Barnette's Zeno's Coffeehouse
Challenge #62 Result
Thanks to Zeno's
Coffeehouse patrons and to all the new patrons who dropped by the
Coffeehouse! ! This challenge prompted over 100 replies, from many
countries around the planet, as Zeno's continues to gather a rich and
diverse group of patrons. which is
most appreciated as we explore the issues!
I have listed
below the original challenge, followed by several respondents' thoughts
on the matter. I
want to thank ALL respondents for their thoughtful time taken with
Zeno's Coffeehouse, and
to encourage your continued support, as critical thinking exercises are
mental growth and recreation. Minds need exercising with shared,
reflective thinking; this is enjoyable and enriching. Help spread the word!
Mirror, Mirror on the Wall
When young Mark walked in to the
Coffeehouse last week, he asked Charles and Maggie to think about
something he experienced as a kid in a barber shop: images while looking at his
reflection in a mirror which reflected this back in a mirror which reflected back in the mirror, which seemed
to go on forever. Zeno's thoughts on infinity now occurred to Mark, which
intrigued him, as he had been reading about the paradoxes of the good
pre-Socratic thinker. But what also occurred to curious Mark was another question:
"Why is it that mirrors reverse images from right to left and not from top to bottom?," he wondered.
Why indeed, as Charles and Maggie thought about Mark's question.
To new and to faithful Coffeehouse patrons, let's see if we can
help young Mark, ok? And thanks, Mark, for this thoughtful challenge, as you pose an intriguing challenge!
Keep up the Zeno's Coffeehouse involvement, as it's good for
I have encluded a few samples of the replies received, which are representative. Most appreciated! Ron Barnette
Maria in Lisbon, Portugal writes:
comments: First, I have to thank you for all these FUNtastic
challenges! Writing you about my thoughts never crossed my mind, but
now, Ron, I have to do it.
This is one of my rules in life: THINK IT SIMPLE before you run to a complex explanation.
Mirrors reverse images from right to left because IT IS THE EASIEST WAY
TO LOOK AT THEM. Otherwise, you had to be upside down to see them
May I add a LOL?
Anthony in Savannah, Georgia USA writes:
comments: could the reason lie in ourselves? that we, in fact, use
mirrors to see the image of ourself, perfect ourselves to a presentable
form. that image that we want to see is reflected in a most nearly
perfect (the closest image to perfection that we, as imperfect humans,
can develop) and easy-to-see form, for our own egotistical "viewing
pleasure". therefor, why would we want a burden, an imperfection on
this image by causing the image to be reflected in any other manner but
the one we are most satisfied with, the image that we developed to near
-from anthony d., 16
Phil in Christchurch, New Zealand, writes:
comments: Mirrors do not reverse images from right to left. If you hold
your left hand up in front of a mirror the reflection is still on the
left side of the mirror. However, your brain interprets the reflection
as being a real person, the two-dimensional image as being a real
three-dimensional human facing you, in which case it is their right
hand which would be raised.
Fernando in El Paso, Texas USA writes:
comments: we have bi-nocular vision, that is, we have two eyes
splitting our vision in left and right vision. this is why we perceive
mirrors as reversing images from left to right.
Chris in Oxford, UK writes:
comments: Mirrors, in fact, don't reverse left/right any more than they
reverse up/down! The issue here is one of frames of reference, and
there are several ways to approach it.
Way one (a bit weak): When someone approaches you, what he regards as
'left' will be on the hemisphere you regard as 'right', and vice versa.
However, what he regards as up is what you regard as up, and ditto for
down. Let's not forget the third dimension: what's forward for him is
backwards for you, and vice versa. Same happens with a mirror (only
that you cannot avail yourself of the mirror image's observations short
of transposing yourself into his position, which however is something I
am not willing to do just yet). Anyway: it seems that the x axis
(up/down) is the only anomalous dimension. Because gravity is a fixed
frame of reference, it will remain fixed, while the other axes do not
have a fixed frame of reference.
Way two (slightly better): A flat mirror creates a two-dimensional
picture which recreates a point P' on the plane of the image so that it
is the closest possible to the real point P while still being on the
plane of the mirror. The result is that the image of your left hand
needs to be in the left hemisphere (all from your perspective, of
course). If the image of your left hand were on the right hemisphere,
there would be at least one depiction (left-left') which has a shorter
distance in space between object-object', hence this would not be a
flat mirror. You see a chap in the mirror that looks just like you
(let's call him you'). You assume that it is identical, but it is not.
Here's how: you see yourself, say, wearing a red glove on your left
hand, and see you' wearing a red glove on his left' hand. Because it
looks just like you, you assume an identity and expect that if you
perform an imaginary turn of either you or you' by 180 degs around your
x axis, you ought to match up. Bu [unfortunately, the rest of Chris'
reply didn't come through. Sorry, but I wanted to include his note...RB]
Troy (a faithful Coffeehouse patron) from Abilene, Texas USA writes:
comments: "Left," "right," "up," and "down" are relative
terms--relative to the perspective of the one doing the observing (in
this case). While "up" and "down" seem fairly fixed, because we
normally operate in a vertical mode, the ability to move around and
view matters from different positions affects how "right" and "left"
For example, suppose two people are sitting at a table, on the east and
west sides, respectively. There are two blocks on the table, a
red one toward the north and a black one toward the south.
Looking at the blocks, the person sitting on the east would say that
the red block is to the right of the black one. The person
sitting on the west, however, would say that the red block is to the
left of the black one. Neither of them is wrong--from their
We understand this, and we compensate accordingly. If I stand
facing a person and place my hands on their shoulders, my right hand is
on their left shoulder. But notice that this wording
automatically takes that adjustment into account; the hand which I call
"right" (from my perspective) is resting on the shoulder that they call
"left" (from their perspective). We learn to function with this
rotation of perspective in mind.
A mirror does not rotate a perspective, though. Instead, it
reflects the image in more of a straight-line fashion. If I stand
facing a mirror, with my right side to the south and my left side to
the north, then the reflection of my image will show my right side on
the south and my left side on the north. This seems
backwards--because when we are facing another individual, we
automatically take the rotation of perspective into account. But
this does not happen with the mirror--nothing is rotated.
Take another example. Suppose I have a sheet of paper with a
large letter "E" printed on it. I am going to look at the letter
in a mirror. I stand in front of the mirror, turn the paper
toward the mirror .......... hold on. I rotated the image.
The mirror doesn't. The mirror simply reflects the image it
So when we say that a mirror "reverses" the image, it really
doesn't. What the mirror does is reflect things that we typically
expect to see rotated. In that sense, the effect presented to us
by a mirror is abnormal, and we suspect that the mirror is doing
something very strange. But it's all a matter of perspective.
Lauri (another faithful Coffeehouse patron) from Karkola, Finland writes:
comments: Friend of mine sometimes challenged me and couple of other
peoples - at the coffee room at our University's philosophy department
- about the concepts of 'left' and 'right'. (Not a situation very
different to Mark's situation, indeed!) I think that in Mark's question
there is a tacit presupposition which is simply wrong: mirrors DO NOT
reverse images from right to left. If you stand in front of a mirror
and move your - let us say - left hand, you can see from the mirror
that left hand indeed moves. Let us imagine that when standing in front
of this mirror on your left side is a wardrobe and on your right side a
bed. Move your left hand and, indeed, in the mirror also the hand on
the wardrobe's side moves. Only if you think that there is another
person in the mirror and try to imagine things from that other person's
viewpoint, would it see like his or her right hand moves when you move
your left one. But there certainly (most probably?, must be cautious in
the philosophy sit
Jemaiel in Tunis, Tunisia writes:
comments: it does! put a mirror in the gound and the skye would be under your feet