Message-Id: <m0syMq6-0000ZSC@xiron.pc.helsinki.fi>
Date:         Thu, 28 Sep 1995 18:21:10 +0100
Reply-To:     ucleaar <ucleaar@UCL.AC.UK>
Sender:       Lojban list <LOJBAN@CUVMB.BITNET>
From:         ucleaar <ucleaar@UCL.AC.UK>
Subject:      Re: direction, dimension & Re: {soi}
To:         lojban@cuvmb.cc.columbia.edu
Content-Length: 1277
Lines: 28

Jorge:
> > > Which direction is the sheet of paper tinsa in?
> > Away from the plane defined by the paper's two principal dimensions.
> So you agree that the direction place is redundant, since there is always
> only one direction in which it can be tinsa, whether the object be of
> spherical or cylindrical sag?

Yes. But I'm not the physicist.

> > I think we have two senses of dimension:
> > (1) pertaining to the space within which the shape of x is defined;
> A one dimensional object can have a shape in a three dimensional space
> (a helix for instance), but I understand what you mean.
> > (2) "axis". A person has 3 "axes"; a ball has none. Both
> > are 3-dimensional.
> How can you tell? A person has an up-down dimension thanks to gravity,
> a front-back one thanks to movement, and a left-right one by virtue
> of having the other two. But from a purely geometrical point of view,
> the only interesting thing about a person is one plane of approximate
> symmetry. Is this "axis" concept purely geometrical, or does it involve
> things like gravity and movement?

It involves things like gravity and movement. Each axis has its own
prototype definition - the transverse is defined principally by
motion, the lateral by symmetry, the vertical by gravity.

---
And