Re: Models. predictions, physicallity, and observations

reany_at_asu.edu
Date: 03/07/05 

Date: 7 Mar 2005 10:51:38 -0800

jem wrote:
> AllYou! wrote:
>
> > "jem" <xxx@xxx.xxx> wrote in message
news:LpEVd.92183$bu.70873@fed1read06...
[snip]

>
> > I've considered your argument, but I'm afraid that this is a
philosophical issue upon
> > which we've reached an impasse. There is only one reality, and
we'll only know what it is

Is this AllYou! talking about "reality"?

> > whenever we know that we've uncovered every secret which nature
hides from us. Until
> > then, all we have is our perceptions of what we observe.
>
> Well, what I said is the same as what you just said, except that I
> added that the clues for uncovering Nature's secrets come *only* from

> observations of Nature's phenomena.
>
> >>Yes, that's not a good thing to do, but you're an offender in this
> >>regard. You don't clearly distinguish between Nature and models
created
> >>to imitate Nature.
>
> > I beg to differ. I've given detailed explanations here over the
last few months that I
> > believe that all we can do is to build models based upon what we
observe. I clearly
> > understand the difference to which you refer, and ask you to show
otherwise. What is it
> > that I've said in this thread which lead you to that conclusion?
>
> Many things you've said have led me to that conclusion. Here's an
> obvious example:
>
> "For instance, what is it that caused a clock to have lost
> *time* as a result of having gone on a trip at relativistic speeds?
> Well, too often the answer is the curvature of spacetime or that
> spacetime was in some other way responsible and that's the answer.
But
> if spacetime is just a mathematical concept, then we've got the cause

> and effect backward. Spacetime is curved because of some natural
> phenomenon, and not the reason for the change in some natural
phenomenon."
>
> Clearly, you haven't recognized that "spacetime" is an element of a
> model. When "spacetime" is proposed as the cause of "lost time", the

> proposition deals strictly with the model and implies nothing about
the
> "real world" (i.e. "spacetime" is not proposed as the cause of any
> "natural phenomena").

To AllYou! this is how it's done:

1) look at the world
2) your experiences tell your intuition what
are the actual "objects of observation"
3) build your models out of actual objects only or else

Or else what? Or else they can't "cause" anything to happen. To AllYou!
there is no free creativity in the discovery (invention) of objects
that go into a theory. It's all supposed to be WYSIWYG. Logical
empiricism (logical positivism), right down to their principle of
verifiability. What he calls "philosophical issues" they called
"metaphysical issues."

>
> > However, I think you and others consistently refuse to draw the
distinction between what
> > we observe and mere concepts and dismiss any insistence for that
distinction as a
> > philosophical issue. I maintain that it's fundamental to the
pursuit of science.
>
> As illustrated by the example I just gave, you're the one who doesn't

> make the distinction.
>
> >>And the mature interpretation of "understanding" coincides with
> >>"predictability".
>
> > Nothing I've said is inconsistant with that..
>
> Your continued attempts to look beyond the measurements are
inconsistent
> with it. The potential for additional understanding ends at the
> measurements.
>
[snip]
> It
> > is not sufficient to declare something a physical by simply
declaring that an instrument
> > reacts to something without ever demonstrating the physicality of
that something.

That's just your opinion and your definition. It doesn't violate
scientific goals.

>
> There is no *something* being declared "physical" other than the
> measurement itself - "physicality" is demonstrated by changes in the
> readings of measuring devices.

I tried to explain this to him too. To AllYou! the "physical concept"
is uniquely determined by the "observation." Spacetime cannot be
observed therefore spacetime is not a legitimate concept in physics.
For that matter, neither is time, he says.

I think the real problem here is not that AllYou! does not distinguish
between the "thing" and the model, but that he has such a narrowly
allowed range of what he claims is a "thing" and a "good" model that
the confusion occurs.

What he dislikes is the physicists' freedom to invent causal
(mathematical) models constrained only by measurements, such as the
model that "gravity is caused by the curvature of spacetime." In other
words, one cannot just invent a theory that says such a thing; one has
to prove such as thing in actuality. AllYou! is not interseted in
theories that work unless they only use physical concepts that suit his
personal notions of existence (physicality) and causality. And then he
claims that the "pphilosophical issues" are ours alone.

Patrick

Relevant Pages

  • Re: Models. predictions, physicallity, and observations
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