Why should proponents of alternative theories learn accepted science first?

[ajb]

Do you maintain that it is impossible for new observations to be made that contradict what is found in text books?

As swansont says this is rather moot and certainly a distraction from the original thread.

 

Anyway, I would maintain that, with the proviso of the domain of applicability, any simplification one makes and experimental accuracy, one is not going to have a good theory of some phenomena or collection of phenomena that completely disagrees with established theory.

 

This does not mean that we cannot have new physics, or that observations will not be made that do not fit within established theory. Quite the opposite, we all know that physics beyond our current understanding should exist and we all hope that experimentation will give us hints as to what this is.

 

That said, whatever this new physics is, one should be able to recover the currently established physics, again being careful with the domain of applicability, simplifications one makes and experimental accuracy.

 

There will most likely be "small corrections" to the current theories in suitable limits of the new theory, but these would have to be smaller than our current experimental accuracy. If not we would have seen these deviations from prediction already. In fact, we do see these today, for example predictions of the cosmological constant are wildly off. This suggest that we have some physics there we do not properly understand.

 

What has happened in the past is not a limit on what can happen in the future.

Maybe, but in the world of philosophy all I can do is say is "what has happened in the past, could be a guide to the future". I mean, what else do we really have to go on?

[rah]

If not we would have seen these deviations from prediction already.

Why would we have seen them already?

 

We may have seen some particular deviations, but you're making another absolute statement here that if there were any more deviations then it must be the case that we would have seen them. Why must it be the case that we would have seen them?

 

[ajb]

Why would we have seen them already?

If the deviations from prediction are large, as compared to the experimental accuracy of what ever experiment has been done, then these deviations would have been observed. One would then most likely question the details of the theory.

 

Of course, as experimental accuracy gets better and different scales get probed, we could have surprises. But still, these won't completely sweep aside what is established.

[rah]

Of course, as experimental accuracy gets better and different scales get probed, we could have surprises.

So then, do you acknowledge that it is possible for there to be new observations that contradict what is found in text books?

[ajb]

So then, do you acknowledge that it is possible for there to be new observations that contradict what is found in text books?

Not exactly. I acknowledge that in extreme circumstances/conditions or when probing parameter spaces not yet probed, that physics that is not to be found in "text books" exists.

 

Again, this does not just wipe away our existing knowledge and new discoveries add a new layer to our understanding. For example, gravity is not well tested at the sub millimetre scale. It is possible that some deviation from Newtonian gravity exists at this scale. However, for this to be consistent, this effect must be small on larger scales, otherwise Newtonian gravity would not be a good model of gravity for a wide range of scales. (This would also have implications for general relativity)

 

Discovering an "additional term" to gravity does not invalidate Newtonian gravity, rather we know that in more "mundane" situations this term can be safely ignored. Or in other words, in some appropriate limits this "new gravity theory" reduces to Newtonian gravity, and so does not contradict text book results. This does not rule out new phenomenology, rather it must be the case that this phenomenology is consistent with what we know now, again taking into account domains of validity and so on.

 

 

I hope that makes sense.

[rah]

If the deviations from prediction are large, as compared to the experimental accuracy of what ever experiment has been done, then these deviations would have been observed.

Why would they have been observed?

[ajb]

Why would they have been observed?

Because they would be comparable to the "resolution" of the experiment. That is, they could not be explained by systematic or inherent errors in the experiment. To paraphrase, "they would sit outside the error bars".

[rah]

they could not be explained by systematic or inherent errors in the experiment.

I asked why deviations (between the model and nature) must have been observed. You've said that deviations would not be explained by errors in "the experiment". However, for deviations to require an explanation, they would have to have been observed.

 

So, in answer to my question "why must the deviations have been observed?", you have answered "because when they were observed, they would have been unexplainable". This doesn't make sense; I'm asking you why they would have been observed in the first place. The subject of my question is an assumption that you're actually making in responding to the question.

 

I'll restate my question a little more fully:

 

Why must deviations have necesarily been observed?

 

[ajb]

Why must deviations have necesarily been observed?

I have answered that.

[rah]

I have answered that.

I can't see where your answer is. Could you possibly restate it?

 

[ajb]

If there were large deviations from prediction of physical observables in well established theories, taking into account the domain of validity, approximations and experimental accuracy then this would have been detected. The reason being that established theories go through a lot of testing against nature. If there was some large deviation then this would be seen in an experiment during the verification of the theory, again taking in to account the domain of validity and so on. If these deviations were large for all observables, then the usefulness of the theory would be in question.

 

The small deviations can also be important, for example relativistic corrections to the hydrogen spectra. But again, this does not mean we should throw out non-relativistic quantum mechanics.

 

 

[rah]

established theories go through a lot of testing against nature. If there was some large deviation then this would be seen in an experiment during the verification of the theory

Why must it have been seen? Why does "a lot" of testing necessarily imply that there are no more large deviations to be observed?

 

[ajb]

Why must it have been seen? Why does "a lot" of testing necessarily imply that there are no more large deviations to be observed?

Many different experiments, many different researchers and techniques, direct and indirect tests...

 

I would find it hard to believe that a large deviation had not been found in the standard established theories of physics. Unless, it is something in the extreme which would point to a new theory with a large domain of validity.

[proximity1]

Now I would like to pose some questions if this is more than a private-line conversation--and they touch on the matters concerning probable hypotheses, current theory, surprises to the current theories, etc. In general, I think I see the basic gist of rah's line of reasoning, questions, and where he's going and why. And in the main, I agree with much or all of that as I understand it.

 

So, I'd like to go back to Post 101, where we have this (by ajb) :

 

..."There will most likely be "small corrections" to the current theories in suitable limits of the new theory, but these would have to be smaller than our current experimental accuracy. If not we would have seen these deviations from prediction already." ...

 

and then consider that alongside this, from Post 103 (also by ajb) :

 

"If the deviations from prediction are large, as compared to the experimental accuracy of what ever experiment has been done, then these deviations would have been observed. One would then most likely question the details of the theory."

 

Notice, please, that in first cite, above, from Post 101, you (ajb) refer to what are apparently, speaking purely hypothetically in this context, various as-yet-unseen "deviations" ("from prediction"). You argue that, first, we don't have such deviations from prediction--not in this "large" sense, and, since we don't, as I understand you, this absence in and of itself lends weight to the view that (as it is implied) the current theory is consequently basically valid for that reason--the absence of significant observed deviations, that is. What I want to emphasize is your chain of reasoning:

 

..."but these (i.e. "small corrections) would have to be smaller than our current experimental accuracy. If not we would have seen these deviations from prediction already."

 

In other words, we assume the theory is correct and accounts for everything because, if it did not, we would expect to see significant deviations from predictions; we don't see that, ergo .... we shouldn't expect to see it, is the conclusion I gather you are making either implicitly or explicitly.

 

Now let's take what we have thus far and add the cite from Post 103, above:

 

""If the deviations from prediction are large, as compared to the experimental accuracy of what ever experiment has been done, then these deviations would have been observed."

 

But from the previous post 101, we have it that there aren't any such deviations. So, you're positing some hypothetically here in Post 103, and then adding that,if they were large then these deviations would have been observed.

 

It strikes me that this is a classic example of circular reasoning. Am I missing something?

 

Let's review the reasoning chain:

 

1) We don't observe significant deviations from predictions ----> (ergo) current theory is sound

 

2) Sound because, if we obseerved large deviations, (this is from post 103; e.g. "If the deviations from prediction are large"...), then these deviations would have been observed."

 

And this, I suggest, is what rah has aptly noticed is circular in character and simply does not follow logically.

 

There is nothing inherent about our current observations that I am aware of which precludes these observations coming to be found incorrect due to their inadequacy either by measurement deficiencies or conceptual deficiencies (deficiencies in the current theory) --and all of that revealed in the course of some unexpected development in (ETA) newly observed data.

 

Comments?

Edited December 18, 2012 by proximity1

[ajb]

In other words, we assume the theory is correct and accounts for everything because, if it did not, we would expect to see signification deviations from predictions; we don't see that, ergo .... we shouldn't expect to see it, is the conclusion I gather you are making either implicitly or explicitly.

Not quite. Rather than assume that a theory will describe everything satisfactorily, assume that it describes some isolated phenomena or collection of such phenomena satisfactorily. By this I mean it makes numerical prediction of physical observables that match the measured observables closely. More carefully, the predicted value of the observables should lie within the experimental limits of the observation.

 

However, it is usual that the theory will not make reliable predictions of the phenomena for all possible values of the parameters involved in the theory. This has to be stated as part of the theory. This is the domain of applicability.

 

For example, classical mechanics is okay as long as we do not consider very small things or things moving very fast.

 

1) We don't observe significant deviations from predictions ----> (ergo) current theory is sound

Okay, taking into account the stated provisos.

 

 

2) Sound because, if we observed large deviations, (this is from post 103; e.g. "If the deviations from prediction are large"...), then these deviations would have been observed."

If we observed large deviations from what is predicted, taking into account the expected domain of validity and so on, the theory would not be considered "good". It would not match the phenomena we want to model in satisfactory. This would then not satisfy 1).

 

 

 

 

 

 

 

 

There is nothing inherent about our current observations that I am aware of which precludes these observations coming to be found incorrect due to their inadequacy either by measurement deficiencies or conceptual deficiencies (deficiencies in the current theory) --and all of that revealed in the course of some unexpected development in observed data.

Right, so making the error bars on your experiment smaller could reveal new phenomena, indeed it did for quantum theory. This will then typically shift the domain of applicability.

 

The claim is that these new phenomena will not simply show that the old theory was wrong. A case at hand is that there is nothing in quantum mechanics that shows us that the classical mechanics of macroscopic objects is wrong. It does give us a new light on the nature of matter and the Universe.

 

 

-------------------------------------

 

Let me put this another way:

 

If we accept that a theory matches nature well, as defined by experimental accuracy, for a specified domain of applicability, also does not match nature well, as defined by experimental accuracy, for the same specified domain of applicability then ...

 

It is a question of consistency.

Edited December 18, 2012 by ajb

[rah]

I would find it hard to believe that a large deviation had not been found

Again, you're now talking about your beliefs. This is different to the absolute statements you've made up until now:

deviations would have been observed

 

 

 

I would find it hard to believe ... Unless, it is something ... which would point to a new theory with a large domain of validity.

Here you are implicitly acknowledging the possibility of a large deviation being observed, in contradiction to your previous statements. I'd like to clarify this point and make it explicit because I think it's very important:

 

Do you acknowledge the epistemological possibility of new observations being made that contradict what is found in text books?

Edited December 18, 2012 by rah

[swansont]

Why would they have been observed?

 

Because that was a condition of the statement. If there is a discrepancy between theory and experiment you must have a result that is disagrees in a statistically significant way. By definition. That's what is meant by the statement.

 

The irony here is that this is all pretty standard knowledge for someone who is familiar with mainstream science. We would have been better off, from the perspective of wasting time, if all involved had that familiarity. QED

[proximity1]

Note: never mind the reference above, ajb said, ...(etc.) all the interior of this post is my formatting. So, I, refer to myself, "prox", below, at "RE : (my)"

 

 

RE: (my)

 

proximity1, on 18 Dec 2012 - 15:27, said:

There is nothing inherent about our current observations that I am aware of which precludes these observations coming to be found incorrect due to their inadequacy either by measurement deficiencies or conceptual deficiencies (deficiencies in the current theory) --and all of that revealed in the course of some unexpected development in observed data.

 

 

(and your,)

 

 

 

Right, so making the error bars on your experiment smaller could reveal new phenomena, indeed it did for quantum theory. This will then typically shift the domain of applicability.

 

The claim is that these new phenomena will not simply show that the old theory was wrong. A case at hand is that there is nothing in quantum mechanics that shows us that the classical mechanics of macroscopic objects is wrong. It does give us a new light on the nature of matter and the Universe.

 

 

-------------------------------------

 

Let me put this another way:

 

If we accept that a theory matches nature well, as defined by experimental accuracy, for a specified domain of applicability, also does not match nature well, as defined by experimental accuracy, for the same specified domain of applicability then ...

 

It is a question of consistency.

 

 

 

Frankly, I can't parse that. I'm not sure whether there's a word missing, such as somewhere between this ...", for a specified domain of applicability, "... and this, ..."also does not match nature well,..." or whether I just fail to grasp your syntax here but it doesn't make sense to me--nor does your "if, then ..." construction of the comment.

 

Do you mean as a clause modified by "If," to include all of the following as in this variation? :

 

"If we accept that a theory which matches nature well, as defined by experimental accuracy, for a specified domain of applicability ,"

 

then add the remaining text as you posted it,

 

..."also does not match nature well, as defined by experimental accuracy, for the same specified domain of applicability then ... It is a question of consistency."

 

we get this:

 

"If we accept that a theory which matches nature well, as defined by experimental accuracy, for a specified domain of applicability, also does not match nature well, as defined by experimental accuracy,for the same specified domain of applicability then ... It is a question of consistency."

 

Is this more like what you are trying to say or less, please? I honestly can't tell. Nor do I really have a good idea of what, if that version just above is correct, this is supposed to mean, either.

 

But, I want to mention another related point. If you're agreeing with me somewhere concerning your, ..."Right, so making the error bars on your experiment smaller could reveal new phenomena, indeed it did"...

 

this suggests to me that the prior observation--namely, that our observations and accepted theories thus far can at any time be overturned, discredited, supplanted, by the discovery of new, unexpected data (based, of course, on observations) (ETA) --is also valid; thus, I don't see how you can also maintain that rah's contention (see Post 106: "Why must deviations have necesarily been observed?") is not a valid point---that is, our observations don't (and really can't) preclude an unexpected upsetting new observed data which falsifies much (if not all) of current accepted theory. That is, again, then, to ask: "Why must (these potential) deviations have necesarily been observed?" (My amendation between parentheses.)

 

If you agree with my remark (at the top of this post's cited comments), then I don't see how you can object to rah's assumption--- implied in his question, "Why must deviations have necesarily been observed?" -- that we could well come to uncover these as-yet-unobserved "deviations".

Edited December 18, 2012 by proximity1

[Semjase]

Let's start with math that is proven if proven correctly it remains valid forever

regardless of the degree of intelligence that scrutinizes it. Scientific data

that is proven accurate to the same degree is the only basis that sound theories

can built, new data discovered that contradicts old theories,require new theories,

as the case with the speed limit of light and relativistic effects on gravity shown to be

incorrect by this experimental data listed below

 

http://news.bbc.co.uk/2/hi/science/nature/841690.stm

 

http://www.sciencedaily.com/releases/2006/03/060325232140.htm

 

 

 

 

[proximity1]

 

Because that was a condition of the statement. If there is a discrepancy between theory and experiment you must have a result that is disagrees in a statistically significant way. By definition. That's what is meant by the statement.

 

The irony here is that this is all pretty standard knowledge for someone who is familiar with mainstream science. We would have been better off, from the perspective of wasting time, if all involved had that familiarity. QED

 

There's a formal term in logic for what you've just argued here. It's called, "begging the question," or petitio principii -- a form of circular argumentation.

 

The question itself concerns the matter of the potential existence of previously unnoticed "deviations", "discrepancies", or what term you prefer. By presuming at the outset (or, "as a condition of the statement) that there are not any and could not be any since, "if there were, we'd have encountered them already in the course of scientific investigations" is precisely what it means to "beg the question."

 

Are we to understand that in this forum, that is an acceptable and effective kind of argumentation? Because, if it is, there is simply nothing that can't be "proved" that way. One simply states as a prior conditional fact the conclusion one seeks to see "proven," and, Presto! "QED".

 

Rubbish.

Edited December 18, 2012 by proximity1

[ajb]

This is all just going round in circles.

 

The key thing with a theory is that you must specify the domain on validity, the observables you can calculate and your defintion of how well it matches nature, which is usually specified statistically in relation to an experiment or collection of experiments.

 

You can have two theories that are different, with different domains of applicability and overlapping sets of observables, and possibily different criteria on the relation to experiment that are complimentary in the sense that they do not contradict each other. The predictions based on each theory agrees well with nature, within its own natural statistical criteria.

 

With this in mind, you can modify theories in many ways, say extending the domain of validity or narrowing the statistical relation with nature. These do not nessisarily mean that the new theory sweeps away the old one. Thus, for example, although we have quantum theories and relativistic theories, these do not invalidate classical Newtonian physics. Here is the tautology: no experiment will show that Newtonian mechanics is invalid within the domain of Newtonian mechanics!

 

 

So, any experiment that does not agree with Newtonian mechanics is an experiment outside the domain of applicability. For example, one may need to include an electromagnetic field or quantum effects. (Taking care that it is not just your calculational tools at fault here)

 

Importantly, the domain of validity of Newtonian mechanics is not trivial, ie. we do have finite parameters in which the theory is good. One could technically, have theories with no domain of validity!

 

I hope that helps, but feel that little more can be added.

[Semjase]

Thats true but if you want closest to 100% accuracy then you have to go with

the theory that most accurately models the physical reality.

[proximity1]

@ 121

 

So the "domains of applicability" make up then just one set among any number of potential factors which are subject to debates concerning theories.

 

That suggests to me that if one can and does insist on any particular & convenient set for the "domains of applicability," this leaves all objectors out of the picture--indeed, as swansont wrote, "by definition." What are various scientists, if any, who question the set's propriety expected to do? ---just take the given "domains of applicability" as an uncontestable "given"? Or may those be subject to debate and disagreement? For, in light of your review, it would seem to be the assumed contention that there is to be no debate over where, in any given set of circumstances, the limits, in that set of circumstances, are to be indicated.

[Semjase]

Something else of interest a mathematical model that accurately predicts the behaviour

of the physical reality may not be accurately describing what is actually

what is physically going on.

[swansont]

 

There's a formal term in logic for what you've just argued here. It's called, "begging the question," or petitio principii -- a form of circular argumentation.

 

The question itself concerns the matter of the potential existence of previously unnoticed "deviations", "discrepancies", or what term you prefer. By presuming at the outset (or, "as a condition of the statement) that there are not any and could not be any since, "if there were, we'd have encountered them already in the course of scientific investigations" is precisely what it means to "beg the question."

 

Are we to understand that in this forum, that is an acceptable and effective kind of argumentation? Because, if it is, there is simply nothing that can't be "proved" that way. One simply states as a prior conditional fact the conclusion one seeks to see "proven," and, Presto! "QED".

 

Rubbish.

 

The simpler version is that a new observation (i.e. a previously unnoticed effect) is not part of the body of data we already have. It is new. BY DEFINITION. This is not a circular argument, but is not the same as what was preciously discussed: that in order to disagree with prediction, you must have data that is "outside the error bars". Agreeing with theory is "inside the error bars". If you do an experiment, in a very basic sense your results will either be inside or outside, i.e. it will either agree or disagree with theory.

 

Starting with the situation that we have a theory and all existing data agree with it, the above discussion is not a circular argument. You are begging a different question than what was presented.

 

It would be nice to discuss rah's position in terms of recent physics history, rather than hypotheticals, but I don't think there is any precedent.

 

Something else of interest a mathematical model that accurately predicts the behaviour

of the physical reality may not be accurately describing what is actually

what is physically going on.

 

In general physics models don't purport to explain what's physically going on — they explain what's going to happen — but that's a discussion for another thread.