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savvo wrote:
[]
> You're confusing and conflating reflex and reflection.

If we try hard enough, I'm sure we'll find a definiton of reflex which
suits us both....

<G>

David

David J Taylor <david-> wrote:
> savvo wrote:
>> On 2008-08-06, David J Taylor
>> <david-> wrote:
>>> savvo wrote:
>>> []
>>>> You might but we shouldn't since the announced system has done away
>>>> with any reflex mechanism.
>>>
>>> The reflex is now electronic, otherwise the image would be rotated
>>> 180 degrees.
>>>
>>
>> That's just gibberish.

> You can call it what you want, but the image needs inversion before it is
> suitable for most of us to view.....

But we must be careful to distinguish between the rotational and
lateral inversions. For example, why do mirrors interchange left and
right but not up and down?

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Chris Malcolm wrote:
[]
> But we must be careful to distinguish between the rotational and
> lateral inversions. For example, why do mirrors interchange left and
> right but not up and down?

Try holding the mirror in a different orientation!

<G>

David

Chris Malcolm wrote:
> David J Taylor <david-> wrote:
>> savvo wrote:
>>> On 2008-08-06, David J Taylor
>>> <david-> wrote:
>>>> savvo wrote:
>>>> []
>>>>> You might but we shouldn't since the announced system has done away
>>>>> with any reflex mechanism.
>>>> The reflex is now electronic, otherwise the image would be rotated
>>>> 180 degrees.
>>>>
>>> That's just gibberish.
>
>> You can call it what you want, but the image needs inversion before it is
>> suitable for most of us to view.....
>
> But we must be careful to distinguish between the rotational and
> lateral inversions. For example, why do mirrors interchange left and
> right but not up and down?
>

A learned person such as yourself asks this question without a smilie?

Mirrors do *not* 'interchange' or 'reverse' left or right. They just..
reflect!

The mirror should not be maligned or imbued with some sort of magical
ability, simply because your body is at fault by having left/right
symmetry only...

(O:

Mark Thomas wrote:
> Chris Malcolm wrote:
>> David J Taylor
>> <david-> wrote:
>>> savvo wrote:
>>>> On 2008-08-06, David J Taylor
>>>> <david-> wrote:
>>>>> savvo wrote:
>>>>> []
>>>>>> You might but we shouldn't since the announced system has done away
>>>>>> with any reflex mechanism.
>>>>> The reflex is now electronic, otherwise the image would be rotated
>>>>> 180 degrees.
>>>>>
>>>> That's just gibberish.
>>
>>> You can call it what you want, but the image needs inversion before
>>> it is suitable for most of us to view.....
>>
>> But we must be careful to distinguish between the rotational and
>> lateral inversions. For example, why do mirrors interchange left and
>> right but not up and down?
>>
>
> A learned person such as yourself asks this question without a smilie?
>
> Mirrors do *not* 'interchange' or 'reverse' left or right. They just..
> reflect!
>
> The mirror should not be maligned or imbued with some sort of magical
> ability, simply because your body is at fault by having left/right
> symmetry only...
>
> (O:

And I'll add there are *very few* webpages that properly explain the
issues - namely our ingrained symmetry and the fact that the terms
'left' and 'right' are NOT NOT NOT the same sort of directions as 'up'
and 'down'.

There's a rather clever conversation about this here:

http://math.ucr.edu/home/baez/physic...l/mirrors.html

"Chris Malcolm" <> wrote in message
news:...
>
> But we must be careful to distinguish between the rotational and
> lateral inversions. For example, why do mirrors interchange left and
> right but not up and down?

....

No they don't.

If you hold up your right arm, the reflection in the mirror
holds up the arm on right arm as well.

However even without a mirror, a person facing you might just
as well claim that the arm you raised was on the left.

In other words whether something is on the left or the right
depends on the direction in which the viewer is facing
relative to what they're describing.

Whereas whether something is up or down never depends on
the direction in which the viewer is facing.

Not until people make more of a habit of standing on their
heads anyway. At which point, further clarification may be
called for.



michael adams

....








>
> --
> Chris Malcolm DoD #205
> IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
> [http://www.dai.ed.ac.uk/homes/cam/]
>

On Aug 7, 3:41*am, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
> David J Taylor <david-tay...@blueyonder.neither-this-bit.nor-this-bit.co.uk> wrote:
>
> > savvo wrote:
> >> On 2008-08-06, David J Taylor
> >> <david-tay...@blueyonder.neither-this-bit.nor-this-bit.co.uk> wrote:
> >>> savvo wrote:
> >>> []
> >>>> You might but we shouldn't since the announced system has done away
> >>>> with any reflex mechanism.
>
> >>> The reflex is now electronic, otherwise the image would be rotated
> >>> 180 degrees.
>
> >> That's just gibberish.
> > You can call it what you want, but the image needs inversion before it is
> > suitable for most of us to view.....
>
> But we must be careful to distinguish between the rotational and
> lateral inversions. For example, why do mirrors interchange left and
> right but not up and down?

They don't chnage left and right, what they do change is front to
back, which is what changes the handedness (if that is a word).

So x and y axis stay the same but z becomes -z.

Scott

Mark Thomas wrote:
> Chris Malcolm wrote:
>> David J Taylor
>> <david-> wrote:
>>> savvo wrote:
>>>> On 2008-08-06, David J Taylor
>>>> <david-> wrote:
>>>>> savvo wrote:
>>>>> []
>>>>>> You might but we shouldn't since the announced system has done away
>>>>>> with any reflex mechanism.
>>>>> The reflex is now electronic, otherwise the image would be rotated
>>>>> 180 degrees.
>>>>>
>>>> That's just gibberish.
>>
>>> You can call it what you want, but the image needs inversion before
>>> it is suitable for most of us to view.....
>>
>> But we must be careful to distinguish between the rotational and
>> lateral inversions. For example, why do mirrors interchange left and
>> right but not up and down?
>>
>
> A learned person such as yourself asks this question without a smilie?
>
> Mirrors do *not* 'interchange' or 'reverse' left or right. They just..
> reflect!
>
> The mirror should not be maligned or imbued with some sort of magical
> ability, simply because your body is at fault by having left/right
> symmetry only...
>
> (O:

Decagon is ten so maybe a decaprism?

--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

Paul Furman wrote:
> Mark Thomas wrote:
>> Chris Malcolm wrote:
>>> David J Taylor
>>> <david-> wrote:
>>>> savvo wrote:
>>>>> On 2008-08-06, David J Taylor
>>>>> <david-> wrote:
>>>>>> savvo wrote:
>>>>>> []
>>>>>>> You might but we shouldn't since the announced system has done away
>>>>>>> with any reflex mechanism.
>>>>>> The reflex is now electronic, otherwise the image would be rotated
>>>>>> 180 degrees.
>>>>>>
>>>>> That's just gibberish.
>>>
>>>> You can call it what you want, but the image needs inversion before
>>>> it is suitable for most of us to view.....
>>>
>>> But we must be careful to distinguish between the rotational and
>>> lateral inversions. For example, why do mirrors interchange left and
>>> right but not up and down?
>>>
>>
>> A learned person such as yourself asks this question without a smilie?
>>
>> Mirrors do *not* 'interchange' or 'reverse' left or right. They
>> just.. reflect!
>>
>> The mirror should not be maligned or imbued with some sort of magical
>> ability, simply because your body is at fault by having left/right
>> symmetry only...
>>
>> (O:
>
> Decagon is ten so maybe a decaprism?

Which would be useful for taking pictures of yourself in the mirror!

--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

Scott W <> wrote in
news:8570e13a-bb2b-47eb-839a-:

> On Aug 7, 3:41*am, Chris Malcolm <c...@holyrood.ed.ac.uk> wrote:
>> David J Taylor
>> <david-tay...@blueyonder.neither-this-bit.nor-this-bit.co.
> uk> wrote:

>> > You can call it what you want, but the image needs inversion
>> > before it
> is
>> > suitable for most of us to view.....
>>
>> But we must be careful to distinguish between the rotational and
>> lateral inversions. For example, why do mirrors interchange left
>> and right but not up and down?

> They don't chnage left and right, what they do change is front to
> back, which is what changes the handedness (if that is a word).
>
> So x and y axis stay the same but z becomes -z.

I am late to this party but what the hell...

Scott's three lines are an admirably concise account of what plane
mirrors do. I, on the other hand, intend to run on for a bit.

Concave mirrors producing a real image invert along all 3 Cartesian
axes, as do lenses creating real images. Optical systems which create
odd numbers of inversions create net inversion. Systems which create
even numbers of inversions create images which are equivalent to a
rotation plus a possible change of scale.

This is of profound significance in the busines of life.

Molecules which cannot be rotated into congruence with their mirror
images created by a plane mirror are called dissymetric. Thus, almost
all amino acids involved in protein molecules are dissymetric.
Humans can metabolize amino acids with one stereochemistry at the
carbon closest to the acid carbon, but not their mirror image
structures. Other such selectivity occurs all through nature.

One of the very earliest insights into this phenomenon came from a
young lady called Alice, she of the looking glass and Wonderland. She
says, at one point, "Perhaps looking glass milk is not good for you."
This is a remarkable piece of thinking for the 19th century,
particularly since both books were written, I think, before van't Hoff
and le Bel published their separate papers on the stereochemistry of
carbon. (Neither of them was the originator of the idea but their work
came along at a time when the world was ready for it.)

- Shankar