If you're communicating with people on another planet, I *guarantee* you they have the concept of left and right down.

They're aliens, they don't know what the Beatles are.

No, this is not correct. We could reckon rotations in any direction and the math works the same. It's dependent on the direction of axes, which we arbitrarily assign.  We have to define the axes in terms that are indisputable. Our plane is defined by up being 'away from our planet', up or +y. Our North is 'shortest length of a shadow caused by our sun during the day (projected onto our plane.) , +z. East is right is the direction in which our sun rises, projected onto our plane, +x. Vector math solves everything else.





 

I've been drinking. What I described is counter-clockwise.

Pi radians is your left.  2 pi radians is your right.  

Take heart. Depending on the direction of axes in the coordinate system, you could still be right.



I've been drinking, too. But I have literally spent hours today solving this very problem, trying to translate a rotation matrix of undefined axes to a known system. Without clear references, I am reduced to trying all combinations of axis directions and handedness, and trying to decipher vector directions.



Now you know why I drink.





 

OP, where is my prize?

Just would like to point out according to OP's later posted caveats to the original such explanation is pointless. Because if you can't assume they won't understand human concepts as right, left, clockwise, sunrise, and where your heart is what is the purpose of the question.

It's a ridiculous assumption to think they understand human speech at all. They likely wouldn't get human anatomy requiring explanation of what a hand is as well. If they did and were observing humans enough to understand English they would already get it. Or a simple explanation would suffice such as:

The hand most humans use to write is the right hand.

Just proves scientists are wasting tax payer money on fraudulent grants.

How about this.

In several cultures, you wipe with one hand and eat with the other.

'left' and 'right' are arbitrary names--it might as well be "banana' and 'canoe'.  any answer to the question really depends on what kinds of linguistic concepts the learner already possesses.  for example:

teacher: "how many feet do you have?"  learner: "two"

teacher: "are you sure they're not one foot that you see two times?"  learner: "yes--they're the same shape, but reversed.  also, if i stub my toe, i can point to one of the feet and say 'that's the foot i hurt'.  the other foot doesn't hurt."

teacher: "then you understand the concept of 'sides'.  one foot is on one side of your body, and the other foot is on the other side of your body.  the same for hands and shoulders--they are divided by the middle of your body."

learner: "what's 'middle'?"

teacher: "that is the place that isn't on a side--it is the straight line between sides, that divides one side from the other.  that line connects your nose and belly button, then goes up to the sky and down to the ground without ever bending.  point to one of your feet (learner points).  the name for that side is 'canoe'.  now touch your canoe foot with the hand that is on the same side of your nose line (learner touches).  that's your canoe hand, which is on the end of your canoe arm, because they are all on the same side of your nose."

learner: "what's the name of the stuff on the other side of my nose?"

teacher: "the other side is named 'banana'.  point to your banana foot with your banana hand (assume correct response).  now let's get more complicated--touch your banana foot with your canoe hand (correct).  did your canoe hand change into your banana hand?"

learner: "no"

teacher: "right.  it is still your canoe hand.  you just put it on the banana side of the middle: your nose.  banana and canoe are just names so that you can tell where something is in relation to a middle.  your canoe hand is the hand that connects to your canoe shoulder, but you can reach across the middle any time you want.


...and then soylent's heart example is probably the best way to ID which name goes for which side.  this of course ignores the problem of 'my canoe' vice 'your canoe' if two people are facing one another, but that's be an even longer post.

Goddammit, I knew it! Another safe thread!

If you face North, the sun will rise on your right and set to your left.

A left jack boot up your ass feels exactly the same as a right jack boot up your ass.

Posted Via AR15.Com Mobile

why would you assume that an alien would have hands, or be bilateral.

Experience?

just defers the problem.  what's 'north'?  another arbitrary name for a direction.

To enjoy a thread this pedantic and Socratic, I would need much more gin and tonic.





Posted Via AR15.Com Mobile

Your left side is the side your heart is on, while your right side is where your appendix is.

I think OP is a teacher trying out a lesson on us.

If not, then...

There is no left or right. There is only weapon and reaction.   Praise be to St. Costa.

Can we say that one's left index finger and thumb make the letter "L" when extended and be done with it?