Philosophy of Light Visibility (from Light: visible or invisible?)

[Furyan5]

On 22/02/2016 at 7:24 PM, The_Believer1 said:

Hello friends!

 

I have a question about light. We all know that we see objects because they reflect light into our eyes. But we never see the actual light. So my question is why can't we see light. Or can we in fact see light. If so, how?

We can't actually see light, but to understand this, you need to understand the subjective human experience of vision. Physics tries to seperate from subjective experiences, so to physics, detection of light is seeing. Neurologically however, detecting light is merely one aspect of the visual process which results in seeing. When our eyes detect light, they send electrochemical impulses to our brains visual cortex. Here our brain creates visual representations of the objects from which the light originates. So we don't see an actual object. We see our brains representation of the object. We definitely don't see light. Light is a noumenal phenomenon. Brightness, colours and the objects we perceive are what we call phenomenal phenomenon. 

[dimreepr]

2 minutes ago, Furyan5 said:

We can't actually see light,

 

Other than this screen and your ability to navigate towards it...

6 minutes ago, Furyan5 said:

but to understand this, you need to understand the subjective human experience of vision. Physics tries to seperate from subjective experiences, so to physics, detection of light is seeing. Neurologically however, detecting light is merely one aspect of the visual process which results in seeing. When our eyes detect light, they send electrochemical impulses to our brains visual cortex. Here our brain creates visual representations of the objects from which the light originates. So we don't see an actual object. We see our brains representation of the object. We definitely don't see light. Light is a noumenal phenomenon. Brightness, colours and the objects we perceive are what we call phenomenal phenomenon. 

To understand this, I'd need some dank weed... dude... 

[StringJunky]

15 minutes ago, Furyan5 said:

We can't actually see light, but to understand this, you need to understand the subjective human experience of vision. Physics tries to seperate from subjective experiences, so to physics, detection of light is seeing. Neurologically however, detecting light is merely one aspect of the visual process which results in seeing. When our eyes detect light, they send electrochemical impulses to our brains visual cortex. Here our brain creates visual representations of the objects from which the light originates. So we don't see an actual object. We see our brains representation of the object. We definitely don't see light. Light is a noumenal phenomenon. Brightness, colours and the objects we perceive are what we call phenomenal phenomenon. 

Yes, there's a lot of intermediate processing which only approximates what is before us; it's a constructed image.

[dimreepr]

5 minutes ago, StringJunky said:

Yes, there's a lot of intermediate processing which only approximates what is before us; it's a constructed image.

Indeed, but it is constructed of light...

Just to be clear, I'm not suggesting the blind can't navigate or communicate; just that those that can see, use light

[StringJunky]

12 minutes ago, dimreepr said:

Indeed, but it is constructed of light...

Just to be clear, I'm not suggesting the blind can't navigate or communicate; just that those that can see, use light

But not in the brain... unless, of course, you think there's a little cinema with a projector in the the middle of it.  

[dimreepr]

1 minute ago, StringJunky said:

But not in the brain... unless, of course, you think there's a little cinema with a projector in the the middle of it.  

Nice try/dodge, we both know what I meant; "unless, of course, you think" sonar is equivalent?

[StringJunky]

16 minutes ago, dimreepr said:

Nice try/dodge, we both know what I meant; "unless, of course, you think" sonar is equivalent?

You can envisage your surroundings with sound.

[dimreepr]

1 minute ago, StringJunky said:

You can envisage your surroundings with sound.

Indeed but, if you can look you will, we're not bats...  

[StringJunky]

1 minute ago, dimreepr said:

Indeed but, if you can look you will, we're not bats...  

But some blind people are adept at it, so we can be like bats  

 

[dimreepr]

1 minute ago, StringJunky said:

But some blind people are adept at it, so we can be like bats  

 

Now that's a stretch, not to mention dishonest, you are conflating different waves and you DO know the difference...

[StringJunky]

5 minutes ago, dimreepr said:

Now that's a stretch, not to mention dishonest, you are conflating different waves and you DO know the difference...

I'm on about what's occurring in the brain. Do you need a humour transplant today?

[dimreepr]

1 minute ago, StringJunky said:

I'm on about what's occurring in the brain. Do you need a humour transplant today?

That's certainly possible, do you need a get out of jail free? 

[StringJunky]

7 minutes ago, dimreepr said:

That's certainly possible, do you need a get out of jail free? 

Not at all. I think we are barking up different trees. 

[Furyan5]

3 hours ago, dimreepr said:

Indeed, but it is constructed of light...

Just to be clear, I'm not suggesting the blind can't navigate or communicate; just that those that can see, use light

Yes, we need light to see objects. The point is, we don't see light itself.

3 hours ago, dimreepr said:

Other than this screen and your ability to navigate towards it...

To understand this, I'd need some dank weed... dude... 

You see the screen. Light allows you to see the screen. You don't see light, you see the screen. It's not that complicated. 

2 hours ago, StringJunky said:

Not at all. I think we are barking up different trees. 

I agree. Echo locating has nothing to do with the visibility of light. But it does allow limited shape and spacial orientation of objects. 

[swansont]

I think this is much more a question of semantics than it is of physics.

[Furyan5]

6 minutes ago, swansont said:

I think this is much more a question of semantics than it is of physics.

Wrong. It has nothing to do with physics. Vision is a neurological process. One which few truly understand. 

[John Cuthber]

On 11/15/2017 at 11:16 PM, Furyan5 said:

The reason most people don't agree is because they believe the reality they perceive exists outside their heads. That's not true. 

If reality isn't here, why are you writing to it?

[Strange]

1 hour ago, Furyan5 said:

Wrong. It has nothing to do with physics. Vision is a neurological process. One which few truly understand. 

This is why it is (also) a question of semantics. Light is (probably) a matter of physics. Vision is (mainly) a matter of neurological process (plus some physics). So to properly answer the question depends on both, and on precisely defining the tiers involved.

51 minutes ago, John Cuthber said:

If reality isn't here, why are you writing to it?

He said that the reality they perceive exists inside their heads, which I would have thought was self-evidently true.

[John Cuthber]

34 minutes ago, Strange said:

He said that the reality they perceive exists inside their heads, which I would have thought was self-evidently true.

How do you know?
Perhaps they are all unicorns and you just have the mistaken  view that they are people?

That's the trouble with that line of "reasoning" it gets you everywhere so it gets you nowhere.

[Furyan5]

1 hour ago, John Cuthber said:

If reality isn't here, why are you writing to it?

You're confusing indirect realism with solipsism. 

9 minutes ago, John Cuthber said:

How do you know?
Perhaps they are all unicorns and you just have the mistaken  view that they are people?

That's the trouble with that line of "reasoning" it gets you everywhere so it gets you nowhere.

If you read properly, you'll see that a use the word "representation", implying that what we perceive is representational of actual reality. Once you truly grasp the concept you'll realize that objective reality isn't perceivable. Look like, is a term we use for subjective perception. Objective reality has no color. 

[swansont]

5 hours ago, Furyan5 said:

Wrong. It has nothing to do with physics. Vision is a neurological process. One which few truly understand. 

Whether or not you can see photons has zero to do with neurology. Nothing that happens after the photon hits the eye has an impact on the answer. 

[Furyan5]

8 hours ago, swansont said:

Whether or not you can see photons has zero to do with neurology. Nothing that happens after the photon hits the eye has an impact on the answer. 

Vision occurs in the visual cortex. Not in the eye. It's a neuropsychological fact. The eyes see nothing. They merely detect light and convert them into electrochemical impulses. The process is called photo transduction and is completely unconscious. 

Edited January 25, 2018 by Furyan5
Explained reasen

[Strange]

20 minutes ago, Furyan5 said:

Vision occurs in the visual cortex. Not in the eye. ... The eyes see nothing. They merely detect light and convert them into electrochemical impulses. 

This is why it is important to have clear and commonly understood definitions of terms (semantics) so that everyone is using the word "vision" or "see" to mean the same thing.

And the eyes do slightly more than detect light (and decode it into colours). The retina also plays a role in detecting motion, including speed and direction (which isn't surprising, from an evolutionary point of view). So I think the entire visual system has to be taken as a whole, rather than saying it is just the brain. 

(I agree completely with your main point, though, that our only conception of reality is what exists in our brain.)

 

[Furyan5]

9 minutes ago, Strange said:

This is why it is important to have clear and commonly understood definitions of terms (semantics) so that everyone is using the word "vision" or "see" to mean the same thing.

And the eyes do slightly more than detect light (and decode it into colours). The retina also plays a role in detecting motion, including speed and direction (which isn't surprising, from an evolutionary point of view). So I think the entire visual system has to be taken as a whole, rather than saying it is just the brain. 

(I agree completely with your main point, though, that our only conception of reality is what exists in our brain.)

 

Thank you. The difference is more than mere semantics however. It distinguishes the nature of the reality we perceive. Realism or indirect realism. 

Yes, the retina plays a part in all aspects of vision, but motion detection occurs in the brain as well. 

The bottom line is that light is noumenal in nature whereas the images we perceive are phenomenal in nature. 

Many people don't truly grasp how indirect realism works. I find the fighter jets in mist analogy helps.

Imagine a squadron of fighter jets, flying in thick mist. They can't see each other directly, so they have radar. On their radar screen, the other jets are represented as dots. This allows them to stay in formation. 

Our brain creates a similar representation in our mind and it includes a representation of us. Our entire lives we only perceive this representation. This leads many to falsely assume that what we see is actual reality. But it's not. It's a simulation of the outside world and our brain is the simulator. 

[Strange]

I haven't come across the term "indirect realism" before. Is the difference between this and idealism (which says that the mental construct is all that exists) that in indirect realism, you acknowledge the external reality exists and, to some extent, matches our mental model? It sounds similar to what I have heard described as "naive realism" (the view that what we see, even though it is entirely a construct of the brain, maps pretty closely on to the external reality).

So, to take your analogy a step further, idealism would say that the dots on the radar are all that exists. The thing they represent may not exist or could just be a simulation.