Re: [lojban] Direction of Rotation

[Escape Landsome <escaaape@gmail.com>]

.

No matter however precise one is, one cannot define the direction of
rotation of a spinning object without giving an arbitrary (or a
"cultural") reference frame.  (Viz, the sun, a clock, some move with
his right hand, and so on).

The reason for this is geometrical and nearly metaphysical : it is a
well-known problem of epistemology, which was first noted by Kant in
his Critique of Pure Reason (in Transcendental Aesthetics), then also
noted by Lewis Carroll and Wittgenstein.

There's nothing in the pure 3d-euclidian geometry that can induce
something such as a "clockwise" or "counter-colckwise" movement, since
there is no arbitrary preference to stipulate the x, y and z-vectors.

Thus, the only thing you can say is that some determinante has value
+1 or -1, and that some rotations share the same value (though you
cannot say which one without arbitrary), and others share opposite
values.

This is such set that, were we bound to communicate with an alien race
in a parallel universe which we could not visit, but only speak about
it, we would have no clue whether some movement would be clockwise or
counterclockwise, and indeed, it is even the case that it would make
no sense at all.

Thus, the only convincing way to define the direction of rotation is
to culturally bind it to some famous move, e.g. the move of the hands
of some clock, for instance.

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