I remember this being mentioned by Charles Peirce as an argument for pragmatism (the philosophical kind): It's a nonsensical question unless you can phrase it in terms where the answer has some practical consequence.
From the title I thought this was going to be a variation on the bear and swimmer puzzle.
I'm probably butchering this, but in my mind it is something like:
1. From the squirrels frame of reference and local coordinate system, the man has remained "in front" of the squirrel. The squirrel is orienting and rotating in sync with the man and therefore has not observed that the man has "gone round" it.
2. From our perspective (and on reflection from the man), the man has circled the squirrel in the global coordinate system of the scene.
As the reader we assume that our perspective is the authoritative one, but I am sure the squirrel disagrees.
One could argue that the moon is orbiting the sun. The fact that it's orbit is a little wobbly because of interferes from the earth is a rounding detail, no?
> An enduring myth about the Moon is that it doesn't rotate. While it's true that the Moon keeps the same face to us, this only happens because the Moon rotates at the same rate as its orbital motion, a special case of tidal locking called synchronous rotation.
My colleagues once spent a good hour trying to explain this fact to me and I still really struggle to accept it. I can see that the moon is rotating on its own axis from the point of view of a space that is external to the system it forms with the earth. But then isn’t everything on earth rotating about its own axis with respect to that external space? It seems arbitrary to isolate the moon from all this other stuff and make a special case of it…
But is a geostationary satellite going around the Earth?
I take it that the squirrel didn't circle the man?
Two squirrels running around the same tree, are they circling each other? Or is it that when two bodies are orbiting the same center, then the body with the larger orbit is circling the one with the smaller?
What is the definition of "circling"?
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Similarly, a rolling wheel
(without slipping and on flat ground) does a pure rotation around the touch point and not its center.
It took me longer than it should to get this!
On reflection, does the squirrel consider itself to have been "gone round"? I don't think so.
Say instead of just walking, the man was laying down a net/barricade around the tree. As soon as the man completes the circumference, the squirrel must admit that it has been gone around.
Now let us suppose the squirrel is at the same distance as the man.
Has the man have gone around the squirrel and the squirrel around the man?
If it's only radii less than the other, where is the limit?
To get it I think I have to re-frame it like this:
If you hold out an object toward the centre, you clearly go around it when completing an orbit.
If you keep extending that to the origin but then go beyond, so your arm is longer than the radius, then you still go around it, until your arm reaches twice the radius.
The article says the man was trying to see the squirrel's back implying a larger radius.
But yeah if your circuit completely fits inside the other person's circuit, then you've been gone around, no matter how slow or fast you both are.
To get what?
That the man technically went around the squirrel without ever having caught up to it.
I remember this being mentioned by Charles Peirce as an argument for pragmatism (the philosophical kind): It's a nonsensical question unless you can phrase it in terms where the answer has some practical consequence.
From the title I thought this was going to be a variation on the bear and swimmer puzzle.
https://www.quantamagazine.org/can-math-help-you-escape-a-hu...
This tickled my brain in a nice way.
I'm probably butchering this, but in my mind it is something like:
1. From the squirrels frame of reference and local coordinate system, the man has remained "in front" of the squirrel. The squirrel is orienting and rotating in sync with the man and therefore has not observed that the man has "gone round" it.
2. From our perspective (and on reflection from the man), the man has circled the squirrel in the global coordinate system of the scene.
As the reader we assume that our perspective is the authoritative one, but I am sure the squirrel disagrees.
One could argue that the moon is orbiting the sun. The fact that it's orbit is a little wobbly because of interferes from the earth is a rounding detail, no?
> An enduring myth about the Moon is that it doesn't rotate. While it's true that the Moon keeps the same face to us, this only happens because the Moon rotates at the same rate as its orbital motion, a special case of tidal locking called synchronous rotation.
https://science.nasa.gov/resource/the-moons-rotation/
My colleagues once spent a good hour trying to explain this fact to me and I still really struggle to accept it. I can see that the moon is rotating on its own axis from the point of view of a space that is external to the system it forms with the earth. But then isn’t everything on earth rotating about its own axis with respect to that external space? It seems arbitrary to isolate the moon from all this other stuff and make a special case of it…
But is a geostationary satellite going around the Earth?
I take it that the squirrel didn't circle the man? Two squirrels running around the same tree, are they circling each other? Or is it that when two bodies are orbiting the same center, then the body with the larger orbit is circling the one with the smaller? What is the definition of "circling"?
Similarly, a rolling wheel (without slipping and on flat ground) does a pure rotation around the touch point and not its center.
It took me longer than it should to get this!
On reflection, does the squirrel consider itself to have been "gone round"? I don't think so.
Say instead of just walking, the man was laying down a net/barricade around the tree. As soon as the man completes the circumference, the squirrel must admit that it has been gone around.
Now let us suppose the squirrel is at the same distance as the man.
Has the man have gone around the squirrel and the squirrel around the man?
If it's only radii less than the other, where is the limit?
To get it I think I have to re-frame it like this:
If you hold out an object toward the centre, you clearly go around it when completing an orbit.
If you keep extending that to the origin but then go beyond, so your arm is longer than the radius, then you still go around it, until your arm reaches twice the radius.
The article says the man was trying to see the squirrel's back implying a larger radius.
But yeah if your circuit completely fits inside the other person's circuit, then you've been gone around, no matter how slow or fast you both are.
To get what?
That the man technically went around the squirrel without ever having caught up to it.
[dead]