Basic Concepts of modern science

[David Levy]

I'm not sure that I fully understand the basic Concepts of modern science.

Therefore, Please advice if you agree with the following descriptions:.

Observation: Whatever we see. For example we see redshift of farthest galaxies.

Evidence: a direct outcome from this observation that had been proved by confirmed theory or physics law. For example based on the redshift observation and Doppler Effect we know for sure that all the farther galaxies accelerating from us. Therefore, this is evidence.

Theory: Any unconfirmed/unproved Idea or Speculation which can give a feasible explanation/ solution for that observation or evidence.

Confirmed Theory: A theory which had been fully confirmed. However, it is forbidden to use the same original evidence for confirmation. Different evidence or a fully proved lab test is needed to confirm a theory.

No Math: It is also forbidden to confirm theory by Math. (unless it is based on a proven physics law or confirmed theory.) For example It is perfectly O.K. to develop a formula in order to get a theory of the dark energy in the universe, but this math can't be used as an approval for that theory.

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

Argument: any idea or speculation which had been offered by any one of us.

Illogical argument: Any unrealistic argument which had been disapproved by confirmed theory or real evidence. Trash must be the only place for those arguments

Logical argument: Any argument which can't be disapproved by confirmed theory or real evidence. It is forbidden to disapprove an argument by Hypothesis.

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

Edited March 11, 2015 by David Levy

[ajb]

In physics one usually uses the words theory and model synonymously; some specific model within some mathematical framework.

 

You don't exactly prove a theory. What you do is ask if your theory matches nature well or not. If it matches well then it is a 'good theory', if not then it is a 'bad theory'. You have to decide what is meant by 'matches well', this would mean something like the predicted phenomena matches the observations to x-many decimal places, where x is whatever. One must also take into account the domain of validity. That is theories are not usual expected to be good for all of the possible range of the parameters, but only for a subset.

 

For example, Newtons laws work very well as long as the particles are not moving too fast and gravity is weak.

 

There is no real difference between a physical law and a theory. Often a law is part of some theory, but the distinction is not hard and fast.

 

So with all this in mind, the mathematics needed to create a good theory, starting from what we know holds well in other circumstances, requires us to consider dark energy.

Edited March 11, 2015 by ajb

[Klaynos]

I'm not sure that I fully understand the basic Concepts of modern science.

Therefore, Please advice if you agree with the following descriptions:.

Observation: Whatever we see. For example we see redshift of farthest galaxies.

 

I'd say it's what we measure. Saying see implies a human eye.

 

Evidence: a direct outcome from this observation that had been proved by confirmed theory or physics law. For example based on the redshift observation and Doppler Effect we know for sure that all the farther galaxies accelerating from us. Therefore, this is evidence.

 

A measurement and prediction that are consistent, you need knowledge of the errors on both for this.

 

Theory: Any unconfirmed/unproved Idea or Speculation which can give a feasible explanation/ solution for that observation or evidence.

 

An accepted mathematical framework to model since aspect of the universe. A theory just have been well tested within its domain. This is the highest state of a science concept.

 

Confirmed Theory: A theory which had been fully confirmed. However, it is forbidden to use the same original evidence for confirmation. Different evidence or a fully proved lab test is needed to confirm a theory.

 

Not a term I've ever heard a physicist say.

 

No Math: It is also forbidden to confirm theory by Math. (unless it is based on a proven physics law or confirmed theory.) For example It is perfectly O.K. to develop a formula in order to get a theory of the dark energy in the universe, but this math can't be used as an approval for that theory.

 

Maths is a tool to create predictions and compare those predictions to reality.

 

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

 

An in evidenced prediction. To be accurate this must be numeric therefore use maths.

 

Argument: any idea or speculation which had been offered by any one of us.

 

I'm not really aware of a distinction to the everyday definition.

 

Illogical argument: Any unrealistic argument which had been disapproved by confirmed theory or real evidence. Trash must be the only place for those arguments

Logical argument: Any argument which can't be disapproved by confirmed theory or real evidence. It is forbidden to disapprove an argument by Hypothesis.

 

Logic has a very specific definition in maths, is suggest you look it up. What it doesn't mean is "it makes sense to me".

 

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

A subsection of a theory. Must be mathematical in its formal definition.

[Strange]

Interesting questions. Here are my attempts to answer. I'm sure others can expand/improve ...

Observation: Whatever we see. For example we see redshift of farthest galaxies.
Evidence: a direct outcome from this observation that had been proved by confirmed theory or physics law. For example based on the redshift observation and Doppler Effect we know for sure that all the farther galaxies accelerating from us. Therefore, this is evidence.

I would say observations and evidence are the same thing. Maybe the only difference is that evidence means observations that are used to support a theory.

Also, evidence could be the results of experiments while observation often means data from things we have no control over.

Also, observations and evidence must be quantitative (i.e. objectively measured values) so they can be tested against the predictions of theories.

So we can observe the red-shift of galaxies and we can also observe that all spiders have 8 legs. The first of these is evidence for the movement of galaxies and hence expansion. The second observation is not evidence for expansion.

Theory: Any unconfirmed/unproved Idea or Speculation which can give a feasible explanation/ solution for that observation or evidence.

Wrong. A theory is a complete (mathematical) description of a phenomenon which has been repeatedly confirmed by observation/evidence.

An unconfirmed idea which can give a feasible explanation is called a "hypothesis". A hypothesis must also be mathematical because it must make testable (i.e. quantitative) predictions that can be tested by being compared with observation or experiment.

If a hypothesis is repeatedly tested and not contradicted by any evidence, then it will eventually be accepted as a theory.

Note that a theory is the closest thing to "true" or "fact" that science gets to. However, theories are still continually challenged and tested and will be modified or discarded as required by evidence.

 

Also (as you note later) a theory has a limited domain in which it is valid. Newton's theory of gravity is good enough most of the time but in some cases you need a more accurate model (e.g. GR is needed to calculate the precession of Mercury).

Confirmed Theory: A theory which had been fully confirmed.

In other words: a theory.

However, it is forbidden to use the same original evidence for confirmation. Different evidence or a fully proved lab test is needed to confirm a theory.

That is a good point. A hypothesis is initially based on evidence. Different evidence is needed to confirm the hypothesis or theory.

When there is a limited data set available, then it will often be split into two (randomly) with half used to build the initial hypothesis and then the second half used to test the predictions made by the hypothesis.

No Math: It is also forbidden to confirm theory by Math. (unless it is based on a proven physics law or confirmed theory.) For example It is perfectly O.K. to develop a formula in order to get a theory of the dark energy in the universe, but this math can't be used as an approval for that theory.

Yes. Although maths is an essential part of any hypothesis or theory it is not enough by itself. The predictions of the maths must be confirmed by comparing against he real world.

This is because it is possible to make up any valid mathematical model, but that description may not describe the real world.

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

Wrong way round. See above.

Argument: any idea or speculation which had been offered by any one of us.

Argument means logical and mathematical reasoning to explain why a piece of evidence supports a hypothesis or theory.

"In logic and philosophy, an argument is a series of statements typically used to persuade someone of something or to present reasons for accepting a conclusion."
http://en.wikipedia.org/wiki/Argument

Illogical argument: Any unrealistic argument which had been disapproved by confirmed theory or real evidence.

Illogical doesn't (necessarily) mean that an argument is disproved by evidence or theory. It means that the argument does not follow the rules of logic, or uses any of the well known logical fallacies.

Logical argument: Any argument which can't be disapproved by confirmed theory or real evidence. It is forbidden to disapprove an argument by Hypothesis.

Again, a logical argument isn't related to evidence. It is an argument that follows the rules of logic. This means that if the initial statements are true then the conclusions are true.

 

For example a typical logical argument is:- All humans are mortal.
- Socrates is human.

- Therefore, Socrates is mortal.

 

Note that an argument can be logical but still lead to wrong results. For example:

- All humans are immortal.
- Socrates is human.

- Therefore, Socrates is immortal.

 

This is the same logical argument. However the conclusion is wrong because one of the premises is wrong.

 

An example of an illogical argument is:

- All dogs are mortal.
- Socrates is mortal.

- Therefore, Socrates is a dog.

 

The conclusion of this argument is wrong because it doesn't follow the rules of logic.

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

 

This is not a well defined term. The best description might be: a mathematical rule derived from a theory.

Also, a law can be purely observational. It may be used as the basis for developing a theory.

 

For example Hubble's Law (the relationship between distance and red-shift) was initially purely a statement about the measurements had been made. There was no theory behind it. Then a number of hypotheses were suggested and tested and we eventually end up with the "big bang" theory/model.

[swansont]

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

No, an hypothesis is not a theory. It is something that is unconfirmed, and doesn't (yet) have the evidence to back it that a theory does.

 

 

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

A law is a straightforward mathematical relationship, often an equation. (e.g. Newton's law of gravitation, Ohm's law, Coulomb's law, Gauss's law). Laws are subsets of theories.

[Strange]

Thinking about the definition of a logical argument, it occurred to me that philosophy is often more concerned with the validity of an argument (i.e. is it logically well-formed) than about the truth of the results. Whereas science is more concerned with the soundness of the argument (i.e. are all the premises correct, the argument valid and therefore the conclusions likely to be correct).

[swansont]

Thinking about the definition of a logical argument, it occurred to me that philosophy is often more concerned with the validity of an argument (i.e. is it logically well-formed) than about the truth of the results. Whereas science is more concerned with the soundness of the argument (i.e. are all the premises correct, the argument valid and therefore the conclusions likely to be correct).

 

And science is concerned with the comparison of the theory with experiment. Sound logic does not guarantee that the theory is correct. Flawed logic means it's invalid (but could still give the right answer, by accident)

[David Levy]

 

Observations and evidence

I would say observations and evidence are the same thing. Maybe the only difference is that evidence means observations that are used to support a theory.

Also, evidence could be the results of experiments while observation often means data from things we have no control over.

Also, observations and evidence must be quantitative (i.e. objectively measured values) so they can be tested against the predictions of theories.

O.K.

 

Hypothesis

An unconfirmed idea which can give a feasible explanation is called a "hypothesis".

Agree.

A hypothesis must also be mathematical because it must make testable (i.e. quantitative) predictions that can be tested by being compared with observation or experiment.

If a hypothesis is repeatedly tested and not contradicted by any evidence, then it will eventually be accepted as a theory.

Why a mathematical is a mandatory requested for Hypothesis? I had the impression that mathematical is an option. However, how shall we call a hypothesis without math?

 

If a hypothesis is repeatedly tested and not contradicted by any evidence, then it will eventually be accepted as a theory.

Why?

Example – Do you remember the idea that the moon was considered as a cheese in the past?

So, at that time, this idea couldn't be contradicted by any evidence.

Therefore, based on this approach, the moon must be made of cheese…

Please try to find better description.

 

Theory

Note that a theory is the closest thing to "true" or "fact" that science gets to. However, theories are still continually challenged and tested and will be modified or discarded as required by evidence.

Also (as you note later) a theory has a limited domain in which it is valid. Newton's theory of gravity is good enough most of the time but in some cases you need a more accurate model (e.g. GR is needed to calculate the precession of Mercury).

Why close to "true". It must be true! Although, we should have the flexibility to set minor adaptation in the future...

 

That is a good point. A hypothesis is initially based on evidence. Different evidence is needed to confirm the hypothesis or theory.

I would say: "A hypothesis is initially based on observation and evidence. However, Different evidence is needed to confirm a hypothesis to theory."

Why do we need to reconfirm a theory? I had an impression that Theory is a confirmed Hypothesis.

Edited March 11, 2015 by David Levy

[robinpike]

I'm not sure that I fully understand the basic Concepts of modern science.

Therefore, Please advice if you agree with the following descriptions:.

Observation: Whatever we see. For example we see redshift of farthest galaxies.

Evidence: a direct outcome from this observation that had been proved by confirmed theory or physics law. For example based on the redshift observation and Doppler Effect we know for sure that all the farther galaxies accelerating from us. Therefore, this is evidence.

Theory: Any unconfirmed/unproved Idea or Speculation which can give a feasible explanation/ solution for that observation or evidence.

Confirmed Theory: A theory which had been fully confirmed. However, it is forbidden to use the same original evidence for confirmation. Different evidence or a fully proved lab test is needed to confirm a theory.

No Math: It is also forbidden to confirm theory by Math. (unless it is based on a proven physics law or confirmed theory.) For example It is perfectly O.K. to develop a formula in order to get a theory of the dark energy in the universe, but this math can't be used as an approval for that theory.

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

Argument: any idea or speculation which had been offered by any one of us.

Illogical argument: Any unrealistic argument which had been disapproved by confirmed theory or real evidence. Trash must be the only place for those arguments

Logical argument: Any argument which can't be disapproved by confirmed theory or real evidence. It is forbidden to disapprove an argument by Hypothesis.

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

 

I'm not sure that I fully understand the basic Concepts of modern science.

Therefore, Please advice if you agree with the following descriptions:.

Observation / evidence: Whatever we see. For example we see redshift of farthest galaxies.

Evidence: Inference / conclusion: a direct outcome from this observation that had been proved by agrees with a confirmed theory or physics law. For example based on the redshift observation and Doppler Effect we knowfor sure conclude that all the farther galaxies accelerating from us. Therefore, this is evidence a conclusion / explanation.

Theory: Any unconfirmed/unproved Idea or Speculation which can give a feasible explanation/ solution for that observation or evidence.

Confirmed Theory: A theory which had been fully confirmed. However, it is forbidden to use the same original evidence for confirmation. Different evidence or a fully proved lab test is needed to confirm a theory.

No Math: It is also forbidden to confirm theory by Math. (unless it is based on a proven physics law or confirmed theory.) For example It is perfectly O.K. to develop a formula in order to get a theory of the dark energy in the universe, but this math can't be used as an approval for that theory.

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

Argument: any idea or speculation which had been offered by any one of us.

Illogical argument: Any unrealistic argument which had been disapproved by confirmed theory or real evidence. Trash must be the only place for those arguments

Logical argument: Any argument which can't be disapproved by confirmed theory or real evidence. It is forbidden to disapprove an argument by Hypothesis.

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

A better description above referred to as evidence might be inference / conclusion.

 

Also, a conclusion, while agreeing with an accepted theory, does not mean that the conclusion is proved for sure.

 

Explanations / conclusions are very difficult to show as proved for sure.

Edited March 11, 2015 by robinpike

[Strange]

Why a mathematical is a mandatory requested for Hypothesis? I had the impression that mathematical is an option. However, how shall we call a hypothesis without math?

 

Because for it to be "scientific" it must be testable (and therefore falsifiable).

 

In order to be rigorously testable, it must make quantified predictions. So the prediction can't be something like: "the volume will increase as it gets hotter" - what does "increase" mean? 100%, 10%, 1%? What does "hotter" mean? 1°, 100°, 1000000°? So mathematics is required to express the relationship between temperature and volume in a precise way. And then mathematics is needed to analyse the results and determine if they support or contradict the hypothesis, given the errors in measurement, uncertainties in the hypothesis, etc.

 

Why?

 

Because that is the definition of theory: Something that has been tested and found to be consistent with the evidence.

Theory

Why close to "true". It must be true! Although, we should have the flexibility to set minor adaptation in the future...

 

Because any theory can, in principle, be overthrown by evidence at any time. It is hard to find examples where this has happened but one obvious one is "phlogiston". At one time the established theory was that combustion was caused by the release of a substance called phlogiston (almost the opposite of modern theory). For about 100 years, the evidence appeared to be consistent with this theory. Then more evidence was gathered and it was found that the theory was incorrect and it was replaced with the modern idea that combustion was caused by oxygen combining with other elements.

 

Why do we need to reconfirm a theory? I had an impression that Theory is a confirmed Hypothesis.

 

Because we can never test every possible aspect of the theory or find every possible piece of evidence. This has been described as the "black sheep" problem. Imagine a farmer looking at a field of sheep. He notices that they are all white and forms the hypothesis that all sheep are white. Being scientific, he decides to test this. He visits his neighbours' farms and finds that all their sheep are white too. He writes letters to friends and relatives all over the country and finds out that all the sheep near them are white as well. So they all agree that there is enough evidence to say that it is a good theory: all sheep are white. Still, whenever he visits a new area or another country he checks the colour of the sheep and confirms they are all white. A very successful theory.

 

Then one of his cousins visits Australia and writes back: "I have just seen a black sheep!" The established theory is instantly overturned.

[swansont]

 

Example – Do you remember the idea that the moon was considered as a cheese in the past?

So, at that time, this idea couldn't be contradicted by any evidence.

Therefore, based on this approach, the moon must be made of cheese…

 

"Not contradicted" is not the same as "confirmed", because no actual evidence existed. I might have a guess that you are more than 2.25 meters tall. But that doesn't become true at any point, simply because I have never gotten any data regarding your height.

 

I would say: "A hypothesis is initially based on observation and evidence. However, Different evidence is needed to confirm a hypothesis to theory."

Why do we need to reconfirm a theory? I had an impression that Theory is a confirmed Hypothesis.

 

It's not reconfirming it, since an hypothesis is not a theory. You have some observation/evidence and you formulate an hypothesis to explain it. Then you need to test that hypothesis to confirm it. If that were scaled up, with large amounts of testing and evidence, and you would call that a theory.

[Strange]

One thing that distinguishes a hypothesis from a theory is that a theory has been tested and confirmed (often in many different ways) by several different teams in different places. Whereas a hypothesis may only be confirmed by the original team that came up with it (and then published it so others can try and replicate the results).

 

There isn't any formal process by which something is declared to be A Theory.

[David Levy]

 

I like the following explanation:

No, an hypothesis is not a theory. It is something that is unconfirmed, and doesn't (yet) have the evidence to back it that a theory does.

A law is a straightforward mathematical relationship, often an equation. (e.g. Newton's law of gravitation, Ohm's law, Coulomb's law, Gauss's law). Laws are subsets of theories.

However, the current definition of theory is quite misleading.

We have to distinguish between a true theory and unproved theory.

For example

Newton theory is a true theory. It is fully proved by evidences.

Some more examples of true theories:

1. General Relativity

2.Special Relativity

3.Heliocentrism

However, the following theories are not fully proved.

Dark energy theory, Dark matter theory.

Therefore, for those theses we shouldn't use the definition - "theory".

[Strange]

We have to distinguish between a true theory and unproved theory.

 

There are only theories which have not been disproved yet and (old, incorrect) theories which have been disproved.

 

An "unproved theory" is a hypothesis.

 

 

However, the following theories are not fully proved.

Dark energy theory, Dark matter theory.

Therefore, for those theses we shouldn't use the definition - "theory".

 

Correct. They are not theories: they are hypotheses.

 

In fact, they are generic names for several different hypotheses. So, for example, here isn't one dark matter hypotheses, there are many - some of which do not involve any "matter".

BTW you will find the word "theory" being widely misused to mean hypothesis, typically in the popular press but also sometimes also by scientists (e.g. "string theory" is not really a theory; but that is because it is very maths-dominated and they use words slightly differently).

Edited March 11, 2015 by Strange

[David Levy]

 

I'm not sure that I fully understand the basic Concepts of modern science.

Therefore, Please advice if you agree with the following descriptions:.

Observation / evidence: Whatever we see. For example we see redshift of farthest galaxies.

Evidence: Inference / conclusion: a direct outcome from this observation that had been proved by agrees with a confirmed theory or physics law. For example based on the redshift observation and Doppler Effect we knowfor sure conclude that all the farther galaxies accelerating from us. Therefore, this is evidence a conclusion / explanation.

Theory: Any unconfirmed/unproved Idea or Speculation which can give a feasible explanation/ solution for that observation or evidence.

Confirmed Theory: A theory which had been fully confirmed. However, it is forbidden to use the same original evidence for confirmation. Different evidence or a fully proved lab test is needed to confirm a theory.

No Math: It is also forbidden to confirm theory by Math. (unless it is based on a proven physics law or confirmed theory.) For example It is perfectly O.K. to develop a formula in order to get a theory of the dark energy in the universe, but this math can't be used as an approval for that theory.

Hypothesis: any theory which had been accepted by our elite scientists. For example Dark energy.

Argument: any idea or speculation which had been offered by any one of us.

Illogical argument: Any unrealistic argument which had been disapproved by confirmed theory or real evidence. Trash must be the only place for those arguments

Logical argument: Any argument which can't be disapproved by confirmed theory or real evidence. It is forbidden to disapprove an argument by Hypothesis.

Physics law: Fully confirmed thesis. However, we must use this law for its specific scale. For example Newton law is applicable for objects but not for particles.

 

A better description above referred to as evidence might be inference / conclusion.

 

Also, a conclusion, while agreeing with an accepted theory, does not mean that the conclusion is proved for sure.

 

Explanations / conclusions are very difficult to show as proved for sure.

Perfect

Can you please update the whole list?

 

There are only theories which have not been disproved yet and (old, incorrect) theories which have been disproved.

 

An "unproved theory" is a hypothesis.

 

 

Correct. They are not theories: they are hypotheses.

 

In fact, they are generic names for several different hypotheses. So, for example, here isn't one dark matter hypotheses, there are many - some of which do not involve any "matter".

 

BTW you will find the word "theory" being widely misused to mean hypothesis, typically in the popular press but also sometimes also by scientists (e.g. "string theory" is not really a theory; but that is because it is very maths-dominated and they use words slightly differently).

Thanks

Great explanation

[David Levy]

An "unproved theory" is a hypothesis

Dark matter Theory and Dark energy Theory are hypotheses.

What are the other cosmological theories which could be consider as Hypotheses?

[Klaynos]

Dark matter and dark energy are neither theories nor hypothesis they are placeholder terms, there are many hypothesis for both being worked on by many people to find the solution.

[Strange]

An "unproved theory" is a hypothesis

Dark matter Theory and Dark energy Theory are hypotheses.

What are the other cosmological theories which could be consider as Hypotheses?

 

I can't think of any cosmological theories that are actually hypotheses. The only hypothesis I can think of that is regularly referred to as a theory is "string theory".

 

You have invented the terms "Dark matter Theory" and "Dark energy Theory". There are no such theories.

[ajb]

The only hypothesis I can think of that is regularly referred to as a theory is "string theory".

But it is a fully fledged mathematical framework to build models that potentially describe nature. In this sense it is a theory (or you can form specific theories within this framework), the hypothesis is that out of all these specific models one of them describes our universe.

[Strange]

But it is a fully fledged mathematical framework to build models that potentially describe nature. In this sense it is a theory (or you can form specific theories within this framework), the hypothesis is that out of all these specific models one of them describes our universe.

 

You are probably right; hypothesis isn't the right description.

 

Perhaps a better way of stating what I was trying to say is: the only untested theory I can think of is string theory. (There may well be some others ... I just can't think of them right now!)

 

That use of "theory" seems to be more common in the mathematical / theoretical physics world and is rather different from the usual use of the word in experimental physics.

[swansont]

Dark matter and dark energy are neither theories nor hypothesis they are placeholder terms, there are many hypothesis for both being worked on by many people to find the solution.

I can't think of any cosmological theories that are actually hypotheses. The only hypothesis I can think of that is regularly referred to as a theory is "string theory".

 

You have invented the terms "Dark matter Theory" and "Dark energy Theory". There are no such theories.

I'd put it this way:

 

We have the theory of general relativity, which is well-tested and works insanely well in these tests. It explains the expansion of the universe and gravitational effects (and, of course at non-extreme scales this is just Newtonian gravity). However we have observations that do not fit in some way, e.g. the acceleration of the expansion and galactic rotations.

 

So we can hypothesize that either there is some new physics (e.g. MOND) or there is some explanation within current physics that explains all of this. The "new physics" attempts don't seem to work over all scales, so we are left with using current physics. That requires extra mass and extra energy, but we don't yet know all of the properties of them, so they have the placeholder names of dark matter and dark energy. That encompasses whatever we find that fits within the mainstream theory.

 

———

 

In a way, this harkens back to the days when beta decay was being investigated. The electron energy in beta decay showed a continuous spectrum and didn't account for all of the kinetic energy the decay should have, and there was the matter of conservation of angular momentum (and linear momentum). One could hypothesize that these very basic concepts were wrong, or that there was some particle we weren't seeing. From what we could observe, we could figure out the properties of this hypothetical particle: it needed to be spin 1/2 and have no charge. It also couldn't be undergoing any electromagnetic interaction (or strong interaction, though I don't recall how far along that model was). From this, scientists devised experiments to test the idea. Eventually, of course, the neutrino was confirmed.

 

Similarly, Pluto and Neptune were discovered because orbital parameters for other planets didn't quite match up with theory. Working from that, scientists were able to figure out about where they should be.

 

Both examples are analogous to dark matter or dark energy. We just had different names ready to go, and were confident that we were looking for a single particle in the case of the neutrino, and planets in the case of Pluto and Neptune (subsequent reclassification notwithstanding). Dark matter and dark energy are more wide open as to the details.

[David Levy]

What about the density wave theory?

[ajb]

What about the density wave theory?

In relation to spiral arm structure of spiral galaxies?

 

If so, we have a mathematical set-up here that makes predictions that can be tested. It is a theory by usual standards. The question of it being a good theory or a bad theory is a different question to it being a theory. I have no idea what the current status of this is.

[swansont]

What about the density wave theory?

 

What about it?

[David Levy]

Density wave theory -

 

Is it a proved theory or hypothesis?

In relation to spiral arm structure of spiral galaxies?

If so, we have a mathematical set-up here that makes predictions that can be tested. It is a theory by usual standards. The question of it being a good theory or a bad theory is a different question to it being a theory. I have no idea what the current status of this is.

 

Sure.

It's not good or bad.

It's a proved theory or unproved.

In any case, I had an impression that math by itself is not an evidence.

Edited March 12, 2015 by David Levy