Scientific testing (split from goal of science)

[Reg Prescott]

Just a useless, worthless comment on "testing"

 

Now, in a driving test one either passes or fails. In a school test, we might get a certain score.

 

And when you claim a scientific theory is "tested", what would it take to fail the test?

 

Observation disagreeing with theoretical predictions?

 

But I think we all know by now, scientists don't do that. They'll cling to a cherished theory until something they like better comes along.

 

This may be provocative, but hey... what fun would it be if we all bray in unison. LOL

P.S.

 

I hear a lot about evolutionary theory being "tested".

 

Will someone please give me an example of one of these tests? Thanks.

 

Just one.

[ajb]

And when you claim a scientific theory is "tested", what would it take to fail the test?

 

Observation disagreeing with theoretical predictions?

In physics we construct models and make predictions that are, or at least can be in principle, tested against nature. We say that at theory is good if it agrees well with nature taking into account the domain of applicability (ie. the range of parameters we expect the theory to be good), the approximations made in the calculations, and then the experimental errors. We also to some extend decide what is good agreement, and this is usually stated in terms of statistics.

 

If the theory does not match well, taking into account the above, then the theory is said to be bad.

 

But I think we all know by now, scientists don't do that.

As a general statement this is false. Many scientists are involved in experimental work testing various predictions of various theories. However, it is also true that theoretical high energy physics is now well past the experimentalists where it comes to string theory and similar.

 

They'll cling to a cherished theory until something they like better comes along.

I agree. In general people are looking for better, more accurate models that cover wider range of phenomena.

 

I hear a lot about evolutionary theory being "tested".

 

Will someone please give me an example of one of these tests? Thanks.

 

Just one.

This sounds like you are anti-evolution.

 

One could give the domestication of animals as a long term experimental test of evolution. These animals now show traits that are very different from their wild ancestors. This is driven by artificial selection rather than natural selection, but the point remains that preferential traits can be passed down generation to generation drastically changing the form of the animals. (You can also add plants here and look at the wide range of, say, onions or cabbages we have)

Edited September 28, 2015 by ajb

[Strange]

And when you claim a scientific theory is "tested", what would it take to fail the test?

 

Observation disagreeing with theoretical predictions?

 

Exactly.

 

But I think we all know by now, scientists don't do that. They'll cling to a cherished theory until something they like better comes along.

 

I don't think we all know that. The "something better" is the theory that isn't falsified by the tests. There is, of course, a reluctance to discard a theory at the first whiff of evidence that might possibly be contradictory. But that conservatism is the reason that science works.

 

Perhaps you could provide some examples of scientists ignoring evidence that contradicts a theory?

 

This may be provocative, but hey... what fun would it be if we all bray in unison. LOL

 

I suppose you deserve minor credit for not using the word "sheeple".

 

I hear a lot about evolutionary theory being "tested".

 

Will someone please give me an example of one of these tests? Thanks.

 

You should probably ask that in the appropriate part of the forum, where you are more likely to get an answer from experts.

But you could start here: http://www.talkorigins.org/

Edited September 28, 2015 by Strange

[Reg Prescott]

The examples are well known. Mercury (or Uranus) doesn't behave as Newtonian physics might lead us to expect. Do scientists thereby drop the theory? You answer.

 

If you'd like more examples, gimme a shout.

[Strange]

The examples are well known. Mercury (or Uranus) doesn't behave as Newtonian physics might lead us to expect. Do scientists thereby drop the theory? You answer.

 

The anomalous precession of Mercury was one reason why an improved/alternative explanation of gravity was being looked at in the early 20th century. And what happened was that Einstein came up with GR which does correctly explain this. So this appears to be a counter-example to your claim.

 

Or are you objecting to the fact that the Newtonian model of gravity is still being used despite the fact we have a more accurate theory? That is just pragmatic: Newtonian gravity is good enough for most work and is much, much simpler.

 

Remember, science is not about "truth" but about models that work; Newtonian gravity still works well enough most of the time.

 

Uranus? Are you thinking of the orbital perturbations that led to the discovery of Neptune? If so, this also seems to counter your claim: the evidence led to a new hypothesis (an unknown planet, the "dark matter" of its time) which was confirmed by observation.

 

So in both cases, unexpected (contradictory) evidence led to new theories and or discoveries. Rather then being ignored to preserve the status quo, as you claim.

There are examples where evidence has shown a theory to be completely wrong and it has been abandoned. But these are pretty rare (for obvious reasons). I can think of phlogiston and the steady state model of the universe. That's about it.

[Reg Prescott]

You see, this is what I find very worrying. And I may get banned for saying this, but perhaps a few others might agree with me. I feel that scientists and science afficionados take a stance of almost religious zealotry when they feel that their beloved science is "under attack", the same way the religious loonies do when they suspect their pet prophet has been slighted.

 

An attitude of "must defend, must defend, no matter if I'm right or wrong"

 

Yes, as you said, science works. And I have the utmost respect for good people working hard to improve the human lot. But that wasn't the issue. Working is not the same as being true. Ptolemaic cosmology works very well too. Do you think it's true?

 

I'm not attacking science. Only the exaggerated and manifestly absurd claims often made on its behalf.

 

Please explain what "test" would result in evolutionary biologists, say, around the world abandoning their theory en masse tomorrow.

 

No, I'm not a Creationist nut.

[swansont]

 

I hear a lot about evolutionary theory being "tested".

 

Will someone please give me an example of one of these tests? Thanks.

 

Just one.

 

 

!

Moderator Note

No. We're not going there. There is plenty of information on evolutionary science out there. We're not going to waste time and space re-hashing these canards. It's off-topic for this thread and tedious elsewhere.

 

edit: even though this has been split from the original, we're still not going to get mired in an "evidence for evolution" discussion

[Reg Prescott]

Sorry, friend, I posted before I read your latest one. Please also explain what would demonstrate a theory to be "completely wrong"?

 

Are you familiar with the Duhem-Quine thesis? If you'd like to refute it, I'm all ears.

 

And peace and love

[Reg Prescott]

and with no offence intended, but with regards "And what happened was that Einstein came up with GR which does correctly explain this."

 

Well, we all thought previous theories explained things.

 

How can you be sure we have "correctly" explained it now?

 

Sorry, but your claim is patently absurd.

Sorry, I'm new here. And I see the mods posting things. I mean no offence to anyone. I'd just like to discuss these things rationally. You can rest assured I will not be abusive.

 

I would also argue there is no such thing that can be properly referred to as "The Scientific Method", but perhaps we'll save that for another day LOL..

 

Don't ban my sorry ass now, nice people.

[Strange]

You see, this is what I find very worrying. And I may get banned for saying this, but perhaps a few others might agree with me. I feel that scientists and science afficionados take a stance of almost religious zealotry when they feel that their beloved science is "under attack", the same way the religious loonies do when they suspect their pet prophet has been slighted.

 

I am baffled by this. Where is there any sign of "religious zealotry"?

 

 

 

An attitude of "must defend, must defend, no matter if I'm right or wrong"

 

Who is doing that? I am happy to admit that sometime scientists get it wrong; either because of deliberate fraud or wishful thinking. But this is, in the long run, corrected by the scientific method.

 

Yes, as you said, science works. And I have the utmost respect for good people working hard to improve the human lot. But that wasn't the issue. Working is not the same as being true. Ptolemaic cosmology works very well too. Do you think it's true?

 

Science has (almost) nothing to do with "truth", whatever that is. For that you want religion.

 

Only the exaggerated and manifestly absurd claims often made on its behalf.

 

What are these absurd claims?

 

Please explain what "test" would result in evolutionary biologists, say, around the world abandoning their theory en masse tomorrow.

 

Evidence that traits are not inherited. Or evidence that there are no new sources of variation in a population. Or evidence that no variants in the population are more or less successful at surviving or breeding. (I can't think of much else. But if you ask in the appropriate forum you will probably get a much better answer.)

Please also explain what would demonstrate a theory to be "completely wrong"?

 

When the new (better) theory completely contradicts the old one (as with phlogiston) rather than just modifying or extending it (e.g. Newtonian vs GR descriptions of gravity).

[Reg Prescott]

"Evidence that traits are not inherited. Or evidence that there are no new sources of variation in a population. Or evidence that no variants in the population are more or less successful at surviving or breeding. (I can't think of much else. But if you ask in the appropriate forum you will probably get a much better answer.)"

 

I see. And if that happens, we can expect biologists around the world to dump the theory tomorrow and twiddle their thumbs? And are you speaking on their behalf?

[Strange]

and with no offence intended, but with regards "And what happened was that Einstein came up with GR which does correctly explain this."

 

Well, we all thought previous theories explained things.

 

How can you be sure we have "correctly" explained it now?

 

GR matches the observed data. That is what we expect scientific theories to do. Other new theories attempted at the time failed to do that. Other alternative theories of gravity since then have also failed to match all the evidence.

I see. And if that happens, we can expect biologists around the world to dump the theory tomorrow and twiddle their thumbs? And are you speaking on their behalf?

 

Of course not (to both of those). Theories are never dropped "just like that". That is why science works. A huge amount of work would, I assume, go into trying to understand how something that is self-evidently true turned out not to be so (which is why the theory of evolution is rather a silly example).

 

But, again, take it to the appropriate forum.

Edited September 28, 2015 by Strange

[ajb]

The examples are well known. Mercury (or Uranus) doesn't behave as Newtonian physics might lead us to expect. Do scientists thereby drop the theory? You answer.

The short answer is no, Newtonian gravity is not dropped. It is realised to be a limit of a more encompassing theory of gravity that describes a wider range of gravitational phenomena. In this sense Newtonian gravity is a good theory, just you have to be careful with the domain of applicability.

 

So, in relation to the opening: we have a model of gravitation called general relativity. This model matches nature very well so far, but it is complicated to work with. As a well defined limit we can recover Newtonian gravity and this is easier to work with and still describes a lot of gravitational phenomena. General relativity is a 'better' theory in that it describes more, but it is a 'worse' theory in that is is much more complicated than Newtonian gravity.

Edited September 28, 2015 by ajb

[Reg Prescott]

Well, you edited an earlier post. I assume because you saw that you were blatantly contradicting yourself. "I said if theory does not agree with observation...."

 

You said "Exactly"

 

Right?

 

Now you've changed your tune.

 

If I'm wrong, I'll apologize.

Sorry, but you're being evasive. You said : "GR matches the observed data. That is what we expect scientific theories to do. Other new theories attempted at the time failed to do that. Other alternative theories of gravity since then have also failed to match all the evidence."

 

Please answer the question I asked.

 

How can you be sure we have the right explanation now?

 

Let me remind you of your earlier remark : ""And what happened was that Einstein came up with GR which does correctly explain this."

 

Focus on "correctly"

 

Sorry, I haven't mastered the quote function yet. Gimme time LOL

To ajb

 

"So, in relation to the opening: we have a model of gravitation called general relativity"

 

Why are you talking to me as if I'm a child?

Sorry, all my posts have ended up in the same, erm, entity. Not good for coherency. Makes me look kinda stoopid. LOL

 

I'm sure it's my fault.

[ajb]

How can you be sure we have the right explanation now?

How do you define 'right'?

 

A theory is a mathematical model. The question is not one of right and wrong, but good and bad. A theory is 'good' if it matches nature well and 'bad' otherwise.

 

If you are asking if we thing that general relativity is the final word on gravity, then the answer is no.

 

We know that general relativity cannot be the complete story. The presence of singularities and the lack of a quantum description tell us this.

 

So again, in relation to the opening post. The best we can do is construct various models and see how well they match with nature. The words 'correct', 'right' etc are not really appropriate here. We are developing a framework to describe nature and this has many layers.

[Reg Prescott]

The other poster said we have the "correct" explanation now.

 

 

Take it up with him

[ajb]

Why are you talking to me as if I'm a child?

Sorry if you took it that way. We should be careful not to hijack this thread into a specific discussion of GR, though we can use it as an example.

[Reg Prescott]

It was another unjustifiable claim. Like the religious loonies make.

 

Do we have the correct explanation?

 

I say maybe. What say you?

[Strange]

How can you be sure we have the right explanation now?

 

You can't. Obviously. All scientific theories are provisional, based on the evidence currently available.

 

Let me remind you of your earlier remark : ""And what happened was that Einstein came up with GR which does correctly explain this."

 

Focus on "correctly"

 

Perhaps it would be more accurate to say that GR produces results that are consistent with observation (while Newtonian gravity doesn't.) That is what I meant by "correct".

It was another unjustifiable claim. Like the religious loonies make.

 

What was?

 

Do we have the correct explanation?

 

We have a more correct description. Currently the best we have. But it is known to be incomplete.

Edited September 28, 2015 by Strange

[ajb]

The other poster said we have the "correct" explanation now.

As in "And what happened was that Einstein came up with GR which does correctly explain this"?

 

By correctly he means that the theory now matches the observations, taking into account experimental errors...

 

This does not mean that GR is 'correct' in any deeper sense. Just that it matches what we observe very well.

[Reg Prescott]

Strange, no offence, but I'm losing all respect for you. You keep backpedaling. I will say no more and trust that other members might adjudicate impartially.

[Strange]

The other poster said we have the "correct" explanation now.

 

No, I said that GR gives the correct value for the precession of Mercury.

Strange, no offence, but I'm losing all respect for you. You keep backpedaling.

 

I think that is because you are reading more into what I write than was intended. That may be a result of me being slightly careless with wording in an informal setting.

[Reg Prescott]

No, you said we have the correct explanation. Please don't make a fool of me. Thanks.

"And what happened was that Einstein came up with GR which does correctly explain this"

 

You in page 1

 

However, I'd like to wish you a blessed day. I hope I didn't come across as aggressive. I just felt some of your claims were unjustifiable. Please be well.

[Strange]

No, you said we have the correct explanation. Please don't make a fool of me. Thanks.

 

I guess I will just have to quote what I said:

 

The anomalous precession of Mercury was one reason why an improved/alternative explanation of gravity was being looked at in the early 20th century. And what happened was that Einstein came up with GR which does correctly explain this.

 

"Does correctly explain this" ["this" being the anomalous precession of Mercury]. Note that I didn't say "GR is correct" or "GR is the correct explanation".

 

GR gives the "correct" value (within experimental error bounds) while Newtonian gravity doesn't. It also provides an explanation for this value.

[Note: "an" explanation, not "the" explanation.]

[Reg Prescott]

Hmm ok. But I can pee further.