Theory Vs. Law

[Neverlandrut]

 

I found this helpful little video which explains the difference between a scientific theory and a scientific law. It corrects the misconception that a law is the highest peak in some hierarchy from hypothesis to theory to law. This is not the case. Laws deal with descriptions and the question of WHAT happens when... A theory deals with the question of WHY that something happens. Laws are descriptive; theories are explanatory. Taking gravity for example, the law of gravity describes, in mathematical terms, what happens when two bodies move in close proximity to one another. The theory of gravitation offers an evidence based explanation of why this happens. While it is true that theories are amendable upon he discovery of new evidence, it is possible to have an extremely high degree of certainty that theories are correct. The speaker uses an example from atomic theory. It is "just a theory," but we have made very accurate predictions based on that theory that have allowed us to make a plethora of electronic devices, huge advances in medicine, etc. These modern marvels would not be possible if our atomic theory wasn't correct. Sure, we don't understand everything about atoms and subatomic particles, but our atomic model is so extremely close I reality that we are able to do the things mentioned. Saying "it's only a theory" so as to suggest that it's simply an educated guess but we don't really know is just plain false. In science, theories represent the highest level of knowledge and understanding.

[RogueScholar]

Difficult differentiation.

 

In general, laws tend to be more specific and are often derived from first principles. A law is then provencial and mathematical in nature. Also, laws tend to assume highly idealised situations. Situations that are difficult if not impossible to perfectly encounter in the "real world."

 

A theory tends to be very general and explain currently observed phenomena and all currently available data supports said theory. They tend to contain laws within the framework of said theories.

 

An example of a law may include Coulomb's law. This is an equation that explains the force that charged objects experience under highly idealised conditions.

 

A theory could be the atomic theory of matter that explains the makeup of the ordinary matter in this universe. However, contained within this theory would be Coulomb's law because atoms contain charged objects that are attracted to one and other.

 

You could also call the Schrodinger equation a law but the comprehensive framework that stems from this equation would be quantum theory.

 

Does that make sense?

[Deidre]

This has been so helpful. I understood the "difference" between law and theory, but definitely gained further clarity from this.

"It's just a theory," is a pet peeve of mine when hearing a Creationist use it to refute the theory of evolution. I should have this thread handy . :-) Thanks for sharing!

[miekko]

I think this video is incorrect. There's no strict difference, as many laws qualify for the requirements of theories and vice versa. There's lots of things that qualify for both terms, and the video just muddies the picture by explaining the difference as though it were a binary difference.

 

Theories don't have to explain things either - a theory can just state that things happen in some certain way, and still be a theory.

[Neverlandrut]

Thanks for the input guys.  I think this discussion is of importance because, although the video may not be entirely accurate, it is an important point that scientific "laws" are not exactly the pinnacle of some hierarchical system.  The point I was hoping to demonstrate is that the hypothesis-theory-law hierarchy idea is an over simplified misconception.  I wanted to point out that theories and laws don't necessarily represent different degrees of certainty as those who use "it's only a theory" suggest.  Again, thanks for the input.  Although I am a huge science enthusiast, I am not a scientist.  You're comments help clarify and correct my thinking.    

[pantheory]

Thanks for posting this. I understood what the speaker was saying. But some of what he described or referred to as "theory" sounded close to being a "law," according to his definitions. But I think that's a point he was making at the end. Some theories are so well backed by evidence and have such a thorough chain of reasoning behind them, that they are close to being laws. Does it seem that I grasped his meaning?

 

I understand it can be confusing. Theories are supposed to be able to explain why things work the way that they do. A law is weaker than a theory in that it has no explanatory power. It says things will always work this way or that way, concerning the results, without proposing any idea of how or why it might work that way. Once a law is shown to be violated it cannot be easily amended, and could be discarded in its entirety. A theory, on the other hand, can be contradicted many times, but unless a better theory is readily available to better explain things, the old theory will be amended and new hypothesis added to it to explain all contradictions. Such was the case with the Big Bang model first adding Inflation, then dark matter, and then dark energy.   When better observational equipment becomes available, theory may be tested to its limits before replacement. After too many contradictions of the old theory, better  theories are often discovered, whether pre-existing or not.

 

Hypothesis, instead, are possible explanations. There may be a number of hypothesis the explain the same observations until clarification of theory is determined.

[RogueScholar]

I'm not even sure "why" is the best way of looking at it as a "why" question can come with significant baggage attached depending on the context involved.

 

A law is basically a rather provencial framework (usually mathematical) that typically predicts a certain outcome in a highly idealised situation under very specific conditions. In other words, it can explain repeated observations under very specific conditions. Most of the laws we talk about only apply exactly in highly contrived situations. However, as stated already, a theory has much broader implications and will contain many laws. A theory will typically tie many things together and make good predictions of many phenomena under diverse conditions. Additionally, a theory will often provide a more detailed mechanistic explanation.

[RogueScholar]

I think you have a good grasp of it. Of course, these definitions are probably not set in stone or universally accepted but I prefer "how" as opposed to "why." I'll be honest however, I never really think about the difference between a law and a theory in my studies. It's actually even more confusing because I use mathematical models. These models are straight up "not real" and not terribly accurate or precise, but they reflect enough "reality" that using them can be help answer questions and even make good predictions. This concept really makes the discussion murky because models can be approximations of laws.

[RogueScholar]

You can always pick it back up. I am by no means a spring chicken. In fact, most of the people in my cohort are rather "mature." Don't fall for that you need to be in your 20's to do good science crap.

[RogueScholar]

At least look at financial options. There are many options out there, particularly for undergraduate degrees. Heck, you could even start at a community college. Many of the core classes such as undergrad physics, maths and general chemistry can be completed at a community college. Many community colleges allow people to obtain associate of science degrees that articulate with bachelors programmes at universities.

[pantheory]

 

 

Thanks for posting this. I understood what the speaker was saying. But some of what he described or referred to as "theory" sounded close to being a "law," according to his definitions. But I think that's a point he was making at the end. Some theories are so well backed by evidence and have such a thorough chain of reasoning behind them, that they are close to being laws. Does it seem that I grasped his meaning?

 

I understand it can be confusing. Theories are supposed to be able to explain why things work the way that they do. A law is weaker than a theory in that it has no explanatory power. It says things will always work this way or that way, concerning the results, without proposing any idea of how or why it might work that way. Once a law is shown to be violated it cannot be easily amended, and could be discarded in its entirety. A theory, on the other hand, can be contradicted many times, but unless a better theory is readily available to better explain things, the old theory will be amended and new hypothesis added to it to explain all contradictions. Such was the case with the Big Bang model first adding Inflation, then dark matter, and then dark energy.   When better observational equipment becomes available, theory may be tested to its limits before replacement. After too many contradictions of the old theory, better  theories are often discovered, whether pre-existing or not.

 

Hypothesis, instead, are possible explanations. There may be a number of hypothesis the explain the same observations until clarification of theory is determined.

 

pantheory

 

Thanks for the further explanation. I think if the word "rule" were used instead of "law," some of the confusion could be avoided. And according to your explanation, a law stating what happens isn't necessarily about something we know better than what a theory is about. A law comes about from observation and conclusion that A leads to B. But a theory speculates as to the why of it. Therefore, there could be several and various laws contained within a theory.

 

Human

 

 

 

yes, exactly

[Orbit]

In my discipline a law is predictive (if x, then y) and a theory is explanatory.

[RogueScholar]

In my discipline a law is predictive (if x, then y) and a theory is explanatory.

That's a pretty high yield way to distill the discussion.

[pantheory]

In my discipline a law is predictive (if x, then y) and a theory is explanatory.

 

I would choose slightly different wording. The: intent of a law is to make calculations based upon mathematical relationships thought to be valid; the intent of theory is to explain observations both verbally and mathematically, as well as make predictions. 

 

The reason for the different wording is that neither laws nor theories will ever necessarily be verified. Very few theories or "laws" have passed the test of time, for instance, which has been shown to be roughly 200 years.

[RogueScholar]

I think we need to give credit where credit is due however. Classical mechanics has been pretty spectacular. The context and applicability of when and how to use the frame work has certainly changed but many problems can be solved using classical framework. It's pretty amazing that ideas from the likes of Newton, Hooke, Leibnez and others from the 1600's are still totally valid methods of prediction when used in appropriate context today. Heck, old Greek and Arabic ideas are still being used today.

 

Say grand unification were to occur today and a new renaissance of understanding were to stem from it tomorrow. Does that mean that if I want to find the resistance of a simple circuit I should just throw out Ohm's law?

[pantheory]

I think we need to give credit where credit is due however. Classical mechanics has been pretty spectacular. The context and applicability of when and how to use the frame work has certainly changed but many problems can be solved using classical framework. It's pretty amazing that ideas from the likes of Newton, Hooke, Leibnez and others from the 1600's are still totally valid methods of prediction when used in appropriate context today. Heck, old Greek and Arabic ideas are still being used today.

 

Say grand unification were to occur today and a new renaissance of understanding were to stem from it tomorrow. Does that mean that if I want to find the resistance of a simple circuit I should just throw out Ohm's law?

 

IMO the problem lies primarily with modern physics, concerning laws and theories. I agree that classical mechanics is close to rock solid. Ohm's law is a good example, as you suggest. But in modern physics a good example of a law that is "wrong" IMO is Hubble's law. I believe it  is off by many factors at the greatest distances (not even close), which has caused "false" concepts like dark energy because of its "wrong formulation."  Also the belief in its validity, IMO, has necessitated numerous more wrong ad hoc hypothesis required by the Big Bang model to explain observations that otherwise would have been simple and straightforward to understand. .

 

Of course mainstream astronomy and cosmology thinks otherwise, which is the reason this equation is still believed to be valid and will continue to be called "Hubble's Law" until eventually someone will figure out how to disprove it in its entirety, IMO. If so, then related wrong law(s), theory(s) and hypothesis would be replaced once better (more accurate) alternatives are realized.

[RogueScholar]

My original statement about much of the classical framework that has been around for hundreds of years still holds. I am not in a position to debate opinions about cosmology so I will have to defer to what "mainstream" cosmology has developed. Perhaps that will change with significant evidence and additional understanding in the future but that still will not change the fact that many laws will still be viable under certain circumstances. As I've stated elsewhere I use models that are simply flat out incorrect, but they still produce viable answers when used in proper context.

[pantheory]

My original statement about much of the classical framework that has been around for hundreds of years still holds. I am not in a position to debate opinions about cosmology so I will have to defer to what "mainstream" cosmology has developed. Perhaps that will change with significant evidence and additional understanding in the future but that still will not change the fact that many laws will still be viable under certain circumstances. As I've stated elsewhere I use models that are simply flat out incorrect, but they still produce viable answers when used in proper context.

 

Yes, there are simplified models used for approximations that are more valuable for practical purposes than more sophisticated models because the input requires less sophisticated data, and their accuracy is adequate for a particular application. Nowadays even the most complicated equations can often be quickly and easily solved by plug-and-chug algorithmic programmed equations, which has lessened the need today for simplified approximation methods for otherwise very complicated equations.