When scientists talk about laws of nature, what do they mean???

I think they mean the theories that have been proven, or at least they think have been proven. Such as gravity, electromagnetism, that the planets orbit the sun, and etc.

EDIT- Slow piece of poo poo.

A universal principle which applies to all situations, such as that force is equal to mass times acceleration. Or the uniformity of the speed of light.

I know all the examples of laws of nature, I'm just curious about what laws of nature are. Preferably using this handy fill-in-the-blank definition:

A proposition P is a law of nature if and only if _________________

I think they mean the theories that have been proven, or at least they think have been proven. Such as gravity, electromagnetism, that the planets orbit the sun, and etc.

That seems wayyy too broad.

A universal principle which applies to all situations,

That also seems way to broad, not to mention vague.

So in short you're asking us a question you already know the answer to? Or am i wrong here?

I think they mean the theories that have been proven, or at least they think have been proven. Such as gravity, electromagnetism, that the planets orbit the sun, and etc.
No.

A universal principle which applies to all situations, such as that force is equal to mass times acceleration. Or the uniformity of the speed of light.
Almost, but lose the "applies in all situations" part.

"Laws" of nature are somewhat arbitrary. In general, they are basic principles that are useful for solving problems.

Often they do not apply in all situations (e.g. Newton's Laws of Motion do not apply in relativistic situations), or they are simply unprovable (e.g. the laws of thermodynamics). But, in each case, when applied correctly, they make very useful predictions that we would have a large amount of difficulty making without them. As an example, if you were asked whether it's possible to create a lens that focuses ambient infrared radiation to start a fire without a source of energy such as the sun, one can easily use the second law of thermodynamics to show that this is impossible, but to use optics to show that it's impossible would be extremely difficult.

Simply put, the "laws" of nature are basic axioms that are assumed to be true to simplify complicated problems.

Loosely speaking, they're relationships between physical quantities that hold under certain conditions. I don't think they are necessarily axiomatic, although they can be.

The thing is, I think your (Mise and Meow) distinctions are still too broad. They make stuff like "All of Fifty's pockets contain some quantity of air" laws of nature. While that statement is true, it doesn't seem to capture what people mean when they talk about laws of nature!

So in short you're asking us a question you already know the answer to? Or am i wrong here?

You're wrong here. I know a bunch of examples of laws of nature, I'm asking for a general definition of what it is to be a law of nature, a definition that captures the stuff we want it to capture, and leaves out the stuff we want to leave out.

The thing is, I think your (Mise and Meow) distinctions are still too broad. They make stuff like "All of Fifty's pockets contain some quantity of air" laws of nature. While that statement is true, it doesn't seem to capture what people mean when they talk about laws of nature!

Oh, the laws typically involve some sort of equation. When I said relationship, that's what I meant -- something that quantifies or otherwise describes a relationship between your pocket and the amount of air in it. Typically this involves a constant of some kind.

For example, if the air in your pocket was related in some way to the time of day, you could say V (volume of Air) = k.t (t = seconds from midnight, k = some constant). If it turned out that this relationship held for all values of t (within some range), and k was indeed constant, this could be a law (that holds within that range of t).

If you did ever find a law that related the amount of air in your pocket to... well... any other physical constant (i.e. not the volume of everything that isn't air...) then it'd be pretty impressive. I can't think of any obvious relationship.

I know it's not a definition -- I won't pretend to have one. But it'll help narrow it down, I suppose.

The thing is, I think your (Mise and Meow) distinctions are still too broad. They make stuff like "All of Fifty's pockets contain some quantity of air" laws of nature. While that statement is true, it doesn't seem to capture what people mean when they talk about laws of nature!

"All of Fifty's pockets contain some quantity of air" is not useful for solving problems, so it fits part of my definition, being an axiom that can be assumed, but it fails to simplify any physical problem, and thus is not useful.

edit - to Mise: laws of nature do not have to be mathematical in nature; for example the second law of thermodynamics is often stated as "one cannot create a heat engine that had the sole effect of transferring heat from a cold object to a warm object." Of course, it can be put in mathematical terms (i.e. the universal change in entropy for any process is greater than or equal to zero), but it is not required.

Perhaps one could phrase it by saying that a law is a generalisation of observed behaviour, but unlike a theory, it doesn't explain the behaviour or provide a mechanism for how it works.

Law of nature - a useful relationship between 2 or more natural forces and/or objects.

The thing is, I think your (Mise and Meow) distinctions are still too broad. They make stuff like "All of Fifty's pockets contain some quantity of air" laws of nature. While that statement is true, it doesn't seem to capture what people mean when they talk about laws of nature!

That assertion is the result of natural laws. Maybe then, natural laws are the principles of physics and chemistry. Is that the definition you are looking for?

edit - to Mise: laws of nature do not have to be mathematical in nature; for example the second law of thermodynamics is often stated as "one cannot create a heat engine that had the sole effect of transferring heat from a cold object to a warm object." Of course, it can be put in mathematical terms (i.e. the universal change in entropy for any process is greater than or equal to zero), but it is not required.

Okay then, perhaps a requirement should be that the law must be statable as a mathematical relationship, even if it isn't mathematical in nature.

Fifty's "air in pockets" example would be ruled out on such grounds.

So, P is a Law iff...

1. ...it can be expressed as a mathematical relationship
2. ...<other stuff>...

Is (1) an acceptable iff?

Well, to be honest, you could express almost anything as a mathematical relationship. You might have to invent new math for it, but you'll be able to do it anyway.

V(air in fifty's pockets) > 0

V(air in fifty's pockets) > 0

That's simply restating other known laws. It's not even doing it in a more useful way, it's just restating, for example, conseration of mass/energy, or axioms of geometry, etc.

If you related it to some other physical quanity, as I suggested time or electric charge etc, that might be worth calling a law, since, AFAIK, that relationship can't be described by any other already known law.

I think in general scientists do not speak about 'laws of nature' unless they are speaking broadly.

Simple mathematical equations that have various properties; it must be true, universal (e.g. applies everywhere in the universe), unchanged since first dicovered (outside of it being used as an approximation for a given range), and have various mathematical symmetries such as space and time symmetry, etc. F = dp/dt is a law of nature, for example; but at the same time, that particular example is just true by definition. They can also be approximations, such as newtonian dynamics being an approximation of relativistic dynamics.

I'm not sure if, for example, Hooke's Law or the Ideal Gas Law would count, e.g. a purely empirical relation that is purely intended as an approximation to begin with; they surely arn't fundamental.

From a Physicists point of view:

A law of Nature is something derived from First Principles (neccessary assumptions), which has no contradictions.

Note: Newton's Laws are NOT laws of nature. That is simply the name they are stuck with for much the same reason the Metric system is not the only system in use today. Relativity proved that the formulae of Newtonian mechanics are WRONG. However, they are a nice approximation for those things which we encounter daily in our framework.


If you can state: Assume that there exists a thing which we shall call 1. This is a thing which is indivisible, and groupable.
Then, this forms the basis for a set which shall be the Real Numbers, and could be called Law. As long as you do not deal with fractions of course. Fractions would be the counter-point.

Mathematics are not required for a Law. Only Logic really. If you change the laws of Logic, then you change the formulation of Laws. However, if you change the laws of mathematics, the Laws are unchanged, they merely have different methods of expression.

From a Physicists point of view:

A law of Nature is something derived from First Principles (neccessary assumptions), which has no contradictions.

Note: Newton's Laws are NOT laws of nature. That is simply the name they are stuck with for much the same reason the Metric system is not the only system in use today. Relativity proved that the formulae of Newtonian mechanics are WRONG. However, they are a nice approximation for those things which we encounter daily in our framework.They are laws of nature - they are a generalisation of observed behaviour. There is nothing about a law that says it must be 100% accurate. Gas laws are another example of laws that are just an approximation.

There are no 'laws of nature'. Only reliable guidelines.

There are no 'laws of nature'. Only reliable guidelines.

I dunno. Heisenberg's Uncertainty principle, Lorentz transformations, time/space/phase symmetry, dynamics, and the laws of thermodynamics seem to deserve a label more than "reliable guidelines" to me.

No, not really. Many people refute the assertions of Einstein already. Lorentz Transformations are only applicable within specific geometries, the Uncertainty principle SEEMS good, but as with anything, that is only due to our current understanding and technology. It has not yet been definitively proven that one cannot know both position and momentum at the same time, especially if you use paired particles in superposition.

And as for the Laws of Thermodynamics, that is just a convenient alignment which makes our universe possible according to some theories. They state that the 3 laws need not neccessarily align, and even postulate the universal constants were they to be shifted slightly. (Basically it is the equivalent of saying life requires the conditions we find here on earth because life here on earth is so well situated to it, having evolved here and all that).

EDIT: Found a Wiki on Arrows of Time (http://en.wikipedia.org/wiki/Arrow_of_time), doesn't do it near as well as the books I have read on it, but I cannot exactly link you to page 66...

A law of Nature is something derived from First Principles (neccessary assumptions), which has no contradictions.That sounds more like the definition of a mathematical theorem.

If you can state: Assume that there exists a thing which we shall call 1. This is a thing which is indivisible, and groupable.
Then, this forms the basis for a set which shall be the Real Numbers, and could be called Law. As long as you do not deal with fractions of course. Fractions would be the counter-point.
This has nothing to do with natural laws; it has absolutely nothing to do with nature. You're describing a purely mathematical abstraction.

"All of Fifty's pockets contain some quantity of air" is not useful for solving problems, so it fits part of my definition, being an axiom that can be assumed, but it fails to simplify any physical problem, and thus is not useful.It's useful for figuring out the amount of air in the pockets of the next pair of pants that Fifty will buy.

Well that is where it is good to define "Law" before you try to define a Law of Nature I suppose. For Physics, things boil down to Math primarily. I think the best quote I have seen for it was:

"In the heirarchy of the Sciences the foundation is laid by Mathematics, and then Physics. Above that the heirarchy branches dramatically and becomes questionable, but nobody refutes the foundation.

A Physicist's work must always answer to the real world and the underlying Mathematics. But a Mathemetician answers only to Math & God. If you can find one so humble to admit it."

But, to be less abstract, I used a numerical example because those are easier. If I tell you that there is no such thing as a point, that is a hard concept for many to grasp. Precisely how important it is to actually grasp the concept that there is no such thing as a point can prove to be beyond some people. And much of "natural law" is based upon the premise of assuming that a point actually and truly does exist and can be defined.

If you are familiar with string theory in any degree, you can grasp the level to which it can redefine even the Heisenburg Uncertainty Principle, by making the mere concept of a particle, with an associated location and moment, obsolete. THAT is what it means to lose your fundamental principles, like the existence of a point.

Mathematics doesn't have laws. It has axioms and theorems. Axioms are basic assumptions that define a branch of mathematics. For example Euclid's five postulates define Euclidean geometry (actually one was proven superfluous). Theorems are proposition that can proved from the basic axioms.

Physics and science in general don't work like that. The scientific method can be described like this: First we make observation. In observations we look for patterns. Patterns that seem to be more or less universally true are called laws. The explanations of why those laws are as they are are called theories.
The key part here is observation. With out observation, there is no science. Mathematics has no parallel to observation. The closest thing is an unproven theorem.

And much of "natural law" is based upon the premise of assuming that a point actually and truly does exist and can be defined.

Very true. But the basic premises like this are not laws. For a more clear example, there are many natural laws that only make sense if we assume that simultenaity is possible -- that it is meaning full to say that two events occur at the same time. As a matter of fact, Einstein demonstrated that this is not the case. He established that the order of event depends on the observer -- that two observers can rightfully disagree on whether two events happen at the same time. This did not invalidate all laws about simultaneous events. It only introduced a frame work in which such laws would not make sense. (The fact that he disproved action at a distance is not where I'm going.)

Axiom, that is the word I was trying to remember. Thank you :)

I must heartily disagree with you that Physics doesn't work by starting with Axioms and working from there to attempt to establish meaningful translations of our world. The largest aspect of training as a Physicist is to learn what assumptions you can safely make in each situation, and which assumptions are ideal to make when none are safe, then how to go back and fix things.

Patterns that seem to be more or less universally true are called laws. The explanations of why those laws are as they are are called theories.

No, no & NO! "more or less universally true" is NOT the basis for a law. And theories do not explain laws. If something is "more or less universally true" that means it is in the stage of being a theory. It is waiting for experimental verification and pausing to allow for people to come up with a counterpoint to disprove it. Once something has withstood arguement, proven to be true under any possible rotation testable, and people have basically given up all hope of proving it wrong, THEN it can move from theory to law.

Raw (theoretical) Physics is not based upon Observation. Physics is Ratified by observation. If you are an Experimentalist, then you go with what you observe, or can infer from what you observe. But as a theorist, you have to start from axioms and through symmetry or other mathematical tools which you enjoy, you must deduce what is "truth." Then, your statements must withstand testing to be decided upon as valid.

However, overall I would say that we have already devolved into what this debate is most likely doomed to be. An arguement over symantics. :( (but at least it is an enjoyable one)

Perhaps we could say that Nature's laws are the rules that govern the behaviour of the universe and our 'Laws of Nature' are the theories we have to desribe this.

Axiom, that is the word I was trying to remember. Thank you :)

I must heartily disagree with you that Physics doesn't work by starting with Axioms and working from there to attempt to establish meaningful translations of our world. The largest aspect of training as a Physicist is to learn what assumptions you can safely make in each situation, and which assumptions are ideal to make when none are safe, then how to go back and fix things.Can you give an example of what you mean by a physics axiom?

Patterns that seem to be more or less universally true are called laws. The explanations of why those laws are as they are are called theories.

No, no & NO! "more or less universally true" is NOT the basis for a law. And theories do not explain laws. If something is "more or less universally true" that means it is in the stage of being a theory. It is waiting for experimental verification and pausing to allow for people to come up with a counterpoint to disprove it. Once something has withstood arguement, proven to be true under any possible rotation testable, and people have basically given up all hope of proving it wrong, THEN it can move from theory to law.
I beg to differ. A theory can never become a law; theories and laws are completely separate. You sound like a creationist, arguing that if something is called a law then it is somehow more true than a theory. A scientific theory is not a conjecture, although scientists do use the word theory to mean conjecture sometime. A scientific theory is a firmly established explanation of how the world works.

By "more or less universally true" I only mean that if something can only apply to one very specific situation, then it is not a law. The key part of being a law is being a pattern, rather than an explanation. A law is an answer to the question "how does it work?". A theory answers "Why?".

Raw (theoretical) Physics is not based upon Observation. Physics is Ratified by observation. If you are an Experimentalist, then you go with what you observe, or can infer from what you observe. But as a theorist, you have to start from axioms and through symmetry or other mathematical tools which you enjoy, you must deduce what is "truth." Then, your statements must withstand testing to be decided upon as valid.I agree, except I'm still unclear what you mean by axiom.

However, overall I would say that we have already devolved into what this debate is most likely doomed to be. An argument over symantics. :( (but at least it is an enjoyable one)Well the OP is asking for a definition.

Can you give an example of what you mean by a physics axiom?

QM has axioms/postulates:

http://vergil.chemistry.gatech.edu/notes/quantrev/node20.html

http://hyperphysics.phy-astr.gsu.edu/Hbase/quantum/qm.html (sec 2)

EDIT: I'd say that Noether's Theorem (http://en.wikipedia.org/wiki/Noether%27s_theorem) can be used as an axiom. I don't know whether or not it is. It certainly seems fundamental, though.

Mise gives some good examples for Physical Axioms. And for an example of the transition from Theory to law you can look at Astronomy. There are not many Astronomical laws, because there is no experimental verification. However, once verification can be established, then it is possible to become a law.

I do not mean to say that just by calling something a law that it is more true than something which is deemed a theory. I mean to say that the word "Law" should be used VERY sparingly in terms of the physical world, or come with massive qualifiers (like Newton's laws being qualified to only apply at non-relativistic speed and low, but not infinitesimal, energies). Hence, until something has had rigorous proof that it is impossible to contradict it, nothing should be deemed as "law," and even then anything so deemed should be constantly reviewed for accuracy as understanding of the macro & micro cosmos develops.

QM has axioms/postulates:

http://vergil.chemistry.gatech.edu/notes/quantrev/node20.html

http://hyperphysics.phy-astr.gsu.edu/Hbase/quantum/qm.html (sec 2)

EDIT: I'd say that Noether's Theorem (http://en.wikipedia.org/wiki/Noether%27s_theorem) can be used as an axiom. I don't know whether or not it is. It certainly seems fundamental, though.Thanks, that helped. Though, I only vaguely understand most of those.

It seems like the term cannot be applied to other fields of science, because they are more experimentally rooted. I suppose axioms are loosely analogous to physical laws in other fields.

Mise gives some good examples for Physical Axioms. And for an example of the transition from Theory to law you can look at Astronomy. There are not many Astronomical laws, because there is no experimental verification. However, once verification can be established, then it is possible to become a law.

I do not mean to say that just by calling something a law that it is more true than something which is deemed a theory. I mean to say that the word "Law" should be used VERY sparingly in terms of the physical world, or come with massive qualifiers (like Newton's laws being qualified to only apply at non-relativistic speed and low, but not infinitesimal, energies). Hence, until something has had rigorous proof that it is impossible to contradict it, nothing should be deemed as "law," and even then anything so deemed should be constantly reviewed for accuracy as understanding of the macro & micro cosmos develops.But it's impossible to prove something 100%.

I disagree with your use of the word law. Evolution, is a theory, not a law. Relativity is a theory. Both are sufficiently proven, and considered widely excepted "fact". Conservation of charge is a Law. Conservation of energy is still properly called a law, even though it doesn't hold for small distances and time frames. String theory is not a law or a scientific theory, because it has not been experimentally verified.

A law is not a proven theory. A law is a pattern. A theory is a explanation.

No, no & NO! "more or less universally true" is NOT the basis for a law. And theories do not explain laws. If something is "more or less universally true" that means it is in the stage of being a theory. It is waiting for experimental verification and pausing to allow for people to come up with a counterpoint to disprove it. Once something has withstood arguement, proven to be true under any possible rotation testable, and people have basically given up all hope of proving it wrong, THEN it can move from theory to law.

...

And for an example of the transition from Theory to law you can look at Astronomy. There are not many Astronomical laws, because there is no experimental verification. However, once verification can be established, then it is possible to become a law.Theories do not become laws. They are different things. As I said, we talk about "gas laws". We also have Newton's law of gravity.

And yes there are astronomical laws - Kepler's Laws, for example. It was named a law, because it was a generalisation to describe observed behaviour, but it did nothing to explain why it worked in that way.

Can you give an example of something which was a theory, then became a law when it was proven correct?

Kepler's Law isn't an astronomical law, it is a law of any orbital motion. And while speaking of Gravitation, that can be your example of the transition from Theory to Law. Belief that the Earth is the center of all creation and that objects desire to return to their "natural state" was a decent theory. Fortunatly it was debunked by a heliocentric theory. Eventually, it all was developed and refined into a simple mathematical framework, and thus we achieved Newtonian Mechanics and the ever so popular Newton's Laws.

I went ahead and did some searching on the net, and it would appear that the general population does indeed speak the way that you guys are speaking. Overall I am feeling more and more like the most intelligent post in this thread was Post #19 by Truronian. ;)

So, the way that I personally use the word Law really doesn't jive with the general public, or apparently even professional way (That would be: very sparingly, well... actually I cannot think of anything at present I am willing to refer to as Law, only axioms).

I think that this article (http://www.wired.com/techbiz/people/magazine/15-11/st_thompson) is pretty close to what Souron meant when saying that I was speaking almost like a creationist. And this other article (http://ola4.aacc.edu/jsfreeman/TheoryandLaw.htm) is probably the proper way I should speak, but it is highly unlikely that I will change much :)

But it's impossible to prove something 100%.

Which is precisely why I personally prefer to refer to something as an axiom (assumed to be true as a basis for further discussion), and never to anything as a Law.

Kepler's Law isn't an astronomical law, it is a law of any orbital motion.What would you count as "astronomical"?

And while speaking of Gravitation, that can be your example of the transition from Theory to Law.In what way? It's still Newton's theory of gravitation, and Einstein's theory of general relativity. The law of gravity refers to Newton's F=Gm1m2/r^2 (as opposed to the theory as a whole), and I've never heard of a law of relativity, so it's consistent with what we've been saying.

Belief that the Earth is the center of all creation and that objects desire to return to their "natural state" was a decent theory. Fortunatly it was debunked by a heliocentric theory. Eventually, it all was developed and refined into a simple mathematical framework, and thus we achieved Newtonian Mechanics and the ever so popular Newton's Laws.Yes, Newtonian Mechanics, not Law. Newton's Laws refers to the three laws of motion - they are named laws because they are generalisations of observed behaviour. This isn't theory itself got upgraded to a law - do we speak of heliocentric law now?

Since the theories humans come up with are unlikely to ever be 100% proven, what's the big deal?

Newton's Laws of Gravity are true to a certain extent. Relativity Theory is true to a different extent. I think it's a little pointless to become myopic over semantics.

In what way? It's still Newton's theory of gravitation, and Einstein's theory of general relativity. The law of gravity refers to Newton's F=Gm1m2/r^2 (as opposed to the theory as a whole), and I've never heard of a law of relativity, so it's consistent with what we've been saying.

Newton's laws were based on Galilean Relativity (or Galilean Transformations (http://en.wikipedia.org/wiki/Galilean_transformation)); Einstein/Lorentz came up with a new set of transformations (Lorentz transformations) that turn an observed kinematic quantity in one frame into an observed kinematic quantity in another frame within the context of Special Relativity.

Well, that's Special Relativity anyway. I'm not well versed in General Relativity to comment on Newton's Law of Gravitation.

However, I agree with a lot of the sentiments here RE laws. I don't think a law is equivalent to an axiom, nor are they formalisations of a theory -- or at least that's not what we commonly expect when we ask for a Law of Nature (or Physics).

I think that what we should be doing is look at all those things that are called Laws (e.g. Newton, Ideal Gas Laws, etc etc) and figuring out what makes those different from theories, axioms, etc. IOW, we should be aiming for a descriptive definition, rather than a prescriptive one. And I think that's what the OP demands anyway.

What would you count as "astronomical"?

In what way? It's still Newton's theory of gravitation, and Einstein's theory of general relativity. The law of gravity refers to Newton's F=Gm1m2/r^2 (as opposed to the theory as a whole), and I've never heard of a law of relativity, so it's consistent with what we've been saying.

Yes, Newtonian Mechanics, not Law. Newton's Laws refers to the three laws of motion - they are named laws because they are generalisations of observed behaviour. This isn't theory itself got upgraded to a law - do we speak of heliocentric law now?

I'd only count something as astronomical if it applied only to astrological bodies. So Magnetohydrodynamics wouldn't count, even though that would be lovely for understanding the solar winds. But singularities in a Black Hole would most probably count, though some speculation exists now about quantum scale black holes which could toss it all into daily life (extremely slim chance on that one... but still).

As for all of the rest, I've already decided that I'm out of the picture on debating what to call a Law and what not to. I am far too conservative about labeling anything that we think we know as Law, because until the word "Force" is removed from the scientific vocabulary I will never believe that we have complete understanding of the cosmos. I was just offering up Gravity because I know that it all started as a wild theory which was not accepted, but has since produced what people call Laws.

If you do not agree that this one is a theory which progressed into Law then that just underscores another area where my views do not match up. IMO you are looking for something far too specific, because EVERYTHING in the world started as hypothesis and then resulted in Theory or Law. I doubt that many things have managed to jump straight from hypothesis to Law without there existing a theory between the two. Did the theory completely disappear, to be replaced wholely by the Law? No... that is preposterous. The theory still exists as the foundation for the Law, and probably explains more than the Law. But you shouldn't be able to deny that the Law has foundation in the Theory. (and in the few cases where a Law developed without any supporting Theory, the theory developed later on to explain the law).

because until the word "Force" is removed from the scientific vocabulary I will never believe that we have complete understanding of the cosmos.

...huh? Force is simply defined as dp/dt. And momentum is quite well defined. How does removing that effect anything? Do you seriously mean that all fundamental forces are essentially pseudoforces like gravity? Hell, gravity is considered to be like pseudoforce only because the force is proportional to the mass of the object, like, say, the Coriolis force or the Centrifugal force. Because this isn't how they are treated at all in QM, and they are in fact real interactions there. They'd still be real interactions in, for example, string theory; gravitons are there as well.

[personal belief statement] I mean that I do not like the raw concept of the 4 fundamental forces. They have advanced considerably from the "action at a distance" standpoint, and the field theories are all complex and innovative and quite nice. But I believe that there is far more to it than what we have thus far. In my mental framework I prefer to establish everything in terms of transformations or rotations, and not to have to rely upon fields in any manner [/personal belief statement]

Which is precisely why I personally prefer to refer to something as an axiom (assumed to be true as a basis for further discussion), and never to anything as a Law.Looking over the axioms that Mise linked, that definition does not seem to fit. A far as I know (and I may be wrong) those axioms are agreed to be universally true according to standard theory. They arn't assumed to be true; they have been demonstrated to be true.

It seems to me that the word axiom is used to emphasize the root principles of quantum theory in derivative theories, since if a derivative theory is found to violate quantum theory then it's not a derivative theory at all. Not agreeing with quantum theory would be the death of any such theory.

But again, I only have a hobbyist's interest in these things. I may be totally wrong.

I'd only count something as astronomical if it applied only to astrological bodies.Astrology? What do you mean by astrological body? Kepler's laws did apply to the planets we observe.

I was just offering up Gravity because I know that it all started as a wild theory which was not accepted, but has since produced what people call Laws.

If you do not agree that this one is a theory which progressed into Law then that just underscores another area where my views do not match up.I thought that Newton's law of gravity was always called a "law"? I don't recall a time when scientists said "Aha, there's enough proof, let's upgrade it to a law!"

I doubt that many things have managed to jump straight from hypothesis to Law without there existing a theory between the two.A law is a generalisation of observed behaviour. I observe some behaviour, write an equation to describe it - that's a law. It doesn't matter that I have no idea why it works, or whether my equation isn't 100% correct. It's still referred to as a "law". It's just a word - I don't see why people have trouble with it.

The theory still exists as the foundation for the Law, and probably explains more than the Law.Exactly - a theory is a model which describes how and why things work.

Looking over the axioms that Mise linked, that definition does not seem to fit. A far as I know (and I may be wrong) those axioms are agreed to be universally true according to standard theory. They arn't assumed to be true; they have been demonstrated to be true.

It seems to me that the word axiom is used to emphasize the root principles of quantum theory in derivative theories, since if a derivative theory is found to violate quantum theory then it's not a derivative theory at all. Not agreeing with quantum theory would be the death of any such theory.

But again, I only have a hobbyist's interest in these things. I may be totally wrong.

It isn't that they have been demonstrated to be true, it is that they have been demonstrated to be self-consistant. In order to set the framework for QM, they had to assume things (like that a wavefunction would completely describe the associated waveform). It can get a bit confusing in Physics because we enter into what is nearly circular logic with quite a few of our fundamental equations and proofs, sometimes without meaning to because we assume a certain base level of knowledge which allows things to be taken as a given.

Astrology? What do you mean by astrological body? Kepler's laws did apply to the planets we observe.

Yes, it does apply to the planets, but it ALSO applies to every other eliptical orbit you can observe. Thus we can actually test his equations and state that they are indeed true. Whereas anything you attempt to specify about a singularity would be completely untestable, and thus impossible to formulate a Law governing it.

I thought that Newton's law of gravity was always called a "law"? I don't recall a time when scientists said "Aha, there's enough proof, let's upgrade it to a law!"

Yes, Newton's Laws were always laws, because he didn't sit around asking people if they thought there ought to be another 2 on the left side, or maybe a factor of Pi in the numerator... what do you think? No. He based them off of the theories of Gravitation, and people called them Laws since the properly summed up the theoretical basis. Could Newton's Laws have existed without any framework/theory of gravity? Not a chance. And hence GRAVITY moved from theory to Law, in that one particular, small regard, and by the lingo of people inclined to toss the term "law" around rather glibly.

A law is a generalisation of observed behaviour. I observe some behaviour, write an equation to describe it - that's a law. It doesn't matter that I have no idea why it works, or whether my equation isn't 100% correct. It's still referred to as a "law". It's just a word - I don't see why people have trouble with it.

So if I observe my Dad sitting on a couch, and write that H*f = 25 * R, that is a Law? Nifty, that's easy...

Yes, you are correct, you can choose to call that a law. Few people will agree with you, and it'll not become anything worthwhile... but you can sure as heck decide to call it a Law. Which is why I have stated what I personally am willing to call a Law (ie - nothing essentially) and attempted to leave the discussion so it can get back to the OP's question, if he still wonders what the answer is of course :)

And in a way to appologize for my sarcasm (I usually attempt to avoid such things in debate), I will conceed that there are some "Laws" which have been fashioned through just observation, and later on when people understood things more they developed a theory to explain that "law."

It isn't that they have been demonstrated to be true, it is that they have been demonstrated to be self-consistant. In order to set the framework for QM, they had to assume things (like that a wavefunction would completely describe the associated waveform). It can get a bit confusing in Physics because we enter into what is nearly circular logic with quite a few of our fundamental equations and proofs, sometimes without meaning to because we assume a certain base level of knowledge which allows things to be taken as a given.But unless such an assumption is justified, how can any non contradictory result be useful?

It'd be like applying a non symmetric theorem* before checking if the conditions are true.

*by this I mean a theorem that is not a biconditional; That the conclusion being true, does not imply that the prerequisites are met.

It can get a bit confusing in Physics because we enter into what is nearly circular logic with quite a few of our fundamental equations and proofs, sometimes without meaning to because we assume a certain base level of knowledge which allows things to be taken as a given.Gothmog used to say stuff like this.

Of course our theories and laws make assumptions, if we could arrive at them by a process of pure reason then science would not be necessary in the first place.

Think of all the possible theories we could have, e.g. "gravity will push a ball upwards out of my hand when I let go of it; and eject it into space." Science is simply the process by which we eliminate theories by comparing them to what we actually observe (and most of the time our theories are already compliant with a certain amount of observation already - which is why no-one has ever suggested the above before)

If our theories could be made without making assumptions, then we would find they were always correct and we wouldn't need to bother with experiments.

The assumptions we make are demonstrated to be true (in our current paradigm) by the virtue that they work.

Absolutely correct. The assumptions that we base our science off of are correct and valid to our best knowledge, and allow everything we have worked out to accurately describe our world to certain degrees (which are by now very precise).

However, one must also realize that the assumptions ARE there, and if something comes along which invalidates them then it shows a flaw in everything which was based from that assumption. Primary example would be Einstein showing that time is not constant. This attacked an axiom which most fields of science relied upon, and thus caused a major shift in all known "facts." A slightly lesser effect volume-wise, but much more profound technology-wise would be wave-particle duality. To shift our thinking away from the search for the Greek "atom" and begin to deal with waves was dramatic. But even more impressive for our technology was the realization of Tunneling effects.

It is due to these that I personally decide to avoid usage of the word "Law" unless attempting to give a partial explanation to someone with a practical concern for the knowledge rather than a raw educational need.

Yes, it does apply to the planets, but it ALSO applies to every other eliptical orbit you can observe. Thus we can actually test his equations and state that they are indeed true. Whereas anything you attempt to specify about a singularity would be completely untestable, and thus impossible to formulate a Law governing it.I still don't see how it isn't an astronomical law. Astrology isn't anything to do with science.

Yes, Newton's Laws were always laws, because he didn't sit around asking people if they thought there ought to be another 2 on the left side, or maybe a factor of Pi in the numerator... what do you think? No. He based them off of the theories of Gravitation, and people called them Laws since the properly summed up the theoretical basis.We agree here - he didn't just think it up out of thin air, he came up with the law from observed behaviour.

Could Newton's Laws have existed without any framework/theory of gravity? Not a chance. And hence GRAVITY moved from theory to Law, in that one particular, small regard, and by the lingo of people inclined to toss the term "law" around rather glibly.Do you have evidence that F=Gm1m2/r^2 was originally a theory? When exactly was it upgraded to a law?

So if I observe my Dad sitting on a couch, and write that H*f = 25 * R, that is a Law? Nifty, that's easy... We covered this on the first page with "All of Fifty's pockets contain some quantity of air". Chairman Meow responded with saying it "is not useful for solving problems". Whether or not such a thing is technically a law, it's not going to be a useful one for solving scientific problems, so won't become a very popular one at all.

Yes, you are correct, you can choose to call that a law. Few people will agree with you, and it'll not become anything worthwhile...Few people as in most people in this thread, and the scientific community. I don't see anyone agreeing with you...

I'm not creating a new definition - I'm just pointing out, as others have done, how "law" is used scientifically (as opposed to the layperson misunderstanding that a law is a "proven theory").

I still don't see how it isn't an astronomical law. Astrology isn't anything to do with science.

The key here is that I said it isn't a PURELY astronomical law. It is something testable in a laboratory.

We agree here - he didn't just think it up out of thin air, he came up with the law from observed behaviour.

Sounds like we don't agree. I said he came up with it from the THEORIES, which came from observed behavior and extrapolation. He did not simply watch a feather falling to the ground and spit out a lovely little equation.

Do you have evidence that F=Gm1m2/r^2 was originally a theory? When exactly was it upgraded to a law?

Again, please read carefully. I said that the equation is the result of many theories which finally culminated in a Law being able to be formed. Did this equation exist in that precise form for decades on end, with G defined and everything, then some day someone said "By gum, I oughta start calling this thing a Law so I can write fewer letters when I am referring to it. Hyuck!"? Most certainly not, and no matter how much you claim that is what I am saying, I have stated as clearly as I am capable that I most certainly am not stating that.

Few people as in most people in this thread, and the scientific community. I don't see anyone agreeing with you...

This statement was in reference to if you made a claim as preposterous as the example on the first page about the air in the pockets, or my brief sarcasm. Not for everything in the thread. I personally stated that according ot my reseach it is quite unlikely that ANYONE in the world will agree with me precisely. The point of stating that was so that people would realize that I am simply stating MY PERCEPTIONS, and realizing that they are not "main stream."

I'm not creating a new definition - I'm just pointing out, as others have done, how "law" is used scientifically (as opposed to the layperson misunderstanding that a law is a "proven theory").

You, like me, are pointing out how you THINK it is used. You are not correct because you are not every scientist in the world. I personally realize that the way in which I frame the word is vastly different from the way in which other people frame it. But I believe that while as a whole, the layperson probably views it as you stated, the scientific community views laws as an integral portion of a field of science.

Were you to present a law as a standalone feature it would be laughably useless. Without all of the theories that explain the basis for the law, the formation of it, and the further understanding of it, the law is meaningless. Even if I hand you F=Gm1m2/r^2 you cannot do anything with it unless you understand that there is no negative mass, that G is defined as a constant for the entire cosmos, that the r^2 term evaluated at 0 does not invalidate the equation at all.... There is an entire branch of science that was devoted to discovering that law. There is an entire branch of science devoted to developing our understanding based on that law. And there are probably going to be entire branches of science in the future devoted to tearing that law to pieces and proving how completely inaccurate it is.

A law does not exist independant of everything which led up to it. And what led up to it is one heck of a lot more than just observations. It is observations, hypothesis, Tests, checks, collaboration and yes, even theories. And once that law is formed, nobody breaths a sigh of relief and hangs up their hat to go home and wait for a Nobel Prize to be handed to them. They scratch it on a sheet of paper and keep on working to develop more theories and to form the support which will be needed to write a paper which might be able to be submitted to a peer-reviewed journal so taht the law can go out into public eyes and begin the true test to see how well it stands.

Laws are simplistically, mathematical functions that accurately define aspects of reality over the broadest area that can be experienced.

I think that the concept of scientific law will be usurped by the idea that all explanation is theory in the future.

When scientists talk about laws of nature, what do they mean???
When I say "Law of Nature" I mean a rule that cannot be broken because it's physically impossible to do so. The speed of light and the conservation of energy, for example.

I once heard/read somewhere something:
Laws of Nature are things that we know how they work, but not why they work so we make a law that defines how they act until the day we prove why it works that way.

Gravity for example. We know how it works and how strong the force that is behind it. But we don't know why gravity works altogether. There are theories but none of them proven yet.