Quick Question:
What’s the difference between a scientific law and a scientific theory?
Is a SL just a combination of theories?
IANASP (Scientific Philosopher), but I believe that (making numbers up here) a theory is something we’re 95% sure of, and a law is something we’re 99.9% sure of. It’s only a matter of degree, and a subjective one at that, that determines which term gets applied.
A law is a statement of what happens. A theory is a statement of how it happens.
Law of Nature is sort of an outmoded concept. Such things are now considered to be generalizations about how nature behaves that are well supported by evidence and against which there are no known counter examples.
Prior to about 1850, the deep discoveries about nature were usually announced in the form of Laws: Newton’s Laws of Motion, the Laws of Thermodynamics.
By the time of Darwin, however, scientists were beginning to realize that to pronounce these insights as “Laws” - even if they knew of no exceptions - were acts of hubris. Hence, the Theory of Evolution, the Theory of Relativity.
I don’t know of any “Laws” that have been announced since that time. Does this mean that the Theories are any less well-founded than the Laws? Not at all. They’re just a different way of expressing the very same thoughts. Now if somebody could just explain this to the creationists…
The distinction between a “law” and a “theory” has more to do with mathematical simplicity and semantics than it does with veracity.
For all the instances I can think of, “laws” can be considered to be tautologies. F=ma is true because it’s defined to be that way. Of course, this “law” has no meaning outside of Newton’s theory of forces. You have to understand what “F” and “m” and “a” are referring to before you can declare F=ma. However, if you know what “F” and “m” and “a” are referring to, then you automatically have Newton’s Second Law.
The same thing goes for thermodynamics. The three (or four) laws of thermodynamics are simply formulations of mathematical tautologies that work within the thermodynamical system (or the physical theory). They are “known” just as much as the microphysical theories upon which they are based. They are simply true in the mathematical system where such things are defined.
A theory is actually a much more powerful tool for scientific investigation than a law is. The theory that is used will make predictions that can then be tested in the lab or through observation. Theories are mathematical or practical formulations of models that the scientific community has come to a consesus are the models that best approximate nature. By definition, therefore, a theory is as correct as you can possibly hope to get in science. Laws are actually less useful from a semantic point of view because they themselves are reliant upon theoretical considerations. E.g. if I don’t know what entropy is, how on Earth can I say I understand that it is increasing in a closed system?