It is often presumed that the laws of nature have special significance for scientific reasoning. But the laws' distinctive roles have proven notoriously difficult to identify--leading some philosophers to question if they hold such roles at all. This study offers original accounts of the roles that natural laws play in connection with counterfactual conditionals, inductive projections, and scientific explanations, and of what the laws must be in order for them to be capable of playing these roles. Particular attention is given (...) to laws of special sciences, levels of scientific explanation, natural kinds, ceteris-paribus clauses, and physically necessary non-laws. (shrink)

Why should science be so interested in discovering whether p is a law over and above whether p is true? The answer may involve the laws' relation to counterfactuals: p is a law iff p would still have obtained under any counterfactual supposition that is consistent with the laws. But unless we already understand why science is especially concerned with the laws, we cannot explain why science is especially interested in what would have happened under those counterfactual suppositions consistent with (...) the laws. It is argued that the laws form the only non-trivially "stable" set, where "stability" is invariance under a certain range of counterfactual suppositions not itself defined by reference to the laws. It is then explained why science should be so interested in identifying a non-trivially "stable" set: because of stability's relation to the best set of "inductive strategies". (shrink)

The thesis that scientists give greater weight to novel predictions than to explanations of known facts is tested against historical cases in physical science. Several theories were accepted after successful novel predictions but there is little evidence that extra credit was given for novelty. Other theories were rejected despite, or accepted without, making successful novel predictions. No examples were found of theories that were accepted primarily because of successful novel predictions and would not have been accepted if those facts had (...) been previously known. (shrink)