Expert: Walter Hintz - 5/21/2009

Question
QUESTION: Hi,
and thank you for answering questions.
I understand that a scientific theory ( evolution, relativity) can be a proven theory ( as proven as possible ) and still be termed a 'theory'.   But another person is telling me that these are termed 'theorys' because they are not yet proven.  Once they are proven they would be upgraded to a scientific law.
 Which is correct?

Thank you.

ANSWER: When something stands up to testing over time it is a Law There is a preponderance of evidence that Gravity is a fact. It is always evident. Therefore it is a natural Law. The same is true of the Laws of motion and the First law of the conservation of matter and energy. Natural Laws tell us the limits of what we can do.  We cannot violate the Law of gravity and we cannot tweak our noses and put dinner on the table.
A theory meets the criteria that we have established.. Evolution is theoretical and meets all the tests and observations that we apply. Establishing physical laws is fairly easy but establishing Biological laws is more difficult.
 The problem here is one of semantics.  When can we say something is proven.  A theory is something that ha snot been proven but at least for now seems to be a reasonable explanation for a phenomena.













---------- FOLLOW-UP ----------

QUESTION: Hi,
thanks for getting back to me.   
But then I guess I do not understand.  What i've read explains that a law tells us what something does, ( law of gravity; what goes up must come down)  and is usually simple and observable, but a theory, like the theory of gravity, trys to explain how and why, and that is why it remains a theory, even though it can be a 'proven' theory.  After all, isn't the germ theory of disease, proven ( as much as it can be) but still a scientific theory?   And have we not pretty much proven Einstein's theory of relativity?
 When I say proven, I mean as close to proven as a scientific theory can be.  At what point would evolution, or relativity become a 'law'?   I understood that they are both so complicated, that they really would never be upgraded to a law?

Answer
You notice that the words Theory an Law tend often to be interchangeable as with Germ theory and atomic theory.  These two things have certainly been proven.  We have not however designated a germ Law.
When we consider anatomy and physiology we use terms like The Law of the Heart and The All or None Law.
So you see that it is difficult to decide when to call something a law. There is a Law of Gravity and there also theories. The theory does not change the law.  Gravity exists. Theories suggest the cause. Newton referred to forces between bodies and Einstein talked about curvature of space. As I stated Laws tell the limits of what we can do.