Gib, aren’t you telling us that a mirror reverses left-right (as opposed to up-down) and how we can do an experiment to show it? We know that this happens. What we (well, I) don’t know is why. (If you’ve already told us then I’ve forgotten!!!)
You know, a thermos flask will keep a hot liquid hot if it is poured into it; or a cold liquid cold. How does it know which to do?
R
There is no cross-over: this is precisely why the image seems “reversed”…
Churro does not have a clue – but then neither, apparently, do you.
The image seems reversed? Why does it seem to be so as opposed not really to being reversed? Moreover, the image seems not to be upside down. Is it really upside down?
All right, let me try again.
Imagine that John Smith has his name written on a piece of paper: “John Smith”. The J is on the left and the h is on the right. This is the way it is when the paper is facing him. But if he wants to look at it in a mirror, he has to turn the paper around 180 degrees. When he does this, he flips the paper around so that the left side (where the J is) ends up on the right side (where the h is), and visa-versa for the other side. You can try this with an actual sheet of paper if you have one. NOTE: YOU DON’T NEED A MIRROR. Any time you flip a sheet of paper around 180 degree, the left side will end up on the right side and the right side on the left - THE LEFT-RIGHT REVERSAL HAPPENS BY YOU FLIPPING THE SHEET, NOT BY THE MIRROR FLIPPING THE IMAGE.
As for the thermos flask, all it does is prevent heat from passing in OR out. So if it’s cold, no heat can get in. If it’s warm, not heat can get out.
PS - The CAPS are for emphasis, not because I’m yelling 
.
Well, the action or rotating the sheet through 180 degrees horizontally is going to reverse the order (as well as orientation) of the letters. I get that bit. The question is: why does the mirror have the same effect without any rotating? I mean, when I (gib-whatever ‘I’ means!) look at my reversed reflection in a mirror, I don’t need to rotate myself first.
In any case, I still don’t understand why my image is reversed horizontally rather than vertically. Perhaps it is and the mind adjusts. If so, why doesn’t it adjust ‘horizontally’?
You’re surely right about the flask, by the way.
R
Gib’s answer explains nothing; it only describes. Remark, who’s a bit more astute than you, already observed that.
No, it would not.
I could leave it at that, but I don’t think it would penetrate your brain that groundless assertions can always be countered by groundless assertions claiming the opposite.
If you’d read and understood my original answer, you’d know that I wasn’t just talking about the position of our eyes. I said:
“Is it not simply because our eyes are always left and right, and never up and down for us?”
When you lie on your right side, for instance, your left eye is still on your left side and your right eye on your right side. But then your right side is down. Your right side can be down or up, but it can never be left for you. This is because there is an “absolute” up and down for us on top of our relative up and down, whereas there is no such thing on top of our relative left and right. The gravity of the earth determines our “absolute” up and down: our whole physique is attuned to it.
Let me put it differently. The image feels reversed to us. It is not: it’s a linear reflection. It feels reversed because we tend to compare our mirror image to real, other people. If you were my avatar, and we would stand facing each other within seeing distance, if I’d raise my right hand you’d also raise your right hand, which would be on the left side of my field of vision. It feels weird to us when our mirror image doesn’t react that way, but there’s nothing weird about it. Our mirror image is not a real, other person, but a virtual, identical person. There you have it; that’s the explanation.
I was referring to Gib’s first answer only. His latest does explain it, though not explicitly.
Remark, you already are rotated when you’re facing the mirror. You facing the mirror correspond to the text facing the mirror.
In the case of the text, there are two possibilities (two that matter here, at least): 1. the text is turned away from the mirror, facing you; 2. the text is facing the mirror, turned away from you.
In the case of you, there is only one possibility: 1. you are turned away from you.
You can never face yourself (i.e., turn your face toward your face).
What I’ve called our relative up and down are relative (i.e., stand in relation) to us; what I’ve called our “absolute” up and down are relative to the earth.
I’m glad you saw that. Tell me: what’s the difference between a description and an explanation in this case (I didn’t think I was explaining things differently the second time; only more thouroughly).
On second thought, I don’t think you explained it at all. The difference between the first and the second description is that the second made it more clear to me what you didn’t say, which was what Remark didn’t see: the explanation. An ex-planation can of course never be im-plicit. The explanation implied by your description was:
“you already are rotated when you’re facing the mirror. You facing the mirror correspond to the text facing the mirror.”
Maybe a description is more instructive than an explanation; but you can’t expect people to spell things out for themselves…
Oh, I see what you mean now. I understood mine to be an explanation of why the text seems reversed (because that’s the typical example of things being reversed in mirrors as far as I’m familiar). I didn’t think that humans being reverse was what’s at issue here.
Reading these posts - many if not all of them steeped in thought and good ideas - it still seems to me that writers are, in the final analysis, confirming that mirrors reverse left-right, and even pointing out situations in which this is true. Well, I think we all know that mirrors do this. There’ve been one or two attempts to address the original issue: why the reversal is across, not up-down.
Okay: suppose I look into a mirror and photograph what I see reflected back. I then print the photograph and perform a gib experiment; i.e., hold the photograph so the image faces mirror. What will the reflected image (of the photograph) show?
Furthermore, suppose (per impossibile) I hold a Euclidian line vertically in front of the mirror. Such a line doesn’t exist in nature: it has no thickness at all but is merely a conceptual entity. Okay, but supposing this was done, would the image still theoretically be reversed?
Now, we are all familiar with those mirrors in fun parks that send us back wonky images - make us appear fat, thin, etc. These mirrors are convex or concave, or both in different places, aren’t they - or some other weird shape. Can anyone describe what a mirror would look like that does reverse up-down? I’ve never seen one.
R
I’ve sometimes seen myself reflected up/down on shiny surfaces which were not meant as mirrors. This is to be explained by the linear plantation of light. But you don’t even recognise that linearity yet. A flat mirror does not reverse anything!
Do a search on Google using the words “mirror”, “reverse”, “up”, and “down”: there are tons of explanations saying the very same thing.
By the way, say you have a square mirror. You think the left and right halves are reversed, but the upper and lower halves are not. Now say you rotate the mirror 90 degrees, like a clock. Shouldn’t it then reverse up and down instead of left and right? But it doesn’t. So the right and left halves, which are now up and down, do not reverse at all. It is you who do the reversing, in your mind! Your mind is warped…
Is it just the mind that does the reversing? I’d say it’s the mind that tries to correct the mirror image so that it is what we’d expect to see. More in a second.
I like your notion of rotating the mirror. Clever idea.
Now, back to the mind: what if I photograph the image I see and give it to someone who doesn’t know me and believes (reasonably) that that is how I look. Will they think the parting in my hair is on the right and not the left, or will their mind do some subtle reversing so that the photograph represents truly the way I look?
You’re driving along and look in the mirror. Do you see traffic behind you traveling in your direction on the wrong side of the road? If you don’t, I guess you never think about it. If the mind did the reversing, wouldn’t you think about it?
They will think the parting is on the right, of course. What’s your point?
I was speaking of your unconscious mind.
My point was: if they will think my parting is on the right (not the left, as it really is) then it is not my mind that does the reversing – nor theirs.
People speak of the ‘unconscious’ mind. What could that possibly be? How do we know there is such an entity if it is ‘unconscious’ – i.e., such that its existence is unknown?
Is it not like postulating fairies at the bottom of the garden – ones we cannot know about?
Just a thought, and thanks for the response.
Then again, no reversing takes place in your example at all! The picture corresponds to the mirror image, doesn’t it?
To be sure, it does not correspond to you! But then, it’s not a picture of you now is it!
How do you know the North Pole exists, then? I’m assuming you’ve never been there.
Perform the following mind experiment:
Imagine you hold the following characters up to a mirror…
[size=200]0[/size] [size=150]0[/size] 0 [size=85]0[/size] [size=50]0[/size]
Remember that when you turn the paper around and read it, the big 0 is on the left and the little 0 is on the right, but when you turn the paper around and look at the writing from the rear it seems to be reversed. Imagine this: (mirror, paper, observer)
[size=50]0[/size] [size=85]0[/size] 0 [size=150]0[/size] [size=200]0[/size]
[size=50]0[/size] [size=85]0[/size] 0 [size=150]0[/size] [size=200]0[/size]
Observer
The ‘________’ corresponds to the back of the mirror, then the back of the paper and then the back of the observer.
In this case the reflection is not reversed but when we turn the paper around to read it; we see (mirror, paper, observer)
[size=200]0[/size] [size=150]0[/size] 0 [size=85]0[/size] [size=50]0[/size]
[size=200]0[/size] [size=150]0[/size] 0 [size=85]0[/size] [size=50]0[/size]
Observer
Does this make sense?
Edit: I just noticed my signature… Teach/Learn… coincidence!
This is not right, because only the back of the paper is reflected in the mirror in this case. This is how it would look:
[size=200]0[/size] [size=150]0[/size] 0 [size=85]0[/size] [size=50]0[/size]
Observer