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Monday, February 26, 2018

Being spun right 'round (like a record)

I like analogies. Sometimes I use them to wrap my head around a situation that I've been experiencing but can't always describe directly. It can be useful when talking about the actual situation causes people to jump to conclusions too early, which then makes them not hear the whole story, and thus they miss the point. This approach allows people to get the pattern straight in their heads before I give them the mapping onto reality.

One of them I thought of requires a bit of visualization. First, imagine a big building that's enclosed but otherwise has a ton of open space in it, like a stadium, or Hangar One at Moffett Field before they tore off the roof covering.

Then park a glorified merry-go-round in it. That is, have a big flat rotating disc that basically fills the space, or at least, fills as much of the space that a circle can fill inside a square or rectangle.

The disc never stops spinning. It always moves in the same direction at the same speed. We'll say it's counter-clockwise (anti-clockwise) as viewed from overhead, like looking down from the roof of the enclosing building.

Now, this is an experiment, so get a bunch of babies and raise them on the disc. They grow up and all they know is being on the disc and going around and around. They don't see anything of the outside world, and there's nobody in the building they can see either. Their entire experience is defined by how things work on the disc.

Let's say one of the kids picks up a ball and wants to throw it to their friend. The kid with the ball is kid A. The friend is kid B. So kid A is standing near the outside of the disc and is looking more or less "spinward", that is, in the direction of the spin. Their friend, B, is some distance in that direction and is facing them, ready to catch the ball.

What happens if A throws the ball directly at B's head? Assume no funny stuff like putting a spin on the ball or anything like that. It's just a regular "move your hand in their direction and then open your fingers and let it fly" type of thing.

Where's that ball going to end up?

From A's perspective, it's going to zoom off to their right, off the disc, and will land somewhere in the room. From B's perspective, it's just backwards: it zooms off to their left, flies off the disc, and lands in the room somewhere.

What happened?

The ball was going in a circle along with everything else on the disc, but as soon as it left A's hand, it was no longer influenced by it. Just like anything else, it's going to go in a straight line, but with a downward curve because of gravity. Then it'll hit the ground.

It won't follow the disc. That would be ridiculous.

Well, after a couple of times of trying this, A is going to learn that in order to throw a ball "spinward" to a friend, you have to aim off-center. That is, you have to actually aim to the left of their head in order to actually hit the friend. The ball still travels straight, but from their frame of reference, it looks curved. The ball gets to where B is going to be at the same time B gets there, and B catches it.

Eventually, all of the kids independently learn that there are rules for how to be successful tossing balls around. You have to do this or that in order to make it actually get there. They probably get pretty good at it, and love teaching other kids how to be successful.

So let's say one day, kid A gets on some web site and starts talking with other kids. These other kids live outside this contraption. They are both interested in sports, and so they get to talking about how to throw a ball. The disc dweller swears up and down that you have to aim off-center and do all of this stuff depending on which way you're facing. The other kid is totally confused by this.

"What do you mean, throw off center? That's ridiculous! You throw the ball straight at their head if you want to hit them in the head. Everyone knows that."

The disc dwelling kid really wants to help the other kid. They aren't lying. They have no ill will. They don't mean any harm. They truly believe that to be successful at ball-throwing, you have to do this special song and dance to make it connect with the other person.

The trick is that they have totally different frames of reference.

This is basically how you can have a bunch of people agreeing on some point, and who deeply care about sharing it with you and insist that it's the only way to be correct, and yet it can be totally wrong at the same time.

It's possible to take their advice and become successful, but you also have to enter their reference frame, and accept that you're going to be spinning in circles for eternity.

Is that really what you want?