Laws of Nature - "Is" vs "Must Be" and Counterfactuals

I am revisiting the Great Course on the Philosophy of Science.  It is so long, and packed with so much to learn and consider, I could not hear it just once.  Dr. Kasser explains the facets of this topic quite well, so most of what I am saying below comes from his lectures, but I also need to react a bit.

I recently heard the pair of lectures which deal most specifically with the idea of Laws of Nature (or scientific laws.)  I'm not sure I can do this topic justice without laying a lot of groundwork, but I am going to write a bit, because I want to get some thoughts down while the lessons are still pretty fresh in my head.
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Preface:  The Philosophy of Science, like the philosophy of pretty much anything, asks questions which challenge us to examine our base assumptions about the subject.  This is part of what I enjoy about philosophy. 

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Let's suppose there are Laws of Nature.  Most of us have learned about them as we took science courses in junior high and high school.  When I am talking about Laws of Nature, think of things like Newton's Laws of Motion, or the laws of thermodynamics or something.  I'll use a specific example below, and by the end, we'll abstract things a bit.

One of the big topics in Philosophy of Science is how much science should claim.  One group of scientists, and philosophers about science, promote the idea that science should describe what does happen, and only that.   These are the Empiricists, and the thrust of their argument is that, in order to avoid metaphysical claims, science needs to make claims only about things which have been observed.

In this viewpoint, then, a Law of Nature, or a Scientific Law, only describes the way things ARE.  The Law contains a set of statements which describe how one interprets all observation into a coherent description of how the observed phenomena fit together.  This version of Laws tells you how to predict future observations based on patterns or relationships.  (It's very reliant on induction, which has its own logical issues, but that's something outside the scope of this post.)  A Law might even claim that there will never be a counter-example to the law.  "All copper conducts electricity" is an example of such a law, used extensively in the course, and in the Empiricist view it describes every piece of copper ever seen, plus every piece of copper we will ever see. 

However, most of us want to give science more power than that.   Most of us want science, and in particular scientific laws, to not only claim what the observations are and will be, but also to claim that they MUST BE what they are.  We want the Law to also say that, for example, every piece of copper MUST be conductive.  The supporters of this view are Necessitarians.  Their statement of the law above would be "Being made of copper necessitates conducting electricity."

In the former view people create laws.  In the latter view, the laws are out there for us to find, and we discover them.

The point about the differences in these approaches is subtle. I grant you that.  But the empiricist view does not deal well with what are called "counterfactuals."  A counterfactual is a statement which conflicts with known facts, but makes a prediction.  To use the example from the lesson, imagine you have a pen.  You could say "If this pen were made of copper, it would conduct electricity."  The known fact is that the pen is NOT made of copper.  But a claim is being made about a world in which the pen were.  Does that make logical sense based on each view of laws?

I think it's clear that the Necessitarian version of the law logically leads to the truth of "If this pen were made of copper, it would conduct electricity." Why?  Because "copper-ness" embues conductivity.  It's right there in the definition of the law.

The empiricist view, though, is not so clear.  Empiricist laws describe how things work in this world. Not in a world where things are different. Counterfactuals deal with a world which does not exist.  That's metaphysics, and not something empiricists think science should address.

Why do counterfactuals matter?  Because, when we examine many of the Laws we were taught in school, they are counterfactual.  The premises of the Laws never happen in reality.

For example, Newton's Laws of Motion tell us how bodies would react in the absence of any other forces.  But such a world does not exist.  All bodies we have ever seen have more than one force acting on them (in the Newtonian sense.)  This means that Newton's Laws never, ever have an observed instance.  Never.  The laws are, in their nature, counterfactual.   And yet we can use those laws to correctly predict motion (within certain limits; outside those limits we need Relativity or Quantum theory.)   

Personally, I believe that Laws are out there to be found.  I'm a necessitarian, I guess. When trying to discover those laws, the intellectual difficulty stems from only having observations from which to work.  From there, if we want to get to counterfactual laws, we have to apply imagination and reason.  Reason can only carry us so far, and once we're into imagination, we're definitely into the "meta" realm.

This is already long, so I will deal with related questions another time:  If the Premise is never True, what good is the Law?  If a Law is False, was it ever a Law?