With a reflection from a mirror, there is an actual object responsible for that light field, which is (at least) very similar to what we seem to be seeing; I think it’s obviously reasonable to say in that case that what we are seeing is the thing in the mirror. But suppose the actual optical apparatus consists of a bunch of lasers and diffractive optical elements and things, and there is no good candidate for “what we’re perceiving” that in any way resembles the apple we seem to be seeing. Personally I’m happy just saying that there isn’t any thing we’re perceiving in that situation, or perhaps that we’re perceiving a non-existent apple, or that we’re perceiving an illusion of an apple, or something. But I can see how someone might find “we’re perceiving the light” a less unsatisfactory answer than those.
A rainbow is an interesting example. When I “see a rainbow”, would you say I’m actually perceiving a rainbow? If so, just what is the rainbow? What kind of thing is it, in your account of the world?
I agree that we see objects. That’s the usual case. That’s why my weird example in which we might want to say something unusual is one which in some ways greatly resembles the usual case of seeing an object, but in which it’s not clear that there’s any good candidate for “the object we’re seeing”.
A rainbow consists of millions of tiny reflections of the sun, off the inner, concave , surface of raindrops, having undergone refraction. You’re seeing multiple reflections of the sun.
When I look at a wall illuminated by the sun, I am also seeing lots of tiny reflections of the sun. So if you’re saying that when I look at a rainbow, the object I am actually perceiving is the sun, why does that not apply equally to the wall of a building?
An obvious alternative would be to say that when I look at a rainbow, what I’m seeing is lots of water droplets. That seems unsatisfactory too, because if I look at the rainbow for a minute then typically there are no water droplets in common between the starting and ending configurations. So maybe I’m seeing an assemblage of water droplets which is stable in something like the way our bodies are stable even though their material is mostly replaced every few weeks. I don’t much like that either, though I have no very concrete objection to make to it. The alternative I actually prefer is to say that these questions are mostly about words rather than about things, and that there’s not much value in picking specific answers to them.
Light from a building is dispersed, light from a mirror is reflected. With dispersed light, we see (in our minds ) the object dispersing the light. Light disperced by raindrops, makes the raindrops visible. Light reflected by raindrops makes the sun visible.
I think you may be making a distinction that isn’t really there. The way in which light from a building is dispersed is by being reflected in different directions off lots of little bits of surface. … Having written this, I wonder whether it’s quite right. If you point a laser at a rough surface, you get a “speckle” effect that derives from interference between different paths the light can take from the laser to your eye; perhaps the appearance of ordinary rough surfaces owes something nontrivial to such interference effects and it’s therefore not adequate to think of it as the result of lots of tiny reflections. It seems to me that the answer to the question “what object, if any, am I looking at when I see a rainbow?” should probably not depend on this level of careful physical analysis.
Let me ask a slightly different question. It seems like you’re very sure that there is a Right Answer to that question. Why? I would say that there probably isn’t a Right Answer, because I don’t think the terms in the question are precisely enough defined for there to be one in difficult cases; and I would say that of course we can make more precise definitions that make there be a definite Right Answer, but I don’t see much need to do so. In any tricky case where that answer really matters I would expect to find that the question we really need an answer to is something else that’s better addressed directly.
No, not like that. That’s a question about words more than about things. (At least, it seems so to me.) I can’t offhand think of any situation in which answering the rainbow question would really matter, or really seem to matter; but if there were one, the sort of “something else” I would expect to be more fruitful to address would be a question about the underlying physics.
How about this, where does a rainbow exist? Is a rainbow the process which results in a light pattern? Or is a rainbow the arch of colors we perceive in our indirect version of reality?
There is no such thing as “where a rainbow exists”. Rainbows aren’t (in so far as they’re properly considered things at all) things that have locations. What a rainbow has is more like a direction: it is located around the cone at an angle of 42 degrees from the line between the sun and you. (Which means that in some sense differently located people see different rainbows, though in practice it’s more convenient to express things differently and treat rainbows seen by two nearby people looking in similar directions as “the same rainbow”.)
I wouldn’t say that a rainbow is a process; I don’t see any way in which that makes anything clearer. I don’t think I’d say it’s “the arch of colours we perceive in our indirect version of reality” either, because if you make a rainbow strictly an artefact of human perception then you have trouble dealing with the fact that e.g. a camera looking in the same direction as you will record “the same” rainbow as you do.
So what? A camera records a light pattern which it later emits to our eyes, resulting in a visual representation. A rainbow is link any other image in a mirror. A virtual image. It exists in the mind of the observer. The same way two people see two different images in a mirror. Technically, we each see two images. One for each eye. We also see two rainbows, uncles we are looking at an image on a screen.
If a rainbow is something that happens in the mind of the observer then it is not possible for a camera to take a picture of a rainbow. At best, it can take a picture that will strike a human observer as rainbow-like, or something like that.
And, sure, you can choose to define “rainbow” that way, as referring to what happens in a person’s mind when they look towards a region where there are lots of water droplets illuminated by a light source behind that person. But I don’t see why we should define “rainbow” that way.
(I don’t think we have any disagreement about what’s actually happening in the world when someone “sees a rainbow”.)
That’s my point, very few people understand the process, but they can all See the rainbow. It is common usage that a rainbow is the perceived arch of colours, not the process.
With a reflection from a mirror, there is an actual object responsible for that light field, which is (at least) very similar to what we seem to be seeing; I think it’s obviously reasonable to say in that case that what we are seeing is the thing in the mirror. But suppose the actual optical apparatus consists of a bunch of lasers and diffractive optical elements and things, and there is no good candidate for “what we’re perceiving” that in any way resembles the apple we seem to be seeing. Personally I’m happy just saying that there isn’t any thing we’re perceiving in that situation, or perhaps that we’re perceiving a non-existent apple, or that we’re perceiving an illusion of an apple, or something. But I can see how someone might find “we’re perceiving the light” a less unsatisfactory answer than those.
A rainbow is an interesting example. When I “see a rainbow”, would you say I’m actually perceiving a rainbow? If so, just what is the rainbow? What kind of thing is it, in your account of the world?
I agree that we see objects. That’s the usual case. That’s why my weird example in which we might want to say something unusual is one which in some ways greatly resembles the usual case of seeing an object, but in which it’s not clear that there’s any good candidate for “the object we’re seeing”.
A rainbow consists of millions of tiny reflections of the sun, off the inner, concave , surface of raindrops, having undergone refraction. You’re seeing multiple reflections of the sun.
When I look at a wall illuminated by the sun, I am also seeing lots of tiny reflections of the sun. So if you’re saying that when I look at a rainbow, the object I am actually perceiving is the sun, why does that not apply equally to the wall of a building?
An obvious alternative would be to say that when I look at a rainbow, what I’m seeing is lots of water droplets. That seems unsatisfactory too, because if I look at the rainbow for a minute then typically there are no water droplets in common between the starting and ending configurations. So maybe I’m seeing an assemblage of water droplets which is stable in something like the way our bodies are stable even though their material is mostly replaced every few weeks. I don’t much like that either, though I have no very concrete objection to make to it. The alternative I actually prefer is to say that these questions are mostly about words rather than about things, and that there’s not much value in picking specific answers to them.
Light from a building is dispersed, light from a mirror is reflected. With dispersed light, we see (in our minds ) the object dispersing the light. Light disperced by raindrops, makes the raindrops visible. Light reflected by raindrops makes the sun visible.
I think you may be making a distinction that isn’t really there. The way in which light from a building is dispersed is by being reflected in different directions off lots of little bits of surface. … Having written this, I wonder whether it’s quite right. If you point a laser at a rough surface, you get a “speckle” effect that derives from interference between different paths the light can take from the laser to your eye; perhaps the appearance of ordinary rough surfaces owes something nontrivial to such interference effects and it’s therefore not adequate to think of it as the result of lots of tiny reflections. It seems to me that the answer to the question “what object, if any, am I looking at when I see a rainbow?” should probably not depend on this level of careful physical analysis.
Let me ask a slightly different question. It seems like you’re very sure that there is a Right Answer to that question. Why? I would say that there probably isn’t a Right Answer, because I don’t think the terms in the question are precisely enough defined for there to be one in difficult cases; and I would say that of course we can make more precise definitions that make there be a definite Right Answer, but I don’t see much need to do so. In any tricky case where that answer really matters I would expect to find that the question we really need an answer to is something else that’s better addressed directly.
Like, is detecting light, perceiving light?
No, not like that. That’s a question about words more than about things. (At least, it seems so to me.) I can’t offhand think of any situation in which answering the rainbow question would really matter, or really seem to matter; but if there were one, the sort of “something else” I would expect to be more fruitful to address would be a question about the underlying physics.
How about this, where does a rainbow exist? Is a rainbow the process which results in a light pattern? Or is a rainbow the arch of colors we perceive in our indirect version of reality?
There is no such thing as “where a rainbow exists”. Rainbows aren’t (in so far as they’re properly considered things at all) things that have locations. What a rainbow has is more like a direction: it is located around the cone at an angle of 42 degrees from the line between the sun and you. (Which means that in some sense differently located people see different rainbows, though in practice it’s more convenient to express things differently and treat rainbows seen by two nearby people looking in similar directions as “the same rainbow”.)
I wouldn’t say that a rainbow is a process; I don’t see any way in which that makes anything clearer. I don’t think I’d say it’s “the arch of colours we perceive in our indirect version of reality” either, because if you make a rainbow strictly an artefact of human perception then you have trouble dealing with the fact that e.g. a camera looking in the same direction as you will record “the same” rainbow as you do.
So what? A camera records a light pattern which it later emits to our eyes, resulting in a visual representation. A rainbow is link any other image in a mirror. A virtual image. It exists in the mind of the observer. The same way two people see two different images in a mirror. Technically, we each see two images. One for each eye. We also see two rainbows, uncles we are looking at an image on a screen.
If a rainbow is something that happens in the mind of the observer then it is not possible for a camera to take a picture of a rainbow. At best, it can take a picture that will strike a human observer as rainbow-like, or something like that.
And, sure, you can choose to define “rainbow” that way, as referring to what happens in a person’s mind when they look towards a region where there are lots of water droplets illuminated by a light source behind that person. But I don’t see why we should define “rainbow” that way.
(I don’t think we have any disagreement about what’s actually happening in the world when someone “sees a rainbow”.)
That’s my point, very few people understand the process, but they can all See the rainbow. It is common usage that a rainbow is the perceived arch of colours, not the process.