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Post by BruceGee on May 2, 2015 0:18:43 GMT -5
I like this discussion of the mirror problem. There’s another slippery word in the question, or rather two: “left” and “right.” What do people actually mean by these things?
Little kids have trouble remembering which is which, after all. I remember frequently getting confused when I was small – eventually I had to remember a way to tell my arms and hands apart, by watches and so forth. Once I’ve learned to memorize which is my right hand, no matter how I spin around or stand on my head, that hand always stays the same. But what does “right” actually mean?
Here’s my proposal: when we say “right” what we really mean is “clockwise from my head.” And left means “anti-clockwise from my head.”
Imagine that you’re holding a disk made of four quadrants: white, green, black, and red. You look at the disk in the mirror, and you see that the white and black quadrants are in the “correct” positions, but the green and red quadrants are “switched.”
Now tilt your head ninety degrees. Voila! Now all of a sudden, the red and green quadrants are “correct” and the black and white ones are “switched.”
So what the mirror does is, it switches clockwise and counterclockwise.
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Post by MikeO on May 5, 2015 16:01:42 GMT -5
BruceGee,
Your idea is interesting. I think the left rignt thing boils down to being able to distinguish a standard right handed coordinate system from a left handed one.
As far as I know, outside of quantum considerations, you can't tell which is which without a standard, like the meter bar stored in Paris that defines the metric system. Once a standard like that is established for left/right, you can use surrogate standards, and need not travel to Paris for every comparison. I use my heart's location as a local and portable surrogate standard. I think most people do this as well.
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Post by BruceGee on Jun 29, 2015 13:53:18 GMT -5
I would argue that the terms "clockwise" and "anti-clockwise" have an objective meaning, in a way that "right" and "left" do not.
Get a hundred disks, half painted white, green, black, red and the other half painted white, red, black, green. Anyone could easily separate them into similar groups, whereas if I told you, "Get all the disks where the red is on the left side," you would scratch your head in confusion. Any play director who has told an actor "Go left! No, your left!" knows what I'm talking about.
You're right, you still can't tell which is clockwise and which is anti-clockwise without an actual clock to compare them with. But you'd still be able to tell that a mirror switches one for the other.
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Post by Robert S on Aug 13, 2017 18:19:24 GMT -5
MY COMMENT ON MIRROR IMAGE RIGHT v LEFT
I had thought about this "problem" for a great many years, finally realizing that the answer has to do with concepts. The terms LEFT/RIGHT refer to a different concept than the terms HEAD/FOOT. Your head is a certain part of your body and it remains such no matter how (directly or in a mirror) you look at it; the same is true of your foot. Further, the SAME IS ALSO TRUE of your hand that is WEARING YOUR WEDDING RING: it remains such no matter how you look at it; ditto for your hand that isn't wearing your wedding ring. In both cases (HEAD/FOOT and RING HAND/OTHER HAND) we're talking about a certain part of your body. We could have identified your RIGHT hand as the hand on the arm that is closer to your liver: it clearly remains such no matter how you look at it. And same is true of the hand on the other arm: it is always farther from your liver. In both cases (HEAD/FOOT and HAND ON ARM CLOSER TO YOUR LIVER/HAND ON ARM FARTHER FROM YOUR LIVER) we are talking about something that doesn't change: a certain part of your body.
The problem is that the terms LEFT/RIGHT may or may not refer to a certain part of your body. If someone who is facing you asks you to raise your LEFT hand, he's using the word LEFT in the same sense as you would: namely, to refer to a certain unchanging part of your body. BUT if, instead, he asked you to raise the hand on the LEFT, you'd probably be unsure as to whether he means on YOUR left or on HIS left. This uncertainty would be because he's now using the word LEFT to refer to a DIRECTION, not to a part of your body. It is analogous to a house only being on the LEFT if you're traveling in a specific direction, not if you're traveling in the opposite direction; although if it’s on the east side of the street, it remains on the east no matter in which direction you’re traveling.
Thus, for the imaginary person in the mirror the hand closer to his liver will be the hand on your right, directly opposite YOUR right hand and, let’s say, to the west of your center line; and if the mirror image could talk, he’d say that, indeed, that hand was both closer to his liver and to the west of his center line.
What you would disagree on is which direction you’d look to see his liver-side hand: you’d say you’d need to look to your right; he’d say, no, he has to look to his left. And both of you would be correct since whether west is to your left or to your right is entirely dependent on in what direction you are facing.
Now, imagine that you are suspended off the floor in a sling that holds you still facing the mirror but rotated 90° so that your LEFT hand is closer to the floor. If you then referred to your head as the part of your body ON THE LEFT, another person might ask you if you're talking about "on the left" from YOUR upright point of view or from the upright point of view of the imaginary person we see in the mirror. Instead of referring to a permanent part of your body by its name, HEAD, you referred to that part of your body based on your specific point of view, and your point of view is opposite to the point of view of the imaginary person in the mirror. It is analogous to saying that a house is on the left without specifying in which direction the observer is facing.
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Post by izowuyirum on Jul 17, 2019 14:25:16 GMT -5
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Post by izowuyirum on Jul 17, 2019 14:26:16 GMT -5
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Post by eomosacep on Aug 29, 2019 5:26:09 GMT -5
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Post by eomosacep on Aug 29, 2019 5:27:41 GMT -5
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