[obol] Re: "theory"

[Mike Patterson]

If we're going to go all pedantic on this stuff, I'm obliged to 
point out that Newton DID NOT produce a theory of gravity.

I quote from the _Principia_:
"Hitherto I have not been able to discover the cause of those 
properties of gravity from the phenomena, and I frame no hypothesis; 
for whatever is not deduced from the phenomena is to be called an 
hypothesis; and hypotheses, whether metaphysical or physical, 
whether of occult qualities or mechanical, have no place in 
experimental philosophy. In this philosophy particular propositions 
are inferred from the phenomena, and afterward rendered general 
by deduction. Thus it was the impenetrability, the mobility, and 
the impulsive forces of bodies, and the laws of motion and of 
gravitation were discovered. And to us it is enough that gravity 
does really exist, and acts according to the laws which we have 
explained, and abundantly serves to account for all the motions 
of the celestial bodies, and of our sea."

Newton formulated a LAW of Gravity which was an equation which 
characterized the force of gravitional attraction in terms of mass 
and distance.  He had no explanation (that would be the theory part) 
for why gravity worked and was criticized by some of his contemporaries
for his "spooky" force over a distance with no defined cause.

Einstein was able to frame a theory, however, defining gravity as
the result of mass change the "shape" of space-time.  His refined
mathematical laws found in the general theory accounted for certain
differences in gravitational behavior not accounted for in Newton's
Law.  

So, Newton's Law of Gravity is different than Einstein's.  And there 
is a difference, science, between a law and a theory.

Dave Mellinger wrote:
> 
> Actually there are two theories of gravity, Newton's and Einstein's.
> 
> Dave
> 


-- 
Mike Patterson               
Astoria, OR                    
celata at pacifier.com  
 
I'm not jealous or 
Why I've never Seen Black-throated Blue Warbler in Oregon
http://www.surfbirds.com/blogs/mbalame/archives/004174.html