Summary
The line of Mathematical Physics runs into more conceptual problems than the ubiquitous point. It is not
that the mathematicians do not know what a line is. It is that they refuse to use the definition of the word
line  consistently (i.e., scientifically). Euclid defines a line as a series of dots, but never uses this definition. 
His book deals with locations. Hilbert's line consists of only two dots, but he never uses them. He uses
the empty space that lies between them. Weyl's line is by far the scariest: a location that moves! Anderson's
line consists of discrete footprints made by an alleged particle called the positron, or maybe of a
continuous trough plowed by Big Foot. Who knows? He never clarifies. The mathematicians haven't
decided whether a line is made of points or locations, whether it is a static geometric figure or a movie of a 
road under construction, whether it is infinite or finite, or whether it consists of a row of apples or of a trace 
scanned by one apple. The line of Mathematics has so many definitions and interpretations and is used so 
inconsistently during any given presentation that it has lost all meaning. It is not surprising, then, that the 
mathematicians usually begin their presentations by saying that the word line is indefinable. Yet they
purport to explain dimensions, coordinates, vectors, geodesics, curves, and String Theory with this 
malleable entity. You be the judge!
Inconsistent usage causes problems in Physics when relativists and mechanics draw sweeping 
conclusions. One infamous claim a mathematician boasts about is that he can fit an infinite number of
points between any two that comprise a line. That's when you suspect that you are not talking to the
doctor, but to one of the patients at the asylum.
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            | A line is NOT the shortest distance between two points!
 
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                  Will this take long, Master Euclid? 
Not that I want to rush you, but I 
have another class in 3 hours.
      
            
        
          
            | Watch carefully now, Student Bill!
 I want you to understand
 WHAT an infinite line IS.
 Keep your eyes on the
 pen. Steady...Steady...
 
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     Copyright © by Nila Gaede 2008