Re: Models. predictions, physicallity, and observations

From: jem (xxx_at_xxx.xxx)
Date: 03/03/05 

Date: Thu, 03 Mar 2005 08:38:21 -0500

AllYou! wrote:

> "jem" <xxx@xxx.xxx> wrote in message news:zx_Ud.89657$bu.65695@fed1read06...
>
>>AllYou! wrote:
>>
>>
>>>"jem" <xxx@xxx.xxx> wrote in message news:h7%Td.89049$bu.32479@fed1read06...
>>
>>
>>>>I wasn't suggesting that the *concepts* of "space" and "time" are
>>>>trivial, only that their definitions are trivial in comparison with a
>>>>definition like "intellectual process".
>>
>>>I know what you meant, and it's still my position that whether or not they are to be
>>>considered physical is not trivial.
>>
>>During the last 100 years Physics has abandoned the attempt to describe
>>Nature as anything more than the phenomena Nature produces. Entities
>>like "space", which are omponents of models created to imitate Nature.
>>aren't presumed to exist outside the models (i.e. don't warrant
>>characterization as physical).
>
>
> And this is where I think a principle has gone too far. As I think I stated here already,
> I believe in the concept that we cannot know what reality is. I think all we can do is
> build a model of what we perceive we observe, and this model consists of various theories.

For our purposes we can treat theory and model as synonymous. Ignoring
the subtle distinction isn't likely to cause any problems.

> Theories are predictions of what we'll observe under specific circumstances, and the
> relative reliability of a theory is the degree to which it's been tested, and the extent
> to which we've concluded the results of those tests are consistent with the predictions.
> This means that some parts of the model can be deemed to be highly reliable, while others
> not as much. And there is also no universal acceptance of just one model. In effect,
> each of us has his own model, and our conclusion as to the reliability of it is influenced
> by the extent to which it's consistent with others.

Well it's not like there are hundreds of competing viable models, more
like a handful.

> So we have these models which are variously reliable, and all we can do is assume that the
> reliability of its various parts equates to the probability that it accurately represents
> nature. So in this respect, I agree with what you've said. However, where I
disagree, is
> that we should therefore lose the distinction between what is physical and what is nothing
> more than a mere concept. Remember that this model is supposed to represent something.
> To claim that because it's just a model, and because we can never know the *real* nature
> of Nature, it doesn't matter whether we build the model of concepts or not. This is
> silly.

This issue is addressed at length in what follows.

> The foundation of the model, that which keeps it together and which serves as the basis
> being able to compare it to others, is the observable world. That is the only anchor
> which keeps the model from freely assuming any form from moment to moment, or from mind to
> mind. We don't know if what we observe is real or not.

Yes, re. observable world as anchor, but what's observed *is* what's
real - nothing that's not observable (in principle) can be considered
real, and everything that is observable must be considered real.

> In fact, we don't even know for
> sure if we've observed what we think we've observed.

Provision is made to ensure that observations are "reliable" by
requiring measurement processes to be repeatable.

   However, the only thing that could
> make this lack of confidence worse is to simply intermix that which we perceive that we've
> observed with that which we freely invent in out minds.

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.

   Let's also not forget the goal of
> science which is to understand that which we perceive affects us.

And the mature interpretation of "understanding" coincides with
"predictability".

>>>>Sort of, but I don't think the "reality" of what's observed is generally
>>>>questioned - probably the most popular view in Science these days is
>>>>that observations are the *only* reality.
>>
>>>In ordered to avoid any philosophical debate, I'll go along with that.
>>
>>When discussing the role of Science - philosophical issues are unavoidable.
>>
>>
>>>>And what exactly is the dividing line between external and internal
>>>>influences?
>>
>>>Physicality. By external, I meant external to the mind.
>>
>>You've just replaced one vague concept with another (i.e. mind).
>
>
> OK, I'll follow your lead down this road. That which is capable of stimulating the
> senses, or that which is capable of effecting that which can stimulate the senses, is
> observable, and that which is observable is physical, and that which is physical is
> external. We are passive recipients of these stimuli.
>
> So the dividing line between *mere* concepts (which I call internal) and that which is
> physical (which I call external) is whether or not that entity is capable, directly or
> indirectly, of stimulating the senses.

The notion of "stimulating senses" is too vague. Whose senses?
Stimulate how? E.g. dreams can stimulate senses, but I don't think you
mean to include dreams on your list of physical things.

Physics deals with this issue more concretely by considering as physical
(i.e. the things of interest to Physics) only the (repeatable)
measurements that can be obtained (in principle) by instruments created
to react to the environment.

>>>>If you subscribe to the idea that observations are the only reality,
>>>>then "reliability of the model" is synonymous with "accuracy with which
>>>>the model represents reality".
>>
>>>I don't want to get into semantics, I just don't want what I post here to be quoted
>
> back
>
>>>to me when I later state my true position. It's my position that we can never know
>>>reality.
>>
>>So what do you mean by "reality"? If something is unknowable in
>>principle, in what sense could it be considered an aspect of reality?
>>That's why the prevailing view in Physics is that "measurable phenomena"
>>and "reality" are synonymous.
>
>
> See the above.

"Knowing" isn't addressed above.

>> How do you know that you're not hypnotized? How do you know this
>>isn't all just
>>
>>>a scheme to get you to believe a certain reality? Without getting into any of that,
>
> I'm
>
>>>simply saying that to decide is something is accurate, we need a basis of comparison,
>
> and
>
>>>if we have reality with which to compare our model, then why do we need the model?
>>
>>Science is concerned only with what's measurable. If your hypothesized
>>hypnosis is detectable then it's part of reality. If not, it's not.
>
>
> I don't think that we're far off here, it's more a matter of how we're expressing it. I'm
> not willing to go as far as to say anything WRT reality because no matter what you say
> about it, I could always ask the question, *how do you know*? I've concluded that there
> is a reality out there, but that the best I can do is build a model which I believe best
> represents it, and I make that assessment based upon the degree to which the model is
> reliable. But the only way I can ascertain its reliability is from whatever I observe,
> and I cannot observe space or time.

You observe what you observe, period. You build models (ie.
hypothetical Natures), which contain *defined* entities like "space" and
"time", in an attempt to produce a model whose hypothetical observables
correspond to the actual observables of Nature. And you realize that
even though you may be able to match up the observables, you can't infer
that the entities of your models are also entities of Nature.

>>>It's not a bone of contention of mine, but just for the record, I subscribe to the
>
> notion
>
>>>that we have no way of *knowing* *reality*, however, we can build a model which is
>>>reliable in terms of its predictability. IOW, we assess the reliability of the
>>>predictions. Again, I only made these comments as a backdrop to my overall point.
>>
>>Again the assumption Science makes is that there is no more to reality
>>than the phenomena. Any aspect that has no associated phenomena is
>>unknowable in principle, so what sense would it make to consider it an
>>aspect of reality?
>
>
> I know nothing of reality. I've only concluded that neither space nor time is observable.

You changed the subject. You said you have no way of knowing reality.
I asked you how something you're incapable of knowing can be considered
an element of reality. That's what you should respond to.

Re, the new subject:

Clearly the readings of measuring instruments are observable. A clock
is a measuring instrument. Time is the reading of a clock. Ergo, time
is observable.

Space too, in the sense that space is frequently used as a synonym for
distance.

>>>>How can we "delude" ourselves? We build mechanisms to tell us what's
>>>>going to happen, and either it happens or it doesn't. In one case our
>>>>mechanism is right (so far), and in the other case it's wrong.
>>
>>>It can be wrong in the explanations. Here's an example: I say that splat rays from Mars
>>>will cause this rock to hit the Earth when I release it. I release it. It hits the
>>>ground. Have I demonstrated anything as to why the rock hit the ground? Did I
>>>demonstrate the existence and/or the effects of spalt rays just because I wove an
>>>explanation into the prediction?
>>
>>Science doesn't try to *explain* phenomena, only predict them. When
>>it's said for example that "gravity" or "curved spactime" causes the
>>rock and the Earth to come together, that's strictly a description of
>>the behavior of entities within models, and the "cause" is logical in
>>nature (i.e. is an inference based on some underlying assumptions), not
>>physical.
>>
>>If you were to create a model that "explained" falling rocks using spalt
>>rays, that would be fine. Of course, in order for it to be a viable
>>model *all* the corresponding predictions based on spalt rays would need
>>to agree with what's observed.
>
>
> And here's the heart of the matter. Here's where I very much want to dive in and explore
> more. But I warn you now so that you've got the choice........I'm a hard sell. I will
> not modify my position just because I'm *told* that I'm wrong. I believe what I believe
> and you believe what you believe.
>
> As to your statement, lets' take time dilation. Is it your position that time dilates,
> and this is what causes a clock to *lose time* after having gone on a trip? If so, then
> how is this different than my spat ray example? The process which the clock facilitates
> slowed for some reason, but all you've shown is a prediction that it would under specific
> circumstances, and that the prediction was reliable. Where is the model of time? Where
> is the theory which allows for a test of the observability of time? Where have you
> demonstrated that time in anything more than a mathematical construct?

OK, my turn to offer a warning. I've told you before, regarding this
"time dilation" issue, that you can't lock on to the English language
descriptions as if they were etched in stone. Such descriptions
represent attempts to translate the mathematics of the models into
terse, common language statements. As such they're bound to be somewhat
incomplete and/or inaccurate. Bear that in mind.

To address your above questions, the "model of time" is the Lorentz
Transformation (suitably extended if accelerated motion is involved),
and the "time" that's referred to in the transformation equations is
compared to the "time" that's indicated by observed clocks. It's as
simple as that.

BTW (and we've gone around on this before too), in the SR model, the
"process which a (standard) clock facilitates" is not slowed. In fact,
(standard) clocks are presumed to be completely unaffected by movement.

>>>To say that we can predict how a clock will function, and that time is what a clock
>
> says
>
>>>it is, demonstrates nothing as the physicality, or as you would say, the reality of
>
> time.
>
>>>All we know is that what we observed of whatever process we've defined as a clock
>
> behaved
>
>>>as we predicted.
>>
>>You're looking at this issue from the wrong angle. Consider devices
>>called thermometers that make measurements (i.e. produce numbers). The
>>name "temperature" has been assigned to those measurements.
>>"Temperature" isn't something that's presumed to exist, which
>>thermometers have been created to measure. If it were it would make
>>sense to ask the question "how do you know that thermometers measure
>>temperature?", but it should be obvious that, if "temperature" is simply
>>a name for the measurements, such a question isn't meaningful.
>
>
>>It's the same with clocks and time. "Time" isn't something that's
>>presumed to exist, which devices must be created to measure. There are
>>devices called clocks (constructed in a prescribed manner) which make
>>measurements, and "time" is just the name that's given to those
>>measurements.
>
>
> Two issues: Temperature is a measure of a quantity of heat. To say that an object has a
> temerature of x is to give a precide measurement of a quantity of heat, and heat is
> physical. So are you saying that time is a measurment of something? If so, what? Of
> what qunatity is time giving an indication? What is being quantified?

You have to recognize the distinction between the "real world" and
models of it. When temperature is described in terms of heat (or
average kinetic energy of a collection of microscopic particles), that
description applies to the entities of a model. Temperature in the
"real world" is simply the reading that appears on a thermometer when
it's exposed to the environment.

>
> Secondly, how does this analogy relate to concepts such as time dilation?

The analogy wasn't intended to relate to "time dilation".

>>>>So you don't like the answer "spacetime curvature causes clocks to lose
>>>>time"? Why not? It's logical. Suppose a clock would register a
>>>>certain elapsed time in a flat spacetime model, and suppose the elapsed
>>>>time registered is reduced when the only change to the model is the
>>>>introduction of a curved spacetime, doesn't it follow that the lost time
>>>>is attributable to the curvature?
>>
>>>Not if the curvature is just an intellectual concept. IOW, let's say we construct a
>
> graph
>
>>>(i.e., a mathematical concept born in the mind) which is used to assist us with
>>>quantification and predictions and the like, and then in order to assure that the
>
> graph
>
>>>remains valid, we *curve* it to remain consistent with predictions and observable
>
> results.
>
>>>Is it then valid to say that the results are caused by the curved graph?
>>
>>No. "Graph" is not an element of the model like e.g. "curved spacetime"
>>is. A graph is a representation of a particular relationship between
>>quantifiable entities - it doesn't make sense to talk about it having an
>>effect on the entities.
>
>
> Exactly. It's not valid to say that the curvature of the graph caused anything. So how
> does the curvature of spacetime, which is also just a mathematical construct, caused
> anything?

No again. My point was that "graph" and "spacetime" aren't equivalent
structures within the models. Because "spacetime" is an entitiy of the
model, it makes sense that it could affect other elements of the model.
  However "graphs" are not entities of the model (they're descriptions
of relationships between quantitative entities), so they can't have an
affect on the model's elements.

>> That's
>>
>>>backwards. The results are caused by something, but not a concept. The problem I
>
> have is
>
>>>that now that we've fooled ourselves into thinking we've actually answered a question,
>
> we
>
>>>move on. We forget the question. What *caused* the clock to *lose time*?
>>
>>There's no "fooling" going on. The "causes" of the lost time are the
>>assumptions that logically lead to that result in the models that have
>>been created to imitate clock behavior. Such causes aren't unique - the
>>same model can be configured in a variety of ways, each of which will
>>provide a different "explanation". However, explanation isn't the goal
>>- prediction is.
>
>
> I don't have much of a problem with any of that. If you'll recall, my argument has always
> been that time is just a concept, and as such, is not physical. However, I do take issue
> that explanation isn't the goal of science. We create theories (i.e., predictions) and we
> test them. Then reliable theories result in speculative explanations which become the
> next theory. IOW, we do all of this in oder to understand that which affects us, and
> inherent in understanding is explanation. The prediction that the moon will appear larger
> in the early evening than it will late a t night is madfe and verified. This leads to the
> question as to why it does that, and an explanation which becomes the next theory.

Well, obviously "Science" doesn't have a goal. The people who do
science have goals which, just as obviously, aren't all the same. I
described what I believe to be the prevelant view at present (goal =
prediction).

The "why questions" have answers only within models. In fact,
essentially all discussion in Physics concerns the entities of models.
The only time the "real world" comes into play is when it's necessary to
"collect a sample" for comparison against what's been anticipated by a
model.

> Post the question as to why a clock will appear to have lost time after having gone on a
> trip, and see what you get for answers.

The answer is "because it does". It just happens to be what happens.

Models get created for the purpose of imitating the behavior that Nature
happens to make happen, but although the behavior of the entities in
models (e.g. lost time) can be explained, those explanations don't carry
over into Nature, regardless of how "reliable" the models happen to be.

>>>Time is a mathematical concept.
>>
>>Only in the sense that "time" can be the interpretation of a variable in
>>some mathematical theory. Of course, every measurement can be
>>considered a "mathematical concept" in this sense.
>>
>>
>>>>But Science doesn't misunderstand what space and time are - they're
>>>>precisly defined in the models that use them (in the language of
>>>>mathematics of course). The confusion is yours.
>>
>>>Maybe, but tell me how time is different than splat rays. Show me how time is
>
> physical
>
>>>such that it can't be confused as I've explained above.
>>
>>"Time" is a measurement - it's the physical representation that appears
>>on a measuring device known as a clock. "Splat rays" are an
>>"explanation" for measurements.
>>
>>
>>>>You say there's a *clear* distinction between physical and conceptual.
>>>>So what is it? It should be a rule that will permit the unambiguous
>>>>classification of anything into one category or the other (or "none of
>>>>the above").
>>
>>>That which is capable of affecting us (e.g., stimulating our senses), either directly
>
> or
>
>>>indirectly, is physical. As I explained, that was the whole goal of physics to begin
>>>with.
>>
>>"Things that can stimulate senses" is all-inclusive. Everything that
>>can be referred to has the potential to stimulate senses.
>
>
> That definition is the line between what is physical and what is not. I can refer to
> mathematics, but that isn't physical. I can refer to Mickey Mouse, but that's an
> abstraction. I can refer to lying, but that's a concept. Only that which stimulates our
> senses is physical.

Each of your examples is capable of stimulating the senses. In fact,
"recognition" isn't possible in the absence of sense stimulation, so the
only things that don't stimulate senses are those things that we're
oblivious of, and the "things" that *everyone* is oblivious of can't be
considered to be elements of reality.

>>>>Sorry, but you don't get to redefine the terms.
>>
>>>I, just like anyone else, get to challenge conventional wisdom of current definitions.
>>
>>There's no "wisdom" associated with definitions (other than "semantical
>>wisdom"). Definitions sre simply word substitutions.
>>
>>
>>>>The generally accepted
>>>>definition of "counting" doesn't infer that the counter has to be aware
>>>>of the underlying "meaning" of the process. If you want to draw such a
>>>>distinction then you can invent your own word. E.g. "splatting" is the
>>>>process whereby humans quantify with understanding and machines quantify
>>>>without understanding.
>>
>>>But I didn't redefine anything. *Counting* is quantification, and the whole notion of
>
> a
>
>>>quantity is a concept born in the human mind.
>>
>>Yes, "counting" can be considered a quantification, but whether or not
>>only human minds are capable of performing it is what we're trying to
>>ascertain - so don't presume it.

> I haven't presumed anything with the possible exception of limiting concepts to *human*
> minds. Maybe I should eliminate that qualification. But machines don't have minds and so
> are incapable of conceptualization. Do you agree with that?

No, but it's not relevant. "Conceptualization" has no applicability
here. All that's of interest is quantification i.e. identifying the
number of items in an collection. This act alone is what's implied by
the word "counting".

>>If a non-human "mind" can produce quantifications that are identical to
>>those produced by humans, then it necessarily follows that the ability
>>to count (i.e. quantify) isn't limited to human minds.

> I'm not getting my point across. There's a difference between what we euphemistically
> refer to as *keeping count* and actual counting.

No there's not. Apparently you imagine one, but you're mistaken.
Counting is quantification, pure and simple - the association of a
positive integer (or a series of them) with a collection. That's the
whole of it.

   This issue arose between us because you
> tried to demonstrate that time was physical because clocks could count, and the operation
> of a clock was physical. My response was that although the operation of a clock is
> physical, the quantification which is attributed to the symbols produced by the clock was
> an intellectual one. So I guess that leaves us with whether or not quantification is an
> intellectual process. Do you *think* it is?

That's what the experiment I proposed is designed to ascertain.
Quantification is a process which only humans are capable of - unless of
course, there exists a non-human, which is also capable of performing it.

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