Distinguish between a theory and a law?

Answer 1

This is a common question, and a common misconception. Unfortunately, most people are taught a hierarchy of certainty: hypothesis becomes theory and then, with more support, a theory becomes law. This is WRONG. Laws and theories serve different purposes and each have a unique nature.

The current consensus among philosophers of science seems to be this: * Laws are generalizations about what has happened, from which we can generalize about what we expect to happen. Laws describe. They pertain to observational data. The ability of the ancients to predict eclipses had nothing to do with whether they knew just how they happened; they had a law but not a theory. * Theories are explanations of observations (or of laws). The fact that we have a pretty good understanding of how stars explode doesn't necessarily mean we could predict the next supernova; we have a theory but not a law. William McComus lists gravity as a modern example of a well-established law for which no really satisfying theory is available. We can use the Law of Gravity, and even correct it for the effects of relativity (General Relativity), but we don't have any consensus notion of howit functions! Is it geometry or gravitons? Oddly enough, I searched the MadSci site and came up with a carefully- written wrong answer along the hierarchical lines you describe above. Embarassingly, several answers I summoned in my search fall into the misconceptions and traps enumerated by McComus! We shouldn't blame our experts; as you and I have seen from our own experience, scientists may have fuzzy notions about this sort of distinction because they don't normally have to make the distinction! A working scientists doesn't tend to worry about whether the First Law of Thermodynamics is an explanation, or the Theory of Evolution a statement of observed facts. They work, she uses them, everything's fine, right? But as McComus points out, the cut-and-dried (wrong) way this is usually presented can be pretty deadly, pedagogically. I am unable to recommend much specific for further reading, although McComus' bibliography looks to be a good place to start. You might try Richard Feynman's distinctly practical take on this problem, The Nature of Physical Law.
laws have been proven, theories are just ideas and have not been proven

Answer 2

A theory is a well supported explanation and a law explains how thinks work in the natural world.

Answer 3

A theory is an idea that has yet to be proven by experimentation. A law is a theory that has been proven correct.