There are certain objects (people, animals, cars, boats, etc.) in which right & left refer to the right & left sides from the objects’ perspective.
However, there are other objects (pieces of paper, buildings, etc.) in which you use your right & left side to reference it.
I assume this has to do with whether we can mentally substitute ourselves in place of the object—we can do that with other living things or with vehicles in which we can ride, but not inanimate objects like a piece of paper.

hmm. int re cars. the vehicle moves ( = animate? ~ de anima ~ does not have its source of motion in itself ~ well except it does actually, it's not being moved, it is moving. so how is that distinct fr? an engine not an anima)

anything in motion,indep of us moving it, wld we say it has a right & left side of its own (from its own perspective)? because it moving gives it a forward direction, and thus a right & left? forward more powerful (as a notion in mind) than simply having a front?


divisbyzero.com/2010/02/04/why-do-mirrors-reverse-right-and-left-but-not-up-and-down-2

Posted by: Dave Richeson | February 4, 2010
Dave Richeson , Associate Professor of Mathematics, Dickinson College
MY BOOK | Euler's Gem: The polyhedron formula and the birth of topology. Princeton University Press 2008


I'm reposting something I wrote last year at this time. I was then, and am now, teaching Calculus III, and we just finished discussing the cross product. I ended the conversation by telling my classes how the cross product helps us answer the question: why do mirrors reverse right and left but not up and down?

Before we answer that question, we have to ask a more basic one: what is “the right”?

“Right” and “left” are a slippery concepts that are hard to define. In fact, you need to know other things about an object before you can determine its right and left. For example, if I handed you a blob-like sea creature and asked you which side is its right side, you may not be able to answer me. If I told you where the top and front sides of the critter were, then you could quickly identify the right side.

yes if there's a top & a front then there's a right & left side. { but...}

which is just wh said to R, defending my rxn when he said the bks "on that book's right". I said if we can speak of it having a front (& top I see now that we'd have to have a (shared) sense of wh is top ~ rb asked th, standing his pen up, if has top & bttm, wld I say it has a right side? ~ laughing at. & I said y since pen had one of those metal ..~clips? wh are those?! I guess fr design of pen to be hooked over shirt pocket so y 'clip'. since it has that, marking a front, then y it has r & l) than we can speak of it having a right.
R thought this preposterous. and alarming sheesh. bcs of the { but...} see below.
it's not preposterous though. ok, convention says that we refer to right & left sides of inanimate objects with reference to our right & left when facing those. but given the phrasing "*its* right", the book's right*, it's not preposterous that I would think he might be specifying a sort of book-right, like stage-right. see int Merriam Webster below. d1. but used wrt any object other than a stage? which is a special object since people stand on it & the norm is that they face other people 'in the house' 'house right'.
*realized myself an argument I'd accept, against taking that phrase that way. wh is that "to the book's right" and "to the right of the book" are syntactically the same, mean the same, just two ways of wording the possessive. genitive. and the latter, being more common in this situation, I recognize as conventionally indicating MY right when I look at the book.

The three directions, top, front, and right are mutually perpendicular and if you know two of them, you know the third. For a person, a car, an animal, etc, the top and the front are unambiguous and intuitive. Then we use them to determine which side is the right side. and note that right side of the car is ITS right side, truly. (wh makes sense I suppose bcs you relate to it by sitting in it, ie facing the same way as it. not just by facing it, ie facing the opposite way as it.)

Here’s a mathematical explanation of what you would be doing mentally. Take the coordinate axes shown below, point the z-axis out of the top of the creature and the y-axis out its front, then the x-axis will point to its right.



{...but }

I’ll end this post with some assorted thoughts about the left and the right.

• One thing that occurred to me while writing this post is that we treat different objects differently. Suppose I was holding a piece of paper out in front of me with my two hands and you were facing me. If I told you to point to the right hand side of the paper, then to point to my right hand, you would point to two opposite sides of the paper! There are certain objects (people, animals, cars, boats, etc.) in which right and left refer to the right and left sides from the objects’ perspective. However, there are other objects (pieces of paper, buildings, etc.) in which you use your right and left side to reference it. I assume this has to do with whether we can mentally substitute ourselves in place of the object—we can do that with other living things or with vehicles in which we can ride, but not inanimate objects like a piece of paper.

good comment, in response to complaint that mirrors are 2d & thrf no front or back
-A mirror may practically be 2d dimensional, but it reflects light that encodes three dimensional information.

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thefreedictionary.com/left

a. Of, belonging to, located on, or being the side of the body to the north when the subject is facing east. int. not as intuitive as..

b. Of, relating to, directed toward, or located on the left side.

c. Located on the left side of a person facing downstream

right = the side to the south when a person or object faces east] so why 'southpaw' = left. that comes from someone who faces west? :) y! [From the practice in baseball of arranging the diamond with the batter facing east to avoid the afternoon sun. A left-handed pitcher facing west would therefore have his pitching arm toward the south of the diamond.]
oh and p.s. "or object" 'when a person OR OBJECT faces east got a face got a right & left

..as
designating the side of something or someone that faces west when the front is turned towards the north
seems more common to talk in terms of facing north. and thrf to correlate: left = west.
and p.s. "SOMETHING or someone."


merriam-webster.com/dictionary/left

Main Entry: ¹left
Function: adjective

Etymology: Middle English, from Old English, weak; akin to Middle Low German lucht left; from the left hand's being the weaker in most individuals

1 a : of, relating to, situated on, or being the side of the body in which the heart is mostly located. ok. that keeps it personal.
b : done with the left hand
c : located nearer to the left hand than to the right
d : (1) : located on the left of an observer facing in the same direction as the object specified ['stage right']
(2) : located on the left when facing downstream ['the left bank'] ah ok d n exactly know th. wonder why that conventn? facing downstream. so if walking upstream against current, the bank on your right is 'the left bank'?
La Rive Gauche (French pronunciation: [la ʁiv ɡoʃ], The Left Bank) is the southern bank of the river Seine in Paris. Here the river flows roughly westwards, cutting the city in two: looking downstream which looking west, the southern bank is to the left, and the northern bank (or Rive Droite) is to the right. ok so that is the model. and I guess I knew term wrt Paris but not extended generally ~ wrt other rivers ~ is it?
"Rive Gauche" or "Left Bank" generally refers to the Paris of an earlier era; the Paris of artists, writers and philosophers, including Pablo Picasso, Arthur Rimbaud, Paul Verlaine, Henri Matisse, Jean-Paul Sartre, Ernest Hemingway, F. Scott Fitzgerald and dozens of other members of the great artistic community at Montparnasse. The phrase implies a sense of bohemianism and creativity. Some of its famous streets are the Boulevard Saint-Germain, the Boulevard Saint-Michel, the Rue de Rennes.
Rive Droite can now be used to refer to a level of elegance and sophistication not found in the more bohemian Left Bank. The Right Bank's most famous street is the Champs-Élysées, but there are others of prominence, such as Rue de la Paix, Rue de Rivoli, Avenue Montaigne.

merriam-webster.com/dictionary/right
Lat. 'regere' to lead straight, direct, rule. Greek. 'oregein' to reach out for, to stretch out.

7 a : of, relating to, situated on, or being the side of the body which is away from the side on which the heart is mostly located

huh to its being #7. after ~ rightous, upright; in accordance with what is just, good, or proper; correct, conforming to facts or truth; appropriate; straight geradeaus; genuine, real.
but before 8 : having the axis perpendicular to the base. & etc.



geradewegs = directly