If we instead think of our image as like ourselves but turned vertically (around the horizontal axis) - like you lept headfirst into the mirror and landed upright on your head - then you'll find that your left and right sides are the correct way round but the image is vertically flipped. It's very hard to think this way because (a) we're mostly symmetric horizontally, certainly a lot more than vertically, and (b) we very often interact with other people that have turned horizontally (around the verticle axis) to face us but very rarely interact with other people that have turned vertically to face us.
Another aspect that makes this hard mentally is that if you have any identifying non-symmetrical features, like birthmarks, then they appear horizontally flipped in the mirror compared to photographs. Again, it's the photograph that's turned incorrectly. This one is particularly hard to sell, because surely a photo with a ground at the top can't be the right way round? The answer is, for the purpose of matching your left and right, the "correct" way round is for the photo to face away from you. Makes logical sense, but very unintuitive.
I see a two identical individuals raising their opposing hands in unison.
We're just not used to seeing the fronts of humans who have not rotated relative to us, so the mirror appears to have flipped the image horizontally.
If we customarily rotated around a horizontal axis, i.e. every time you look "behind" you're upside down (note this won't actually work very well given that you'd normally want to rotate around the axis perpendicular to the surface of the Earth, but just for sake of argument...), then we might believe that the mirror has flipped things vertically. It still hasn't actually flipped anything, it's just that we are viewing the front of a person who has not rotated.
Take a piece of paper, write a word onto it, and turn it towards the mirror. Now observe the word. Is it flipped left to right? If so, it's because when turning it towards the mirror _you_ turned it around the vertical axis. Do this again, this time rotating the paper around the horizontal axis and voilà, the word is now flipped upside down.
IIRC that's Feynman who have written somewhere that mirrors do not flip things right to left, nor top to bottom. They flip things front to back.
You're still right of course.
A table football player looking at himself in the mirror would wonder why he was upside down.
I disagree. In this sort of conversation, "up" refers to the direction from your feet to your head, not away from the ground. If you do a handstand and hold your piece of paper up to the mirror then you'll still find it flipped left-to-right but not top-to-bottom if you turn it the instinctive way, and still find it flipped top-to-bottom but not left-to-right if you turn it vertically.
I disagree. To me, "up" is opposite the direction of gravity. If I were doing a handstand on the ground and someone told me to look up, I'd look toward my feet.
A light source moving away from you to a mirror is getting dimmer, but it’s reflection is getting brighter. That’s a measurable physical property that’s reversed. Similarly, a red or blue shifted object between the mirror has a reflection that’s revered in the other direction. However, when looking at an object behind you that doesn’t happen as the reflection shows the same side.
The distance to the light source grows if you move it away toward the mirror it gets dimmer. The the distance of the light in the reflection however gets shorter so it get brighter.
If the light is right next to you the distance is zero. The reflected light however traveled 2 times the distance to the mirror (dimmer). If you move the light to the mirror both "lights" are one mirror distance away so they have the same brightness (assuming a perfect mirror). There is no "physical property reversed" at all. You could remove the mirror and measure the light intensity twice the distance away instead. Then move the light to the middle where the mirror was and obviously the sensor would measure and increase while you see a decrees in brightness.
In a sense if you replace the mirror with a real reflected universe the same photons will hit your eyes and your perception of the reflection will be identical as if you are seeing an alternate world. That is what we perceive instinctually and we wouldn't be able to tell the difference. You literally cannot prove it, but that's besides the point.
When people refer to flipping in the reflection they are not referring to the physical phenomenon of reflection but they are referring to the interpreted equivalent meaning that if the reflection was replaced with an identical universe to our own how is this reflected universe transformed relative to ours? The answer is: Something flipped.
In this case what we are saying is that the z-axis flipped.
I didn't comment the last part because as its simply wrong. Nothing is flipped at no axis at all. If what you see in the mirror would be another universe then it would have to me MIRRORED to look like we see things in a mirror. Every row of atoms right-angled towards the mirror would have to have the exact opposite order. Would the other universe be flipped? No it would not. The wrong assumption is that your universe and the one you see in the mirror is identical. But it would have to be mirrored it can not be identical and also not flipped. No matter how you would flip the other universe it would never look like what you see in a mirror.
Just use 2 identical but non-simple objects place them next to each other for example 2 coins. No matter how you flip or rotate the coins it will never look like there is a mirror in between. You would need a mirrored coin for that.
The full post is saying that the interpretation of what you see is NO DIFFERENT from an alternate universe. I am not saying this is actually what's going on.
All reflections on all surfaces can be interpreted this way.
The point of the example is to say that the language people use to refer to reflections is to refer to this alternate higher level interpretation and is still valid. Only the most pedantic person will say "nothing" has flipped and call it just bouncing photons.
> If what you see in the mirror would be another universe then it would have to me MIRRORED to look like we see things in a mirror.
This is exactly what I'm saying nothing precludes the alternate universe to be MIRRORED. The alternate universe is a mirrored universe, Get it?
>The wrong assumption is that your universe and the one you see in the mirror is identical.
This is your assumption. I never said this. I said ALTERNATE universe. <--- read the word ALTERNATE. I'm assuming here that you might be delusional and seeing the word IDENTICAL instead of alternate.
>No matter how you would flip the other universe it would never look like what you see in a mirror.
Again if the atoms in this universe and flip them across the Z-axis the light bouncing off those atoms would produce exactly what you see in the mirror.
>Just use 2 identical but non-simple objects place them next to each other for example 2 coins. No matter how you flip or rotate the coins it will never look like there is a mirror in between. You would need a mirrored coin for that.
When I say a z-axis flip I mean inside out. Imagine holding a glove, then turning that glove inside out. That is a z-axis flip. Your coin analogy is completely off.
>I did and I pointed out why your theory is garbage.
I never even made a theory I just used the alternate universe thing as an example of the vernacular people use... people refer to the reflection as a real object and not as bounced photons and this interpretation is valid because it can't be proven otherwise. You just didn't get it. Hopefully you reread my post and realized that it is not my "theory" that's garbage but your brain.
A typical 6-year old can say what their left-hand is. But if you tell them to point to MY left hand, they will instead point to my right hand. It takes additional effort and training to teach young children how to see from other people's perspective.
The concepts of North and South also fail dramatically when close to the poles.
No they don't. They only fail when on the poles.
No dude. The mirror flips left and right Relative to you. The mirror ignores up and down relative to you. The paradox is real when thought of in these terms.
Truth be told the flip is neither left or right nor up and down. actually It is actually inside out on the z axis: towards you. Translational coordinates along the xy plane must be preserved and this is what causes the perceived left right flip.
The actuality is nothing was flipped along x or y, it was kept the same.
That's what trips everyone up.
and your distinction of 'real' vs 'conceptual' relative to paradoxes doesn't make sense. a paradox is real because it's conceptual, as paradoxes are relative to humans (or more generally, earthly life).
Yeah that's a good question. If I'm sitting in my car and looking at an ambulance in the rear-view mirror, it's not the mirror itself that reverses the lettering, and that's the key thing to understand.
The only thing the mirror is doing is reversing the Z-axis. So the question becomes, why does a Z-axis reversal cause me to perceive that the X-axis is getting reversed?
If I turn around to look at the ambulance, I just took my head through a 180 degree rotation around the Y-axis. Then (and only then) does the image get reversed on the X-axis.
If you could imagine being behind the ambulance, and it were made of some imaginary transparent material, you would still see the lettering as not reversed.
The key is to be precise when you use words to describe an optical phenomenon. A mirror reflects, and that's all it does.
The words “up” and “down” are absolute, but the words “left” and “right” are relative to you. If we instead of “left” and “right” use the words “south arm” and “north arm”, then the mirror suddenly does not “flip” anything. This is a strong clue that the apparent paradox is conceptual, not real.