Light: visible or invisible?

[Eise]

13 minutes ago, koti said:

you state that Im using your definitions

Yes, you did: See1 = See2. 

I think the only argument against my distinction is that it is practically useless. That's fine. But it does not really help to answer the OP.

Do you think we disagree on semantics or on physical processes? When it is semantics, how would you flesh out these semantic differences? 

 

Edited February 15, 2018 by Eise

[koti]

On 9.02.2018 at 8:07 AM, Eise said:

Then you must conclude that the daily use of 'seeing', in the sense of 'seeing houses, cars and apples' is the wrong meaning.

 

6 minutes ago, Eise said:

 

Do you think we disagree on semantics or on physical processes? When it is semantics, how would you flesh out these semantic differences? 

 

Since you assert that the use of the word "seeing" is wrong, I see no point in continuing besides what I already stated in this thread. If you want a detailed explanation please use this tool:
https://randomwordgenerator.com/
 

[Eise]

39 minutes ago, koti said:

Since you assert that the use of the word "seeing" is wrong,

I did not do that. I distinguished two different meanings, repeatedly saying that in daily use this distinction plays no role. But of course, when somebody reduces the meaning of 'seeing' to only one of these two meanings, he necessarily leaves out the other. That is e.g. what the OP did. Nowhere I said that saying 'I see light' is wrong. But what I did say is that 'I see1 light' is wrong, because we do not see light because it reflects light. 

[koti]

1 hour ago, koti said:

 

Since you assert that the use of the word "seeing" is wrong...

 

11 minutes ago, Eise said:

I did not do that.

Yes you did:

On 9.02.2018 at 8:07 AM, Eise said:

 

Then you must conclude that the daily use of 'seeing', in the sense of 'seeing houses, cars and apples' is the wrong meaning.

 

[Area54]

4 minutes ago, koti said:

Yes you did

Eise appears to say that "you" must conclude the daily use of 'seeing', in the sense of 'seeing houses, cars and apples' is the wrong meaning. He does not say that he concludes this.

[koti]

2 minutes ago, Area54 said:

Eise appears to say that "you" must conclude the daily use of 'seeing', in the sense of 'seeing houses, cars and apples' is the wrong meaning. He does not say that he concludes this.

I must conclude that his line of thought is correct (which I think it isn’t) and at the same time he doesn’t need to conclude his stated line of thought is correct? Oh this keeps getting better and better...

We might as well start defining the uses of the words „you” and „better” in various contexts and sentences. It would be asinine to do so.

[Eise]

On 09/02/2018 at 8:07 AM, Eise said:

Then you must conclude that the daily use of 'seeing', in the sense of 'seeing houses, cars and apples' is the wrong meaning.

This is what you said:

On 08/02/2018 at 11:00 PM, koti said:

All we can see is light - nothing less, nothing more - only light.

What you were describing ('you see only light') fits to my description of 'see2'. With that 'only' you exclude 'see1'.

I put it in your mouth ('Then you must conclude...'), not in mine. I would never agree with your statement that we only see light. Usually I see all kind of things, thanks to their reflection. I see cups on my desk, which I see of course too, my computer screens (OK, these emit light), outside I see cars. If you say we only see light, i.e. 'seeing light' is the only correct use of 'seeing', then you should say I am wrong when I describe my environment, and I should use another word instead of 'seeing', e.g. 'observe by visually means'. But that would be a bit weird, isn't it?

And we had the problem of the 'perfect black dog'. As it neither reflects, nor emits light, one had to say one does not see this dog. Which makes no sense too.

 

 

20 minutes ago, Area54 said:

Eise appears to say that "you" must conclude the daily use of 'seeing', in the sense of 'seeing houses, cars and apples' is the wrong meaning. He does not say that he concludes this.

Started posting before I saw yours. Yep, that is exactly what is going on.

[koti]

9 minutes ago, Eise said:

 I would never agree with your statement that we only see light. Usually I see all kind of things, thanks to their reflection. I see cups on my desk, which I see of course too, my computer screens (OK, these emit light), outside I see cars. If you say we only see light, i.e. 'seeing light' is the only correct use of 'seeing', then you should say I am wrong when I describe my environment...

Eise please correct me if Im wrong: You are making a distinction between seeing emitted light and seeing reflected light and you’re basing your definitions of see1 and see2 on this distinction? This is plain nuts.

[Eise]

31 minutes ago, koti said:

Eise please correct me if Im wrong: You are making a distinction between seeing emitted light and seeing reflected light and you’re basing your definitions of see1 and see2 on this distinction? This is plain nuts.

Please read the OP, and just try to think what he could possibly have meant. Do not yet think he is right or not, but what could be the reason he asks such a question. He more or less gives it away himself: "We all know that we see objects because they reflect light into our eyes." Now by reducing the meaning of seeing to 'seeing objects because of reflected light', he can conclude that we do not see light, because light does not reflect light. Just taste it first. 

Now I see this distinction, and tried to make it explicit by defining:

1. See1: seeing macro objects because they reflect or emit light (e.g. cars and computer monitors)
2. See2: seeing light because it enters the eye.

So it is not the distinction between reflected or emitted light, as you think that I think. My distinction is based on the observation that one cannot see a light beam that is passing close by you, and shining light on it does not help in seeing it: it must enter your eye (and then you do not see a light beam, but a light spot).

The complete visual system always tries to construct an image of a thing, i.e. a macro object. If just plain light enters the eye, it still tries to see what macro object it is that it sees. The worst that can happen is that you cannot identify it at all, and you see only a bright, blurry spot. 

So in my opinion, with this little philosophical instrumentarium, we can answer the OP clearly:

If you only define 'see1' as seeing, then you are right: then light is invisible. On the other side, it is very artificial to say that light is invisible. So I personally would also include 'see2' in the normal meaning of 'seeing': and then light is visible.

Why would this not be a satisfactory reaction?

[koti]

18 minutes ago, Eise said:

Please read the OP, and just try to think what he could possibly have meant. Do not yet think he is right or not, but what could be the reason he asks such a question. He more or less gives it away himself: "We all know that we see objects because they reflect light into our eyes." Now by reducing the meaning of seeing to 'seeing objects because of reflected light', he can conclude that we do not see light, because light does not reflect light. Just taste it first. 

Now I see this distinction, and tried to make it explicit by defining:

1. See1: seeing macro objects because they reflect or emit light (e.g. cars and computer monitors)
2. See2: seeing light because it enters the eye.

So it is not the distinction between reflected or emitted light, as you think that I think. My distinction is based on the observation that one cannot see a light beam that is passing close by you, and shining light on it does not help in seeing it: it must enter your eye (and then you do not see a light beam, but a light spot).

The complete visual system always tries to construct an image of a thing, i.e. a macro object. If just plain light enters the eye, it still tries to see what macro object it is that it sees. The worst that can happen is that you cannot identify it at all, and you see only a bright, blurry spot. 

So in my opinion, with this little philosophical instrumentarium, we can answer the OP clearly:

If you only define 'see1' as seeing, then you are right: then light is invisible. On the other side, it is very artificial to say that light is invisible. So I personally would also include 'see2' in the normal meaning of 'seeing': and then light is visible.

Why would this not be a satisfactory reaction?

I still think its nuts. You don’t see a laser beam in a vacum because physics not because „see1” and „see2”.

[Eise]

40 minutes ago, koti said:

You don’t see a laser beam in a vacum because physics not because „see1” and „see2”.

Of course. The difference between see1 and see2 is based on physics.

Things do not fall because we have a word for it. They fall because of physics, and because we clearly see the difference between an object lying on a table, it made sense to have a word to describe falling. Having different words for seeing macro objects and for seeing light is of nearly no interest, but one can make the distinction, if one wishes.

40 minutes ago, koti said:

I still think its nuts.

I find it disappointing, that you cannot leave, at least temporary, your own frame of thought, get to know another one, and only then evaluate, based on arguments, what you think is the best position. 

On 09/02/2018 at 6:08 PM, CharonY said:

The discussion goes in circles because it is down to semantics. But considering the rest of the discussion one can make a the distinction that they can only see light (i.e. differences in brightness) but are unable to see objects. Or, as has been mentioned, we perceive light directly (on the retina) but need additional information (and mechanisms) to perceive objects.

As most have conceded, that is a meaningless distinction in terms of OP, but it is pretty much one of the distinctions that spawned these nine pages. Obviously, we always need the former to be able to do the latter. But if we wanted to make a distinction, we could.

Just to show I am not the only one. Is this comment nuts too?

Edited February 15, 2018 by Eise

[koti]

1 hour ago, Eise said:

Of course. The difference between see1 and see2 is based on physics.

Things do not fall because we have a word for it. They fall because of physics, and because we clearly see the difference between an object lying on a table, it made sense to have a word to describe falling. Having different words for seeing macro objects and for seeing light is of nearly no interest, but one can make the distinction, if one wishes.

I find it disappointing, that you cannot leave, at least temporary, your own frame of thought, get to know another one, and only then evaluate, based on arguments, what you think is the best position. 

Just to show I am not the only one. Is this comment nuts too?

I am willing to leave my frame of thought for useful purposes, I refuse to leave it in this case, to find an alternative meaning to the word „see” as I am fairly familiar with both the physical and physiological aspects of what/how/why species see. I am overwhelmed by your statement that:

„Now I see this distinction, and tried to make it explicit by defining:

1. See1: seeing macro objects because they reflect or emit light (e.g. cars and computer monitors)
2. See2: seeing light because it enters the eye.”

The above „see1 & see2” distinction is plain wrong in my opinion. There can be no distinction between things we see caused by emitted or reflected light - its the same thing. There can be no distinction between see1 which is „light entering the eye” and see2 which is „exactly the same gd thing”  The eye doesn’t care if the light which hits it comes straight from the source or from an object which reflected light.

[John Cuthber]

10 hours ago, Eise said:

Just the OP. Nothing more. You can google yourself. You will find some similar questions and reactions.

So... you think the OP was asking if a car was the same as light...

That's an unorthodox way to look at it. Admittedly, given that the OP makes assertions that are not true you might  use it to generate all sorts of paradoxes.

 

11 hours ago, Eise said:

This is what Koti said:

On 2/14/2018 at 1:29 PM, koti said:

See1 = See2

I know  what he said, but it's not relevant. You said

 

On 2/14/2018 at 2:04 PM, Eise said:

You see a car because it enters your eye?

which is nonsense, but your implication was that someone else had said it.

They hadn't.

[koti]

1 hour ago, John Cuthber said:

 

I know  what he said, but it's not relevant. You said

For the record, I repeated Eise’s words, they are not mine. „See1 & See2” is not my „concept”

[MigL]

For the record...
The majority of us decided long ago that this argument was based on semantics and incomplete definitions.

Eise, the only one who thought to properly define the terms and take some of the ambiguity out of the definitions, is being pilloried and called a 'dick'.

Come'on guys, we're better than that.

[StringJunky]

9 minutes ago, MigL said:

For the record...
The majority of us decided long ago that this argument was based on semantics and incomplete definitions.

Eise, the only one who thought to properly define the terms and take some of the ambiguity out of the definitions, is being pilloried and called a 'dick'.

Come'on guys, we're better than that.

Eise is too nuanced for most but with his keenness for proper philosophy, it's not surprising because it requires delineating subtleties of language and closely related concepts, which is what's happening here and people are struggling with.

[Eise]

12 hours ago, John Cuthber said:

Admittedly, given that the OP makes assertions that are not true you might  use it to generate all sorts of paradoxes.

What is not true? To reformulate the OP as a statement instead of a question:

If we define seeing as 'seeing by reflected light', then we cannot see light, because light does not reflect light.

And that is a true sentence. You might object that we usually do not define seeing like that, but that does not make the 'if'-sentence as a whole false.

14 hours ago, koti said:

The above „see1 & see2” distinction is plain wrong in my opinion. There can be no distinction between things we see caused by emitted or reflected light - its the same thing.

Again: that is not the distinction I make with 'see1' and 'see2'. Both are covered by 'see1':

See1: seeing macro objects because they reflect or emit light

12 hours ago, John Cuthber said:

which is nonsense, but your implication was that someone else had said it.

Koti said:

See1 = See2.

So build a logical argument. Let's take the definitions again:

1. See1: seeing macro objects because they reflect or emit light (e.g. cars and computer monitors)
2. See2: seeing light because it enters the eye.

Then the logical argument goes as follows:

1. We see1 cars (according definition)
2. See1 = See2 (Koti's proposition)
3. We See2 cars (substitute see1 with see2)
4. Plug in the definition of see2
5. We see cars because they enter the eye.

That is wrong of course. But it follows from the definitions of see1 and see2, together with Koti's proposition. If Koti does not acknowledge the difference between see1 and see2, he at most can argue that we cannot distinguish between how we see macro objects and how we see light. But that is pertinently false. We can make the distinction, based on plain physics, if we want. But not wanting to do that is not the same as not being able to make the distinction.

@Migl and StringJunky: thanks for your support.

Edited February 16, 2018 by Eise

[koti]

8 hours ago, MigL said:

For the record...
The majority of us decided long ago that this argument was based on semantics and incomplete definitions.

Eise, the only one who thought to properly define the terms and take some of the ambiguity out of the definitions, is being pilloried and called a 'dick'.

Come'on guys, we're better than that.

Saying colloquially that Eise used a „being a dick fallacy” is by no means equall to calling him a dick - I would not do that, I’ve seen his contributions to this forum and I have too much respect for him to insult him.

7 hours ago, StringJunky said:

Eise is too nuanced for most but with his keenness for proper philosophy, it's not surprising because it requires delineating subtleties of language and closely related concepts, which is what's happening here and people are struggling with.

Thats why I’m still in this thread trying to understand Eise’s alternative point of view. 

2 hours ago, Eise said:

What is not true? To reformulate the OP as a statement instead of a question:

If we define seeing as 'seeing by reflected light', then we cannot see light, because light does not reflect light.

And that is a true sentence. You might object that we usually do not define seeing like that, but that does not make the 'if'-sentence as a whole false.

Again: that is not the distinction I make with 'see1' and 'see2'. Both are covered by 'see1':

See1: seeing macro objects because they reflect or emit light

Koti said:

See1 = See2.

So build a logical argument. Let's take the definitions again:

1. See1: seeing macro objects because they reflect or emit light (e.g. cars and computer monitors)
2. See2: seeing light because it enters the eye.

Then the logical argument goes as follows:

1. We see1 cars (according definition)
2. See1 = See2 (Koti's proposition)
3. We See2 cars (substitute see1 with see2)
4. Plug in the definition of see2
5. We see cars because they enter the eye.

That is wrong of course. But it follows from the definitions of see1 and see2, together with Koti's proposition. If Koti does not acknowledge the difference between see1 and see2, he at most can argue that we cannot distinguish between how we see macro objects and how we see light. But that is pertinently false. We can make the distinction, based on plain physics, if we want. But not wanting to do that is not the same as not being able to make the distinction.

@Migl and StringJunky: thanks for your support.

Eise you are making an argument based on your see1 and see2 distinction which I do not accept. I put an equall sign between the two to emphasize that there should be no distinction in my opinion. I find your distinction between

1. Seeing objects because they emit or reflect light and

2. Seeing light because it enters the eye.

extremely frustrating and I’m sory but I don’t see the nuances mentioned by StringJunky. All I see is a false definition of „seeing” based on a null premise that there is a distinction.

Edited February 16, 2018 by koti

[Eise]

Hi Koti,

I do not understand why this is so difficult to understand. I only feel a huge resistance against splitting the meaning of seeing in 2 slightly different ones, whereby both together encompass the daily meaning of 'seeing'. 

I am 100% sure that you (and John) understand the physics on which my distinction is based. I do not plead that we from now on must say that light is invisible. I do plead to understand that there is a tiny difference in the meanings of 'to see' between seeing macro objects and light. (Again, I also do not say you should from now on always be fully conscious of these different meanings.)

What I do say is that if you reduce the meaning of 'to see' to one of these meanings you per definition cannot see something in the other sense.

Say I redefine the word 'car' as 'cup of tea'. Then I can drink a car. So I can build the simple sentence:

• If we define 'a car' as 'a cup of tea' then I can drink a car.

This sentence is true

Just as this negative:

• If we define 'a car' as 'a cup of tea' then I cannot drive home with it.

And now try this one again:

• If we define 'seeing' as 'seeing by reflected light', then we cannot see light, because light does not reflect light.

That is all. Nothing more is happening here. The only relevance is when somebody explicitly asks how people could possibly say that light is invisible.

After dealing with this semantics exercise, one can immediately follow up by saying that it is a very artificial way of defining 'to see' and that, if one does this, one must say that light is invisible. And some of you already referred to the difference between visible and invisible light (infra red, e.g.), which would be a funny difference if all light were invisible. So better stick to the normal definition of 'to see', where you can see cars and light.

[Area54]

On 15/02/2018 at 1:07 PM, koti said:

I must conclude that his line of thought is correct (which I think it isn’t) and at the same time he doesn’t need to conclude his stated line of thought is correct? Oh this keeps getting better and better...

We might as well start defining the uses of the words „you” and „better” in various contexts and sentences. It would be asinine to do so.

With respect you appear to be allowing emotion to overrule comprehension skills. On that basis I'm out.

[koti]

5 hours ago, Eise said:

Hi Koti,

I do not understand why this is so difficult to understand. I only feel a huge resistance against splitting the meaning of seeing in 2 slightly different ones, whereby both together encompass the daily meaning of 'seeing'. 

I am 100% sure that you (and John) understand the physics on which my distinction is based. I do not plead that we from now on must say that light is invisible. I do plead to understand that there is a tiny difference in the meanings of 'to see' between seeing macro objects and light. (Again, I also do not say you should from now on always be fully conscious of these different meanings.)

What I do say is that if you reduce the meaning of 'to see' to one of these meanings you per definition cannot see something in the other sense.

Say I redefine the word 'car' as 'cup of tea'. Then I can drink a car. So I can build the simple sentence:

• If we define 'a car' as 'a cup of tea' then I can drink a car.

This sentence is true

Just as this negative:

• If we define 'a car' as 'a cup of tea' then I cannot drive home with it.

And now try this one again:

• If we define 'seeing' as 'seeing by reflected light', then we cannot see light, because light does not reflect light.

That is all. Nothing more is happening here. The only relevance is when somebody explicitly asks how people could possibly say that light is invisible.

After dealing with this semantics exercise, one can immediately follow up by saying that it is a very artificial way of defining 'to see' and that, if one does this, one must say that light is invisible. And some of you already referred to the difference between visible and invisible light (infra red, e.g.), which would be a funny difference if all light were invisible. So better stick to the normal definition of 'to see', where you can see cars and light.

Why would you want to define seeing as seeing the reflected light when we see by perceiving both reflected and emitted light straight at its source? Its like saying that the number 24 is a 2 from now on and start to draw conclusions from this. 

1 hour ago, Area54 said:

With respect you appear to be allowing emotion to overrule comprehension skills. On that basis I'm out.

You* are right Area54, I do tend to be emotional and Im sure it does constrain my comprehension skills at times... it enables me at times as well.

*I used the word „You” to refer to the person called Area54 on this forum.

Edited February 16, 2018 by koti

[Eise]

From one of my postings above:

On 16.2.2018 at 9:26 AM, Eise said:

If Koti does not acknowledge the difference between see1 and see2, he at most can argue that we cannot distinguish between how we see macro objects and how we see light. But that is pertinently false. We can make the distinction, based on plain physics, if we want.

So the question is: are you not able to see this distinction, or do you simply refuse it? (Because you are attached to the meanings of words?)

It seems to me that you just refuse: what I say is nuts, you do not  accept it, is frustrating, and, yes, you really said it:

On 15.2.2018 at 7:05 PM, koti said:

I refuse to leave it in this case, to find an alternative meaning to the word „see” as I am fairly familiar with both the physical and physiological aspects of what/how/why species see.

I know a little about it, and nothing in the physical and physiological aspects of how species see gives you any argument that one cannot make this distinction. From an evolutionary point of view it is also clear. From primitive organisms that only detect light, we as higher animals can use the light to recognise objects around us. Our brain is completely trimmed on this. We immediately recognise objects around us (food, or dangerous animals; nowadays cars, and tables etc). It is impossible for us not to see objects around us (if there is enough light to see them). 

On 16.2.2018 at 11:36 AM, koti said:

All I see is a false definition of „seeing” based on a null premise that there is a distinction

Then you must learn the physical difference between light and macro objects. The difference is based on the physical fact that you can see macro objects by shining light on it, which you cannot do with a light beam that passes in front of you.

19 hours ago, koti said:

I do tend to be emotional and Im sure it does constrain my comprehension skills at times... it enables me at times as well.

It does constrain you when weighing the pro- and contra-arguments for a position as objective as possible. And that is what I am trying to do here.

This is a picture I made many years ago in the city of Utrecht. Lasers were pointed at the Dom tower. Do you think this picture would have been better if I had made it at day light? Why not? 

Edited February 17, 2018 by Eise

[koti]

8 minutes ago, Eise said:

From one of my postings above:

So the question is: are you not able to see this distinction, or do you simply refuse it? (Because you are attached to the meanings of words?)

It seems to me that you just refuse: what I say is nuts, you do not  accept it, is frustrating, and, yes, you really said it:

I know a little about it, and nothing in the physical and physiological aspects of how species see gives you any argument that one cannot make this distinction. From an evolutionary point of view it is also clear. From primitive organisms that only detect light, we as higher animals can use the light to recognise objects around us. Our brain is completely trimmed on this. We immediately recognise objects around us (food, or dangerous animals; nowadays cars, and tables etc). It is impossible for us not to see objects around us (if there is enough light to see them). 

Then you must learn the physical difference between light and macro objects. The difference is based on the physical fact that you can see macro objects by shining light on it, which you cannot do with a light beam that passes in front of you.

It does constrain you when weighing the pro- and contra-arguments for a position as objective as possible. And that is what I am trying to do here.

I really don’t have to learn that light from a passing beam in a vacum which doesn’t enter the eye is not visible - I have that knowledge. As for me being constrained - I will let this go right here. I understand your point of view on your semantical/philosophical issue but I don’t share your concern/need to analyze it.

[Eise]

6 minutes ago, koti said:

I really don’t have to learn that light from a passing beam in a vacum which doesn’t enter the eye is not visible - I have that knowledge. As for me being constrained - I will let this go right here. I understand your point of view on your semantical/philosophical issue but I don’t share your concern/need to analyze it.

But if you understand the physics behind it, then it is easy to understand the difference I make. So you understand the difference, but you refuse to acknowledge it, even if somebody asks you directly (as the OP did).

PS In 2011 they obviously did a much better job:

Edited February 17, 2018 by Eise

[koti]

20 minutes ago, Eise said:

From one of my postings above:

So the question is: are you not able to see this distinction, or do you simply refuse it? (Because you are attached to the meanings of words?)

It seems to me that you just refuse: what I say is nuts, you do not  accept it, is frustrating, and, yes, you really said it:

I know a little about it, and nothing in the physical and physiological aspects of how species see gives you any argument that one cannot make this distinction. From an evolutionary point of view it is also clear. From primitive organisms that only detect light, we as higher animals can use the light to recognise objects around us. Our brain is completely trimmed on this. We immediately recognise objects around us (food, or dangerous animals; nowadays cars, and tables etc). It is impossible for us not to see objects around us (if there is enough light to see them). 

Then you must learn the physical difference between light and macro objects. The difference is based on the physical fact that you can see macro objects by shining light on it, which you cannot do with a light beam that passes in front of you.

It does constrain you when weighing the pro- and contra-arguments for a position as objective as possible. And that is what I am trying to do here.

This is a picture I made many years ago in the city of Utrecht. Lasers were pointed at the Dom tower. Do you think this picture would have been better if I had made it at day light? Why not? 

I have a 600mW 532nm laser with a decent enough divergence to see the beam even in daylight. So what?