Definitions of ...

[Tormod]

The last statement (before Turtle's post) is correct IMHO. For something to be a theory, it needs to make predictions. As far as I am aware string theory has not yet made any predictions. I seem to remember news to the contrary a while ago but can't remember it off the top of my head. But without predictions the idea will remain a hypothesis.

[InfiniteNow]

...or a conjecture. :D

[Tormod]

...or a conjecture. :D

 

Now that's a fact. :D

[cwes99_03]

It's funny, Tor. I was just reading another thread and you posted this. Hope you don't mind, but it demonstrates how even you call some things "only theory" and other things "theory".

 

Good question. According to the standard model, most of it was annihilated together with the same amount of matter in the very early universe. Luck had it (for us) that there was an inbalance in the matter/antimatter ratio so we ended up in a mostly matter universe with only a small amount of antimatter (relatively).

 

This is of course only theories but that is how they explain it, even if we don't yet have any real understanding of it.

http://hypography.com/forums/110207-post43.html

[pgrmdave]

Yes, because 'theory' has multiple meanings, and we all use them that way. It doesn't diminish the meanings in any way, it is simply that there are different meanings for one word. If you are so determined that words should have only one meaning, provide a definition for "run".

[cwes99_03]

[Edited by self for not being nice.] Of course there will be different definitions for the word, depending on context.

 

However, for the word "theory" we are all using the same context, but some are using the word to mean that it has been completely established and cannot be disproven or questioned. This goes against the word's meaning completely.

[Raskolnikov]

cwes,

I disagree whole heartedly that nothing can be accepted as absolute fact.

 

I tell you it is absolute fact that you can not jump into the air and fly into outer space. Newtonian gravity tells us that.

The notion of "absolute" is incompatible with an empirical worldview since any commitment to empiricism necessarily requires that one abandons ideas that don't conform to new observations. Technically all a strict empiricist can ever say is that a particular idea has conformed with all of his observations to date, and that the idea has been useful in making accurate predictions. The latter is what science is all about.

 

Also, I get the impression that you're trying to push some kind of scientific realism, and, if so, I'd like to point out that from the realist point of view Newtonian gravity is actually wrong. Newton's law of universal gravitation makes make predictions that don't conform to certain observations at all.

I tell you it is absolute fact that man cannot cause an evolution in species (not even a mutation), thus evolution is still a theory. By this same definition you can call intelligent design a theory, because it's results cannot be reproduced by men.

Why do you insist on using a nonstandard definition of "theory" when you know what the rest of us mean by this is different? What word should I use for a predictively powerful statement which has conformed to all observations to date? Law?

 

Anyway, evolution has actually been observed in the lab. If you want to discuss evoltuion, we should start another thread (as I thought we were going to do anyway).

As I said, parts of SR are well supported by observation, and some by reproduceable experimentation. Those parts are not in question. However, to say that "SR has been verified experimentally" is a lie. The whole of Einstein's thought experiments have not been verified experimentally, because they cannot. Until they can, it is simply describing an observation.

Einstein's thought experiments were the means he used to arrive at SR, but they don't really have anything to do with the theory itself (nor with the verification of the theory). What parts of SR are you alluding to, anyway?

Thus the theory that the earth was at the center of the universe was a theory because it described the observation of the stars at night rising in the east and setting in the west. It wasn't until someone observed retrograde motion that this theory became defunct, since it did not correctly describe the situation.

Agreed.

Newtonian physics is correct, and to a very high precision, for ranges of data. Thus it is not defunct, nor is it a theory. To get higher precision, or to describe data outside of those limits, you must use other laws, however, these laws do not make Newtonian physics false or bad.

I agree, but I wouldn't say that Newtonian physics is "correct" either. Newtonian physics is predictively powerful within certain parameters, and this is more or less what scientific theories are--they are ideas which are predictively powerful within certain parameters.

A hypothesis is a statement that is as of yet unverified, it is the opening part of a theory. However, a theory may be made up of one or more hypotheses.

Agreed. Actually, I think any theory must necessarily be made up of infinitely many hypothesis.

[Raskolnikov]

However, for the word theory we are all using the same context, but some are using the word to mean that it has been completely established and cannot be disproven or questioned. This goes against the words meaning completely.

This is more or less what I mean when I say theory in a scientific context (though I don't think anything's beyond being disproved/questioned). What other word would be appropriate for this if not "theory"?

[Tormod]

It's funny, Tor.

 

Just for the record, Tor is not my nick (it is a common name in Norway). Tormod or plain "T" is fine.

 

I was just reading another thread and you posted this. Hope you don't mind, but it demonstrates how even you call some things "only theory" and other things "theory".

 

I think that very post simply proves what I said in my previous post - theories need to be able to make predictions. The standard model in big bang cosmology *does* make predictions (for example, that the universe would be cooling down) which can be tested and verified (edit: *or*, more commonly, falsified, of course).

 

Your behaviour in this thread is akin to trolling - you're pounding home a point and I'm not even sure what you actually mean.

 

I have a high regard for you cwes, you don't need to prove anything my friend. :)

[cwes99_03]

Well the point for this whole thread was that some people argue over definitions of things in threads and get off topic. I was hoping that short discussions/arguments about definitions in a separate thread could straighten things out, when an easy definition (which you demonstrated earlier how to link) are not easily come by.

 

You all have noted above so far that some things are weak theoretically, while other things are well established, and yet more things are completely accurate but only within certain limitations. Yet, very often on this site people mix these things up in their conversations.

The demonstration that I have used here is Evolutionary theory. Rask, we can start a thread, you may do it and send me a link so I can join in. In that thread I would hope to use these points here for discussion of whether Evolution is weak theoretically, well established, or completely accurate within limitations (and if the last what limitations we must place on that theory.)

 

I think that more people need to be careful when discussing things that they call theories (not just on this site, but across the entire scientific world). Some things may be well understood but not well established and we would be misleading everyone if we didn't make that clear.

[Tormod]

You all have noted above so far that some things are weak theoretically, while other things are well established, and yet more things are completely accurate but only within certain limitations. Yet, very often on this site people mix these things up in their conversations.

 

Not only do we mix them up, we also have different perceptions of how good a theory is, and were we draw the limit to accept something as fact (as compared to Truth).

 

There are many facts that are not truths. A case in point is your example of global warming: while we know that many things *may* contribute to global warming, there is as of yet no conclusive evidence that the increasing temperature over the past 30 years are due to human activity. However, we can make theories and create predictions, and when these predictions are found to be correct we will say that the theory has strong obsevational support, ie it is a good theory (although it may still be completely *wrong*).

 

This has been discussed at length before here at Hypography, but it's a discussion that will pop up every now and then. What is Truth, and what is fact in science, and how good are the definitions of the words and phrases we use? It will always boil down to semantics.

[Erasmus00]

I think the whole difficulty of this thread is that science doesn't have a word for when things become more and more experimentally verified. Even the time tested, never failed are still theories. No matter how much experimental evidence we have (both explicit and implicit), classical mechanics is still the theory of classical mechanics. Relativity is still the theory of relativity. Quantum mechanics is still the theory of quantum mechanics. Evolution is still the theory of evolution.

 

Some people will claim that once things have a degree of certainty they are elevated to "laws" which just doesn't seem to be the case. Very few physical principles are regarded as laws, and these are nearly always observational facts, not the theory underlying them.

 

Personally, I don't think this is a bad thing. Theories just provide models that match some set of data. The possibility that they won't meet the next set is ever present. Maybe relativity will fail in the strong field gravitational limit.

-Will

[cwes99_03]

Will, hits on a point along with Tormod ( :) ).

 

In the legal system, we have laws. However, we also have a judicial system that has a right called judicial review. Does this mean that all laws are just theories until someone finds a way to break it and get away with it?

Some have instead said "law is fluid" it changes when it needs to but otherwise is still there and still law.

 

We have the Laws of Thermodynamics. We have the Perfect Gas Law. We have the three laws put forth by Newton (For every action there is ...) These are laws, not theories, right? If we can't trust them, and can't demonstrate them over and over and over again in a controlled environment like a laboratory, then why do we teach them to every child.

 

Math has laws. 1+1=2. This is not debatable. Two odd numbers when added together equal an even number.

 

Are you in agreement that there are no such laws in physics?

[pgrmdave]

No, there are laws, but they differ from theories in their scope. A theory underlies laws, or groups many of them togeather. Laws are also very basic and simple, while theories are complex. A theory is more like a system, a framework, than a measurement.

[Tormod]

Does this mean that all laws are just theories until someone finds a way to break it and get away with it?

 

Yes. If you could claim that a law is absolute, it would be a breakthrough in science. Laws are merely axioms, from which every theory is derived. Sometimes the experiments made to find out if a theory is correct or not, means that the laws have to be rewritten.

 

One recent example is the experiments done by Paul Davies et al on the varying speed of light, in which they found that the speed of light must have changed over the last two billion years. (Technically they studied the alpha constant, also known as the fine structure constant, and found that it must have changed, and this forces a change in the speed of light).

 

This is a direct challenge to one of the most fundamental constants of modern physics (and in fact most of our technology): the speed of light as used in Einstein's [math]E=mc^2[/math].

 

We have the Laws of Thermodynamics. We have the Perfect Gas Law. We have the three laws put forth by Newton (For every action there is ...) These are laws, not theories, right? If we can't trust them, and can't demonstrate them over and over and over again in a controlled environment like a laboratory, then why do we teach them to every child.

 

Because they are the best explanations we currently have. Don't forget that natural laws of the past are not necessarily the laws of today. The realization that something was not right in Newton's physics was the cornerstone of the scientific revolution driven in the 1800s by Faraday, Maxwell etc, and which lead directly to the relativity theory - which is being challenged every day.

 

Math has laws. 1+1=2. This is not debatable. Two odd numbers when added together equal an even number.

 

But these are not laws of nature, as Dave points out above. They are merely semantic absolutes in the language of mathematics. I could just as easily say that "Bluejay is a bird, and that is not debatable". But in my language there are no birds called bluejays.

 

We need to know in which cases 1+1=2 are true. If you use the equation 1+1 to imply the fusion of two Hydrogen atoms (as in solar fusion) the result is not 2H or H2 but Helium (He) which is slightly lighter than two separate Hydrogen. The rest is the energy that the fusion creates.

 

Also, the statement 10+10=20 is false in the binary system, the hexadecimal system, and every other counting system that is not a Base10 system. Thus relying on 1+1=2 as a law is fallacious.

 

Are you in agreement that there are no such laws in physics?

 

I say there are no laws in mathematics that dictate nature, rather it is the laws of nature that dictate mathematics. Or to put it simpler, mathematics is a language devised to express the laws of nature as simply as possible.

 

There are many laws in physics, but they must *never* be accepted as God-given, unchanging laws. We must *always* assume that there is something about a system we do not know. Strictly based on empiricial experience, which is what the scientific methods of our day is all about, we cannot guarantee that what happens today also happens tomorrow.

 

The things we call laws are seen as never-changing and thus become laws. But they are merely our best bet. And that's what we need to teach kids, so that they start thinking for themselves that "hey, maybe our understanding of the way atoms work has some flaws in it too...how can I explain that with my own words."

[cwes99_03]

No, there are laws, but they differ from theories in their scope. A theory underlies laws, or groups many of them togeather. Laws are also very basic and simple, while theories are complex. A theory is more like a system, a framework, than a measurement.

 

So would you say that - For every action there is a reaction - is a law of physics? It is very basic and simple (of course I'm leaving out the equal and opposite). If you would, wouldn't you also agree that it is meaningless for the most part?

 

One recent example is the experiments done by Paul Davies et al on the varying speed of light, in which they found that the speed of light must have changed over the last two billion years. (Technically they studied the alpha constant, also known as the fine structure constant, and found that it must have changed, and this forces a change in the speed of light).

 

This is a direct challenge to one of the most fundamental constants of modern physics (and in fact most of our technology): the speed of light as used in Einstein's .

 

I myself am not familiar with the experiments done by Davies, yet. However, I would suggest that his experimental results are theoretical at this time, until they are proven. The speed of light and the results that govern its definition are well established by repeatable experimentation.

Maybe Davies has something and it will become a part of the laws governing our definition of c, but I say they are laws not just theories. I don't think that just because any number of persons "thinks" that c may have varied over the years, that E=mc^2 is no longer trustworthy. Perhaps, E and m also varied so that the equation itself never changed, or perhaps Davies has some error. Either way, repeatable experimentation allows the verification of E=mc^2.

 

Because they are the best explanations we currently have. Don't forget that natural laws of the past are not necessarily the laws of today. The realization that something was not right in Newton's physics was the cornerstone of the scientific revolution driven in the 1800s by Faraday, Maxwell etc, and which lead directly to the relativity theory - which is being challenged every day.

It wasn't the realization that Newton was wrong. It was the realization that there was more than just gravity. Misapplication of a law does not mean that the law was wrong. Instead they found new things and made adjustments.

Also you say the best explanation. Perhaps this is a good point. Are there any other reasonable explanations? In my mind the best explanation for the existence of life and the universe is that God created everything according to the account in Genesis. Others disagree. But when asked to teach it, only one version is taught to school children, and it is taught as truth and law, though called a theory. While I don't involve myself in whether or not Intelligent Design should be taught, and this is not a thread about that, I do have a problem with people saying that Evolution is verified, reproducable, and well-founded.

 

The notion of "absolute" is incompatible with an empirical worldview since any commitment to empiricism necessarily requires that one abandons ideas that don't conform to new observations.

 

Not abandonned, but adjusted or limited to certain boundaries (as is done with Mathematics).

 

Science, as in math, requires proof for something to be removed from the theoretical into the tested and accepted.

[Raskolnikov]

Not abandonned, but adjusted or limited to certain boundaries (as is done with Mathematics).

 

Science, as in math, requires proof for something to be removed from the theoretical into the tested and accepted.

I don't really agree with any part of this. First of all, I don't think anything is ever really adjusted in mathematics except that possibly certain poorly delineated ideas are made more explicit by formalization. I can't think of a single example of a mathematical idea being adjusted in the same sense a scientific framework is. Secondly, I don't think proof is involved in science at all. There's no deductive way to generalize any amount of evidence to an analytically true statement as far as I know. Can you give me an example of this?