Re: [asa] YEC--What can we offer them?

Don -

The statement "Scientific theories go where experiments lead" doesn't quite apply to your initial example of general relativity. At the beginning of the 20th century there was no compelling experimental/observational reason to change Newton's gravitational theory, & even the 1 small discrepancy in the orbit of Mercury could be taken care of with a minor change in the force law. Theoretical reasons drove Einstein to develop GRT. Of course if it hadn't resolved the problem with Mercury & predicted the correct value of light deflection most physicists wouldn't have seen much need to accept the new theory.

Shalom
George
http://web.raex.com/~gmurphy/
  ----- Original Message -----
  From: Don Winterstein
  To: asa ; Dawsonzhu@aol.com
  Cc: Randy Isaac
  Sent: Thursday, July 05, 2007 2:08 AM
  Subject: Re: [asa] YEC--What can we offer them?

  Wayne wrote:
  "I don't really see things like relativity theory being
  as much a paradigm shift as an extension of the limiting
  case of Newton's law of gravitation."

  Newton's gravity is rather the low-velocity limit of general relativity. And the jump to general relativity constitutes a paradigm shift if there ever was one: With Newton, there's an attractive force between objects at a distance that determines relative trajectories; with Einstein, four-space geometry determines trajectories, where the shape of the four-space depends on the masses within it. There's no attractive force; objects simply follow their geodesics in space-time.

  General relativity differs radically from Newton in its way of looking at space, time and motion. The practical consequences are minuscule compared with the magnitude of the paradigm shift behind them! Newton was not wrong, but his theory lacked generality.

  Quantum mechanics revealed that entities at micro-scale behave nothing like entities at macro-scale. So QM also introduced a paradigm shift, because the general assumption had been that objects should behave similarly at all scales.

  In this case physicists were wrong (their "theories were invalidated") because they assumed objects should behave similarly at all scales.

  Earth scientists early last century were wrong about plate tectonics because they (often vociferously) derided the idea of continental drift.

  In both these cases--QM and plate tectonics--experimental data shoved scientists by the seat of the pants kicking and screaming into new paradigms.

  Therefore I'd revise Randy's claim as follows: Scientific theories go where experiments lead. In no case have scientists gone back to an old theory once data and theorists made it clear there was a better theory. (Exception: Sometimes an old theory still has pedagogical or computational uses.)

  I'd never say a theory had been validated. Consistent with all data and able to make good predictions--that's as good as it gets.

  Don

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Received on Thu Jul 5 06:48:34 2007