorous
> in your definition of terms in the real sciences, such as physics.
<snip>
In a previous incarnation as a journalist I had occasion to cover a
cosmology conference for one of the wire services. In an interview with
one of the participants, I asked him why physics seemed to be so far
ahead of biology in explaining its aspect of the universe.
"Because," he said, "physics is easy and biology is hard."
Baron Bodissey
They are ill discoverers that think there is no land when they see
nothing but sea.
- Francis Bacon
Kleuskes & Moos
Ian H Spedding schreef:
Nobody said anything about seeing fotons flying through space as little
balls or something, but what causes us to see is light, fotons. We can
have a semantic battle about what "seeing" is until the cows come home,
but , ultimately, the question is not how we see, and why we see only
particular fotons (which is a quite definate "Good Thing (tm)", IMHO),
but what we see. Excluding hallucinations, for the sake of sanity, what
we see, ultimately, are photons. Just as waves of compressed air is
perceived as sound and *what* we hear, is sound. If there are no more
photons around you can detect, you don't seen anyting but (maybe)
splashes of color.
No sane physics student measure anything but a current with an
Ampere-meter, although actually, he may be balancing torque against
magnetic forces caused by a coil through which a portion of the current
flows he intends to measure and is _actually_ measuring the angular
displacement relative to equilibrium when no current is flowing through
the coil. Nor will he be surprised to learn that if he does not
actually connect his meter to a circuit, he will measure nothing more
insteresting than a little noise (peaking in the 50-60 Hz, band
probably, depending on location).
John Harshman
I'm sorry, but that was very silly. I suppose you're reaching back to
some notion that sight is an active process of action at a distance. Of
course we can't see photons that don't hit our retinas. How would we see
them? What would "see" even mean in such circumstances? Sounds like
Daredevil's radar sense to me.
John Harshman
> NashtOn wrote:
>
> <snip>
>
>>If you're trained in biology, no wonder you can't be adequately rigorous
>>in your definition of terms in the real sciences, such as physics.
>
>
> <snip>
>
> In a previous incarnation as a journalist I had occasion to cover a
> cosmology conference for one of the wire services. In an interview with
> one of the participants, I asked him why physics seemed to be so far
> ahead of biology in explaining its aspect of the universe.
>
> "Because," he said, "physics is easy and biology is hard."
>
> Baron Bodissey
Sure, you're going to say that, just because you wrote a book called
"Life". (Loved the reviews.)
SRNissen
We do, actually. The japanese built a huge tank of water with some
sensors. During a solar flare, they caught 10, I believe.
Jeffrey Turner
>
>
> A better way to put this is that we can't perceive individual photons (I
> believe it takes around 6 or 7 to produce a visible flash), and so have
> no capability to notice that light is quantized.
No, in perfect darkness we can see a single photon. At least
this is what I was taught in physics class some-odd years ago.
--Jeff
--
The shepherd always tries to persuade
the sheep that their interests and
his own are the same. --Stendhal
Baron Bodissey
Ah, a Vance fan! It seemed apropos in the context of T.O..
r norman
wrote:
>
I interpreted the subject not to be "do we see light in general which
we argue is nothing more than a collection of photons" but rather "can
we demonstrate that photons as discrete objects exist by seeing them
individually". We certainly can not see discrete photons.
Kleuskes & Moos
SRNissen schreef:
> We do, actually. The japanese built a huge tank of water with some
> sensors. During a solar flare, they caught 10, I believe.
You're absolutely right of course (other endevours are also on the way,
i might add), but i meant "we, individually", not "we, the human race".
You do not have any senses which can detect neutrino's as you
(presumably) can detect light, sound and the presence various chemicals
(and combinations) in the air.
NashtOn
Did I ever say one could see or sense a neutrino?
>
> However, the dispute is not about what "seeing" is, but what we see,
> and what we see is light. What you, in your own way, try to describe is
> how we see, which is an entirely different matter. So, technically, all
> we see is photons, _how_ we see them, is still very much an open
> question.
The question was: "What do you see?" Implicating the process therefore
has to be included in the explanation.
When you shine a light in the woods and there is nobody there to
perceive it, it isn't light. It's energy in the form of particles
(photons) or EM waves. What you see is what stimulates your retina,
which is essentially an entity carrying energy, causing a chemical
reaction within the specialized cells of the retina and causing a nerve
cell to depolarize.
Therefore, what you see and ultimately perceive is the energy signature
of either particles or waves.
If you want to call light photons, go right ahead. If you want to call
it EM waves within a certain range of lambda, go ahead.
What you're forgetting is that these mental concepts are there for us to
be able to better predict how light behaves. In fact, if you go to the
definition of a photon, it's a quantum, nothing more, nothing less, of
the quantity of energy it takes to increase the orbit of an electron by
one orbit (6×10-17 eV). Conversely, it's the amount of energy emitted
when an electron loses it's energy and goes to an inferior orbit.
To put it succinctly, do you perceive "horsepowers" or Joules or m/sec^2?
No, you perceive the respective phenomena that they measure.
>
>>>> Just like you can't see electrons when you've just touched a live wire and feel the current going
>>>> through your body.
>>>>
>>>> It's that like must be comprised of photons, since it *behaves* as if it
>>>> does, some of the time, when it doesn't behave as a wave.
>>> Huh? Care to elucidate on that?
>> Do your own research. If you can't understand the dual nature of light,
>> you need to take up high school physics.
>
> Ah... So you _do_ understand, or so you claim. Hence I ask, do you
> seriously try to imply that a photon acts like a particle some of the
> time and as a wave when it's not?
Many people have a misunderstanding about the paradox of the nature of
light. Try Wikipedia for an excellent explanation and history.
>
>>> <snip>
>>>
>>>> If you're trained in biology, no wonder you can't be adequately rigorous
>>>> in your definition of terms in the real sciences, such as physics.
>>> And biology isn't a real science in what sense exactly? And if biology
>>> isn't that what is?
>> Physics, chemistry, geology etc.
>
> And what, pray tell, is the (notoriously) B I G difference?
Rigor.
>
>>> Might I also inqquire what exactly your credentials are? Since if you
>>> make claims like that, surely you _have_ mastered real sciences like
>>> physics.
>> I know quite a it about about physics and obviously a heck of a lot more
>> than the schmucks that can't differentiate between seeing light,
>> perceiving darkness and photons and how the latter serves to explain the
>> nature of the beast.
>
> I freely admit I haven't a clue what you're talking on about. Would you
> care to explain that paragraph in a little more detail? How do
> perceiving darkness and/or photons serve to explain the nature of the
> beast, for instance? I do admit i find that sentence fascinating.
>
> Did you have any particular schmucks in mind, or do you mean schmucks
> in general?
From what you've already stated, I don't think that your background in
physics is enough for me to waste my time trying to describe the
difference between light, photons and their operational definitions.
r norman
<jtu...@localnet.com> wrote:
>John Harshman wrote:
>>
>>
>> A better way to put this is that we can't perceive individual photons (I
>> believe it takes around 6 or 7 to produce a visible flash), and so have
>> no capability to notice that light is quantized.
>
>No, in perfect darkness we can see a single photon. At least
>this is what I was taught in physics class some-odd years ago.
>
The physicist was wrong. My recollection is that it takes perhaps a
dozen photons entering the eyeball and at least two or three
activating receptor cells before we can detect a flash of light. The
original work was
Hecht, S., Shlaer, S., and Pirenne, M.H.:
Energy, Quanta, and Vision,
J. Gen. Physiol., 25: 819, 1942.
See, for example
http://www.princeton.edu/~wbialek/PHY562/060207.pdf
http://www.madsci.org/posts/archives/oct2000/971133010.Ns.r.html
Kleuskes & Moos
NashtOn schreef:
Nope. The question simply is "_What_ do you see", not "_How_ do you see
it."
<snip>
> > Ah... So you _do_ understand, or so you claim. Hence I ask, do you
> > seriously try to imply that a photon acts like a particle some of the
> > time and as a wave when it's not?
>
> Many people have a misunderstanding about the paradox of the nature of
> light. Try Wikipedia for an excellent explanation and history.
It's rumoured that men exist, reputed wise for saying nothing. I see
you've wisened up enough to stay out of this one. But you operate on
the motto: "If at first you don't succeed, redefine succes", don't you?
<snip semantic wriggling>
> > And what, pray tell, is the (notoriously) B I G difference?
>
> Rigor.
Sure. Care to explain the rigor? Sloganism is no substitute for proper
definition. If you claim there is a fundamental difference between
Geology and biology in the sense of wether or not it's "real science",
you should at least be able to state what it is you call "rigor". Rigor
mortis?
> >>> Might I also inqquire what exactly your credentials are? Since if you
> >>> make claims like that, surely you _have_ mastered real sciences like
> >>> physics.
> >> I know quite a it about about physics and obviously a heck of a lot more
> >> than the schmucks that can't differentiate between seeing light,
> >> perceiving darkness and photons and how the latter serves to explain the
> >> nature of the beast.
> >
> > I freely admit I haven't a clue what you're talking on about. Would you
> > care to explain that paragraph in a little more detail? How do
> > perceiving darkness and/or photons serve to explain the nature of the
> > beast, for instance? I do admit i find that sentence fascinating.
> >
> > Did you have any particular schmucks in mind, or do you mean schmucks
> > in general?
>
> From what you've already stated, I don't think that your background in
> physics is enough for me to waste my time trying to describe the
> difference between light, photons and their operational definitions.
My background is enough to see you wriggle out of a tight corner. But
still, it's characters like you who provide much of the entertainment
around here, so thank you.
John Harshman
> John Harshman wrote:
>
>>
>>A better way to put this is that we can't perceive individual photons (I
>>believe it takes around 6 or 7 to produce a visible flash), and so have
>>no capability to notice that light is quantized.
>
>
> No, in perfect darkness we can see a single photon. At least
> this is what I was taught in physics class some-odd years ago.
I was taught differently. Or perhaps I misremember.
John Harshman
> John Harshman wrote:
>
>>Baron Bodissey wrote:
>>
>>
>>>NashtOn wrote:
>>>
>>><snip>
>>>
>>>>If you're trained in biology, no wonder you can't be adequately rigorous
>>>>in your definition of terms in the real sciences, such as physics.
>>>
>>>
>>><snip>
>>>
>>>In a previous incarnation as a journalist I had occasion to cover a
>>>cosmology conference for one of the wire services. In an interview with
>>>one of the participants, I asked him why physics seemed to be so far
>>>ahead of biology in explaining its aspect of the universe.
>>>
>>>"Because," he said, "physics is easy and biology is hard."
>>>
>>>Baron Bodissey
>>
>>Sure, you're going to say that, just because you wrote a book called
>>"Life". (Loved the reviews.)
>
>
> Ah, a Vance fan!
Isn't everyone?
NashtOn
Listen Kooskoos or whatever, some things just can't be beaten into your
head until you study them.
There are no excuses anymore, the net is there for everyone.
Josh Miles
> If you're trained in biology, no wonder you can't be adequately rigorous
> in your definition of terms in the real sciences, such as physics.
Nicolas says that biology isn't science, but says that his physical
therapy degree is a science degree. So according to Nicolas, biology
isn't science, but physical therapy is. What a retard.
Kleuskes & Moos
<snippety>
> > My background is enough to see you wriggle out of a tight corner. But
> > still, it's characters like you who provide much of the entertainment
> > around here, so thank you.
> >
>
> Listen Kooskoos or whatever,
Yes NashNash or whatever?
> some things just can't be beaten into your head until you study them.
Oh, but i have. Studied them, i mean. And no violence was neccesary.
You didn't and you don't like it if someone points it out.
That's why you're all grumpy.
> There are no excuses anymore, the net is there for everyone.
Have I EVER claimed otherwise, sugarpop?
Kermit
Ian H Spedding wrote:
> r norman wrote:
> > On 10 Jun 2006 05:08:35 -0700, "Kleuskes & Moos" <kle...@xs4all.nl>
> > wrote:
> >
<snip>
> The simplest evidence is that, if you go out on a dark and clear night
> and shine a torch/flashlight away from you, the beam of light is not
> visible. We cannot see the photons themselves. We see when photons
> strike photoreceptors in the retina and the absorption of of that
> energy by certain chemicals stimulates the cell to emit an electrical
> signal.
I don't think your evidence supports your correct conclusion.
If I pick up a handful of pebbles and throw them away from you, you
will not feel them. That doesn't mean that if I throw them so they
strike you, you will not feel them with your touch (and maybe pain)
nerves.
Someone who insisted that we could see individual photons would simply
point out that demanding photons actually reach the retina to see them
is as reasonable as asserting that pebbles must touch the skin to feel
them.
>
> Ian
>
> --
> Ian H Spedding
Kermit
Windy
John Harshman wrote:
> Baron Bodissey wrote:
> > John Harshman wrote:
> >>Baron Bodissey wrote:
> >>>"Because," he said, "physics is easy and biology is hard."
> >>
> >>"Life". (Loved the reviews.)
> >
> > Ah, a Vance fan!
>
> Isn't everyone?
I think "The Men Return" describes what would happen if the world would
work as creationists think it does.
-- w.
Kermit
NashtOn wrote:
> Kleuskes & Moos wrote:
<snip>
> >>>
> >>>> If you're trained in biology, no wonder you can't be adequately rigorous
> >>>> in your definition of terms in the real sciences, such as physics.
> >>> And biology isn't a real science in what sense exactly? And if biology
> >>> isn't that what is?
> >> Physics, chemistry, geology etc.
> >
> > And what, pray tell, is the (notoriously) B I G difference?
>
> Rigor.
>
There are of course two differences between fields like physics and
fields like biology. One is that biology is the study of an arena of
activity that is far more complicated than physics. Try doing a
controlled experiment on organisms in a lab - the number of variables
which are different is staggering, and there is undoubtedly a large
number of unknown variables. It is impossible a priori to know which
variables matter ahead of time. I remember one experiment with rats in
which their reaction to a drug was being monitored. Some rats did much
better than others, and when the researcher went to look at them after
seeing the paperwork, he realized that a disproportionate number of
them were in the lower shelves. It turned out that the technician who
fed and watered them was short. He would maintain all of them, but the
ones he could easily reach he tended to pet. The rats - social animals
all - did better with the attention. This sort of confounding
interference rarely shows up in physics.
The other difference, of course, is that biology has come to
conclusions which dispute your religious beliefs. So what? That is no
problem for science.
There are two ways to make scientific arguments: one way is to present
evidence (even indirectly) and conclusions derived from that evidence.
The other is to quote an authority in the field, and assume that he or
she has done certain fundamental work in that area. You, a physical
therapist, do no trump real scientists in your education. You are a
technician like me, who may have - like me - taken some classes in
science. but we are not scientsts, because we do not *do* science.
If you or I wish to make an argument, we can present mainstream
opinions by quoting a real authority, or we can offer evidence and our
conclusions, and see if it flies.
> >
> >>> Might I also inqquire what exactly your credentials are? Since if you
> >>> make claims like that, surely you _have_ mastered real sciences like
> >>> physics.
> >> I know quite a it about about physics and obviously a heck of a lot more
> >> than the schmucks that can't differentiate between seeing light,
> >> perceiving darkness and photons and how the latter serves to explain the
> >> nature of the beast.
> >
> > I freely admit I haven't a clue what you're talking on about. Would you
> > care to explain that paragraph in a little more detail? How do
> > perceiving darkness and/or photons serve to explain the nature of the
> > beast, for instance? I do admit i find that sentence fascinating.
> >
> > Did you have any particular schmucks in mind, or do you mean schmucks
> > in general?
>
> From what you've already stated, I don't think that your background in
> physics is enough for me to waste my time trying to describe the
> difference between light, photons and their operational definitions.
I have no trouble for the sake of discussion with your using the word
"light" to refer to the perception of light, but it isn't how most
physics books or websites use it. I would think that anyone who "knew
quite a bit about" physics would understand that. My daughter's physics
book (Serway and Beichner, Physics for Scientists and Engineers, 5th
ed., p.1108) says "Light exhibits the characteristics of a wave in some
situations and the characteristics of a particle in other situations".
This after a several page description of the history of theories of
light.
> --
> Nicolas
>
>
<snip Joyce>
<snip lawyer>
Kermit
Ye Old One
group when s/he wrote:
>You don't see photons
Are you sure your name is not McClueless?
--
Bob.
carlip...@physics.ucdavis.edu
[...]
> I would have thought that photons would be the only things we actually
> can observe.
Probably muons as well: see Nature 232, 574 - 575 (20 August 1971),
although you might argue that it's still photons (from Cherenkov
radiation produced by the muons passing through the eye). Astronauts
have reported "light flashes" that may be visual effects of heavy
ions from cosmic radiation. There's a proposed experiment on the
International Space Station ("ALTEA") to investigate these effects;
I don't know the present status.
Steve Carlip
SRNissen
In English, they're photons, not fotons.
- SRNissen
FABRICATE DIEM, PVNC
John Harshman
Except that we would have to wander into a retroactive area of weird
space-time, so that everything would change from the beginning.
NashtOn
> On 10 Jun 2006 05:08:35 -0700, "Kleuskes & Moos" <kle...@xs4all.nl>
> wrote:
>
>> NashtOn schreef:
>>
>>> John Harshman wrote:
>>>> Zoe wrote:
>>>>
>>>>> AC, sorry about the delay. You had asked me why I think electrons
>>>>> exist. Here's why:
>>>>>
>>>>> Even though electrons are not themselves observable, they apparently
>>>>> have properties that can be observed. Some of these properties are
>>>>> charge, spin, velocity, energy, position, and so on. By observation
>>>>> of these properties, and through experimentation, scientists find it
>>>>> reasonable to extrapolate the existence of the electron, and I accept
>>>>> their extrapolation based on solid experiments.
>>>>>
>>>>> It is also just as reasonable to extrapolate the existence of the
>>>>> photon. While neither the electron nor the photon can be observed,
>>>>> they are evident through their interaction with matter.
>>>> I would have thought that photons would be the only things we actually
>>>> can observe. But I suppose that what we really observe are nerve
>>>> impulses, or the pictures they summon up in our heads, eh?
>>> You don't see photons, Harshman.
>> Then what _do_ do see, Oh great Grandpoobah, if it isn't the photons?
>>
>
> NashtOn is certainly an idiot but that doesn't me he can't
> accidentally have an ounce of truth in what he posts.
Color me hurt.
John Harshman
> got it right in saying that we claim to "see" is really the result of
> nerve activity.
What we see is the result of associative regions of the brain that are
hierarchically way above the mere depolarization of nerve cells caused
by the initial chemical/physical stimulus at the
mechanoreceptor/nociceptor level.
We just as easily "see" electrical stimulation of the
> retina, the optic nerve, or visual regions of the brain. And even if
> you want to argue that we really do "see" light, that doesn't mean we
> actually observe photons. I "feel" the keys underneath my fingers as
> I type but that doesn't mean that I am detecting individual atoms on
> the keyboard. The more accurate statement is Zoe's: "While neither
> the electron nor the photon can be observed they are evident through
> their interaction with matter.".
Erm nope. They are part of matter. Photons have an infinitesimally low
amount of matter, electrons *are* part of what we call matter.
Neither Zoe nor you have grasped that what you perceive is what your
brain interprets and lets you perceive. Even that is temporary given
that the CNS is essentially a novelty detector and once accommodation
sets in, you perceive less and less until you perceive *nothing* even if
you're staring at a bright object.
Even "photographs" of atoms are not
> direct observation. They are representations of the way that atoms
> interact with highly specialized and elaborate machinery presented in
> a graphical form.
You need to read up on Heisenberg and abandon Bohr's atomic model. There
are nothing but probabilities at the atomic level.
What's tremendously surprising is that most of you "scientists" are so
clueless about definitions and simple notions of physics, you are
arrogant enough to think that you have a grasp of anything you're
babbling about.
Priceless.
NashtOn
> activity. He's saying that the idea of photons only takes into account
> the particle nature of light, not its wave nature. This would come as a
> big surprise to physicists.
No Harshman. You misunderstood again.
I established the operational definition of a photon.
The dual nature of light is not surprising to a physicist neither is the
notion of perception.
>
>> John Harshman
>> got it right in saying that we claim to "see" is really the result of
>> nerve activity. We just as easily "see" electrical stimulation of the
>> retina, the optic nerve, or visual regions of the brain. And even if
>> you want to argue that we really do "see" light, that doesn't mean we
>> actually observe photons. I "feel" the keys underneath my fingers as
>> I type but that doesn't mean that I am detecting individual atoms on
>> the keyboard. The more accurate statement is Zoe's: "While neither
>> the electron nor the photon can be observed they are evident through
>> their interaction with matter.". Even "photographs" of atoms are not
>> direct observation. They are representations of the way that atoms
>> interact with highly specialized and elaborate machinery presented in
>> a graphical form.
>
> A better way to put this is that we can't perceive individual photons (I
> believe it takes around 6 or 7 to produce a visible flash), and so have
> no capability to notice that light is quantized.
Just as you can't see m/cm^2, but you "feel" the acceleration.
This has been my point all along.
>
> But the big question would be "What is direct perception, anyway?" All
> sense impressions are heavily processed in our brains. Our images of the
> world contain all manner of shortcuts and inferences, which is why
> optical illusions work as they do. "Direct observation" is a mystical
> concept not unlike "free will".
LOL. Now you're entering the world of QM where waves collapse with your
senses, subjectivity melts into objectivity and the world is nothing but
interference patterns until you perceive it. And can you say Idealism?
Direct observation is not mystical, it's the basis of science. Direct
observation with measurements adds internal and external validity to a
measurement. But how would you know this since you dabble in biology
where direct observation takes a back seat to inference?
David Ewan Kahana
This is a bit of a crazy thought, but ...
I wonder whether a charged particle could in principle
sometimes more directly initiate the primary visual event,
which is described as absorption of photons by rhodopsin,
resulting in vertebrates in rapid (200 femtosecond) isomerization
of 11-cis-retinal, bound to lysine in the chromophores to an
all trans form, which event then later induces conformational
changes in the rhodopsin.
http://www.jbc.org/cgi/reprint/269/20/14329.pdf
Suppose for example that a delta-ray (fast electron) were
produced in one of these putative intraocular heavy ion
events, and that it happened to pass near some of these
11-cis-retinal molecules or even hit them directly. Might
there be enough energy transfer to begin the cascade
of events, assuming that the process is not too
destructive?
Of course such a process could still be said to involve a
photon exchange, but if it is only a virtual photon then it
seems as if the line between `seeing' photons and seeing
electrons might become a bit blurry.
In any case, there's no particle identification system built
into the eyes. Evolution doesn't seem to have provided us
with the necessary tiny magnets and drift chambers ;->
David
NashtOn
> Ian H Spedding schreef:
>
>>> On 10 Jun 2006 05:08:35 -0700, "Kleuskes & Moos" <kle...@xs4all.nl>
>>> wrote:
>>>
>>>> NashtOn schreef:
>>>>
>>>>> John Harshman wrote:
>>>>>> Zoe wrote:
>>>>>>
>>>>>>> AC, sorry about the delay. You had asked me why I think electrons
>>>>>>> exist. Here's why:
>>>>>>>
>>>>>>> Even though electrons are not themselves observable, they apparently
>>>>>>> have properties that can be observed. Some of these properties are
>>>>>>> charge, spin, velocity, energy, position, and so on. By observation
>>>>>>> of these properties, and through experimentation, scientists find it
>>>>>>> reasonable to extrapolate the existence of the electron, and I accept
>>>>>>> their extrapolation based on solid experiments.
>>>>>>>
>>>>>>> It is also just as reasonable to extrapolate the existence of the
>>>>>>> photon. While neither the electron nor the photon can be observed,
>>>>>>> they are evident through their interaction with matter.
>>>>>> impulses, or the pictures they summon up in our heads, eh?
>>>>> You don't see photons, Harshman.
>>>> Then what _do_ do see, Oh great Grandpoobah, if it isn't the photons?
>>>
>>> NashtOn is certainly an idiot but that doesn't me he can't
>>> got it right in saying that we claim to "see" is really the result of
>>> nerve activity. We just as easily "see" electrical stimulation of the
>>> retina, the optic nerve, or visual regions of the brain. And even if
>>> you want to argue that we really do "see" light, that doesn't mean we
>>> actually observe photons. I "feel" the keys underneath my fingers as
>>> I type but that doesn't mean that I am detecting individual atoms on
>>> the keyboard. The more accurate statement is Zoe's: "While neither
>>> the electron nor the photon can be observed they are evident through
>>> their interaction with matter.". Even "photographs" of atoms are not
>>> direct observation. They are representations of the way that atoms
>>> interact with highly specialized and elaborate machinery presented in
>>> a graphical form.
>> and shine a torch/flashlight away from you, the beam of light is not
>> visible. We cannot see the photons themselves. We see when photons
>> strike photoreceptors in the retina and the absorption of of that
>> energy by certain chemicals stimulates the cell to emit an electrical
>> signal.
>
> Nobody said anything about seeing fotons flying through space as little
> have a semantic battle about what "seeing" is until the cows come home,
> but , ultimately, the question is not how we see, and why we see only
> particular fotons (which is a quite definate "Good Thing (tm)", IMHO),
> but what we see. Excluding hallucinations, for the sake of sanity, what
> we see, ultimately, are photons. Just as waves of compressed air is
> perceived as sound and *what* we hear, is sound. If there are no more
> photons around you can detect, you don't seen anyting but (maybe)
> splashes of color.
>
> No sane physics student measure anything but a current with an
> Ampere-meter, although actually, he may be balancing torque against
> magnetic forces caused by a coil through which a portion of the current
> flows he intends to measure and is _actually_ measuring the angular
> displacement relative to equilibrium when no current is flowing through
> the coil. Nor will he be surprised to learn that if he does not
> actually connect his meter to a circuit, he will measure nothing more
> insteresting than a little noise (peaking in the 50-60 Hz, band
> probably, depending on location).
>
What we see is light.
Light is either photons or a wave.
A photon is a unit of measure of light under specific circumstances,
nothing more, nothing less.
What toasts your bread in the morning is a toaster that uses
electricity, measured in Amperes. Amperes do not brown your toast, the
phenomenon of electricity browns your toast.
Why this has turned out into a battle of semantics is beyond me.
NashtOn
An easy way to remember this is that anything derived from Greek that
sounds like an "f" is spelled "ph."
>
>> We can
>> have a semantic battle about what "seeing" is until the cows come home,
>> but , ultimately, the question is not how we see, and why we see only
>> particular fotons (which is a quite definate "Good Thing (tm)", IMHO),
>> but what we see. Excluding hallucinations, for the sake of sanity, what
>> we see, ultimately, are photons. Just as waves of compressed air is
>> perceived as sound and *what* we hear, is sound. If there are no more
>> photons around you can detect, you don't seen anyting but (maybe)
>> splashes of color.
>>
>> No sane physics student measure anything but a current with an
>> Ampere-meter, although actually, he may be balancing torque against
>> magnetic forces caused by a coil through which a portion of the current
>> flows he intends to measure and is _actually_ measuring the angular
>> displacement relative to equilibrium when no current is flowing through
>> the coil. Nor will he be surprised to learn that if he does not
>> actually connect his meter to a circuit, he will measure nothing more
>> insteresting than a little noise (peaking in the 50-60 Hz, band
>> probably, depending on location).
>>
>
NashtOn
I'll run a Matheson FCE on you after an injury and wait to repeat the
FCE a few months later.
I'll look at norms for the population, use SD for maximum effort and
interpret the results.
I'll run an EMG on you after a nerve injury to see if you suffered
denervation and compare to the other side and register differences.
Everything I do, *every* moment of my day is based on science, from my
Dx to outcomes to what modalities I'll use to treat you.
Thyen I'll spend many hours a week on Pubmed and PABLO looking for valid
research to use in my practice.
Dunno about you, but I'd say PT is science.
Windy
NashtOn wrote:
> Kleuskes & Moos wrote:
> > balls or something, but what causes us to see is light, fotons. We can
> > have a semantic battle about what "seeing" is until the cows come home,
> > but , ultimately, the question is not how we see, and why we see only
> > particular fotons (which is a quite definate "Good Thing (tm)", IMHO),
> > but what we see. Excluding hallucinations, for the sake of sanity, what
>
> What we see is light.
> Light is either photons or a wave.
No, it's both. Somewhat like a wave in the ocean is still composed of
individual water molecules, although it behaves as a wave (although
this example does not match the light example very well).
> A photon is a unit of measure of light under specific circumstances,
> nothing more, nothing less.
It is the smallest unit of light under all circumstances.
> What toasts your bread in the morning is a toaster that uses
> electricity, measured in Amperes. Amperes do not brown your toast, the
> phenomenon of electricity browns your toast.
The ampere is an arbitrary unit of measurement. A better comparison is
the electron: it is the smallest "unit of electricity" like a photon is
the smallest unit of light.
-- w.
Jeffrey Turner
"Sitting quietly in a dark room, we can detect the arrival of
individual photons at our retina."
"The first group to record the single photon responses in
vertebrate rod cells was led by Denis Baylor at Stanford in the
late 1970s. ... Single photon responses observed in this way are
about a picoamp in amplitude vs. a continuous background noise
of 0.1 pA rms, so these are easily detected."
This paper has a graph which shows that the probablity of seeing
a single photon (K=1) can be unity for a high enough light
intensity.
> http://www.madsci.org/posts/archives/oct2000/971133010.Ns.r.html
"A dark-adapted rod photoreceptor can actually detect individual
photons -- this is an absolutely spectacular feat of
amplification within the cell!1"
1 S. Hecht, S. Schlaer and M.H. Pirenne, Energy, Quanta
and vision Journal of the Optical Society of America, 38,
196-208 (1942);
Baylor, D.A., Lamb, T.D. & Yau, K.-W. (1979). Responses of
retinal rods to single photons Journal of Physiology 288,
613-634;
Baylor, D.A., Nunn, B.J. & Schnapf, J.L. (1984). The
photocurrent, noise and spectral sensitivity of rods of the
monkey Macaca fascicularis Journal of Physiology 357, 575-607.
Though he also claims that "Under optimum conditions, it has
been found that fewer than 100 photons striking the eye (10 rods
per 1/10 of a second) are enough for rod-mediated vision. 4"
4 David R. Copenhagen and Tom Reuter
Our eyes can certainly detect single photons. Whether we would
be conscious of such obviously requires more in-depth analysis
than these two short papers.
--Jeff
--
The shepherd always tries to persuade
the sheep that their interests and
his own are the same. --Stendhal
Jeffrey Turner
> SRNissen schreef:
>
>
>
>>We do, actually. The japanese built a huge tank of water with some
>>sensors. During a solar flare, they caught 10, I believe.
Isn't (something like) cleaning fluid the usual solution?
> You're absolutely right of course (other endevours are also on the way,
> i might add), but i meant "we, individually", not "we, the human race".
> You do not have any senses which can detect neutrino's as you
> (presumably) can detect light, sound and the presence various chemicals
> (and combinations) in the air.
If we _did_ see a neutrino, how would we distinguish that
unusually rare event from the usual background of photons?
What I mean is, if a neutrino happened to trigger the usual
response of our photo-receptors... I admit the odds are
extremely long. But neutrinos do occasionally interact with
other matter, maybe even the rods of the eye.
bullpup
"NashtOn" <na...@na.ca> wrote in message
news:nashton-zqKig.20436$A26.4...@ursa-nb00s0.nbnet.nb.ca...
> Josh Miles wrote:
> > NashtOn wrote:
> >> If you're trained in biology, no wonder you can't be adequately
> >> rigorous in your definition of terms in the real sciences, such as
> >> physics.
> >
> > Nicolas says that biology isn't science, but says that his physical
> > therapy degree is a science degree. So according to Nicolas, biology
> > isn't science, but physical therapy is. What a retard.
> >
>
> I'll run a Matheson FCE on you after an injury and wait to repeat the
> FCE a few months later.
>
> I'll look at norms for the population, use SD for maximum effort and
> interpret the results.
>
> I'll run an EMG on you after a nerve injury to see if you suffered
> denervation and compare to the other side and register differences.
>
>
> Everything I do, *every* moment of my day is based on science, from my
> Dx to outcomes to what modalities I'll use to treat you.
> Thyen I'll spend many hours a week on Pubmed and PABLO looking for valid
> research to use in my practice.
>
> Dunno about you, but I'd say PT is science.
No more or less than an auto mechanic.
Boikat
Jeffrey Turner
>
> What you're forgetting is that these mental concepts are there for us to
> be able to better predict how light behaves. In fact, if you go to the
> definition of a photon, it's a quantum, nothing more, nothing less, of
> the quantity of energy it takes to increase the orbit of an electron by
> one orbit (6×10-17 eV). Conversely, it's the amount of energy emitted
> when an electron loses it's energy and goes to an inferior orbit.
Photons come in all sorts of energy levels, as do the
differences between electron orbitals (orbit doesn't really
describe what the electron does).
Windy
NashtOn wrote:
> Josh Miles wrote:
> > NashtOn wrote:
> >> If you're trained in biology, no wonder you can't be adequately
> >> rigorous in your definition of terms in the real sciences, such as
> >> physics.
> > Nicolas says that biology isn't science, but says that his physical
> > therapy degree is a science degree. So according to Nicolas, biology
> > isn't science, but physical therapy is. What a retard.
> >
> I'll run a Matheson FCE on you after an injury and wait to repeat the
> FCE a few months later.
>
> I'll look at norms for the population, use SD for maximum effort and
> interpret the results.
>
> I'll run an EMG on you after a nerve injury to see if you suffered
> denervation and compare to the other side and register differences.
>
> Everything I do, *every* moment of my day is based on science, from my
> Dx to outcomes to what modalities I'll use to treat you.
> Thyen I'll spend many hours a week on Pubmed and PABLO looking for valid
> research to use in my practice.
>
> Dunno about you, but I'd say PT is science.
No, you apply the results of science in your work. To do actual science
would be something like making a hypothesis about a new treatment,
taking 100 Joshes, applying the treatment to 50 of them randomly and
using the other 50 as control, and seeing if it had an effect.
-- w.
AC
Zoe <muz...@aol.com> wrote:
> AC, sorry about the delay. You had asked me why I think electrons
> exist. Here's why:
>
> Even though electrons are not themselves observable, they apparently
> have properties that can be observed. Some of these properties are
> charge, spin, velocity, energy, position, and so on. By observation
> of these properties, and through experimentation, scientists find it
> reasonable to extrapolate the existence of the electron, and I accept
> their extrapolation based on solid experiments.
The only thing we can *observe* about electrons is the effect they have
on things we can observe. We cannot observe charge, spin, velocity,
energy or position of these alleged particles, we can only infer them.
>
> It is also just as reasonable to extrapolate the existence of the
> photon. While neither the electron nor the photon can be observed,
> they are evident through their interaction with matter.
We only know photons exist because of the effect they have. In the case
of photons, they activate specialized nerves in our eyes. What we're
seeing isn't photons, but the end result of photons stimulating rods and
cones.
>
> Or take the wind. "Who has seen the wind? Neither you nor I, but
> when the trees bow down their heads, the wind is passing by." A
> simple childhood poem, but the same principle of extrapolation is
> involved here. The existence of something called "wind" is evidenced
> by its activity.
That's right. We can infer the existence of things which we cannot
observe directly.
>
> In the same way, I extrapolate the existence of Intelligence in nature
> -- through observing the properties of mental activity as reflected in
> nature.
Even if that's true, Zoe, it has nothing to do with my point. However,
you aren't inferring design, you're simply assuming your conclusion.
You really have no methodology at all.
>
> Now, again, I ask you, why did you ask me that question?
Because you seem to reject inference as a tool for biologists to
determine long-term evolution and Common Descent. But it's nice to see
that you reject the tired old "you weren't there so you can't know"
line.
--
Aaron Clausen
mightym...@gmail.com
Windy
NashtOn wrote:
> r norman wrote:
> > Even "photographs" of atoms are not
> > direct observation. They are representations of the way that atoms
> > interact with highly specialized and elaborate machinery presented in
> > a graphical form.
>
> You need to read up on Heisenberg and abandon Bohr's atomic model. There
> are nothing but probabilities at the atomic level.
Don't you mean the sub-atomic level? I'd say the atoms pictured here
have rather high probabilities of being where they seem to be:
http://www.physics.queensu.ca/~nanophys/stm.html
> What's tremendously surprising is that most of you "scientists" are so
> clueless about definitions and simple notions of physics, you are
> arrogant enough to think that you have a grasp of anything you're
> babbling about.
>
> Priceless.
Says Mr. "when light behaves exclusively as a wave, there are no
photons involved."
-- w.
Baron Bodissey
Windy wrote:
<snip>
> I think "The Men Return" describes what would happen if the world would
> work as creationists think it does.
>
> -- w.
Not remembering that (I hang my head in shame), I dug it out and
re-read it. Good call though. Vance makes no secret of his disdain for
organized religion and his depictions are usually devastating, sad, and
hilarious at the same time. Although I can't recall him directly
writing about evolution, his worlds are hothouses of its results.
John Burton
[...]
> In the same way, I extrapolate the existence of Intelligence in nature
> -- through observing the properties of mental activity as reflected in
> nature.
>
And those properties are? Do you have a measurement or detection method
which is repeatable by independent researchers?
[...]
John
Ian H Spedding
>
> Ian H Spedding schreef:
> >
> > and shine a torch/flashlight away from you, the beam of light is not
> > visible. We cannot see the photons themselves. We see when photons
> > strike photoreceptors in the retina and the absorption of of that
> > energy by certain chemicals stimulates the cell to emit an electrical
> > signal.
>
> balls or something, but what causes us to see is light, fotons. We can
> have a semantic battle about what "seeing" is until the cows come home,
> but , ultimately, the question is not how we see, and why we see only
> particular fotons (which is a quite definate "Good Thing (tm)", IMHO),
> but what we see. Excluding hallucinations, for the sake of sanity, what
> perceived as sound and *what* we hear, is sound. If there are no more
> photons around you can detect, you don't seen anyting but (maybe)
> splashes of color.
If I say that I see a car I mean that I see an image of the vehicle,
not the individual photons that were reflected off the car and entered
my eyes.
The retina is only a photon detector like a CCD. It does not "see"
anything in the sense of human sight because human sight involves the
processing by the brain of the electrical signals stimulated in the
nervous system by the absorption of the photons' energy by
photoreceptors - specifically, the rod and cone cells - in the retina
in order to create an image.
In other words, the eye detects photons but it does not construct an
image of them, which is what I mean by 'seeing'.
Ian H Spedding
>
> Ian H Spedding wrote:
[...]
> > The simplest evidence is that, if you go out on a dark and clear night
> > and shine a torch/flashlight away from you, the beam of light is not
> > visible. We cannot see the photons themselves. We see when photons
> > strike photoreceptors in the retina and the absorption of of that
> > energy by certain chemicals stimulates the cell to emit an electrical
> > signal.
>
> I'm sorry, but that was very silly. I suppose you're reaching back to
> some notion that sight is an active process of action at a distance. Of
> course we can't see photons that don't hit our retinas. How would we see
> them? What would "see" even mean in such circumstances? Sounds like
> Daredevil's radar sense to me.
As I wrote to Kleuskes & Moos, for me, 'seeing' involves the
construction by the brain of an image of what is being seen. The eye
detects photons but we are unable to create an image of the photons
themselves. We do not see light, we see *by* light.
Josh Miles
> Josh Miles wrote:
>> NashtOn wrote:
>>> If you're trained in biology, no wonder you can't be adequately
>>> rigorous in your definition of terms in the real sciences, such as
>>> physics.
>> Nicolas says that biology isn't science, but says that his physical
>> therapy degree is a science degree. So according to Nicolas, biology
>> isn't science, but physical therapy is. What a retard.
>>
>
> I'll run a Matheson FCE on you after an injury and wait to repeat the
> FCE a few months later.
>
> I'll look at norms for the population, use SD for maximum effort and
> interpret the results.
>
> I'll run an EMG on you after a nerve injury to see if you suffered
> denervation and compare to the other side and register differences.
>
>
> Everything I do, *every* moment of my day is based on science, from my
> Dx to outcomes to what modalities I'll use to treat you.
> Thyen I'll spend many hours a week on Pubmed and PABLO looking for valid
> research to use in my practice.
>
> Dunno about you, but I'd say PT is science.
Nope, not science. You rely on the work scientists do, but don't do any
science yourself. Sorry.
r norman
<jtu...@localnet.com> wrote:
Even the 1942 Hecht, Schlaer, and Pirenne paper I cited acknowledged
that the several photons required for "seeing" were almost certainly
detected by different cells. It is most definitely established that
photoreceptor cells can respond to single photons. The question
remains, though, whether we multicellular humans can "see" and respond
to such cellular events. The psychophysical experiments seem to
indicate that we cannot. Several cellular events must summate to
produce a signal large enough to produce an organismal response we
call "seeing".
I saw the paper you referenced but could find no support in it for its
introductory sentence: ""Sitting quietly in a dark room, we can detect
the arrival of individual photons at our retina." except to mean that
individual cells in our body, not we humans, can do the detection.
r norman
You don't know when you are right and think it is so for the wrong
reasons. And you clearly cannot read for comprehension. My reference
to "nerve activity" includes the concept that brain is made of nervous
tissue and all activity of the brain is, in fact, nerve activity. Of
course we only perceive what our brain interprets. Who suggested
otherwise? And the mass of a photon is quite irrelevant to the fact
that we "observe" it only through its interaction with matter.
Perhaps we "scientists" are so much better versed in definitions and
simple notions of physics that we actually know more than you.
Priceless (in the sense of having value equal zero).
wf3h
Zoe wrote:
> AC, sorry about the delay. You had asked me why I think electrons
> exist. Here's why:
>
> Even though electrons are not themselves observable, they apparently
> have properties that can be observed.>
> -- through observing the properties of mental activity as reflected in
> nature.
she defeats her own argument.
how does one measure 'mental activity' in the same way one measures the
properties of electrons? the answer is you don't.
she has a belief...a religious belief. she manufactures conclusions
based on that belief and then rationalizes it....like any good
islamist/christianist does.
wf3h
NashtOn wrote:
>>
> You don't see photons, Harshman. Just like you can't see electrons when
> you've just touched a live wire and feel the current going through your
> body.
and yet we can measure properties of both photons and electrons. we
can't measure 'mental activity' of the 'intelligent designer'. thus
zoe's original contention is wrong. as is nasht's support for it.
> >
> If you're trained in biology, no wonder you can't be adequately rigorous
> in your definition of terms in the real sciences, such as physics.
>
it's poor form for someone so hostile to science to reveal his
christianist bias by lecturing scientists.
wf3h
NashtOn wrote:
> >
> >> If you're trained in biology, no wonder you can't be adequately rigorous
> >> in your definition of terms in the real sciences, such as physics.
> >
> > isn't that what is?
>
> Physics, chemistry, geology etc.
all of which nasht thinks are wrong regarding biology. and yes, we
scientists DO consider biology to be a science.
>
> >
> > Might I also inqquire what exactly your credentials are? Since if you
> > make claims like that, surely you _have_ mastered real sciences like
> > physics.
>
> I know quite a it about about physics
it must be true because he said it. he has no training in science, has
a 500 year old view of it, but he's an expert, you see, because he said
he is.
carlip...@physics.ucdavis.edu
[...]
> What you're forgetting is that these mental concepts are there for us to
> be able to better predict how light behaves. In fact, if you go to the
> definition of a photon, it's a quantum, nothing more, nothing less, of
> the quantity of energy it takes to increase the orbit of an electron by
> one orbit (6×10-17 eV). Conversely, it's the amount of energy emitted
> when an electron loses it's energy and goes to an inferior orbit.
This is wrong. First of all, photons come in a huge range of energies,
from below 10^{-9}eV for radio photons to 10^{20}eV for the highest
energy cosmic rays. A photon with an energy of 6x10^{-17}eV could
exist in principle, but it would correspond to a wavelength of about
20 billion meters; I doubt very much that anything close to this is
observable.
Second, there isn't a fixed amount of energy that an electron emits
when it changes an energy level ("orbit," though that's a misleading
and obsolete term). It depends on the atom. An electron dropping
from the 2S to the 1S level of hydrogen, for example, emits a photon
with an energy of about 10eV. An electron dropping from the 10S to
the 9S level of hydrogen e,its a photon with an energy of about .03eV.
I have no idea where this 6x10^{-17}eV came from.
Steve Carlip
Windy
carlip...@physics.ucdavis.edu wrote:
> NashtOn <na...@na.ca> wrote:
>
> [...]
> > What you're forgetting is that these mental concepts are there for us to
> > be able to better predict how light behaves. In fact, if you go to the
> > definition of a photon, it's a quantum, nothing more, nothing less, of
> > the quantity of energy it takes to increase the orbit of an electron by
> > one orbit (6×10-17 eV). Conversely, it's the amount of energy emitted
> > when an electron loses it's energy and goes to an inferior orbit.
>
> This is wrong. First of all, photons come in a huge range of energies,
> from below 10^{-9}eV for radio photons to 10^{20}eV for the highest
> energy cosmic rays. A photon with an energy of 6x10^{-17}eV could
> exist in principle, but it would correspond to a wavelength of about
> 20 billion meters; I doubt very much that anything close to this is
> observable.
Perhaps he is trying to describe Dembski's infinite wavelength
photon...
-- w.
r norman
Isn't that commonly called "DC"?
ave1
> > Zoe wrote:
<snip>
> > Now, again, I ask you, why did you ask me that question?
>
> Because you seem to reject inference as a tool for biologists to
> determine long-term evolution and Common Descent. But it's nice to see
> that you reject the tired old "you weren't there so you can't know"
> line.
>
> --
> Aaron Clausen
The inference is confirmed by repeatable measurements of the actual
phenomena associated with the electrons or photons.
The problem with an inference that purports to take observed active
biological changes (of the processes that explain variation) and
extrapolate into some idea that represents the making of things with
high order and high complexity (ie. an eye or an archer fish's instinct
of accurately spitting water at bugs on leaves above them to get some
lunch), is that there aren't repeatable experiments to substantiate the
inference. It's based on reason alone, and that's not science.
Physical biochemist Arthur Peacocke states it this way:
"I would like to point out that I don't think there is, first of all, a
real contrast between religion and science in the sense of one being
faith and the other being reason. I think both can be reasonable. And
it's interesting that in science, one often refers to the best
explanation, and the best explanation then often involves postulating
the existence of something you would never observe or ever could
observe.
Sometimes the best explanation involves postulating the existence of a
quark or something like that, depending on the nature of the question.
But very often it becomes historical. If it's geology, you're
postulating how the Alps formed or how the seas formed or how certain
geological formations got there. In no way can one go back and test
one's experiment and repeat the experiment. You're doing a detective
job. And the same applies, of course, in much of evolutionary theory.
One is making the most sense out of most of the data and inferring,
like a good detective, what happened in the past.
A lot of science is like that. It's not all repeatable experiments as
in physics and chemistry. And I think with the area of faith, the data
of faith involve all sorts of broader considerations and the religious
experience of humanity. Again, one is inferring to the best
explanation, the best way of referring to the realities which are
experienced in religion, in the past and in the present. So I think
there is a false assumption in the question, which I would like to
point to."
http://www.pbs.org/wgbh/evolution/religion/faith/discuss_01.html
There is a big difference between inference in the historical science
realm and the inference of applied science outside of that category,
and the difference has its basis in real-time active process
observation.
Steve
---
Did mind come before matter in the universe or matter come before mind?
Chapters 1 and 2 have your answer:
http://www.bottomlayer.com/bottom/reality/Intro.html
Zoe
>On Sat, 10 Jun 2006 01:11:36 GMT,
>Zoe <muz...@aol.com> wrote:
>> AC, sorry about the delay. You had asked me why I think electrons
>> exist. Here's why:
>>
>> Even though electrons are not themselves observable, they apparently
>> have properties that can be observed. Some of these properties are
>> charge, spin, velocity, energy, position, and so on. By observation
>> of these properties, and through experimentation, scientists find it
>> reasonable to extrapolate the existence of the electron, and I accept
>> their extrapolation based on solid experiments.
>
>The only thing we can *observe* about electrons is the effect they have
>on things we can observe. We cannot observe charge, spin, velocity,
>energy or position of these alleged particles, we can only infer them.
well, aren't those very effects recognized in terms of charge, spin,
velocity, et cetera, using whatever means scientists use to determine
those properties?
Maybe you can answer some questions I have about the wave-particle
duality of photons.
First, if a wave needs a medium in which to travel, how do photons
travel through a vacuum in which there is no medium for a wave to
travel? Do they change and act as a particle when passing through a
vacuum?
Also, in the double-slit experiment, it seems that when photons are
fed through a double slit, one at a time, with a detector to keep
track of which slit each goes through, there is no interference
pattern on the other side. Yet, without the detector, there is an
interference pattern.
The Copenhagen interpretation says that until the particle is detected
at any location along a probability wave, it actually exists at every
point, therefore it will pass through both slits, resulting in an
interference pattern. Tell me, please, is it possible for an
indivisible particle to divide and pass through both slits at the same
time?
Having come up against that oddity, I find myself speculating. Bear
with me.
What if the interference pattern, suggestive of a wave, is really due
to an optical illusion, something that the human brain gets tricked
into seeing? Since keeping track of single photons keeps the
interference pattern from developing, then maybe the wave-like
interference pattern is a result of the brain's inability to keep up
with the high-speed movements of the photons? I mean, if you don't
keep track of the photons, they move so fast and pile up so fast that
they leave the illusion of light and dark fringes? Which would mean
that photons or electrons are really only particles, never waves? The
wave-like pattern is only in the eye of the beholder?
Okay, I know I'm probably way off in left field here, but hey, it's MY
sandbox. I remember looking at a ceiling fan, and the blades were (as
usual) a blur, appearing as just a single, solid, rotating circle.
But if I followed the movements of the blades by rotating my head in
sync with the movement of the blades (yeah, I know this sounds loony)
I could once again see the individual blades of the fan.
So, could it be some form of relativity going on with the observations
in the double-slit experiment? The same way the movement of the
blades blur or separate relative to the stillness or parallel
movements of the observer, likewise the high-speed movement of photons
appears to produce interference, relative to the still position of the
scientist?
>
>>
>> It is also just as reasonable to extrapolate the existence of the
>> photon. While neither the electron nor the photon can be observed,
>> they are evident through their interaction with matter.
>
>We only know photons exist because of the effect they have. In the case
>of photons, they activate specialized nerves in our eyes. What we're
>seeing isn't photons, but the end result of photons stimulating rods and
>cones.
okay, I could buy that. What we're seeing is the world made visible
through the interaction of photons on our seeing apparatus? No
photons, no vision? That's why the need for a first command such as
"Let there be light"?
>
>>
>> Or take the wind. "Who has seen the wind? Neither you nor I, but
>> when the trees bow down their heads, the wind is passing by." A
>> simple childhood poem, but the same principle of extrapolation is
>> involved here. The existence of something called "wind" is evidenced
>> by its activity.
>
>That's right. We can infer the existence of things which we cannot
>observe directly.
>
>>
>> In the same way, I extrapolate the existence of Intelligence in nature
>> -- through observing the properties of mental activity as reflected in
>> nature.
>
>Even if that's true, Zoe, it has nothing to do with my point.
well, you didn't tell me what your point was, so I had to feel my way
through the photon-less darkness here.
> However,
>you aren't inferring design, you're simply assuming your conclusion.
>You really have no methodology at all.
and here is where I need to resurrect my languishing laws of
intelligence. Tomorrow is another day....
snip>
Baron Bodissey
<snip>
> The inference is confirmed by repeatable measurements of the actual
> phenomena associated with the electrons or photons.
>
> There is a big difference between inference in the historical science
> realm and the inference of applied science outside of that category,
> and the difference has its basis in real-time active process
> observation.
Granted, the historical sciences operate somewhat differently than the
experimental sciences; nevertheless inference plays a crucial role in
the scientific method in all sciences. You seem to think that somehow
makes the historical sciences inferior to the experimental sciences.
I can only speak from my rather narrow specialization: insect
systematics, or as it often called, taxonomy. By the way Darwin
practiced taxonomy, as well as Stephen J. Gould and many other
well-known names in evolutionary biology, so it seems an honorable
calling.
Taxonomy was criticized, with some justification, by other scientists
in the past as being more of an art than a science since it was almost
entirely descriptive in much the same way that purely descriptive
astronomy seems to have fallen out of favor. Classifications were based
on whatever criteria the classifier felt were important.
Beginning in the '60s methods began to be developed, first manual, now
much computerised, to analyze phylogenetic relationships and using the
results of that analysis to reconstruct hypothesized phylogenies, from
which can be built classifications thought to reflect actual
evolutionary relationships. The analysis involves the use of
characters, usually at first morphological structures but now often
gene sequences, and the search for taxa that possess uniquely derived
characters.
Often these analyses are performed repeatedly, as new characters are
discovered. The systematist always has a starting hypothesis which the
analyses (experiments) may or may not support. The resulting phylogeny
and associated character matrix are almost always published together so
that other taxonomists can replicate the results or refine them with
additional characters or different techniques (of which they are
several). The phylogeny is the hypothesis and it is falsifiable both by
the use of different character sets (say morphological vs. genetic, or
larval versus adult) AND each time a new taxon is discovered and added
to it through the same procedure, which in insect systematics is VERY
frequently.
What we are doing here is daunting actually. Most systematists do not
have fossils to work with or at least not very many. Picture if you
will the giant tree of life, with thousands of limbs, hundreds of
thousands of branches, and millions of twigs, not all of course
reaching the top of the tree. Now, with giant hedge clippers chop off
the top inch of the tree, throw all those twigs on the ground, and stir
well. Now, put them back on their correct branches in the correct
order.
None of us, I think, believes that what we arrive at is a 100% accurate
reflection of the evolutionary relationships of the organisms with
which we work. They are approximations based on the data we have NOW.
Further testing with additional data can only result in more robust
approximations, which they will always remain. And I'm cool with that.
What this perhaps excessive account (hell, I love what I do) is aiming
at is: Why is this not science? It is rigorous; the peer reviewers will
make sure of that. It involves hypthesis testing, experimentation,
falsifiability, and produces a usable product, the classification.
r norman
Your left field is pretty much in the same location as everyone
else's. The problem is that people look at quantum mechanics through
the rose-colored glasses of familiarity with classical phenomena of
experience with large objects that don't show those effects. So the
quantum-mechanical effects defy experience and become hard to grasp
conceptually.
First, the "wave" notion is a metaphor for a disturbance that
propagates at a certain velocity. In the case of classical
electromagnetism, it is the electric and magnetic "fields" that
wiggle. As Michelson and Morley showed, to much consternation in the
world of physics, there is no "ether" to act as a medium. Particles
like photons, of course, don't have that problem and relativity solves
the constancy of velocity problem. Light does not "become" a
particle under some circumstances and a wave under others. Rather,
the notion of a particle is appropriate for describing it under some
circumstances and the notion of a wave is better for describing it
under others. But what light really IS is another situation that is
simply not an intuitive notion. It is what it is and we have tools to
describe its behavior in all instances that we have found, sometimes
using wave-like methods and sometimes using particle-like methods as
needed.
Light (photons? waves?) ALWAYS shows interference as long we have some
means of detecting what happens. If there is absolutely no way of
telling whether or not it shows interference then there is absolutely
no way of knowing what it does. But if you try to set up an
experiment "without detectors" but then later cheat and peek into what
happened, the light "knew" you were going to look and interfered with
itself. Even a single photon "knew". No, that is not the proper way
of explaining things, but it will do.
When I took quantum mechanics, the professor told us (paraphrasing
some famous physicist whose name I forget) to forget our ideas and
stop thinking and just believe the mathematics. Set up the
foundations in a mathematical form and go with the math. It predicts
what happens and experiment confirms it. That is about all we can say
about "reality".
And no, some of the ideas really don't make sense. But when you do
the experiments, that is really what happens!
ave1
<snip>
> What this perhaps excessive account (hell, I love what I do) is aiming
> at is: Why is this not science?
Where did I say that the historical science category isn't real
science? I never said this, nor did I imply it. For goodness sake, I
will be the first to admit that Intelligent Design theory rests solidly
in that realm.
What my point had been was that in the realm of historical science
there is a different kind of inference-- the analogical method (AKA
abductive inference)-- than the inference which will go on when
discussing quarks or electrons. And the difference has its basis in
real-time active-process repeatable observations.
Science in the historical realm is not illegitimate, but it has more of
a reliance on one's philosophical inclination (which is often based on
assumptions that are not scientifically grounded-- since we're talking
about philosophy here), than does science outside of the historical
realm.
> It is rigorous;
I agree.
> the peer reviewers will make sure of that.
True.
> It involves hypthesis testing, experimentation,
> falsifiability, and produces a usable product, the classification.
>
> Baron Bodissey
Yes, you can have hypotheses, testing, falsifiability in the historical
realm of science. The fact of the matter, though, is that
interpretation of the historical data (which is often originated in the
unseen and unrepeatable past) has subjectivity which often relies on
the worldview of those scientists who bring forward the hypotheses and
theories.
AC
>> AC wrote:
>> > Zoe wrote:
><snip>
>> > Now, again, I ask you, why did you ask me that question?
>>
>> Because you seem to reject inference as a tool for biologists to
>> determine long-term evolution and Common Descent. But it's nice to see
>> that you reject the tired old "you weren't there so you can't know"
>> line.
>>
>> --
>> Aaron Clausen
>
> The inference is confirmed by repeatable measurements of the actual
> phenomena associated with the electrons or photons.
And yet the electron is inferred. It cannot be directly observed. Only
its influence on the world around it is detectable. That is perfectly
adequate. We do not need to directly observe phenomona to verify their
existence.
>
> The problem with an inference that purports to take observed active
> biological changes (of the processes that explain variation) and
> extrapolate into some idea that represents the making of things with
> high order and high complexity (ie. an eye or an archer fish's instinct
> of accurately spitting water at bugs on leaves above them to get some
> lunch), is that there aren't repeatable experiments to substantiate the
> inference. It's based on reason alone, and that's not science.
You are mistaken about the nature of science. Experiments are a way of
gaining data. They are not the only way. I cannot create volcanoes or
black holes, and yet we can study them. What you have presented is
simply a Creationist caricature of science.
Nowhere in this does he reject inference. I realize that finding quotes
by scientists that appear to support you must be satisfying, but I'm
afraid you aren't going to impress me.
>
> There is a big difference between inference in the historical science
> realm and the inference of applied science outside of that category,
> and the difference has its basis in real-time active process
> observation.
>
There is differences in inference in every science. But you're just
trying to build an artificial wall, because you know damn well that
electrons are not directly observable, and thus by taking your rejection
of large scale evolutionary change to its extreme.
Every single aspect of the universe you observe is infered. You do not
directly observe your computer. It's filtered through your complex
mental hardware. You just don't like the inference that the biological
sciences have revealed, but because physics doesn't rub you so much the
wrong way, you're willing to accept it there.
Now, have you observed an electron or not?
--
Aaron Clausen
mightym...@gmail.com
David Ewan Kahana
> On 11 Jun 2006 01:55:22 GMT, AC <mightym...@gmail.com> wrote:
>
> >On Sat, 10 Jun 2006 01:11:36 GMT,
> >Zoe <muz...@aol.com> wrote:
[snip]
> Maybe you can answer some questions I have about the wave-particle
> duality of photons.
>
> First, if a wave needs a medium in which to travel, how do photons
> travel through a vacuum in which there is no medium for a wave to
> travel?
Not all waves require a medium in order to be able to
propagate. Various kinds of waves appear to be able to
propagate through vacuum.
Electromagnetic waves, the classical waves of which light
was said to be ultimately made before quantum mechanics came
along are one case of this.
The probability amplitude waves of quantum mechanics, which
describe (probabilistically) the motion of the individual
photons that make up classical light waves are another such
case.
Still: for quite a while, it _was_ thought that a real
medium was required in order for classical light waves
to be able to propagate. There was no idea of quantum
mechanics yet when the Maxwell equations were written
down of course, so no one worried about probability
waves then.
But the fact is that the equations describing classical
light waves actually do not require or imply the existence
of any medium. They are simply mathematical equations
after all, which allow for the electric and magnetic
fields in the equations themselves, whose motion they
describe, to create waves which propagate all on their own,
by the following rough mechanism: a time varying electric
field creates a time varying magnetic field in a region
nearby, which in turn creates a time varying electric field a bit
further away ... and this cyclic process can continue ad
infinitum, producing an _electro-magnetic wave_ that moves
through empty space, even in the absence of any medium of
which that wave could be said to be a disturbance.
Still, even after the equations describing this process were
written down, almost everyone imagined that, nevertheless,
there _must_ be a medium through which light
travelled. Maxwell in fact had derived the final form of the
equations by assuming such a medium existed, and by making
up a detailed mechanical model for it.
So your question is very natural.
But when numerous experiments failed to detect any effects
of this supposed medium -- it was called luminiferous aether, or
aether for short -- and when it became clear that relativity
theory explained the failure of all such experiments as well
as many other observed phenomena relating to light and other
questions, the idea that light waves required any medium
in order to propagate was given up.
> Do they change and act as a particle when passing through a
> vacuum?
>
No.
> Also, in the double-slit experiment, it seems that when photons are
> fed through a double slit, one at a time, with a detector to keep
> track of which slit each goes through, there is no interference
> pattern on the other side. Yet, without the detector, there is an
> interference pattern.
>
Yes, assuming such a detector could be built. But a photon
can only be detected once, since photons are destroyed in
the process of detection, so if a photon is detected going
through slit 1, it could never reach the back wall at all.
But: a similar experiment could be done for electrons or
neutrons, say, and in that case it _might_ in principle be
possible to really build a detector which could say what
path the neutron or electron had followed. In that case, the
prediction of quantum mechanics is that what you say above
would happen.
Double slit experiments described in many places you will
read about them are often, to a very large extent, gedanken
experiments. That is they are descriptions of what one
thinks would happen in the given situation.
Not everything that you read about has actually been done.
Some real experiments of the general type _have_ been done,
though, and all of those that have been done do agree with
the predictions of quantum mechanics.
> The Copenhagen interpretation says that until the particle is detected
> at any location along a probability wave, it actually exists at every
> point, therefore it will pass through both slits, resulting in an
> interference pattern.
No. This is not quite right.
What the Copenhagen interpretation says is that before the
experiment is done and a particle is detected, together
possibly, with what path that particle actually took through
the experimental apparatus, the only information that can be
given by theory about what might happen in the experiment is
to specify the form of the probability amplitude.
This probability amplitude evolves in time according to the
Schroedinger equation.
Now the evolution is a well-defined notion, so there's
no ambiguity about what it means to say what I've said
here. It's a purely mathematical statement.
But then, the Copenhagen interpretation says, there occurs a
measurement process, by which the experimenters eventually
become aware of what has actually happened in the
experiment.
Now clearly, this measurement process is not very well
specified so far, so there is ambiguity there.
There is also some ambiguity about what is meant by the
probability amplitude or wavefunction, and people in fact are
divided in what they say about it.
Some people hold that it is a real physical thing, and that
leads to the kind of statement that you made above
about the particle actually existing at every point.
For my part, I hold that the probability amplitudes
themselves are not strictly speaking physical quantities, so
just the fact that a probability amplitude can be said to
`exist' everywhere along the possible paths that a photon
might travel, does not mean that the photon _actually_
exists at every point of those paths.
You see?
For me, the wavefunction is a theoretical object, and
discussions about what it does, though very common
and even useful, are meta-theoretical discussions.
Those are not quite as bad as meta-physical discussions
in my view, but they can become almost as bad, if
you are not very careful in what you say.
I know that this may seem like a very subtle difference, but
I think it is also a very important one.
The theoretical statement that is made under this view is
*not* that the photon actually passes through both
slits. The statement is that it _might_ pass through either
one.
That's why the basic objects that quantum mechanics deals
with are waves of probability amplitudes in fact.
Here's a bit more detail on how the theory goes
in the double slit experiments. I've reverted to
talking about photons, since you started out that
way. But all of the caveats I mentioned apply.
Let's call the source of the photons behind the two slits
s. Let's call the point on the other side of the two slits,
1, and 2, at which the photon is to be detected: x. For the
moment, forget about the possibility that there are photon
detectors d1 and d2 that could tell us through which slit
the photon actually went.
The detectors can be included in the analysis and we can
discuss how it is that they destroy the interference
pattern. But this is more complicated. I'm not going
to do it for you.
If there are no detectors, we can write the total
probability amplitude for the photon to be detected as:
PA(x,s) = < x | s >
Now since the motion is completely unknown, before
it actually happens and the photon is detected or not,
it's necessary for us to include all possible contributions
to the probability amplitude in our calculation of PA(x,s).
That includes the possibility that the photon passes
through slit 1, after leaving the source s, as well
as the possibility that the photon passes instead
through slit 2. Thus, we write:
PA(x,s) = < x | 1 > < 1 | s > + < x | 2 > < 2 | s>
= pa1 + pa2
In other words, to find the total probability amplitude that
the photon starts at s, and finishes at the point x, we add
up the probability amplitudes for all of the possible ways
in which the photon could go from s to x, and also, to find
the probability pa1 that the photon goes first from s to
slit 1, and then from slit 1 to point x, we multiply the
probability amplitudes for the successive steps along this
path.
Now of course, x could have been any point at all behind the
wall in which the two slits were cut. So if we can further
specify the forms of the basic probability amplitudes for
going from point a to point b: < b | a >, we will have
actually written down a quite general result, in fact. I
won't do that explicitly, but it isn't in fact too hard to
do.
Now in fact, there were a lot of hidden assumptions
in that discussion.
It was assumed that the slits are very narrow in comparison
to the wavelength of the light source producing the photons
involved in the experiment, and it was also assumed that
there was no possibility that the photon simply doesn't make
it through one or the other of the slits, or that the photon
possibly hits the wall of the slit and is reflected back
towards the side of the wall on which the source s, is
sitting, when it reaches a slit.
But one could handle all of these possibilities too, in an
exactly similar fashion.
The Copenhagen interpretation then says further that in
order to find out the actual probability that a photon makes
it from s to x, one should `square' the probability
amplitude. Actually, since the amplitudes are generally
complex numbers, `square' is shorthand for multiplying
the amplitude by its complex conjugate.
So after doing all of the above, and putting in the
explicit mathematical amplitudes for a photon
to propagate from point a to point b as required,
we then calculate:
P(s,x) = | PA(s,x) |^2 = | pa1 + pa2 |^2
Working out the square of the sum of pa1 and pa2 in this
expression for the probability of detecting a photon at x
will result in an expression involving the sum of the
squares of pa1, pa2, as well as an interference term
involving the product of the two.
The expression for the probability will yield the prediction
of the double slit interference pattern.
If we were to do a similar analysis using electrons instead
of photons, and with detectors in place that could allow us
to see which slit the electrons actually went through, then
the expression for P(s,x) would be significantly changed.
It would emerge that whenever we could say which slit an
electron went through, no interference pattern would result
for those electrons, but whenever we could not say for sure
which slit an electron went through, an interference pattern
would result.
> Tell me, please, is it possible for an
> indivisible particle to divide and pass through both slits at the same
> time?
>
No.
This possibility would lead to serious problems: half a photon
would presumably have half of the energy, and if the slits
were finite sized, this could be expected to make a
detectable difference in the pattern observed. And the
suggestion would not resolve the basic problem in any case,
which is that light is observed to have _both_ particle-like
and wave-like aspects to its behaviour in these experiments.
Photons can be said to be detected as discrete events on the
other side of the wall containing the slits in the right
circumstances, say, if the flux of light is made very low
and if one had a CCD camera on the back end with a fast
cycle time: one could then see every once in a while, a
discrete amount of charge being ejected from a specific cell
on the camera, which would correspond to a single photon
hitting that spot.
Similarly one could use ordinary film, and do successively
longer exposures. For short exposure times, one would see
basically random patterns of exposed spots on the film,
corresponding mostly to individual photons hitting the film
if the light intensity were very low. But over time, an
interference pattern would build up, either for the CCD or
for the ordinary film, showing that there was a wavelike
behaviour.
However, if the experimental apparatus doesn't allow one to
detect which slit the photon went through, then we simply
cannot say where it has gone.
Neither can we say that it has passed through both slits,
thought it's very clear that it is the fact that there
exists a possibility for a photon to pass through either
slit that allows for the interference pattern to be built
up: just block one of the slits, and the interference
pattern will go away.
This is the basic puzzle in quantum mechanics, and my
tendency is to resolve it in this case by saying that the
wavefunctions, which `exist' in both of the slits, are not
real physical objects. They are theoretical objects which we
manipulate according to definite rules to obtain the
prediction of what will happen in the experiment.
Thus I claim that it's not possible to say that there is any
dividing of the single photon in these experiments, or any
passing of pieces of it through both slits. The experiment
cannot detect what particular possible path the single
photon has followed, at the same time as also detecting an
interference pattern characteristic of a wave that passes
through both slits.
Nevertheless, it may be possible to detect individual photons,
or electrons in the detectors at the back of the experiment.
> Having come up against that oddity, I find myself speculating. Bear
> with me.
>
> What if the interference pattern, suggestive of a wave, is really due
> to an optical illusion, something that the human brain gets tricked
> into seeing?
No. The brain of the experimenter is irrelevant to what
happens. The interference pattern is quite real: it can
be preserved on film, or registered in a position sensitive
electronic detector and the results then recorded in a
computer, and we can then look and see what the result
was, play it back at our leisure and at any speed which
we desire. It isn't a matter of the limited nature of
human vision, or the assumptions built into
our visual perception systems.
The interference patterns are not optical illusions, and
they are not produced by the influence of the brains
of the experimenters. The experiments can be run
with no experimenters anywhere near to the apparatus,
and the same thing will happen.
> Since keeping track of single photons keeps the
> interference pattern from developing, then maybe the wave-like
> interference pattern is a result of the brain's inability to keep up
> with the high-speed movements of the photons?
It's not keeping track of single photons that matters, per
se, but trying to keep track of how and by what path each
individual photon has passed through the experimental
apparatus. As I said, one can't do that for single photons,
since photons are destroyed as soon as they are detected.
But setting up a double slit experiment where it was
possible to do that for single electrons would destroy the
interference pattern.
> I mean, if you don't
> keep track of the photons, they move so fast and pile up so fast that
> they leave the illusion of light and dark fringes? Which would mean
> that photons or electrons are really only particles, never waves? The
> wave-like pattern is only in the eye of the beholder?
>
Electrons or photons, whenever they are capable of being
detected as singles, are always only detected as particles.
But under the right circumstances both can be made to
display wave-like behaviour.
Both aspects are real enough in both cases. The basic
peculiarity is that certain kinds of experiments which one
might expect are possible to do if photons and electrons
are either particles or waves are in fact _in principle_
impossible to do ... namely an experiment which would
allow one to say what slit an electron passed through
in a double slit interference experiment, and still detect
a double slit interference pattern. The wavelike behaviour
of the electrons would be destroyed if the experimental
apparatus were such as to constrain the electrons to
behave like particles to the extent that it were possible
for experimenters to find out where the electrons actually
went.
[snip]
David
Ye Old One
group when s/he wrote:
>What we see is light.
>Light is either photons or a wave.
No, it is both.
>A photon is a unit of measure of light under specific circumstances,
No, a photon is a photon.
>nothing more, nothing less.
>What toasts your bread in the morning is a toaster that uses
>electricity, measured in Amperes. Amperes do not brown your toast, the
>phenomenon of electricity browns your toast.
Does it? Funny that, my cooker runs on gas.
>
>Why this has turned out into a battle of semantics is beyond me.
Just about anything scientific is beyond you.
--
Bob.