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

Don -

I can't agree that Newton's theory is simply "wrong." Of course a lot depends on what one understands "Newton's theory" to be. Certainly a model in which masses exert instantaneous inverse square forces on other masses which move in accord with F = ma is inferior to Einstein's model of curved space-time & can't even be considered an approximation to it: masses exerting forces are qualitatively different things from non-Euclidean geometries. But the fundamental model is the math. Newtonian gravitation in that sense is then Poisson's equation for the potential with mass density in the source term plus the statement that ma is minus the gradient of the potential. & that statement, while not as accurately in agreement with observation as Einstein's equations, is an approximation to the latter equations under well-defined conditions.

Lest this seem to Platonic, note a couple of other facts. 1st, when we we want to know how to correlate the math objects in Einstein's theory with physical entities we look at the Newtonian limit. In that sense Einstein needs Newton. & 2d, it's pretty certain that Einstein's theory itself will have to be extended to make it consistent with quantum theory, & thus that classical general relativity is only an approximation to a better theory. If we apply your criteria it seems that we have to say that Einstein's theory is "wrong" even though we don't yet have any observations that it disagrees with & don't yet know what to replace it with if any discrepancies were to found.

Shalom
George
http://web.raex.com/~gmurphy/
  ----- Original Message -----
  From: Don Winterstein
  To: asa
  Cc: Randy Isaac
  Sent: Saturday, July 07, 2007 1:53 AM
  Subject: Re: [asa] YEC--What can we offer them?

  Randy wrote:

  "By the way...I ended up claiming that, as far as I could tell,
  there has been no case where a scientific theory which has been validated by
  data from many independent sources and which is accepted as consensus by the
  mainstream community, has been later invalidated. I'd love to hear of any
  examples that any of you might think of."

  I wrote earlier that QM and plate tectonics were theories that had invalidated earlier accepted theories, but "Newton was not wrong, but his theory lacked generality." On second thought I now claim that Newton also was wrong, that his theory of gravitation was invalidated by general relativity. The reason his theory is wrong is the same reason the others were wrong: they were based on the wrong models.

  Let me explain: What does it mean for a scientific theory to be invalid or wrong? Globally all theories are wrong because none is absolutely true. What we mean when we say a theory is correct is that it is the best theory currently available. When we say a theory is the best available, we mean that we prefer its underlying models over those of any competing theory, because those models give results in some way superior to results of competing models.

  So the underlying models--or paradigms, as I've been calling them--are absolutely decisive in any effort to determine whether or not a theory is wrong. While a theory based on the wrong models may sometimes give good quantitative answers, from the point of view of theoretical science the underlying models are more important than the answers (within limits, of course). Even absurd theories can sometimes give good answers.

  Newton's paradigm assumed space-time was absolute and independent of masses within, and it assumed masses fall towards one another because of a force between them acting at a distance. General relativity, the better theory, says those assumptions are not true. Therefore Newton's theory is wrong because it's based on invalid models. Even though general relativity gives Newton's formalism in a limiting case, from the point of view of scientific theory it doesn't make Newton's theory right.

  Science advances in a sort of bootstrap fashion by replacing current models with new models. In the process the replaced models become obsolete as theory--in other words, wrong.

  So I'd revise Randy's claim to read as follows: Scientific theories go where experiments and human minds 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.)

  Of course, this may well not be the kind of thing Randy wanted to say!

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Received on Sat Jul 7 15:47:36 2007