Elephant spreading himself thinner.....
GLENN WROTE:
> science has shown in the 20th century that light of distant
> galaxies, which took thousands of years to reach us, form a spiral
> shape, and Newton's gravity is partly responsible for that shape. This
> shows gravity predates Newton and so he discovered, not invented it.
ELEPHANT:
Well no, it doesn't show that. Empirical observations justify technological
conclusions, (ie about the sort of craft we would have to use to navigate
the furthest galaxies). That's what pragmatism is: the connection of
observational content and action. But empirical observations are neither
here nor there on purely philosophical questions like, for instance, whether
we should regard scientific progress as one of invention or discovery:
because such a question has no bearing whatsoever on action, or atleast, not
in any direct way.
It doesn't bear directly on action, this question between discovery and
invention, but does bear directly on the coherrence or otherwise of our
concepts. Is it more *coherent* to suppose that scientific laws are
invented, or that they are discovered?
-'Well, discovered, obviously! After all it would be thoroughly incoherent
to say that the moon only began orbiting the earth in Newton's lifetime!'
Well that's true. But then, it's also completely irrelevant.
The orbiting of the moon and the law of gravity are not *the same thing*.
It would sound like strange english to say that "gravity is the behaviour of
the heavenly bodies" - after all there are more "forces" involved than
gravity, and the idea of a universe that consisted entirely of force and not
of anything for the force to act on wouldn't make much sense either. What
would sound much more grammatical and scientific is to say that "the
heavenly bodies behaviour is *in accord with* the law of gravity".
That's right isn't it?
So, what exists, and what we say has existed for countless billions of
years, is *in accord* with Newtons Laws of gravity (or altleast, as near as
makes no difference unless you actually do want to travel to the stars, in
which case you have to ditch Newton and read some General Relativity, which,
so far as we know, is the best instruction manual going... this year). But
(nearly) *in accord* or not, the fact that light from ancient galaxies
spirals in (nearly) just the right way to be *in accord with* gravity does
nothing to show that that the thing they happen to be in accord with is as
old as they are.
Look:
I've recently bought an alarm clock.
It tells the time.
I have a french clock from 1850 that I inherited from my grandmother
It also tells the time.
The old clock and the new clock are (nearly) in accord.
Therefore:
My new alarm clock was built in 1850.
Not a very good argument, I think you will agree. But exactly your
argument:
The old galaxy and newtonian Gravity are (nearly) in accord.
Therefore:
My newtonian gravity was buit when the galaxy was built.
Codswallop you will agree - and naturally what you won't agree to is my
characterisation of your argument. Well, put me right.
Looking forward to that Glenn,
Elephant
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