Light

[Rosa Lichtenstein]

Sultan:


so we see the light they sent out so many years ago

When was the last time you actually saw light?

We see by means of light, but we do not see light.

[Jazzratt]

Originally posted by Rosa [email protected] 08, 2007 10:51 am
Sultan:


so we see the light they sent out so many years ago

When was the last time you actually saw light?

We see by means of light, but we do not see light.
To be pedantic one can only see light - it is the light that our eyes pick up, we do not literally see objects, rather the photons reflected from these objects. That's how I always understood it anyway.

[Devrim]

Originally posted by Rosa Lichtenstein+September 08, 2007 10:51 am--> (Rosa Lichtenstein @ September 08, 2007 10:51 am) Sultan:


so we see the light they sent out so many years ago

When was the last time you actually saw light?

We see by means of light, but we do not see light. [/b]
What on earth are you talking about?

Of course we see light.


Wiki
Eyes are organs of vision that detect light.

We don't 'see' the picture, we 'see' light reflected off the surface of the object.

Devrim

[Rosa Lichtenstein]

Jaz:


To be pedantic one can only see light - it is the light that our eyes pick up, we do not literally see objects, rather the photons reflected from these objects. That's how I always understood it anyway.

So, you see photons and waves do you?

Once more we see by means of light, we do not see light.

Devri:


What on earth are you talking about?

Of course we see light.

Same comment.

[Dr Mindbender]

Originally posted by Jazzratt+September 08, 2007 12:00 pm--> (Jazzratt @ September 08, 2007 12:00 pm)
Rosa [email protected]ptember 08, 2007 10:51 am
Sultan:


so we see the light they sent out so many years ago

When was the last time you actually saw light?

We see by means of light, but we do not see light.
To be pedantic one can only see light - it is the light that our eyes pick up, we do not literally see objects, rather the photons reflected from these objects. That's how I always understood it anyway. [/b]
actually it hasnt been proven conclusively yet that photons even exist. They are hypothetical particles of 0 mass that were suggested in order to part explain the wave-particle duality.

[Rosa Lichtenstein]

Ulster Socialist:


actually it hasnt been proven conclusively yet that photons even exist. They are hypothetical particles of 0 mass that were suggested in order to part explain the wave-particle duality

Maybe so, but whatever it is made of, we do not see it.

[Dr Mindbender]

Originally posted by Rosa [email protected] 08, 2007 03:38 pm
Ulster Socialist:


actually it hasnt been proven conclusively yet that photons even exist. They are hypothetical particles of 0 mass that were suggested in order to part explain the wave-particle duality

Maybe so, but whatever it is made of, we do not see it.
light is made of 'waves' or in the case of photons 'packets of energy' neither of which have mass so therefore neither are tangible objects so either way, technically do not exist.

[Rosa Lichtenstein]

Ulster Socialist:


light is made of 'waves' or in the case of photons 'packets of energy' neither of which have mass so therefore neither are tangible objects so either way, technically do not exist.

Yes, I am well aware of physical theory, but if such things do not exist, you have to ask yourself what it is that has the properties you attribute to 'them'.

And there are plenty of intangibles that do exist.

So 'tangibility' is not a reliable criterion of existence.

[But, then again, it depends on what you mean by 'intangible'.]

[Dr Mindbender]

Originally posted by Rosa [email protected] 08, 2007 03:47 pm
Ulster Socialist:


[b]light is made of 'waves' or in the case of photons 'packets of energy' neither of which have mass so therefore neither are tangible objects so either way, technically do not exist.

Yes, I am well aware of physical theory, but if such things do not exist, you have to ask yourself what it is that has the properties you attribute to 'them'.

And there are plenty of intangibles that do exist.

So 'tangibility' is not a reliable criterion of existence.


Damn, this has got me thinking

*needs to read up on Quantum Physics* :P

[Rosa Lichtenstein]

Not really; you will find even top Physicists saying stupid things, which make no sense at all once you ask such awkward questions (based, dare I say it, on common sense).

So reading up on Quantum Physics will not actually help you.

Not that you shouldn't do it; but do not expect it to clear such things up.

[Jazzratt]

Originally posted by Rosa [email protected] 08, 2007 03:28 pm
Jaz:


To be pedantic one can only see light - it is the light that our eyes pick up, we do not literally see objects, rather the photons reflected from these objects. That's how I always understood it anyway.

So, you see photons and waves do you?

Well, yes. As do you. Eyes are just very sensitive light detectors.

US:


actually it hasnt been proven conclusively yet that photons even exist. They are hypothetical particles of 0 mass that were suggested in order to part explain the wave-particle duality.

I am aware of this but I'm personally quite a fan of photon theory. Naturally however I will change my views if given enough evidence but currently I think photons to be the most logically coherent explanation.

[Rosa Lichtenstein]

Jaz:


Eyes are just very sensitive light detectors

No doubt about it, but do you see light?

I.e., photons and/or waves?

[lithium]

Yes. Eyes are quantum detectors of photons/waves. When you see something red, you are seeing long wavelength EM radiation (light) reflected from that object; when you see something blue, you see short wavelength EM radiation being reflected.

So yes, you see light. You observe objects by means of light, and cannot view them without observing the light reflected from them.

lithium, astrophysicist

[Rosa Lichtenstein]

lithium:


Yes. Eyes are quantum detectors of photons/waves. When you see something red, you are seeing long wavelength EM radiation (light) reflected from that object; when you see something blue, you see short wavelength EM radiation being reflected.

So yes, you see light. You observe objects by means of light, and cannot view them without observing the light reflected from them.

You are confusing 'detect' with 'see'.

If you actually saw photons/waves, we would hardly need to have physicists try to prove they exist, would we?

Once more: we may be able to detect light with our eyes, but we cannot see light.

We see other things by means of light, as I said.

[mikelepore]

As for whether photons exist, experimental results are about the best information we can ever get, and the photoelectric effect and the Compton effect both indicate the involvement of photons.

[Devrim]

Originally posted by Rosa [email protected] 08, 2007 08:22 pm
You are confusing 'detect' with 'see'.


This is real semantic nonsense. In addition it is not even good semantics. Detect is not the right word. The right word is perceive. You could argue there is a difference between 'see' and 'perceive', but 'see' and 'detect' have the same meaning here.


Once more: we may be able to detect light with our eyes, but we cannot see light.

We see other things by means of light, as I said.

Eyes are light sensitive cells, nothing more, nothing less. We do detect light with them. This is exactly what 'seeing' is; the detection of light.

Devrim

[Rosa Lichtenstein]

Dev:


This is real semantic nonsense. In addition it is not even good semantics. Detect is not the right word. The right word is perceive. You could argue there is a difference between 'see' and 'perceive', but 'see' and 'detect' have the same meaning here.

Get your facts right; I only used the word 'detect' because others wanted to use it.

'Perceive' is a general word used in such contexts, but it has wider connotations connected with inferences we make about what we see, hear, feel...

And, even though you tell us these two words have the same meaning here, they cannot, for our eyes might be able to detect light, but they do not see it --, otherwise you would be able to see photons.

So, your semantics are somewhat addrift.

But, whether you use 'see' or 'perceive', we do not 'see' or 'perceive' photons, otherwise we would not need physicists to tell us they exist.


Eyes are light sensitive cells, nothing more, nothing less. We do detect light with them. This is exactly what 'seeing' is; the detection of light.

Who wants to deny the first part of this?

But the second part only works because you too are confusing 'light sensitive' and 'detect' with 'see'.

We see with our eyes, but we do not see the means by which we see (i.e. light).

But, if I am wrong, and you can 'see' photons, contact your nearest physics lab immediately; you will be able to make a fortune.

However, I claim 10% commission for the idea...

[Devrim]

Originally posted by Rosa [email protected] 09, 2007 10:41 am

Eyes are light sensitive cells, nothing more, nothing less. We do detect light with them. This is exactly what 'seeing' is; the detection of light.

Who wants to deny the first part of this?

But the second part only works because you too are confusing 'light sensitive' and 'detect' with 'see'.

We see with our eyes, but we do not see the means by which we see (i.e. light).

But, if I am wrong, and you can 'see' photons, contact your nearest physics lab immediately; you will be able to make a fortune.

However, I claim 10% commission for the idea...
I think that you need to check some basic physics books. We see the light. Our brains do not perceive it as waves, or particles, but that doesn't mean that we don't see the light. I also do not perceive this desk that I am writing at to be mostly empty space. I perceive it as a solid object. That doesn't mean that it actually is*.

If you don't think we see light, what do you imagine we see?

Devrim

*Of course on a human level in all practical ways it is.

[gilhyle]

I agree with Rosa, though maybe from a different perspective. Even technically, its not a matter of seeing light, but of seeing the nuances in light consequential on them having bounced off objects. Blind people can often see light.

Its philosophically of some importance not to fall into the idea that we 'see' with our eyes alone. The mechanism for perception (and I take seeing to be equivalent to perception for the purposes of this comment) is more complex involving both eyes and brain and various bits and pieces in between. 'Seeing' is more complex than detecting light.

Common usage is not much help here. Take a person whose brain had been so damaged that they could no longer process the data from their eyes. One could sensibly say, his 'eyes work perefectly, they react to intense light, but he cant actually see anything.'Our usage is not consistent. You could say he sees objects, but he cant recongise them. However, we would commonly say to someone while jointly trying to identify a distant object 'Can you see it'.....and so on : usage is not clear.

The point that is a bit more important is to avoid the empiricist notion of seeing as a passive activity of the eye rather than an active process. Seeing is one of the ways animals relate to the external world. The sustainable model of seeing, for a materialist, is a model which understands it as a process of deecting objects, which relies on light, not a process for detecting light.

[Rosa Lichtenstein]

Gil:


Blind people can often see light

They are blind, so they can see nothing.

What they have are visual experiences (connected with the excitation of nerves, etc), and nothing to do with light.

Unless, of course, they were not blind to begin with.


Take a person whose brain had been so damaged that they could no longer process the data from their eyes.

The eyes do not send 'data' (since they are not human beings).

[gilhyle]

Picky rosa, picky......but since Im agreeing with you about the use of the term 'see' I accept your first point with one caveat : my usage was inconsistent with my argument because common usage of this verb is inconsistent.

But of course a blind person would explain to you why there is such inconsistent usage....cos the reality of blindness is more complex than either blind or sighted. However, thats all beside the point of this thread.

As to the second point, delete the metaphor, insert your correct term and...the argument remains intact.

[Rosa Lichtenstein]

I am well aware of what blind people say; my one and only Marxist teacher at university was blind (in fact he was the first to translate the 1844 manuscripts into English), and you can read what he had to say in 'Blindsight', a book he co-authored with Brian Magee.

One thing they do not see is light, for there are no photons getting through (unless, of course, they are not blind).

And I am picky over the misuse of language, because most people (ie., philosophers and scientists) are not, and they fall into confusion as a result.

And as for this:


Take a person whose brain had been so damaged that they could no longer process the data from their eyes.

I would not put it that way at all, metaphor or no metaphor.

[gilhyle]

Fine...being picky then I assume you mean the first to translate 'all' the 1844 manuscripts....unless you were lucky enough to be taught by CLR James.

I assume if I talked about a case where the optic nerve was cut that might work...or maybe ischemic anterior optic neuropathy....given particularly that the optic nerve is usually considered an extention of the brain, rather than part of the eye. But maybe you'd insist on my example speculating on dysfunction of the optic chiasm.....what does it all matter ?

[Vinny Rafarino]

Originally posted by rosa
We see by means of light, but we do not see light.



I hate when you try to pull this crap.

Here's how the human eye operates: rhodopsin proteins in the photoreceptor neurons of the retina absorb light that enters the eye. These photoreceptors then send specific signals to a group of neurons that generate the electrical impulses that are sent to the brain.

Your brain then interprets these signals into what we call vision.

So actually Rosa, All you see is light.

[Guifes]

Physics isn't meant to explain what light is, it's meant to explain how light behaves. On this matter physics states that in some cases light behaves like a wave and in some (in general smaller scale) cases light behaves like particles. This particle aspect of light is called a photon, just for the sake of simplicity. In fact this duality is observed in all matter but because of the size of material things we are familiar with the wave aspect is completely dominated by the particle aspect.

Calculating your own wave-length for instance can be done quite easily using the de Broglie hypothesis which can be found at http://en.wikipedia.org/wiki/De_Broglie_hypothesis

[Rosa Lichtenstein]

Devrim:


I can't really understand why Rosa is still arguing that you don't.

Look in a basic physics book

How many more times do I have to say this: it has nothing to do with science.

If you or I could see light, we would not need scientists to tell us what it is; we'd all know it was made of waves and/or photons.

We see by means of light, we do not see light.

[Rosa Lichtenstein]

Devrim:


Oh dear, the physical world has 'nothing to do with science'.
I don't think you have any understanding of what you are talking about at all.
You would have thought they would have taught you something at that university.
Anyway, I can't be bothered anymore. Go on in ignorance.
Devrim

There are loads of things in the world that science has nothing to do with.

One is the ordinary use of language.

Why? Because scientists have to use language too, and if they misuse it, they fail to make sense.

This is one example of that; you cannot see light, you see by means of light.

Not even the greatest scientist who ever lived saw light.

He/she might have seen by means of it, but we already established that.

And there is no need to get snooty about what I did or did not learn at university; I do not want to fall out with you.

Unless you can explain how you see light (i.e., waves and photons), and why we need scientists to tell us what light is (when we would all know, if we actually saw light), you have no case to make.

So far you have failed to do that. I suggest you shut up then.

You too can go, but not in ignorance: in total confusion. Ignorance can be corrected.

But, you will still be confused tomorrow...

[Vinny Rafarino]

Originally posted by Rosie
Unless you can explain how you see light (i.e., waves and photons), and why we need scientists to tell us what light is (when we would all know, if we actually saw light), you have no case to make.

This is just philosophical nonsense.

Scroll up to where I explained how the human eye works and read the post again.

Keep reading it until it finally sinks in.

[Rosa Lichtenstein]

VR:


This is just philosophical nonsense.

Scroll up to where I explained how the human eye works and read the post again.

Keep reading it until it finally sinks in.

Once more: this has nothing to do with science, but has everything to do with describing things accurately.

So you can make references to eyes and physiology all day long, it will make no difference to the fact that we do not see light, we see by means of light.

Science tells us about the latter, not the former.

[Vinny Rafarino]

Originally posted by rosie
Science tells us about the latter, not the former.

You're wrong.

I would suggest that whatever "science" you've been listening to you stop listening immediately.

[Rosa Lichtenstein]

VR:


You're wrong.

I would suggest that whatever "science" you've been listening to you stop listening immediately.

Been listening to the same science as you.

And, even you know you have never seen light.

How do I know?

If you had, you would be able to see photons.

So, if you can see photons, I will withdraw my claim.

Can you?

[Vinny Rafarino]

Been listening to the same science as you.

And, even you know you have never seen light.

How do I know?

If you had, you would be able to see photons.

So, if you can see photons, I will withdraw my claim.

Can you?

What's the point?

You rationalization that seeing light means seeing photons is equally absurd as your previous assertion that seeing light means seeing the actual light waves.

[Qwerty Dvorak]

What is light then?

[Rosa Lichtenstein]

VP, at last stuck for words:


What's the point?

You rationalization that seeing light means seeing photons is equally absurd as your previous assertion that seeing light means seeing the actual light waves.

So, you can't see light, as I said.

Your mumbling response confirms my earlier prediction:


And, even you know you have never seen light.

How do I know?

If you had, you would be able to see photons.

So, if you can see photons, I will withdraw my claim.

Can you?

And labelling something 'absurd' is a lazy cop out. Why is it absurd?

If you claim to be able to see light, and light is made of photons, then you must be able to see photons.

So, either light is not made of photons, or you cannot see light.

Which is it to be?

Now, can we move on?

[Rosa Lichtenstein]

RS1916:


What is light then?

The means by which we see.

If you want to know what it is made out of, VR will tell you.

[Photons and waves, I think he will say, even though he has never seen either.]

[Qwerty Dvorak]

Thank you Rosa that's what I thought, I was just trying to get VR's opinion on the matter.

[Vinny Rafarino]

Originally posted by rosa
So, you can't see light, as I said.

And it appears that stubborn ignorance is set in quite firmly.


And labelling something 'absurd' is a lazy cop out

To you maybe.

To me it's either call your crapola absurd or spend an eternity trying to educate someone who refuses to be educated.


If you claim to be able to see light, and light is made of photons, then you must be able to see photons.


If you claim to be able to see wood, and wood is made of atoms, then you must be able to see atoms.

See how silly you are?

I'll go back to just saying absurd now.

[Rosa Lichtenstein]

VR:


And it appears that stubborn ignorance is set in quite firmly.

Ah, at last we have a reasoned response, not bluster and abuse:


If you claim to be able to see wood, and wood is made of atoms, then you must be able to see atoms.

Several crucial differences:

1) Wood does not allow us to see other things. Light does.

2) Objects made of wood (or those made of any other substance) manifest themselves to us in identifiable ways. So, we see tables and chairs, trees and floor boards, and the like.

But, how does light as such manifest itself to us?

We do not see it. We certainly do not see objects made of light, unlike those we see made of wood.

Sure, you may see beams of light, but then that is merely the scattering of light off dust particles in the air (or some such).

Now if I asked you what wood looks like you would be able to give me some adjectives to describe what it looks like to you.

So, if I ask you to describe light, what could you tell me?

All you could respond with are its effects on other objects already there.

Now that is why I have been posing this question to you repeatedly: if you claim to be able to see light, then you must be able to see photons, for you have no other way of telling me about your claimed experience.

This is totally unlike wood, where you do have alternative ways of reporting seeing it.

So, once more: light is the means by which we see (things like wood), but we do not see light itself.

Now, if you still think we see light, give me a few words to describe what it is you actually see when you see light itself (not the objects it allows you to see because of it).

[Vinny Rafarino]

Originally posted by Rosa
Ah, at last we have a reasoned response, not bluster and abuse:

The chick who issues wishes of death is lecturing me on "bluster and abuse".

That's rich. :lol:


Several crucial differences:

In your mind.


But, how does light as such manifest itself to us?

Since light lacks consciousness it really can't "manifest itself" to anyone.

If you want to know how humans perceive how light is manifested then try this little experiment:

Shut your eyes real tight; that blackness you see is the absence of light.

Now open them up.

Bingo, you got light.


So, if I ask you to describe light, what could you tell me?

Depending of course on the frequency of the wavelength I would tell you what color the light was.

Have you never seen a rainbow? That's what science calls visible light.

Rather than try to explain it to you just click this link. (http://www.usbyte.com/common/approximate_wavelength.htm)

[Rosa Lichtenstein]

VR: any more sexist language, and I will refer this to the CC:


The chick who issues wishes of death is lecturing me on "bluster and abuse".


Since light lacks consciousness it really can't "manifest itself" to anyone.

If you want to know how humans perceive how light is manifested then try this little experiment:

Shut your eyes real tight; that blackness you see is the absence of light.

Now open them up.

Bingo, you got light.

It's Ok for you to use metaphor, but not me, apparently.

Fine, let's put this in more concrete terms so that even you can understand it:

When you look at wooden objects you see things like tables and chairs

So you see woo in forms like this.

In what form does light appear to you?

And, what you see when you open your eyes are objects all around you (which you can see by means of light). But you do not see light itself.


Depending of course on the frequency of the wavelength I would tell you what color the light was.

Have you never seen a rainbow? That's what science calls visible light.

I have never denied you can see colour; but even in a rainbow you do not see light, merely colours.

[Pawn Power]

I maintain that the debate is semantical.

But it was entertaining nevertheless.

[Rosa Lichtenstein]

PP:


I maintain that the debate is semantical.

But it was entertaining nevertheless.

No really: if we cannot describe what we see, or state it a comprehensible form, no possibility has been presented yet for our consideration.

That is why VR is dodging about for he has yet to tell us what the options before us are.

The real question he side-steps is: How can we see the means by which we see?

[Vinny Rafarino]

Originally posted by The dear leader Rosa
That is why VR is dodging about for he has yet to tell us what the options before us are.

The real question he side-steps is: How can we see the means by which we see?


I already explained that to you yet to still can't seem to grasp this relatively simple concept. Your pseudo-scientific analysis just doesn't hold water.


I accept your surrender.

Accept and think whatever you want.

When you decide to fly back from Neptune, let me know so I can collapse the net.

[Rosa Lichtenstein]

I hesitate to reply to VR now that he has been booted off this board, but here goes:


I already explained that to you yet to still can't seem to grasp this relatively simple concept. Your pseudo-scientific analysis just doesn't hold water.

I beg to differ; what you succeeded in doing is confusing what we see with the means by which we do it.


Accept and think whatever you want.

When you decide to fly back from Neptune, let me know so I can collapse the net.

Eh? :blink: