h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Mirrors And Perception - A879762
Author: Lucinda (et al) - U129960

Why things in mirrors are reversed left-to-right, but not up-to-down.

I'm sure this entry is wrong in many ways, but not sure which, so let me know...

-Martin

Hi Lucinda!

The first thing I have to say is, I agree entirely with your explanation of the phenomenon. I'm not going to argue with that.

But I think that your explanation is so long that people will lose track of it. Is there anyway it could be said in a more direct way, without losing the point?

I think you should mention "Front-Back reversed" at some point rather than "reflected". We know that the image is reflected, but the particular meaning you have of it might escape the reader.

You could improve the section on Writing by thinking of a few loved-ones' names that are changed to unusual words by the two processes you describe.

I've rejigged the section on 'people' in line with your suggestions - take a look?

-Martin

Another thought experiment along the same lines as the others in the entry:

Snow is standing facing her reflection Magnolia, and you think: "How is she going to get where Magnolia is, and what is the difference between Snow and Magnolia when she gets there?".

The common sense, obvious, standard perspective style way of doing this is for Snow to walk behind the mirror and turn around to face the back of the mirror, at which point Magnolia is a left-right reversed version of Snow.

The weird perspective version is for Snow to climb over the top of the mirror and hang down with her feet hooked over the top of it, so she is now facing the back of the mirror, at which point Magnolia is an up-down reversed version of Snow.

As you say in the entry, we are more likely to think of walking behind the mirror than climbing over the top, though the Beholder floating in outer space sees no difference between the two interpretations - and really all this walking about or climbing over and turning around confuses the issue:

The direct perspective way to see how to get Snow to where Magnolia is for Snow to walk directly forward through the mirror, at which point Magnolia is a front-back reversed version of Snow.

Having a quick look at this first thing in the morning before going to work. Got about halfway through, and thought too difficult for this time in the morning.

Spotted a couple of typos, though (typical Virgo!):

Magnolis > Magnolia
wriing > writing

Another observation is that table football seems to bring back memories of studenthood. Perhaps it's just me.

I'll have a look later, when I've more time.

This was way too confusing, and I could only make sense of the idea of back-front reflection right at this moment when I thought about what would happen if the Snow White was see through, or what happens in a printing press, or what happens when a kindergartner carves a potato to make a funny stamp.
Well, maybe I read with only half my mind, this being so early, but what I'm left with is a disturbing fantasy involving Snow White's panties.

Lucinda, while the original explanation was too long, you seem to have cut it out completely, leaving nothing!

Your problem is that you understand what you are explaining. Try and read the entry as if you didn't understand and see does it explain it adequately.

First of all: Great topic! One of the GREAT mind-clogging mysteries!

Then: I am agreeing with Gnomon that the Explanation you provide is a bit too long for an easy problem. Maybe these more 'complete explanations' should be preceeded by a shorter explanation. Here's one:

The problem is that we KNOW where's up and down (eg. due to gravity), whereas left and right is mere convention. We don't know it because we are symmetric. We CANNOT explain to someone where's left and right without using a common reference. If we were bubble-shaped we would think mirros swap "up" and "down" too, because to us, then, the terms "left", "right", "up" and "down" would make no sense.

I don't know if all people understand this explanation I have provided ... So it's good to have more text, like it is now.

Dunno, just thinking.

HELL

Whoa, I started writing my reply over 15 minutes ago... I was referring to Gnomon's previous post. Not this one.



H

OK. Nothing much... I still agree with gnomon and my post above still holds.

See you around,

HELL

That's a great thought experiment, HenryS! I think I'll use that: It really makes it obvious what the issues are - without needing to talk about things in terms of nasty mathematical stuff

cheers for the typo anyway, stuff to be getting on with here, so I'll tell y'all when it's done.
-Lucinda

This reminds me of berks who say stuff like ...

"Driving on the right is such a stupid idea. You have to give way to the left at roundabouts ... causes all sorts of gridlock."

Jackson Pollocks.

It's the same as driving on the left as if SHE* had put a mirror in the sky. In fact it's just another way for the British to express their xenophobia.


DMT

* She, i.e. Mother Nature

*Loads shotgun*

Wayne oi foind owrt wort zen0phobia means yow forine types is gurner gerrit!

A good one to freak my teenagers out with.

You've done really well explaining this without diagrams (I did little line diagrams whilst reading it just so I understood)

Fancy having a go at why double reflections don't always put things right ?

There's a typo at the end about lying on floor and the carpet needing vacuuming - well 2 really - first its vaccuuming and second "sie" needs cleaning.

Its very confusing, but I'm not sure how you could simplify it without losing anything, it is just a confusing subject. Maybe a summary of it all at the end might help, i don't know...

Congratulations on doing so well with such a horrible topic!

Tango

Wayne oi foind owrt wort zen0phobia means yow forine types is gurner gerrit!

Translation for non-Brummy speakers:

When I find out what xenophobia means, you foreigners will be severely chastised.

Stuart

Isn't it enough just to say 'mirrors invert depth, not width', and have done with it??

Felonious, you are falling into the classic trap! You feel that just because you understand something, everybody else must too! Most people will not understand your explanation. They know that when they wave their left hand, the mirror image waves its right hand. That is what Lucinda's article is trying to explain.

Probably.

I've decided to remove this entry from Peer Review (and indeed from h2g2). Thanks for all your comments, and sorry to spring this surprise on y'all - I only decided myself a couple hours ago.

Best wishes and fantasies about Snow White's panties
-Martin