I’m bothered by something else now: the great variety of things that would fit in your category of counterfactual laws (as I understand it). The form of a counterfactual law (“your perpetual motion machine won’t work even if you make that screw longer or do anything else different”) seems to be “A, no matter which parameter you change”. But isn’t that equivalent to “A”, in which case what makes it a counterfactual law instead of just a law? Don’t all things we consider laws of physics fit that set? F=ma even if the frictionless sphere is blue? E=mc^2 even if it’s near a black hole that used to be Gouda cheese?
The form of a counterfactual law (“your perpetual motion machine won’t work even if you make that screw longer or do anything else different”) seems to be “A, no matter which parameter you change”.
I don’t think this is right. As I am using it, ‘counterfactual’ refers to a statement about whether something is possible or impossible. Statements of the form “A, no matter which parameter you change” are not always like this. For example if A=’this ball has a mass of 10kg’. This is not a statement about what is possible or impossible. You could frame it as ‘it is impossible for this ball to have a mass other than 10kg, no matter which parameter you change’, but doesn’t give us any new information compared to the original statement.
Another important feature is that the impossibility/possibility is not restricted to specific dynamical laws. In your example ‘F=ma, even if the frictionless sphere is blue’, this statement is only true when Newton’s laws apply. But the statement ‘it is impossible to build a perpetual motion machine’ refers, in principle, to all dynamical laws-even ones we haven’t discovered yet-which is why principles like this may help guide our search for new laws.
I’m bothered by something else now: the great variety of things that would fit in your category of counterfactual laws (as I understand it). The form of a counterfactual law (“your perpetual motion machine won’t work even if you make that screw longer or do anything else different”) seems to be “A, no matter which parameter you change”. But isn’t that equivalent to “A”, in which case what makes it a counterfactual law instead of just a law? Don’t all things we consider laws of physics fit that set? F=ma even if the frictionless sphere is blue? E=mc^2 even if it’s near a black hole that used to be Gouda cheese?
I don’t think this is right. As I am using it, ‘counterfactual’ refers to a statement about whether something is possible or impossible. Statements of the form “A, no matter which parameter you change” are not always like this. For example if A=’this ball has a mass of 10kg’. This is not a statement about what is possible or impossible. You could frame it as ‘it is impossible for this ball to have a mass other than 10kg, no matter which parameter you change’, but doesn’t give us any new information compared to the original statement.
Another important feature is that the impossibility/possibility is not restricted to specific dynamical laws. In your example ‘F=ma, even if the frictionless sphere is blue’, this statement is only true when Newton’s laws apply. But the statement ‘it is impossible to build a perpetual motion machine’ refers, in principle, to all dynamical laws-even ones we haven’t discovered yet-which is why principles like this may help guide our search for new laws.