Re: New addition to the list of Relativity Critics/Skeptics

LaurenceClarkCrossen <clzb93ynxj@att.net> wrote:

You're mistaken about infinity not being in Euclid's parallel lines
according to his article:
 
"He began by studying Euclid's postulate that a straight line has infinite
length."
 
 
"THE PARALLEL POSTULATE"
 
Author(s): Raymond H. Rolwing and Maita Levine
 
Source: The Mathematics Teacher, Vol. 62, No. 8 (DECEMBER 1969), pp. 665-669
 
Published by: National Council of Teachers of Mathematics
 
Stable URL: http://www.jstor.org/stable/27958258
 
I think that the geometries opposed to Euclid do not contradict his
because they depart from plane geometry. For example, a triangle with
other than 180 degrees is not on a plane surface, nor are parallel lines
that diverge or meet. please read the article and see what I mean!
 
Euclid's geometry is about plane geometry and the non-Euclidean's are not.

Euclid's 5th postulate can (and was) given as:
===
5. If two lines are drawn which intersect a third in such a way that the
sum of the inner angles on one side is less than two right angles, then
the two lines inevitably must intersect each other on that side if
extended far enough. This postulate is equivalent to what is known as
the parallel postulate. (Wolfram)
===

The domain of Euclidean geometry is the open Euclidean plane.
No actual infinity is involved, [1]

Jan

[1] You can extent Euclidean geometry by adding a 'point at infinity'.
This is called projective geometry, and it is something else.
(and also irrelevant for disproving general relativity)