Is a rainbow a physical object?

[Copernicus]

Like most questions in philosophy, there is a very simple answer. The problem is that philosophers disagree on the meaning of the question. If first they would all agree on the definition of the words physical and object then the answer becomes obvious.

Getting people to agree on meaning, even the meaning of what we think of as precise concepts, is illusory. We all have similar, but different, experiences of the world, so an expression like "physical object" is going to have a range of meaning that varies across contexts of usage. The best we can do is agree on broad slices of similar experiences when we debate the meaning of words. So we get a range of different reactions to questions like the one in the OP.

Unter has an interesting approach because of his focus on a perceptual description. We can contrast his approach with Bilby's, which focuses on a non-perceptual physical description. Both are reasonable ways to look at the problem, but from different ends of the range of components that go into our understanding of what a rainbow is. We have a physical model for describing the perception--rods and cones in the structure of the eye, photons that trigger neural activity, the subjective experience of color (or shades of gray).

The essential fact about a rainbow is that it cannot exist without an act of perception. There has to be a perceiver with the right sensory equipment. There has to be an external event that causes the perception (or, at a minimum, a hallucination--perception triggered by something other than incoming sensory input). Two different people standing next to each other can be said to see the same rainbow, but two people standing a kilometer apart will be seeing different rainbows (or none), depending of the refraction of light through the atmosphere. A camera can record the event and be used to reproduce an image of it later. So the phenomenon is definitely real, but it is also an illusion of circumstance.

The philosophical issue here is whether any physical object is fundamentally different from a rainbow. Remember that tables and chickens appear to exist even when nobody is observing them, but it would seem to be impossible for a rainbow to exist independently of an observer. So one is tempted to say that a rainbow is not a physical object in the same way, but it is still a physical object. So maybe BWE's "yes and no" response begins to make more sense.

 

[untermensche]

How do you know that the table is still there if nobody sees it?

We're doing philosophy, right?

You can touch a table.

But the question is about a rainbow.

If there is no color are you talking about a rainbow?

 

[ruby sparks]

Does a camera detect non-physical things? I don't think so. How would it do that? It's just a camera. Something hits the sensor, right?

 

[ruby sparks]

So maybe BWE's "yes and no" response begins to make more sense.

Not so fast. Ask him if a table exists.

 

[Copernicus]

How do you know that the table is still there if nobody sees it?

We're doing philosophy, right?

You, being from Ireland, would drag Bishop Berkeley into this, wouldn't you? Phooey! You do know that he went mad in the end, don't you?

 

[ruby sparks]

How do you know that the table is still there if nobody sees it?

We're doing philosophy, right?

You, being from Ireland, would drag Bishop Berkeley into this, wouldn't you? Phooey! You do know that he went mad in the end, don't you?

It's impossible for an Irishman to go mad. We could just say he was Irish and that would cover it.

 

[untermensche]

Does a camera detect non-physical things? I don't think so. How would it do that? It's just a camera. Something hits the sensor, right?

What looks at the product of a camera?

With no ability to discern color or shades of grey you can take all the pictures you want.

You will never think a rainbow is there.

 

[Copernicus]

So folks appear to want to focus on the table and ignore the chicken. Fine. Can the table exist independently of an observer? I'm not going to do the Berkeley thing about tables disappearing when nobody is observing them. That is absurd. But is it absurd that a table can exist independently of a mind to become aware of it and conceive of it as a table? IOW, is it not true that every physical object is like a rainbow? If every living thing on Earth were to suddenly disappear, would rocks cease to exist? If so, do rocks exist on all those planets out there with no life on them? (Wait, is that what Berkeley was trying to say?)

 

[untermensche]

So folks appear to want to focus on the table and ignore the chicken. Fine. Can the table exist independently of an observer? I'm not going to do the Berkeley thing about tables disappearing when nobody is observing them. That is absurd. But is it absurd that a table can exist independently of a mind to become aware of it and conceive of it as a table? IOW, is it not true that every physical object is like a rainbow? If every living thing on Earth were to suddenly disappear, would rocks cease to exist?

We can believe a table exists independently of our mind and that is a fruitful speculation.

But we can never prove the table is there.

All we have are our subjective experiences, even if it is the experience of pain and blood as the Hulk smashes the table over our head.

All we can have are our subjective experiences.

We can never have the objective table, only a belief it is there.

 

[Testy Calibrate]

How do you know that the table is still there if nobody sees it?

We're doing philosophy, right?

You can only ever know what your model predicts. Confidence in your predictions leads to confidence in your ontology. That doesn't mean in any way that an ontology is "correct", just that it is useful.

 

[fast]

Does a camera detect non-physical things? I don't think so. How would it do that? It's just a camera. Something hits the sensor, right?

What looks at the product of a camera?

With no ability to discern color or shades of grey you can take all the pictures you want.

You will never think a rainbow is there.

Truth is independent of knowledge, yet truth implies knowledge. In other words, if you know P, then P is true, but we need not know P for P to be true.

Our physical inability to detect certain wave lengths without instrumentation never gave rise to suspect there were things we couldn't see with the naked eye, but as technology advanced, we began to know things through discovery that were true all along. With extreme skepticism aside, it's reasonable to think that ultraviolet light continues even should we lose all aperatices to detect it. There are charts that show the range in a spectrum for which animals can normally sense.

If we all became blind tomorrow, we could not see a rainbow with the naked eye, but the knowledge of their occasional occurances is partly how we continue to know they exist independent of our ability to sense them.

With extreme skepticism not set aside, then the issue of knowledge is likely elevated to a different sense that invokes Cartesian certainty--which is a separate issue than knowledge. Never can we be so certain of anything that guarantees us to be mistake free; knowledge, on the other hand, is a much more down to earth issue that doesn't require such a stringent standard that negates the possibility of mistake.

I am quite confident in my claim to know things, even while recognizing that I might be mistaken. If I have a justified belief that P IS true (as opposed to a justified belief that MUST be true), and barring gettier type examples, that's sufficient reason to espouse knowledge of P--so long as I'm willing to retract having knowledge if shown to be mistaken.

 

[untermensche]

Does a camera detect non-physical things? I don't think so. How would it do that? It's just a camera. Something hits the sensor, right?

What looks at the product of a camera?

With no ability to discern color or shades of grey you can take all the pictures you want.

You will never think a rainbow is there.

Truth is independent of knowledge, yet truth implies knowledge. In other words, if you know P, then P is true, but we need not know P for P to be true.

If something is not detectable because the brain does not create color or shades of grey then nobody would ever know it is there.

The rainbow exists because of a brain and a mind.

It does not exist without one.

All the same physical attributes could be there but no rainbow would be there.

Nobody would say they think a rainbow is being created by the phenomena under examination.

 

[fast]

It took me a good minute (as the yes and no was enticing), but I went with "yes."

I believe "entity" is broad enough in common philospeak to warrant a quicker yes, but an object? Well, this is where ambiguity rears its ugly head. We are amidst a pleathora of terms that have multiple scopes, best generalized by being of either a narrow or broad type.

Consider the difference between some thing vs something. A stomach is some thing, and being as such, it's something, so it's some thing (in the narrow sense) and something (in the broad sense). Awe, but what about digestion? That's no more an actual thing than is running, yet so while a stomach is a thing and something, digestion, though something, is not a thing per se.

Deeply enough, even "thing" can be so elusive. A noun, for instance, is a person, place, or thing, and as such, a person is not a thing, yet on a broader note, 'things' change.

Also, "object" has a history of sapping the life out of philosophical souls who ponder it. I've discovered through many a days of wracking this issue about that it's a benchmarking word.

Consider the difference between a physical object and mental object. The "object" after mental is placed for comparative purposes. Never was it ever meant to suggest that there are in fact objects that are mental like we would as we do when we think of physical objects as objects that are physical.

In an attempt to classify the referent of words often described as being mental (I.e. Thoughts, ideas, concepts etc) and to distinguish them from more concrete physical distinctions, the word "object" was injected and actually takes on a broader scope than "object" when placed after "physical", rendering "physical object" as being not a technical term but instead an adjective followed by a noun" whereas "mental object" is more a term of art and ought not be regarded in similar fashion.

In fact, terms like "mental object," "abstract object," and "imaginary object" are better regarded as mere labels or complex terms with meanings that ought not derive by coupling the meaning of their constituent parts--similar to how it would be a mistake to do that for "logical possibility" and "free will."

A rainbow. Yes. An object. Unlike many objects, yes, but an object still.

 

[fast]

If something is not detectable because the brain does not create color or shades of grey then nobody would ever know it is there.

We already know it! Why bring the nighttime issue of knowledge in on a daytime topic of existence? Our knowledge of what exists expires when we do, but the existence of those things we knew carry on.

The rainbow exists because of a brain and a mind.

The atoms in the atmosphere need no brain to be as they are. Sure, there's no perception of what we perceive when there's no one to perceive what's there, but it's what's there that we perceive that we call the rainbow.

 

[untermensche]

If something is not detectable because the brain does not create color or shades of grey then nobody would ever know it is there.

We already know it!

We know what we label the thing our mind perceives. We label this arrangement of colors we perceive in the sky: a "rainbow".

The rainbow is only something a mind perceives.

The air that creates it is not a rainbow.

And without the perception of color you would have no arrangement of colors in the sky.

You would have no reason to think colors could be there.

 

[fast]

If something is not detectable because the brain does not create color or shades of grey then nobody would ever know it is there.

We already know it!

We know what we label the thing our mind perceives. We label this arrangement of colors we perceive in the sky: a "rainbow".

The rainbow is only something a mind perceives.

The air that creates it is not a rainbow.

And without the perception of color you would have no arrangement of colors in the sky.

You would have no reason to think colors could be there.

Just to narrow this down a tad, I need to make sure of something.

What about the sun? Not the term, "sun." The referent of the word: the sun. That's something we perceive. Must we perceive that too?

 

[Copernicus]

Consider the fact that the rainbow does not exist independently of the observer, because one would see different rainbows from different perspectives. The observer has to be in a location where the refraction of light through water will produce the perceptual effect. Hence, from a physical perspective, there are as many rainbows as there are potential observers in suitable locations in order to experience the illusion. However, an observer is necessary in order for the rainbow to be reified. Otherwise, it is just light (photons) passing through water. Is the same true for a table or a rock? Is the observer necessary in order for those objects to undergo a reification process?

 

[untermensche]

We know what we label the thing our mind perceives. We label this arrangement of colors we perceive in the sky: a "rainbow".

The rainbow is only something a mind perceives.

The air that creates it is not a rainbow.

And without the perception of color you would have no arrangement of colors in the sky.

You would have no reason to think colors could be there.

Just to narrow this down a tad, I need to make sure of something.

What about the sun? Not the term, "sun." The referent of the word: the sun. That's something we perceive. Must we perceive that too?

We can feel the sun.

We can infer that some heat source must exist.

And the color of the sun changes. It is not an entity totally dependent on the ability to perceive color.

You would still call a blue sun a sun.

 

[ruby sparks]

Consider the fact that the rainbow does not exist independently of the observer, because one would see different rainbows from different perspectives. The observer has to be in a location where the refraction of light through water will produce the perceptual effect. Hence, from a physical perspective, there are as many rainbows as there are potential observers in suitable locations in order to experience the illusion. However, an observer is necessary in order for the rainbow to be reified. Otherwise, it is just light (photons) passing through water. Is the same true for a table or a rock? Is the observer necessary in order for those objects to undergo a reification process?

Well, I think when you said, "it is just light (photons) passing through water" you may well have answered the OP question.

But on the other thing, maybe there are differences between tables and rainbows in the way you're exploring. But how different? I mean, no two observers (human or manmade) see the same table either.

I might say that neither the table nor the photons need to be reified in order to exist physically.

 

[fast]

According to a link, "Thus, a rainbow is not an object and cannot be physically approached."

https://en.m.wikipedia.org/wiki/Rainbow

The answer hinges on what it means to say of something that it's an object.

One might think "yes and no" is applicable, but not as a contradiction.